The Natural History of the Snakes and Lizards of Iowa (Bur Oak Guide) 1609388372, 9781609388379

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THE NATURAL HISTORY OF THE SNAKES AND LIZARDS OF IOWA

A BUR OAK GUIDE

Holly Carver, series editor

THE NATURAL HISTORY OF THE SNAKES AND LIZARDS OF IOWA Terry VanDeWalle U n i v e r s i t y of Iowa Pr e s s  |  Iowa C i t y

University of Iowa Press, Iowa City 52242 Copyright © 2022 by Terry VanDeWalle uipress.uiowa.edu Printed in the United States of America Design by April Leidig No part of this book may be reproduced or used in any form or by any means without permission in writing from the publisher. All reasonable steps have been taken to contact copyright holders of material used in this book. The publisher would be pleased to make suitable arrangements with any whom it has not been possible to reach. Printed on acid-free paper Library of Congress Cataloging-in-Publication Data Names: VanDeWalle, Terry, author. Title: The Natural History of the Snakes and Lizards of Iowa / Terry VanDeWalle. Description: Iowa City: University of Iowa Press, [2022] | Series: Bur Oak Guides |   Includes bibliographical references and index. Identifiers: LCCN 2021043892 (print) | LCCN 2021043893 (ebook) |   ISBN 9781609388379 (paperback) | ISBN 9781609388386 (ebook) Subjects: LCSH: Snakes—Iowa. | Lizards—Iowa. Classification: LCC QL666.O6  V37 2022 (print) | LCC QL666.O6 (ebook) |   DDC 597.9609777—dc23/eng/20211020 LC record available at https://lccn.loc.gov/2021043892 LC ebook record available at https://lccn.loc.gov/2021043893 Unless otherwise noted, all photos are by Terry VanDeWalle.

CONTENTS

Preface vii Acknowledgments xi Introduction 1 Biogeography of the Snakes and Lizards of Iowa, Neil P. Bernstein  13 Identifying Iowa’s Lizards and Snakes  21 Key to Iowa Lizards  21 Key to Iowa Snakes  22 PART ONE. LIZARDS

Family Anguidae: Glass Lizards and Their Relatives  33 Western Slender Glass Lizard  35 Family Scincidae: Skinks  43 Common Five-Lined Skink  45 Great Plains Skink  53 Northern Prairie Skink  61 Family Teiidae: Racerunners and Whiptails  69 Prairie Racerunner  71 PART TWO. SNAKES

Family Colubridae: Colubrids (Nonvenomous)  85 Western Wormsnake  87 North American Racer  95 Prairie Ring-Necked Snake  105 Plains Hog-Nosed Snake  113 Eastern Hog-Nosed Snake  123 Prairie Kingsnake  133

Speckled Kingsnake  143 Eastern Milksnake  151 Plain-Bellied Watersnake  161 Diamond-Backed Watersnake  169 Northern Watersnake  177 Smooth Greensnake  187 Western Ratsnake  195 Western Foxsnake  205 Bullsnake 215 Graham’s Crayfish Snake  225 Dekay’s Brownsnake  233 Red-Bellied Snake  241 Orange-Striped Ribbonsnake  249 Plains Gartersnake  257 Common Gartersnake  267 Lined Snake  279 Western Smooth Earthsnake  287 Family Viperidae: Vipers and Pit Vipers (Venomous)  295 Eastern Copperhead  299 Timber Rattlesnake  307 Prairie Rattlesnake  317 Eastern Massasauga  327 Prairie Massasauga  339 Quick Reference Guide to Snakes  348 Glossary 351 References 353 Life Lists  375 Index of Scientific and Common Names  377

PREFACE

My major goal in this book is to provide information on the natural history of the snakes and lizards of Iowa that will be useful to professional and amateur herpetologists, students, wildlife biologists, and all other readers interested in these fascinating creatures. I have combined general information with technical details about the morphology, distribution, ecology, behavior, and reproduction of each species and subspecies of snake and lizard found in Iowa. In addition to a review of the pertinent literature, much of the information in this book is based on my experiences and the experiences of my great friend and mentor James L. Christiansen—professor emeritus of biology at Drake University in Des Moines, Iowa. I dedicate this book to Jim, whose lifetime of devotion to Iowa herpetology has contributed immeasurably to the knowledge and understanding of Iowa reptiles and amphibians. This book would not have been possible without his many years of research, his work on an earlier concept for the book, and his tireless commitment to science and herpetology. Jim developed an interest in herpetology as a boy growing up on the family farm in Cherokee County, Iowa. He became captivated with reptiles and amphibians as he watched a red-sided gartersnake visit a pond on the farm each evening to feed on leopard frog tadpoles. Jim attended Buena Vista College in Storm Lake as an undergraduate; in 1961, during his senior year, he published his undergraduate research, “A Survey of Reptiles and Amphibians of Buena Vista County, Iowa,” in the Proceedings of the Iowa Academy of Science. He did this survey despite never having met a professional herpetologist and using only Roger Conant’s A Field Guide to Reptiles and Amphibians as his inspiration. After serving as an assistant to John M. Legler on an expedition collecting and cataloging freshwater turtles in Central America in 1962, he completed a master’s degree at the University of Utah under Professor Legler’s direction. After a second expedition in 1965 focusing on the turtles of Mexico, he went on to complete a Ph.D. in herpetology at the University of New Mexico. In fall 1969, Jim returned to Iowa, where he accepted a position at Drake University and began studying the distribution and life histories of Iowa’s amphibians and reptiles. Equally important, he founded the Drake University Research Collection. With the help of many excellent undergraduate and graduate students over the years, he published a wide variety of papers on Iowa’s reptiles and

viii  Preface

amphibians and built the Drake University Research Collection into a renowned research and teaching collection. I first became acquainted with Jim in 1984 as an undergraduate, when my adviser told him that he had a student interested in herpetology and asked whether I might be able to assist with any of his work. Jim responded by saying that I was welcome to help a student of his who was studying yellow mud turtles in southeast Iowa. I spent a month trapping turtles but never actually met Jim in person. When I finished, Jim sent me a letter thanking me and saying that when I was ready to work on a master’s degree to let him know. In 1990, not having been in contact with Jim for six years, I called him to inquire about graduate school. I introduced myself and asked, “I am not sure if you remember me?” He immediately said, “Yes, you trapped mud turtles with Joe Spurgeon.” I mentioned his note about contacting him when I was ready for graduate school. Jim’s response was, “When do you want to start?” I went on to become one of Jim’s graduate students from 1991 to 1993 and continued to work with him on many projects until he retired from Drake in 2005 and moved to Texas. Our many years of field studies along with our examination of hundreds of Iowa museum specimens, where we compiled Iowa-specific morphological and reproductive data found nowhere else, have provided much of the basis for this book. In addition to the great body of knowledge that Jim and his many students gained during his more than thirty-five years at Drake, this book includes information from the studies of early herpetologists who collected data in Iowa between approximately 1920 and 1950. Comparing their records and observations with those of researchers doing work in Iowa since 1960 (there was largely a hia­t us in major herpetological studies in the state during the 1950s) allows us to see changes in distribution through time. Reeve M. Bailey—zoology professor at Iowa State University from 1938 to 1943 and at the University of Michigan from 1944 to 1981—in particular built a substantial collection of museum specimens at Iowa State. Before his death in 2011, he gave Jim access to those specimens and contributed his personal field notes to Jim for use in several joint publications on Iowa herpetology. Jim provided these meticulous field notes for use in this book, and they substantially enhance our knowledge of snakes and lizards in Iowa. The Drake University Research Collection holds more than 7,500 Iowa amphibian and reptile specimens. Jim and I used snake and lizard specimens from this collection, along with many from the Iowa State Natural History Collection at Iowa State University, to analyze the morphology, diet, reproduction, and changes in distribution presented in this book. These museum specimens provide

Preface  ix

unmatched data on the reproduction, parasites, food habits, and morphology of Iowa snakes and lizards and serve as voucher specimens to document the presence of each species at a particular time and location in the state. While readers will be able to identify Iowa’s snakes and lizards through its species accounts, identification keys, maps, and photographs, this work is intended to be more than a field guide. I want to give the reader a glimpse into the life histories of these intriguing and often misunderstood animals. Confucius wrote, “Everything has beauty, but not everyone sees it.” It is my hope that by learning more about the lives of snakes and lizards, the reader will see the beauty in these creatures, learn about their importance to healthy ecosystems, and come to care about them and want to protect them.

ACKNOWLEDGMENTS

I wish to gratefully acknowledge Robert Foley, my adviser at Kirkwood Community College. Bob encouraged my interest in herpetology and was the one who first introduced me to Jim Christiansen. Many thanks to Jim for taking me on as a graduate student and being my teacher, mentor, and friend for the past thirty years. My success as a herpetologist is due in large part to him, and for that I am ever grateful. Jim had a vision for a book similar to this and worked on it over the years. He generously contributed his data and field notes for use in this book. It is my hope that it comes close to his earlier vision. Neil Bernstein and Jeff Parmelee both worked with Jim in the past on an earlier concept of a herps of Iowa book, Jeff collecting specimen data and Neil editing text, and although that book did not come to fruition, they should be applauded for their hard work. I wish to especially thank Neil for his thoughtful essay on the bioregions of Iowa and for his encouragement and counsel throughout the preparation of this book. Neil is a great friend and I value his words. In addition, I thank Jean Prior, Phil Kerr, and Keith Schilling for providing Neil with information and helpful comments. Very special thanks go to my family: my wife, Wendy, and my daughters, Nicole and Sarah, as well as my mother, Sharon, who always supported me and although afraid of snakes allowed me to keep my first snake in the house. Wendy is a birder who has learned to look down once in a while to find snakes; she has spent many hours over the years tracking eastern massasaugas. Nicole and Sarah grew up with snakes in the house and understood Dad being away tracking snakes. My family has been a constant source of support during the writing of this book. Many individuals have assisted me over the years with fieldwork by measuring specimens, implanting transmitters, or radio tracking or by providing records. Although I am sure I have forgotten someone—and for that I apologize—I want to thank the following people who helped me in a variety of ways: Jason Auel, Bruce and Marlene Ehresman, Frank Frederick, Paul Frese, John Goedeken, Robb Goldsberry, Daryl Howell, Jim Jansen, Karen Kinkead, Ryan Kurtz, Jeff LeClere, Dale Maxon, Mike Olsen, Josh Otten, Stacey Parks, Doug Peterschmidt, Kelly Poole, Ryan Rasmussen, Terri Rodgers, Stacey Snyder, and Karen Williams as well as the many Hawkeye Community College natural resources students who have helped over the years.

xii  Acknowledgments

Althea Archer produced all the maps and Michaela Henke created all the illustrations in this book. Both are to be commended for producing such outstanding graphics, which significantly contribute to the quality of the book. I thank them both for their hard work. A huge thank-you to Muir Eaton of the Drake University Research Collection and Kevin Roe of the Iowa State Natural History Collection for providing data and access to lizard and snake specimens, without which the Iowa-specific morphological and reproductive information and much of the distribution data in this book could not have been compiled. I am also indebted to the many researchers who have deposited specimens in the Drake collection over the years and to Reeve Bailey, whose early work on Iowa herps is invaluable. I also thank the many other museums and their curators and collection managers who provided me with the Iowa records in their collections, including the Academy of Natural Sciences of Drexel University, American Museum of Natural History, Borror Laboratory of Bioacoustics, Brigham Young University Life Science Museum, California Academy of Sciences, Carnegie Museum of Natural History, Central College, Chicago Academy of Sciences and its Peggy Notebaert Nature Museum, Coe College Collection, Cornell University Museum of Vertebrates, Des Moines Historical Society, Field Museum of Natural History, Florida Museum of Natural History, Illinois Natural History Survey, James Ford Bell Museum, James R. Slater Museum, Los Angeles County Museum of Natural History, Louisiana State University Museum of Natural Science, Luther College, Michigan State University Museum, Milwaukee Public Museum, Mount Mercy University, Museum of Comparative Zoology–Harvard University, Museum of Southwestern Biology at the University of New Mexico, Museum of Vertebrate Zoology at the University of California, Berkeley, National Museum of Natural History–Smithsonian Institution, Northern Illinois University BIOS Herpetology Collection, Royal Ontario Museum, San Diego Natural History Museum, Staatliches Museum für Naturkunde Stuttgart, Texas Cooperative Wildlife Collection, University of Colorado Museum of Natural History, University of Illinois Museum of Natural History, University of Iowa, University of Kansas Biodiversity Institute– Herpetology Collection, University of Michigan Museum of Zoology, University of Nebraska State Museum, University of Northern Iowa, University of Washington Burke Museum Herpetology Collection, University of Wisconsin Zoological Museum, Utah Museum of Natural History, and Western Illinois University. I also wish to thank the Iowa Department of Natural Resources for giving me access to records from its Natural Areas Inventory Database and the Iowa Multiple Species Inventory and Monitoring Program—and a special thanks to

Acknowledgments  xiii

the department for its financial assistance for this book. I also thank Don Becker and Christopher Smith at HerpMapper for making Iowa lizard and snake records available. I am especially grateful to Jeff Parmelee, Paul Frese, and Dan Fogell for generously providing their personal data for use in the book. I am indebted to the many individuals who responded to my requests for photographs, and I appreciate their generosity in allowing me to use them without charge. For this I thank John Atkins, Don Becker, Nick Blay, Jessica Bolser, Jim Christiansen, Mike Fisher, Dan Fogell, Paul Frese, Luke Hodges, Jeff LeClere, Carter Oliver, Josh Otten, Ryan Rasmussen, Matt Ricklefs, Jim Scharosch, Casey Trine, Nicole VanDeWalle, Sarah VanDeWalle, Wendy VanDeWalle, Marlowe Wilson, and Riggs Wilson. A big thank-you goes to Paul Frese for reviewing an earlier version of the manuscript and for providing thoughtful and very helpful comments, which contributed greatly to this book. A heartfelt thank-you to Holly Carver, a great editor, coach, cheerleader, and friend. Holly is an absolute pleasure to work with, and without her constant support and “how hard can it be?” attitude, this project very likely would not have been completed. Thanks, Holly, and I look forward to the next one. Finally, I wish to express my sincere thanks to the University of Iowa Press for publishing this book.

Lyon

Osceola

Sioux

Dickinson

O'B rien

Plymouth

Emmet

Winnebago

Clay

Palo Alto

Ida

Monona

Sac

Crawford

Mitchell

Howard

Floyd

Chickasaw

Hancock Cerro Gordo

Cherokee Buena Vista Pocahontas Humboldt

Woodbury

Worth

Winneshiek Allamakee

Kossuth

Webster

Calhoun

Carroll

Greene

Wright

Franklin

Butler

Hamilton

Hardin

Grundy

Boone

Story

Clayton

Black Hawk Buchanan

Delaware

Dubuque

Jones

Linn

Benton

Tama

Marshall

Fayette

Bremer

Jackson Clinton

Harrison

Shelby

Audubon

Guthrie

Dallas

Polk

Iowa

Poweshiek

Jasper

Johnson

Cedar Scott Muscatine

Pottawattamie

Cass

Adair

Madison

Warren

Marion

Mahaska

Keokuk

Washington

Mills

Montgomery

Adams

Union

Clarke

Lucas

Monroe

Wapello

Jefferson

Fremont

Page

Taylor

Ringgold

Decatur

Wayne

Appanoose

Davis

Van Buren

Iowa’s 99 counties.

Louisa Henry

Lee

Des Moines

THE NATURAL HISTORY OF THE SNAKES AND LIZARDS OF IOWA

INTRODUCTION I can no more explain why I like natural history than why I like California canned peaches.—Theodore Roosevelt, “My Life as a Naturalist” Snakes. Why did it have to be snakes?—Indiana Jones, Raiders of the Lost Ark

H

“

ere, hold this,” my high school biology teacher said as she handed me a western ratsnake. As I stood there with the snake at arm’s length, trying to look brave in front of the others in the room and thinking, “What if this thing bites me?” I realized that I was afraid of snakes. It was 1981, and I was a high school junior in Cedar Rapids, Iowa. At the time, the school had a fairly large collection of live animals, including many aquariums filled with tropical fish, various small mammals, and several snakes, including a speckled kingsnake, a bullsnake, an eight-foot-long common boa, a twelve-foot-long Burmese python, and the western ratsnake I was holding. The school offered a class where students cared for the animals in the lab and took some of them out to elementary schools in town to present live animal programs to the younger kids. My interest in biology had ignited over the previous year, and I thought it would be fun to take care of the animals. Because I was the biggest guy in the class and the only one believed to be strong enough to handle the boa and the python, I was chosen to take care of the snakes and do the snake programs. That all sounded great, except for one little problem. I was afraid of snakes. Herpetophobia, fear of reptiles, is a common phobia. In most cases, this fear is misplaced. Often it is the result of a cultural bias due to the portrayal of reptiles, particularly snakes, as evil in historical or mythological writings or to a lack of knowledge about reptiles and the important roles they play in ecosystems. Many people consider themselves experts on wildlife, but much of their information comes from movies, television, or the internet, not from firsthand experience. As a result, many myths have arisen concerning snakes and lizards, and these falsehoods have often led to the persecution of these two groups, much to their detriment, as evidenced by M. P. Somes in 1911: “One of the most absurd sights I ever witnessed was in the park of a small city, where three men and five small boys succeeded in killing a small ‘Garter Snake’ while several women stood around interestedly admiring the heroes.”

2  Introduction

Ophidiophobia, fear of snakes, is one of the most common phobias. Even people who have never encountered a snake or never had a bad experience with one are often afraid of them. Carl Sagan has suggested that infant baboons appear to be born with only three innate fears—falling, the dark, and snakes—so perhaps there is an evolutionary basis for this phobia. Sagan considers that humans and other primates may be hardwired to fear snakes and other reptiles and that this may date back to the Mesozoic era, the Age of Reptiles, when dinosaurs and other reptiles ruled the earth. Mammals at the time were small creatures that lived in trees and primarily came out at night when the reptiles were sleeping. As a result, they developed a natural fear of falling out of a tree, of being eaten by nocturnal predators, and of the reptiles that dominated their world. Most nonhuman primates fear snakes as much as most humans do. Numerous studies have shown that primates, both nonhuman and human, visually detect snakes faster than other kinds of visual stimulus such as flowers, butterflies, or geometric shapes. Anthropologist Lynne Isbell, hypothesizing that detection and avoidance of snakes have had a substantial impact on the evolution of primate vision, fear, and intelligence, has put forth the snake detection theory. She suggests that in primates, including humans, one of the main evolutionary forces that sharpened our visual skills was our constant need to spot and identify snakes, a major predator of primates, leading eventually to our fear and avoidance of them. Quan Van Le and colleagues found that certain nerve cells in our brain respond only to snakes, and the researchers hypothesized that these snake-dedicated nerve cells are a legacy from our past. The nerve cells are located in a region of the brain known as the pulvinar, which receives signals from our eyes and helps direct our attention quickly to certain objects. Most mammals have a pulvinar, but the primate pulvinar is unique—it contains extra nerve cells that evolved specifically for recognizing snakes. Based on this and other indirect evidence, the researchers hypothesized that these primate-specific regions of the pulvinar evolved in part to help primates detect and thus avoid snakes. Although we may be hardwired to fear snakes, many people are not afraid of them, and those who are can often overcome their fear. In my own case, spending time around snakes and caring for them in the biology lab showed me that they are not evil and are in fact captivating creatures that are important for maintaining healthy ecosystems. Since that first day holding the western ratsnake, I have gone on to complete a graduate degree in herpetology, presented hundreds of programs with live snakes to people of all ages, and for over twenty-five years have conducted field research on Iowa’s snakes and other reptiles and amphibians. Not bad for a guy who used to be afraid of snakes.

Introduction  3

TA XONOMY

Snakes and lizards both have backbones and are therefore classified as vertebrates. Together with crocodilians, turtles, and tuataras they belong to the class Reptilia, a group of animals all of which are cold-blooded—ectothermic—and have dry scaly skin. Snakes and lizards are further divided into the subclass Lepi­dosauria and the order Squamata. Within Squamata, snakes are classified into the suborder Serpentes and lizards belong to the suborder Lacertilia. Iowa snakes are divided into two families: Colubridae (nonvenomous) and Viperidae (venomous). Three lizard families occur in Iowa: Anguidae (glass lizards), Scincidae (skinks), and Teiidae (racerunners and whiptails). In the main body of this book, I have grouped the species and subspecies accounts by family, and each group begins with a brief description of its family. STATUS AND CONSERVATION

Twenty-eight snake species are found in Iowa, and snakes are found in all ninety-nine counties. However, the number of species present is not uniform across the state, ranging from one species recorded in Osceola County to twenty-three recorded in Lee and Louisa Counties. The number of species recorded in any given county is likely influenced by the level of search effort in that county— some counties are more heavily searched due their proximity to colleges and universities, larger cities, natural areas, or known occurrences of certain species. Nevertheless, some distribution patterns do emerge. For instance, more snake species are found in the southern half of the state, in particular the southeast quarter, than in the northern half, and highly agricultural counties tend to have fewer species than those that have more natural areas. Five lizard species occur in Iowa, and lizards have a patchier distribution than snakes. The number of lizard species ranges from zero recorded in numerous counties to three recorded in five counties: Allamakee, Fremont, Lee, Mills, and Pottawattamie. The northern prairie skink is the only lizard with a moderately widespread distribution in the state. The remaining four lizards are limited to certain regions based on habitat or their location on the periphery of their species’ range. Snakes and lizards in Iowa face many threats. In 2000, herpetologist Whit Gibbons and his colleagues identified six significant global threats to reptile populations: habitat loss and degradation, invasive species, environmental pollution, disease, unsustainable use of habitat, and global climate change. The Iowa Wildlife Action Plan, developed by the Iowa Department of  Natural Resources in 2006 and last revised in 2015, recognizes very similar threats to reptiles in the

4  Introduction

state. Of the eleven threat categories evaluated in the plan, seven are classified as very high and two others as high for reptiles. Historically, by far the most serious threat to wildlife in Iowa, including snakes and lizards, has been habitat loss and degradation. Since December 1846, when Iowa became a state, native prairies have been reduced by more than 99 percent, prairie pothole wetlands have been reduced by about 95 percent, and over 50 percent of Iowa’s original woodlands have been lost. The largest percentage of this loss is due to the conversion of natural land cover to row-crop production. During the first half of the 1900s, Iowa’s farmers employed mixed-use agriculture; small farms had a combination of row crops, livestock in pastures, and hayfields. Beginning around the mid-1960s, farmers switched to more intensive agriculture with larger row-crop fields, the removal of fencerows, fewer pastures for livestock, and a much greater use of industrial chemicals. As row-crop production became more intense and farms grew larger, along with the expansion of urban and suburban areas, less and less habitat that was suitable for snakes and lizards was available, especially for those species with unique needs. Iowa has over 114,000 miles of roads, and roads pose a significant threat to snakes that is only increasing over time. In 1938 Thomas Scott, discussing wildlife mortality on Iowa’s highways in the 1930s, reported that the state had approximately 4,820 miles of hard-surfaced roads. As of 2014 (the most recent data available), Iowa had over 40,000 miles of paved roads. Roads warm up during the day and remain warm for some time after the sun goes down. As the temperature cools in the evening, snakes crawl onto the warm roads. When roads fragment habitat or are located between overwintering and summer foraging sites, snakes must make dangerous trips across them. Thousands of snakes are killed on roads each year in Iowa. Roads may also form a barrier to movement and cut off access to critical nesting and overwintering areas. Numerous studies have shown that some species are reluctant to cross paved roads. Diseases and parasites affect snakes and lizards as well. Snake fungal disease, a disease caused by an infection that has been confirmed in numerous species across North America, including Iowa, is particularly concerning. Symptoms include crusted or ulcerated scales, nodules under the skin, and facial disfiguration that can be quite severe, leading to emaciation and death. Pathogens such as snake fungal disease have the potential to cause substantial declines in populations, particularly small populations of already imperiled species. Of all the threats faced by snakes and lizards in Iowa, the threat posed by climate change may be the worst in the years to come. Climate change is occurring

Introduction  5

Western foxsnake crossing a road in Buchanan County. Photo by Nicole VanDeWalle.

twenty times faster today than it has during any period over the past 2 million years. Iowa is already experiencing the effects of climate change in the form of increased precipitation and frequency of extreme precipitation events, higher temperatures and humidity, increased soil erosion and water runoff, and more favorable conditions for the spread of invasive species, all of which affect snakes and lizards to varying degrees. As the climate changes and extreme weather events escalate, animals may need to make rapid changes in habitat, which may not be possible for reptiles due to their inability to quickly colonize new locations. Lizards may be highly vulnerable to climate change because their reproduction is closely tied to narrow windows of time in the spring and summer when suitable temperature and moisture conditions are present for critical activities such as foraging and mating. As the effects of climate change accumulate over time, it is likely that changes in the distribution and abundance of snakes and lizards will occur, with some species disappearing from the state and others moving in from neighboring states. The cumulative effects of climate change combined with the other threats faced by snakes and lizards may be devastating for some species.

6  Introduction

As a result of the many and sometimes dire threats that snakes and lizards face in Iowa, in 2015 the Iowa Department of Natural Resources considered 86 percent of Iowa’s snakes (twenty-four species) and 100 percent of Iowa’s lizards (five species) to be species of greatest conservation need, that is, species with low and declining populations. Three snakes (11 percent) and one lizard (20 percent) are listed as threatened—in danger of becoming endangered—and six snakes (21 percent) and one lizard (20 percent) are listed as endangered—in danger of becoming extinct. One species, the eastern massasauga, is listed as federally threatened under the Endangered Species Act of 1973. Two additional snake species are listed as being of special concern—species about which problems of status or distribution are suspected but not documented. Historically, the protection and conservation of reptiles, snakes in particular, have not been a priority, and in fact programs such as bounties designed to eliminate certain snakes have been common. At times, this bias has even extended into popular works on natural history, such as Hobard Zim and Herbert Smith’s 1953 Reptiles and Amphibians: A Guide to Familiar American Species, in which they stated, “As a group [reptiles] are neither ‘good’ nor ‘bad,’ but are interesting and unusual, although of minor importance. If they should all disappear, it would not make much difference one way or the other.” The opinion voiced in the field guide was common at the time due to the fact that wildlife management up to that point had focused on game species—species that can be hunted—and the interconnectedness of organisms was not fully understood or appreciated. Nongame species were considered to be of little significance. However, beginning in the 1960s, the importance of nongame species in ecosystems started to be recognized by both the public and wildlife managers. Snakes and to some extent lizards still often do not receive the same level of concern as other nongame species, such as songbirds; nevertheless, many people do now recognize the need to conserve and protect them. On a statewide level, the Iowa Wildlife Action Plan recognizes specific threats to reptiles and the need for reptile conservation and management. The Iowa Multiple Species Inventory and Monitoring Program systematically collects data on reptiles, including their occurrence and distribution across the state, and provides the information to wildlife managers for use in conservation planning. In 2007, the Iowa Department of Natural Resources dedicated the Southeast Iowa Amphibian and Reptile Conservation Area, the first such area in the nation specifically established for amphibians and reptiles. The 470,000-acre (190,202.5-ha) area covering portions of seven counties in southeast Iowa is home to approximately 70 percent of Iowa’s amphibian and reptile species, including a significant percentage of the state’s threatened and endangered species. Twenty-four of

Introduction  7

Iowa’s twenty-eight snake species (86 percent) and two of Iowa’s five lizard species (40 percent) occur within this area. The Nature Conservancy also manages land in Iowa with an eye toward endangered snakes. Dedicated conservation areas such as these, along with preservation and proper management of public natural areas, greenbelts, and wildlife management areas, are critical to the conservation of snakes and lizards. Equally important as management of public land are the protection and good management of private land. You can take a number of steps to protect and conserve snakes and lizards by focusing on the feeding, breeding, and sheltering needs of the species found where you live, including: 1. Learn the natural history of your local snakes and lizards. With knowledge come understanding and appreciation. 2. Do not indiscriminately kill snakes and lizards when you encounter them. While it is true that five species of venomous snakes occur in Iowa, your chances of encountering one are very small. 3. Watch for snakes on the road and in your yard and avoid running over them with your car and lawn mower. If possible and if it is safe to do so, move snakes off the road. 4. C  reate good habitat for snakes by leaving portions of your yard unmowed, maintaining buffer strips of native vegetation between croplands and woodlands and incorporating fencerows where possible, putting farm fields into grasslands, establishing and maintaining wetlands, and constructing artificial overwintering sites. 5. Manage woodlands by limiting grazing and leaving dead trees, rotting logs, bark, and brush piles to serve as shelter, as places where snakes and lizards can lay eggs, and as habitat for prey such as invertebrates and small mammals. 6. Provide cover in the form of brush piles, cement blocks, or piles of large rocks along woodlands, streams, and farm fields to allow snakes and lizards to safely bask while reducing the threat of predation and providing habitat for prey. 7. I f you use fire to manage grasslands, if at all possible burn between November 1 and March 31—outside of their active season—to avoid killing snakes and lizards. 8. I ncorporate personal actions into your daily life to reduce climate change. The Iowa Wildlife Action Plan recognized that reptiles appear to be one of the species groups most vulnerable to climate change.

8  Introduction

Conservation of snakes and lizards, as with all species, is important. They serve key ecosystem functions as both predators and prey and help keep populations of small mammals in check. They provide important constituents for medicines used to treat strokes, diabetes, and blood clots, among other disorders, and recent research has shown that a molecule in the venom of a Brazilian pit viper inhibits coronavirus reproduction in monkey cells, a possible first step at combating COVID-19. And they are valuable ambassadors in environmental education. Unlike that opinion in the 1953 field guide, if all the snakes and lizards were to disappear, it would make a difference, and our lives would be less rich as a result. In the words of the naturalist William Beebe, “The beauty and genius of a work of art may be reconceived, though its first material expression be destroyed; a vanished harmony may yet again inspire the composer; but when the last individual of a race of living beings breathes no more, another heaven and another earth must pass before such a one can be again.” ORGANIZATION OF THIS BOOK

I have organized the species accounts by families first, based on phylogenetic order, followed by their respective genera in alphabetical order, then alphabetically by species and subspecies where appropriate. Each account includes the lizard’s or snake’s common name followed by its scientific name and species author—the person or persons credited with the first formal use of the name. When the author’s name is enclosed in parentheses, it means the species has been placed in a genus different from the one in the original description. The year in which the species was first described follows the author’s name. Organisms are known by both a common name and a binomial—the genus plus the specific epithet—scientific name. Subspecies are known by a trinomial—the genus, the specific epithet, and a subspecific epithet. Common names have the disadvantage of varying by geography and over time. For example, a blacksnake may be the northern black racer, not found in Iowa, or the western ratsnake, which is found in Iowa, and the eastern hog-nosed snake has been known by nearly fifty different common names. The use of scientific names eliminates confusion about which species is being discussed. That is not to say that scientific names do not change over time—they do as new information is learned about a species’ relationship to other species, and where appropriate I have included information about changes in scientific names in the species accounts—but scientific names provide a formal system of naming species. I have used Brian Crother et al.’s Scientific and Standard English Names of Amphibians and Reptiles of North America North of Mexico, with Comments Regarding Confi­

Introduction  9

dence in Our Understanding, 8th edition, 2017, as the standard for common and scientific names. Each species account is organized into twelve or thirteen (for venomous snakes) main sections as follows. Iowa Status. The conservation status of the species in Iowa. Historical Summary. A sampling of the common names for each species in the past, the first specimens collected in the state, and a brief history of the early Iowa literature related to each species. Where appropriate, I also discuss taxonomic changes. Description. The colors, patterns, and scale arrangement of the species. If juveniles differ from adults, the juvenile pattern is also described. Jim Christiansen and I, along with help from Jeff Parmelee, various students, and others, examined hundreds of Iowa museum specimens, primarily in the Drake University Research Collection, and gathered data on scale arrangement and sexual dimorphism of Iowa specimens. We relied only on specimens in good enough condition to give us reliable data. I combined these data with the morphological data collected by Reeve Bailey and provided to Jim and used the combined dataset for the sexual dimorphism information in this section. Size. The typical size range for each species, including the total body length— from the tip of the snout to the tip of the tail, excluding the rattle in rattlesnakes— of the largest male and female museum specimens in the Drake University collection. The record length for each species comes from Robert Powell, Roger Conant, and Joseph Collins’s Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America, 4th edition, 2016. Similar Species. Other Iowa species with a similar appearance along with characteristics that can be used to distinguish among species. Distribution. Begins with a short description of the national range of the species,

as shown in the Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America, 4th edition, 2016, followed by a discussion and a map of its range in Iowa. To illustrate changes over time, the distribution maps show preand post-1960 records, and they indicate whether a county has only pre-1960 (blue shading) or only post-1960 (yellow shading) records or both (green shading). This break is justified by a hiatus in major herpetological studies in Iowa from about the mid-1950s until 1969, when Jim arrived at Drake University. The source for all records can be tracked to a verified specimen in the research or teaching

10  Introduction

collections of Iowa’s colleges, universities, and museums or in those museum collections outside Iowa containing Iowa specimens (forty-four total collections), Reeve Bailey’s personal field notes, the Iowa Department of Natural Resources Natural Areas Inventory Database and Iowa Multiple Species Inventory and Monitoring Program records, the citizen-science online database HerpMapper, literature citations, or what I consider to be a reliable personal observation verified with a photo. In total, I used 11,572 lizard and snake records, ranging from the mid-1800s to 2020, to develop the maps. Reeve Bailey took extensive notes on specimens he found (mostly road-killed animals) that were not preserved as well as many specimens he examined. His field notes on discarded specimens along with pre-1950 literature records are the only records included on the distribution maps that are not represented by a specimen in a research collection or supported by a photograph. I am aware that additional observations reported by the public or by qualified observers exist; however, I decided to use only records available to me supported by the above sources for the maps. Habitat. Information from literature accounts, direct field observations by Jim and me, and Reeve Bailey’s field notes. Behavior. Temperament, daily or seasonal activities or movements, overwin-

tering habits, and defenses, among other aspects of behavior, from literature accounts, observations in the field by Jim and me, and Reeve Bailey’s field notes. In an effort to characterize the seasonality of each species in Iowa, I analyzed the collection/observation dates of the over 11,000 Iowa records used for the distribution maps to produce the activity charts in this section. These records often may reflect the schedule of the observer rather than the activity of the species being studied; however, because the records involve many different observers across nearly 150 years at numerous locations across the state, I feel that any search bias is minimal and that the dates provide a good snapshot of the activity period of each species. Because Iowa is at or near the northern edge of the range of many of the lizard and snake species in the state, the charts show how the seasonality of any given species may differ from that in other parts of its range. Venom and Bites (pit vipers only). A discussion of venom and its effects along

with a summary of bites in Iowa. Threats. Threats from predators and anthropogenic threats—threats posed by

humans.

Introduction  11

Domestic cat with a snake in Buchanan County. Photo by Wendy VanDeWalle.

Northern watersnake in Van Buren County catching a sunfish. Photo by Ryan D. Rasmussen.

Food and Feeding. Information on the primary prey consumed by each species

and its method of subduing prey based on literature accounts, field observations by me and Jim, and Reeve Bailey’s field notes. In addition, Jim and I examined the stomachs of hundreds of Iowa museum specimens, and a list of any food items we found is provided in this section.

12  Introduction

Reproduction. Various aspects of the reproduction of each species, including

mating behavior, growth of ovarian follicles (small fluid-filled sacs on the outside layer of the ovaries that contain immature eggs), ovulation (rupture and release of a matured egg for fertilization when the follicle has grown to the right size), oviposition (egg laying), incubation period, hatching or birth dates, and size at hatching or birth. Along with information from pertinent literature, Iowa-specific data are based on the internal examination of Iowa female museum specimens by Jim and me along with information from Reeve Bailey’s field notes. Longevity. The known life span of each species based primarily on Andrew

Snider and Kevin Bowler’s Longevity of Reptiles and Amphibians in North American Collections, 2d edition, 1992, along with other published accounts. Also included in the book are a discussion of Iowa snake and lizard biogeography by Neil Bernstein, illustrated keys for identifying them, a quick reference guide to snakes, a glossary of terms, references, life lists, and an index of scientific and common names.

BIOGEOGRAPHY OF THE SNAKES AND LIZARDS OF IOWA Neil P. Bernstein

E

xplanations for the distribution of Iowa’s snakes and lizards begin in the Pleistocene epoch approximately 2.5 million to 12,000 years ago, when species’ ranges expanded and contracted in response to advances and retreats of the northerly ice. While proximity to ice produced colder conditions, interglacial periods produced warmer climates that promoted the movement of reptiles. Before the last major glacial advances, the Sangamon Interglacial produced three climatic regimes in the Midwest: an initial climate characterized by precipitation exceeding evaporation that favored development of deciduous woodlands and produced overflowing aquatic habitats, followed by a climate similar to present-day conditions where precipitation approximately equaled evaporation with prairie- and oak savanna–like habitats dominating the landscape, and finally a warmer, drier climate just prior to the Wisconsinan glaciation with conifers interspersed with prairie-like vegetation. The warmer, drier Sangamon period would have been favorable to reptiles, as evidenced by the fossils of giant land tortoises found in the Sangamon formations of south-central Illinois and southern Indiana. As ice descended southward during the Wisconsinan episode, habitats present at the end of the Sangamon Interglacial were replaced by open tundra at the southernmost advance of the ice. While the area that is now Iowa would not have been hospitable to reptiles near the ice, the climate warmed after the ice retreated and tundra was replaced first by spruce woodlands and then by deciduous woodlands. This was followed by the xerothermic period, which promoted the spread of grasslands in North America. The high temperatures and dry conditions of this period favored the formation of prairies across much of Iowa, with extensive woodlands being confined mainly to eastern Iowa. The xerothermic period probably encouraged reptile migration as grasslands replaced woody vegetation over central North America. In 1935, Edgar Transeau famously defined the prairie peninsula, an eastern extension of the tallgrass prairie that covered most of Iowa, and the distribution of Iowa’s more arid-adapted lizards and snakes can be explained, in part, by former connections to popula-

14  Biogeography of the Snakes and Lizards of Iowa

tions in grasslands and similar habitats to the west and southwest. Over time, the climate changed and woody species spread, especially in eastern Iowa, creating the early nineteenth-century vegetation encountered by the first Euro-American settlers. As the climate changed and Iowa was settled, connections of some Iowa reptile populations, such as Great Plains skinks and plains hog-nosed snakes, to those farther to the west were broken, and Iowa’s populations became disjunct. Euro-American settlers massively altered Iowa’s habitats. Surveys by the General Land Office between 1832 and 1859 indicated a landscape dominated by prairie and savanna, with woodland areas concentrated in northeast Iowa and along major rivers and wetlands concentrated in central and north-central Iowa. By 1900, large areas of Iowa had been converted to agriculture and development, a process that continues today. Few native habitats remain in the state, and random weather events, such as the historic derecho in August 2020, severely damage those woodland areas that survive. The current preponderance of corn and soybeans also reflects a far less diverse array of crops than was present in the early twentieth century, and habitats contain fewer native species and more introduced ones. In addition, roadways presented barriers to safe animal migration, woodlands were harvested and grazed, irrigation and groundwater withdrawals increased, and wetlands were drained. Rivers that were once shallow, especially during drought years, were altered by locks and dams as flow levels came under human control. As a result, today’s deeper rivers present barriers to some reptiles where barriers did not exist before the twentieth century. Today’s monocultural landscape obscures a biogeographic history that once supported a diverse ecosystem within a landscape that was primarily grassland. However, to understand current snake and lizard distribution in Iowa, some knowledge of post-Pleistocene natural history is required, and the pioneering works of Paul Christiansen and Jean Prior’s deservedly much-cited Landforms of Iowa form a basis for this understanding. Viewing glacial history over the last 2.5 million years, Jean proposed seven landform regions defined by geologic deposits and landscape features. To discuss reptile distribution, I have separated her Alluvial Plains into the Missouri and Mississippi Alluvial Plains. Note that snake and lizard biogeography can be explained only partially by these landforms; an understanding of larger areas is also important because state boundaries often intersect these ecologically relevant ecoregions. Paleozoic Plateau. Formerly called the driftless region, based on the false concept that the area had never been glaciated, this northeast Iowa landform has gone unglaciated for the past 2.5 million years but nevertheless contains deposits from

Biogeography of the Snakes and Lizards of Iowa  15

mo

Northwest Iowa Plains

Paleozoic Plateau

r ai n e s

Iowan Surface

Silur ian Es car pm ent

Des Moines Lobe paha

East-Central Drift Plain

Loess Hills Iowa-Cedar Lowland

Missouri Alluvial Plain

Southern Iowa Drift Plain

0

0

25

25

50

50

75

75

Mississippi Alluvial Plain

100 Miles

Kilometers 100

Landform regions of Iowa. Courtesy of the Iowa Geological Survey.

previous glaciations. Because the region lacks recent glaciation and has straight channeled streams that deeply eroded the bedrock, it has Iowa’s most rugged topography. Sedimentary rocks, especially limestone, dolomite, sandstone, and shale, dominate the scenic terrain. Cliffs, ridges, and deep valleys with cold fast streams are common. Sinkholes, caves, springs, and seeps of cold air reflect the karst conditions within the lime-rich bedrock beneath. Unique habitats include cool microclimates at the base of north-facing rocky slopes and dry hill prairies on steep southwest-facing bluffs. Row crops are limited because of topography; thus, a greater portion of woodlands is still present, although much altered by logging and grazing, and lizards and snakes adapted to cliffs, rock outcrops, hill prairies, and dense woodlands make their homes here. This region shares a geologic and ecological history with southeast Minnesota, southwest Wisconsin, and northwest Illinois. The Mississippi River separates Iowa, Wisconsin, and Illinois, and while the river may not always have been a complete barrier to lizards and snakes, especially during summer droughts, differences in species assemblages east and west of the river do exist. In contrast, because no barriers to movements exist between northeast Iowa and southeast Minnesota, numerous species are common between the two states. The rugged

16  Biogeography of the Snakes and Lizards of Iowa

bluffs of the Paleozoic Plateau provide good habitats for timber rattlesnakes and prairie racerunners in both states, and while western ratsnakes are not limited to northeast Iowa, the species reaches its northernmost distribution in the Paleozoic Plateau areas of Iowa and Minnesota while closely related eastern ratsnakes are found in southwest Wisconsin and northwest Illinois. Most of Iowa’s common five-lined skink populations also occur in the Paleozoic Plateau in a relatively disjunct Upper Midwest population. Iowan Surface. The Iowan Surface formed through weathering and movements of rock and soil downslope during freeze-thaw episodes in the late Wisconsinan episode, which was followed by deposition of windblown silt. These forces left a gently rolling landscape eroded into old glacial deposits composed of pebbly clay. The Wapsipinicon and Cedar Rivers and their drainage systems are prominent features of the terrain. The northern border of this landform is continuous with Minnesota’s original prairies, the southern border blends into the Southern Iowa Drift Plain close to an area of high reptile diversity—the Mississippi Alluvial Plain—and the southeast extent of the Iowan Surface is bordered by the Mississippi River. Historically, prairie was the region’s dominant vegetation except for wooded river corridors and silt-capped northwest-to-southeast elongated ridges known as pahas. Abundant upland deposits of windblown sand and scattered large boulders are the result of intense erosional scouring by both wind and water that persisted when the most recent glacial ice fronts stood just north and west of this region. The silt and sand deposits provide well-drained soils for lizards and snakes adapted to dry environments, such as racers and prairie racerunners. However, intensive cultivation in this region has greatly reduced its natural habitats. Lizards and snakes adapted to prairies, dry sandy habitats such as sand prairies, and wooded riparian corridors occur here. Des Moines Lobe. This distinctive landform reflects direct contact with the last glacial ice to enter Iowa. As the glaciers melted and retreated northward, they left behind a landscape of wetlands and upland prairies that was once continuous between Iowa and Minnesota. Movements of rock, soil, and water downslope during freeze-thaw episodes created a landscape that remains poorly drained, with a myriad of lakes, wetlands, potholes, knobby hills, gravelly ridges, moraines, and pebbly clay. The Des Moines River is the major drainage system, and tallgrass prairie once dominated the uplands with bur oaks and other fire-tolerant trees along the stream corridors and the eastern shores of lakes. Lizards and snakes adapted to prairie and wooded riparian corridors occur here.

Biogeography of the Snakes and Lizards of Iowa  17

Since settlement, wooded corridors along the Des Moines River have been substantially reduced along with the species that occupy them. Some of the richest soils in the world are found here, and as a result the area has been nearly completely converted to row crops, bringing about the loss of nearly all native prairies and over 95 percent of the original wetlands. This massive alteration of the landscape has caused low diversity of snakes and lizards and the subsequent apparent loss of species such as Graham’s crayfish snakes throughout much of northcentral Iowa. However, in the last few decades, partnerships between private and public organizations have restored thousands of acres of wetlands and grasslands, benefiting species like smooth greensnakes and northern prairie skinks, but damage to native flora and fauna is still widespread. Northwest Iowa Plains. Northwest Iowa has a landscape history similar to

the Iowan Surface, with gently rolling terrain and a well-developed network of streams. Drainage here flows westward to the Missouri and Big Sioux Rivers with the major divide between the Mississippi and Missouri River basins found along this landform’s eastern contact with the Des Moines Lobe. There is a nearly continuous deposit of silt across the region blown in from exposed sediment along the Missouri River valley. Elevations are higher and precipitation rates are lower here than elsewhere in the state. The area was once dominated by prairie, with few trees, but the native grasslands here and in neighboring South Dakota and Minnesota have overwhelmingly been converted to agriculture with some woodland encroachment. Lizards and snakes adapted to prairie occur here, such as northern prairie skinks, plains gartersnakes, and lined snakes. This landform supports the lowest diversity of snakes and lizards; however, Gitchie Manitou State Preserve in extreme northwest Lyon County offers a unique refuge within an outcrop of Sioux Quartzite that continues into South Dakota and Minnesota. Loess Hills. The Loess Hills rise dramatically from the Missouri River valley

along Iowa’s western border and gradually transition eastward to the Southern Iowa Drift Plain. The hills continue south into northwest Missouri and north into southeast South Dakota. Unique to North America, the Loess Hills contain unusually thick deposits of the windblown silt known as loess that mainly accumulated during the late Wisconsinan episode. Similar to the Paleozoic Plateau, this landform has some of the most distinctive habitats in the United States. The south- and west-facing slopes as well as the ridgetops receive intense solar radiation and westerly winds, which combine with the well-drained loess to form dry landscapes with rates of water loss more typical of the Great Plains farther to the west. Much of the area was formerly covered in shortgrass prairie

18  Biogeography of the Snakes and Lizards of Iowa

and wooded valleys and includes plant species more characteristic of western ecosystems. Widespread cultivation is limited in this landform by its high relief, arid conditions, and susceptibility to erosion; however, succession from grasslands to mainly eastern red cedar trees, whose spread was aided by fire suppression after settlement, is an ongoing threat. Its soils’ increased susceptibility to erosion makes this the most fragile of Iowa’s landforms. Private and government organizations are acting aggressively to protect and manage native habitats. Lizards and snakes adapted to prairie occur here, and some more typical of the Great Plains are found in isolated populations, including two of Iowa’s rarest reptiles: the Great Plains skink and the prairie rattlesnake. Missouri Alluvial Plain. The valley floor of the Missouri River is underlain by porous sand and gravel deposits left by the flow of the river over time. The great width of the valley was carved by large floods of meltwater that flowed from glaciers to the north. Modern flood events continue to redeposit and rearrange the alluvial sand, gravel, silt, and clay; oxbow lakes, backwaters, and wetlands define past migrations of the river channel. With modern channelization and upstream water control, the Missouri River has lost the shallow braided channels with sandbars, wetlands, submerged tree snags, and periodic high-low flow cycles that were typical before settlement. The broad floodplain is extensively cultivated and the river is highly channelized, leaving few of the original habitats observed by Lewis and Clark as they made their way up the Missouri. Species found in this landform are habitat generalists such as North American racers and common gartersnakes. Southern Iowa Drift Plain. This large landform encompasses much of southern Iowa, and the boundaries between surrounding landforms are often subtle. Most of southern Iowa shares a geologic history with northern Missouri with no barriers to movement of lizards and snakes between the states, and populations are probably continuous. The landscape is underlain by deposits from the oldest episodes of glacial activity in Iowa. Time has eroded the pebbly clay deposits into a well-drained landscape of steeply rolling hills and deeply incised valleys. A mantle of wind-deposited loess is draped across the glacial drift throughout the area. Outcrops of sedimentary bedrock occur along some of the deeper river valleys, especially those draining into the Mississippi River. Sand dunes occur along the southeast margins of several larger river valleys, especially in Johnson, Cedar, Louisa, and Muscatine Counties. Major artificial reservoirs and numerous small impoundments are present due to the topographic relief and drainage network. Uplands were once dominated by tallgrass prairie with wooded areas concentrated along the corridors of the Des Moines, Iowa, Cedar, and Skunk Rivers,

Biogeography of the Snakes and Lizards of Iowa  19

which flow toward the Mississippi, as well as the Nishnabotna River and others that drain into the Missouri. Although grasslands and woodlands remain, much of this landform is now dominated by agriculture. Lizards and snakes adapted to prairie and open savanna occur here, many at the northern or western edge of their range, such as western slender glass lizards, eastern copperheads, western wormsnakes, prairie kingsnakes, speckled kingsnakes, prairie massasaugas, and western smooth earthsnakes. Of particular significance to snake and lizard distribution is the presence of flat uplands concentrated in southeast Iowa, with smaller areas in south-central and east-central Iowa, that were once dominated by tallgrass prairie. These flat uplands become rarer in southwest and western Iowa, where Jean Prior described the hills appearing to be aligned “in long, parallel crests of steep waves with broad troughs between them.” Several large wooded state parks and state forests are located in this landform, and a large-scale prairie-savanna restoration, Neal Smith National Wildlife Refuge, is ongoing on once-cultivated land near Prairie City. The combination of upland habitats, wooded river valleys, proximity to both the Loess Hills and the Mississippi Alluvial Plain, sand dunes, and climates more similar to areas south of Iowa provides a diverse mix of habitats for snakes and lizards. Mississippi Alluvial Plain. This landform consists of broad expanses of floodplain and elevated alluvial terraces along Iowa’s southeast border. The valley floor is underlain by deep deposits of sand and gravel owing to the large volume of water and sediment released from melting glacial ice to the north. Modern floodwaters continue to erode and redeposit sediment downstream. The Cedar and Iowa Rivers meander across the landscape, leaving a series of oxbow lakes, backwater wetlands, sand deposits, and wooded sloughs that become more apparent toward the south and suggest small versions of the southern swamps that inspired Jim Christiansen to call this area Iowa’s bayou country. In some river valleys, the floodplains are unusually wide because of the large amounts of glacial melt­ water that once flowed through them, and large sand deposits have formed in some areas. While low-lying wetlands are not generally hospitable to agriculture, the region’s sandy soil and shallow groundwater do favor cultivation of a variety of melons along with row crops. Although this landform supports the greatest diversity of Iowa’s amphibians and reptiles among the landforms, including the largest percentage of the state’s threatened and endangered snakes and lizards, irrigation and agriculture have greatly reduced the amount of suitable habitat. Lizards and snakes adapted to floodplain woodlands, oxbow wetlands and sloughs, and sand prairies occur here, including plain-bellied watersnakes,

20  Biogeography of the Snakes and Lizards of Iowa

diamond-backed watersnakes, plains hog-nosed snakes, and prairie racerunners. In the past, before alteration of the Mississippi and Des Moines Rivers deepened these rivers, populations of some species in the Mississippi Alluvial Plain may have had some connectivity with those in Illinois and Missouri during low-water periods. Watersnakes likely still move back and forth across the rivers.

IDENTIFYING IOWA’S LIZARDS AND SNAKES

T

he following keys are designed to help you identify the lizards and snakes in this book. The keys are organized into a series of numbered paired choices of characteristics: 1a and 1b, for example. For each pair, beginning with number 1, choose the description that best fits the animal you wish to identify. Move to the next numbered pair indicated at the end of the description. Continue until you reach a description that ends in the name of the animal. When there is more than one subspecies, the keys do not distinguish among them; however, names of subspecies are included to help you find the appropriate account for identifying them. KEY TO IOWA LIZARDS

1a No legs; ear openings; movable eyelids; groove on each side of body . . . . . . . . . . . . . . . . . .  Western slender glass lizard, Ophisaurus attenuatus attenuatus 1b Four legs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  2 2a Scales on back small and granular; scales on belly large . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Prairie racerunner, Aspidoscelis sexlineata viridis 2b Scales on body large, smooth, and shiny . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  3 3a Lateral scales between front and back legs run diagonally with dorsal scales . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Great Plains skink, Plestiodon obsoletus 3b Lateral scales between front and back legs run parallel with dorsal scales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  4 4a No postnasal scales; midback stripe fades; if present on head never forked; light stripes on body similar in width to dark stripes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Northern prairie skink, Plestiodon septentrionalis septentrionalis 4b Postnasal scales; midback stripe if present on head always forked; light stripes on body narrower in width than dark stripes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Common five-lined skink, Plestiodon fasciatus

KEY TO IOWA SNAKES

Rostral Internasal Prefrontal Supraocular

Frontal

Preocular

Eye Supraocular

Parietal

Eye

Postocular Temporal

Postnasal Internasal Rostral

Prenasal Nostril Supralabial

Dorsal view of snake head showing scales.

Infralabial

Lateral view of snake head showing scales.

1a Scales smooth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  2 1b Scales keeled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  10

a.

b.

c.

Snake scales showing (a) keeled scales, (b) smooth scales, and (c) method of counting scale rows.

Identifying Iowa’s Lizards and Snakes  23

2a Anal plate single . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  3 2b Anal plate divided . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  5 Anal Plate Single

Anal Plate Divided

Ventral views of snake tails showing single and divided anal plates and single and divided subcaudal scales.

3a Back black with white or yellow spots  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Speckled kingsnake, Lampropeltis holbrooki 3b Back red or brown with blotches or bands  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  4 4a Back with brown, gray, orange, or red dorsal blotches or bands bordered in black on white, gray, or brown background; belly spots black contrast­ ing with white or cream background; usually 21 dorsal scale rows at midbody . . . . . . . . . . . . . . . . . . . .  Eastern milksnake, Lampropeltis triangulum 4b Back tan, light brown, or gray with dark brown, black, or reddish blotches alternating with dark spots; belly cream with scattered gray to black rectangles; 25–27 dorsal scale rows at midbody . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Prairie kingsnake, Lampropeltis calligaster 5a Neck ring . . . . . . . . . . .  Prairie ring-necked snake, Diadophis punctatus arnyi 5b No neck ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  6 6a Back gray or tan with gray or brown blotches disappearing before reaching tail; tail brown, unmarked both dorsally and ventrally . . . . . . . . . . . . . . . . . . . . Juvenile North American racer (eastern yellow-bellied racer, blue racer), Coluber constrictor 6b Back unpatterned  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  7 7a Body sharply bicolored; belly salmon pink with pink extending up sides to third lateral scale row; 13 dorsal scale rows at midbody  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Western wormsnake, Carphophis vermis 7b Body not sharply bicolored; more than 13 dorsal scale rows at midbody. . . .  8

24  Identifying Iowa’s Lizards and Snakes

8a Loreal scale long, horizontal, touching orbit of eye; brown, reddish brown, or tan with unmarked back; dorsal scales smooth anteriorly, may be weakly keeled posteriorly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Western smooth earthsnake, Virginia valeriae elegans 8b Loreal scale not touching orbit of eye; back unpatterned . . . . . . . . . . . . . . . . .  9 9a Back and head green; white to cream belly; white or yellow supralabials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Smooth greensnake, Opheodrys vernalis 9b Back pale blue, slate gray, bluish gray, or olive green; belly bluish white to cream with white throat and chin or cream to intensely yellow with yellow extending onto throat and chin  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Adult North American racer (eastern yellow-bellied racer, blue racer), Coluber constrictor 10a No facial pit between eye and nostril; round pupil; subcaudal scales divided . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  11 10b Facial pit between eye and nostril; vertically elliptical pupil; anal plate and subcaudal scales single  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  26 Facial Pit

Head of colubrid snake without a heatsensing facial pit and with a round pupil.

Head of pit viper with a heat-sensing facial pit and a vertically elliptical pupil.

11a Anal plate single . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  12 11b Anal plate divided . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  16 12a No stripes along sides of body; narrow snout with enlarged scale at tip; 4 prefrontal scales . . . . . . . . . . . . . . . . . . . . . .  Bullsnake, Pituophis catenifer sayi 12b Stripes along sides of body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  13 13a Belly with double row of black half-moons down center  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Lined snake, Tropidoclonion lineatum 13b Belly lacking double row of black half-moons down center . . . . . . . . . . . . . .  14 14a Lateral stripes confined to scale rows 2 and 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Common gartersnake (eastern gartersnake, red-sided gartersnake, Chicago gartersnake), Thamnophis sirtalis 14b Lateral stripes on scale rows 3 and 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  15

Identifying Iowa’s Lizards and Snakes  25

15a Back light brown, black, greenish, or red with prominent dorsal stripe; dark spots between vertebral and lateral stripes; dark bars on labial scales; tail less than 1/4 total body length . . . . . . .  Plains gartersnake, Thamnophis radix 15b Back dark brown to black with white or light green dashes, narrow orange dorsal stripe, and yellow lateral stripes; no dark spots between vertebral and lateral stripes; pair of bright spots on top of head touch; no black bars on labial scales; tail 1/3 or more total body length  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Orange-striped ribbonsnake, Thamnophis proximus proximus 16a Snout pointed, upturned . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  17 16b Snout not pointed, not upturned . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  18 17a Snout slightly upturned; belly light or dark; underside of tail always lighter than belly; 25 dorsal scale rows at midbody  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Eastern hog-nosed snake, Heterodon platirhinos 17b Snout sharply upturned; belly black; underside of tail black; 23 or fewer dorsal scale rows at midbody . . . . . . . . .  Plains hog-nosed snake, Heterodon nasicus 18a No loreal scales  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  19 18b Loreal scales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  20 Loreal Scale

Dekay’s brownsnake showing no loreal scale.

Western smooth earthsnake showing loreal scale.

19a Back light to dark brown, coppery brown, olive black, or grayish with 3 small light spots on nape of neck and either 4 narrow dark stripes along sides and back or 1 wide pale vertebral stripe; belly red or pale orange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Red-bellied snake, Storeria occipitomaculata 19b Back gray, reddish brown, or brown with 2 parallel rows of dark spots separated by pale stripe down middle; belly cream to pinkish, often with 2 rows of somewhat scattered small black dots  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Dekay’s brownsnake, Storeria dekayi

26  Identifying Iowa’s Lizards and Snakes

20a Loreal scale long, horizontal, touching orbit of eye; brown, reddish brown, or tan with unmarked back; dorsal scales smooth anteriorly, may be weakly keeled posteriorly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Western smooth earthsnake, Virginia valeriae elegans 20b Loreal scale does not touch orbit of eye . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  21 21a Dorsal scale rows at midbody 19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Graham’s crayfish snake, Regina grahamii 21b Dorsal scale rows at midbody more than 20 . . . . . . . . . . . . . . . . . . . . . . . . . . . .  22 22a Scales weakly keeled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  23 22b Scales strongly keeled  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  24 23a Ventral scales fewer than 216; head tan to copper, sometimes reddish; body yellow, tan, or light gray with dark blotches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Western foxsnake, Pantherophis ramspotti 23b Ventral scales more than 220; head black; adult body shiny black with trace of black blotches . . . . . . . . . . .  Western ratsnake, Pantherophis obsoletus 24a Belly unmarked . . . . . . . . . .  Plain-bellied watersnake, Nerodia erythrogaster 24b Belly marked . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  25 25a Back gray to tan with wide dark gray to brown bands extending across anterior 1/3 that break into rectangular blotches that alternate along back and sides over remainder of body and extend onto tail; belly cream to yellow with reddish brown half-moons; 21–25 dorsal scale rows at midbody . . . . . . . . . . . . . . . . . .  Northern watersnake, Nerodia sipedon sipedon 25b Back olive, gray, or most often light brown with series of dark dorsal blotches often attached to lateral blotches by thin dark line connecting in chainlike pattern down midline; belly cream to yellow with black halfmoons; 25–31 dorsal scale rows at midbody  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Diamond-backed watersnake, Nerodia rhombifer 26a No rattle; back with brown hourglass-shaped cross-bands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Eastern copperhead, Agkistrodon contortrix 26b Rattle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  27

Identifying Iowa’s Lizards and Snakes  27

27a Nine large plates on top of head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  28 27b Top of head covered with granular scales . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  29 Left: Top of massasauga head showing 9 large plates. Right: Top of timber rattlesnake head showing granular scales.

28a Belly black with white or cream mottling on edges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Eastern massasauga, Sistrurus catenatus 28b Belly light with dark gray mottling on outer edges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Prairie massasauga, Sistrurus tergeminus tergeminus 29a Back yellow, gray, brown, or orangish brown with large dark jagged, almost zigzag bands with light borders; red to reddish orange vertebral stripe may be present; tail uniformly black . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Timber rattlesnake, Crotalus horridus 29b Back tan, yellowish brown, or slightly greenish with irregular brown dorsal blotches outlined with white that become narrower near tail; tail not uniformly black; cross-bands usually distinct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  Prairie rattlesnake, Crotalus viridis

PART ONE

LIZ ARDS

Cloaca

Snout-Vent Length

Tail Length Total Body Length Cloaca

Lizard standard measurements. Snout-Vent Length Total Body Length

Tail Length

A

pproximately 7,000 lizard species are recognized worldwide, ranging in size from the tiny Jaragua lizard at just 0.63 inch (16 mm) long to the Komodo dragon measuring over 10 feet (3 m) long and weighing up to 300 pounds (136 kg). Only two lizards are venomous, the Gila monster found in the southwestern United States and Sonora, Mexico, and the beaded lizard found in Mexico and Central America. Iowa has five lizard species. Lizards are reptiles covered in overlapping scales that generally have short torsos, four legs, long tails, movable eyelids, and external ear openings. In Iowa, the western slender glass lizard does not fit this mold; it is an elongated lizard lacking legs, but it does retain movable eyelids and external ear openings. Unlike snakes, the dry scales covering the body of a lizard are shed in flakes and pieces as the lizard grows. Iowa’s lizards are carnivorous, using superb color vision, an acute sense of smell, and speed to catch prey. A lizard catches prey by using its mouth to grab and smash it, then often shakes it to remove large appendages and most often swallows it whole. Unlike snakes, the two lower jawbones are solidly fused. Iowa’s lizards are oviparous with females laying flexible shelled eggs. Many lizard species have evolved special vertebrae that allow the tail to selfamputate as a mechanism to escape predators or during aggressive interactions with other lizards. Contracting special muscles around fracture planes in the vertebrae cause the tail to fall off along the line of weakness. Muscle contraction also prevents blood loss, and a flap of skin folds over the wound to seal it and prevent infection. The detached tail, sometimes brightly colored, continues to wriggle, possibly distracting the predator and allowing the lizard to escape. The tail may partially regenerate over a period of weeks but is shorter than the original and supported by cartilage rather than bone.

FAMILY ANGUIDAE GLASS LIZARDS AND THEIR REL ATIVES

T

he family Anguidae has a nearly worldwide distribution with representatives on every continent except Antarctica and Australia. Members of its 11 genera and approximately 100 species are varied in form—some have full limbs, some have reduced limbs, and still others are legless but retain remnants of limb girdles—but even the legless species have movable eyelids and external ear openings. Two genera occur in the United States: Gerrhonotus, commonly referred to as alligator lizards due to their vague resemblance to an alligator, and Ophisaurus, the legless glass lizards. Iowa has a single anguid species, the western slender glass lizard. Glass lizards have long fragile tails that break off easily, giving rise to their common name. Members of the family are distinguished by a somewhat rigid body resulting from the bony plates—osteoderms—that underlie each scale. The plates reinforce the scales but reduce flexibility. Some members of the family, such as glass lizards, have deep grooves on each side of the body that help compensate for the lack of flexibility. These lateral grooves are covered with granular scales and more flexible skin, allowing for some expansion of the body during breathing, movement of food through the digestive tract, and egg development. The family includes both oviparous and viviparous species.

WESTERN SLENDER GLASS LIZARD Ophisaurus attenuatus attenuatus Cope 1880

Western slender glass lizard from Decatur County. Photo by Ryan D. Rasmussen.

Iowa Status. Threatened; species of greatest conservation need. Historical Summary. The western slender glass lizard has also been called the joint-lizard and glass snake. The first confirmed specimens in the state appear to be in 1887 near Keokuk in Lee County (Goodman 1948) and in 1895 near Des Moines in Polk County (Des Moines Historical Society). The History of Fremont County, Iowa (Anonymous 1881a) listed the “glass snake” as occurring in the county, Osborn (1892) mentioned specimens in the Iowa State Natural History Collection, and Somes (1911) listed western slender glass lizards as occurring in Iowa. Two subspecies of the slender glass lizard, Ophisaurus attenuatus, are currently recognized, only one of which, the western slender glass lizard, O. a. attenuatus, has a range that includes Iowa. Description. Western slender glass lizards are long slender snakelike lizards with

no legs whose scientific name perfectly describes this beautiful animal: Ophi­ saurus comes from the Greek ophis meaning “snake” and saurus meaning “lizard,”

36  Western Slender Glass Lizard, Ophisaurus a. attenuatus

Western slender glass lizard from Lee County.

literally, snake-lizard; attenuatus is Latin meaning “tapered, drawn out, thin.” The background color is gray, tan, or brown with dark stripes along the back and sides, including a distinct stripe along the midback. A noticeable lateral groove along the sides of the body runs from the neck to the vent. The lateral groove, along with movable eyelids and external ear openings, identifies this animal as a lizard and not a snake. The indistinct head has a pointed snout, and the face below the eye and the area along the neck are mottled black and white. The belly is white and the tail when complete is long (more than twice snout-vent length) with dark stripes on the underside. Hatchlings are similar in appearance to adults but have a more vivid pattern. Western slender glass lizard scales have a foundation of bony plates that make the skin extremely tough and give the body a rigid feel. Internally folded lateral grooves composed of softer skin covered with small granular scales allow for some expansion as the lizard breathes or when it swallows a large meal. Although some of the dorsal scales are keeled, the lizard has a smooth shiny appearance; unlike snakes, the ventral scales are not broad but are about the same size as the dorsal scales but flattened. Examination of 10 specimens (6 males; 2 females; 2 juveniles) in the Drake University Research Collection along with data on 2 specimens measured by Reeve Bailey found no significant difference between the sexes with regard to scale arrangement. In adult males, the tan areas of the back and sides

Ophisaurus a. attenuatus, Western Slender Glass Lizard  37

develop white flecks and black speckles that become more prominent with age, forming irregular light cross-bands on the back and tail; the face is more heavily marked; and the average relative tail length is approximately 4 percent greater than that of females. Size. Iowa’s largest lizard, the western slender glass lizard generally ranges from 22

to 46.5 inches (56–118.1 cm) total body length. The largest complete specimen in the Drake University Research Collection is a male from Lee County measuring 24.4 inches (62 cm) total body length; the largest female is from Clarke County measuring 22.7 inches (57.7 cm) total body length. The maximum snout-vent length reported for O. attenuatus is 14.25 inches (36.2 cm). Similar Species. All other Iowa lizards have legs. Snakes lack movable eyelids,

external ear openings, and lateral grooves and have broad ventral scales. Distribution. Western slender glass lizards are found from southern Wisconsin and northwest Indiana south to western Louisiana and west to eastern Texas, Oklahoma, Kansas, and southeast Nebraska. In Iowa, they occur in widely scattered populations only in the southern two tiers of counties in the southeast quarter of the state. In the mid-1940s, the species was known from 7 counties. At present, records exist from only 12 of Iowa’s 99 counties, 3 (25%) of which have only pre-1940 records. The Polk and Johnson County populations that were present early in the twentieth century seem to have disappeared quickly, along with any others that may have existed in adjacent counties, likely due to habitat loss as native grasslands were converted to croplands. Western slender glass lizard distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

Habitat. In Iowa, these lizards inhabit grasslands, grassy roadsides, and open woodlands near wetlands or other water features. Although no extensive habitat studies have been conducted in the state and few specifics regarding requirements here are known, work by Jim Christiansen and his students in Appanoose County

38  Western Slender Glass Lizard, Ophisaurus a. attenuatus

provides some insight. The lizards they found were most often in areas with dense grass 6 to 12 inches (15.2–30.5 cm) high and always within a few hundred feet of water. The grasslands were often dominated by nonnative smooth brome although sometimes had a combination of shortgrass and tallgrass prairie species. Brome and bluegrass pastures were also used, including an area of reclaimed pasture. Other habitat reports from Iowa include a natural spring, grassy areas with scattered shrubs, woodland openings with prairie vegetation, second-growth oak woodlands, grassy openings on clayey soils and hillsides, and an area listed as a wooded bluff, pasture, pond, and stream. In Kansas, tall grass was considered to be essential for western slender glass lizards, including smooth brome pastures that were not heavily grazed (Fitch 1989). Where pastures were heavily grazed, the lizards were exceedingly scarce. In addition, an abundant supply of small mammals, such as mice, voles, moles, and shrews, is important for providing burrows used by glass lizards as escape shelters, hibernacula, and nesting sites. In Wisconsin, these lizards are limited to areas with soils composed of nearly pure sand (Vogt 1981), which is not the case in Iowa. Behavior. Western slender glass lizards rely on camouflage to go unnoticed and

may either remain motionless when approached or dart away with surprising speed. Although not overly aggressive, if handled they have no reservations about chomping on a finger. If an attempt is made to capture the lizards, the pursuer

Western slender glass lizard from Monroe County missing its tail. Photo by Ryan D. Rasmussen.

Ophisaurus a. attenuatus, Western Slender Glass Lizard  39

quickly learns why they are called glass lizards. Their tails, which make up more than two-thirds of their total body length, are highly fragile due to a fracture plane in each vertebra. When the tail is grabbed, it fractures, breaks off, and undergoes vigorous spasms that distract a predator as the lizard makes its escape. In some cases, a sudden scare may be enough to cause the tail to break off, even though it has not been touched. The wriggling may go on for up to ten minutes, and even when it has stopped, touching the tail may cause it to twitch again. Tails regenerate over time, although the regenerated tail is always shorter than the original. Regrowth occurs rapidly during the first few weeks after the break; a year later growth has mostly stopped, with the regenerated tail attaining up to 30 percent of the length of the original. Tails serve important locomotion and fat storage functions, and if a glass lizard loses its tail, it may be slower to escape and lose needed fat reserves. The collection/observation dates of 59 Iowa western slender glass lizards show the species is active from April through October with the earliest record from Decatur County on April 15. In spring and fall, the lizards are primarily diurnal, spending much of the day under leaf litter or underground in small mammal burrows, but they may become crepuscular or even nocturnal during the summer. In Wisconsin, activity during midsummer shifted to morning and evening hours to avoid the midday heat, and during the peak of the summer it shifted entirely to the evening hours (Pleyte 1976). Two peaks of terrestrial activity were observed in Arkansas western slender glass lizards: one during the breeding season in April and May and the other in October and November as the lizards sought overwintering sites (Trauth 1984). When latitudinal differences between Arkansas and southern Iowa are accounted for, Iowa western slender glass lizards show a similar bimodal pattern with peaks in May and June (44 percent of records), a decrease in July and August, and an uptick in September and October (22 percent of records). The latest Iowa records are from Appanoose County on October 25. Western slender glass lizards prefer air temperatures between 73 and 82° F (23–28o C). In Kansas, average home range size was 0.35 acre (0.14 ha) for juveniles and 1.1 acres (0.44 ha) for adults (Fitch 1989); in Wisconsin home range size was much smaller, ranging from 0.17 to 0.37 acre (0.07–0.15 ha) (Pleyte 1976). The lizards tend to stay within a familiar area, although their home ranges do not have a well-defined structure or boundary, and they are slow to disperse into new areas. Unlike snakes, which may move long distances to suitable overwintering locations, these lizards do not leave their summer range or make sudden changes in activity in the fall; instead they hibernate underground below the frost line in small mammal burrows within the same area in which they spent the summer.

40  Western Slender Glass Lizard, Ophisaurus a. attenuatus

14

15 Number of Records

12 10

8

8

6

4

5

0

7

0

0

0

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

0

0

Nov

Dec

Month Collection/observation dates of 59 western slender glass lizards in Iowa.

As fall progresses, surface activity declines and the lizards move farther underground as temperatures drop. Threats. Many avian and mammalian predators likely feed on these lizards,

including raccoons, foxes, opossums, skunks, domestic dogs and cats, and raptors such as red-tailed hawks, along with many others that may come upon them opportunistically. Small mammals such as eastern moles, short-tailed shrews, white-footed mice, and harvest mice are potential predators, especially during hibernation. In Kansas, four snake species have been found to consume western slender glass lizards—eastern copperheads, North American racers, prairie kingsnakes, and prairie ring-necked snakes (Fitch 1989)—all of which overlap with this lizard in Iowa. Human activities resulting in habitat loss have likely taken the greatest toll in Iowa, however, through conversion of suitable grassland habitat to cropland or other incompatible uses. Pesticide use affecting the lizard’s primary foods also has to be considered a threat along with climate change. Use of roadside habitat puts the lizards in close proximity to automobiles, and numerous instances of road mortality have been reported in the state. Food and Feeding. When hunting, the western slender glass lizard moves slowly

and silently through the vegetation, taking long pauses to use vision or scent to find prey. Once prey is located, the lizard slowly crawls toward it and when within range makes a quick lunge to grab the food with its mouth. The diet consists of a wide variety of insects, spiders, and other invertebrates as well as small reptiles and probably young rodents. In Kansas, the proportion of each food type was

Ophisaurus a. attenuatus, Western Slender Glass Lizard  41

found to be 51.3 percent grasshoppers, katydids, and crickets, 17.3 percent beetles, 11.6 percent spiders, 10.4 percent miscellaneous insects, 1 percent snails, and 8.4 percent vertebrates including small snakes, lizards, frogs, toads, and mice; interestingly, 2 percent of the droppings examined contained shed glass lizard skins (Fitch 1967). The diet varied by season, with caterpillars, beetles, snails, and spiders important early in the year but scarce or absent after midsummer and grasshoppers, katydids, and crickets more important later in the summer. Examination of the stomach contents of specimens in the Drake University Research Collection found two grasshoppers in one specimen, a cricket and a caterpillar in another, and only unidentifiable insect parts in a third. Reproduction. Because Trauth (1984, Arkansas) and Fitch (1989, Kansas) provide the most complete descriptions of western slender glass lizard reproduction, I have used their accounts in this section. Males may reach sexual maturity as early as their second year at around 6 inches (15.2 cm) snout-vent length, while females mature during their third or fourth year at around 7.5 inches (19 cm) snout-vent length. During the breeding season, April and May, the production of spermatozoa in males is synchronized with the presence of enlarged egg cells in females. Vitellogenesis begins shortly after emergence from hibernation with mating occurring in May, although some females may breed only every other year. Western slender glass lizards are oviparous, with females using the undersides of flat rocks and rotting logs or abandoned small mammal burrows as nest sites. Nesting and egg laying occur in late June and early July, with females laying 5 to 16 (average 10) eggs per clutch. The female coils around the eggs and stays with them during incubation, although she is not aggressive and does not defend them. The eggs hatch sometime in late August or early September after a 50- to 60-day incubation period. Hatchlings range from 4.4 to 5.2 inches (11.2–13.2 cm) total body length. Longevity. A wild-caught adult female survived in captivity an additional 4 years and 18 days. A wild-marked individual, estimated to be 9 years old, was recaptured in Kansas.

FAMILY SCINCIDAE SKINKS

T

he family Scincidae has a nearly worldwide distribution with representatives on every continent except Antarctica. It is much better represented in the Old World than the New and better represented in the tropics than in temperate regions. With nearly 160 genera and more than 1,500 species, the family is one of the most diverse lizard families. Only the Plestiodon genus occurs in Iowa. Members of the family have smooth and shiny overlapping scales containing bony plates—osteoderms—flattened heads with large uniform plates, slender bodies, and small legs. Some species lack legs altogether. Unlike iguanids and teiids, scincids have no femoral pores. The tail is fragile and will quickly break off if grasped by a predator. It will regenerate but is shorter than the original and often dull gray. The family includes both oviparous and viviparous species.

COMMON FIVE-LINED SKINK Plestiodon fasciatus (Linnaeus) 1758

Adult common five-lined skink from Jones County. Photo by Jeff LeClere.

Iowa Status. Protected nongame; species of greatest conservation need. Historical Summary. The common five-lined skink has also been called the

blue-tailed lizard and red-headed skink. The first confirmed specimens in the state appear to be three individuals collected in 1887 near Keokuk in Lee County (Goodman 1948). The History of Fremont County, Iowa (Anonymous 1881a) listed the “blue-tailed lizard,” along with the former scientific name of the common five-lined skink (Eumeces fasciatus), as common; however, the sightings may well have been juvenile Great Plains skinks as no confirmed common five-lined skink records exist from that portion of the state. Osborn (1892) mentioned a specimen in the Iowa State Natural History Collection and Somes (1911) listed common five-lined skinks as occurring in Iowa. Taylor (1935) cites an Academy of Natural Sciences of Drexel University specimen labeled “Sioux City, Woodbury County, Dakota” with the note “possibly from across the river.” This location is suspect as the species is not known to have occurred in northwest Iowa.

46  Common Five-Lined Skink, Plestiodon fasciatus

Description. Common five-lined skinks have smooth shiny scales, with those

on the sides between the front and hind legs running parallel to the dorsal scales, and light and dark stripes (fasciatus comes from the Latin meaning “banded” or “striped”). The 5-lined pattern is characteristic of hatchlings but gradually changes as the lizard ages, becoming dull and eventually disappearing. As a result, body color varies with sex and age. Hatchlings and juveniles are black with 5 narrow white or yellowish stripes extending from the head to the base of the tail, a V-shaped mark on the head, and a bright blue tail. Adult females are brown with dark brown lateral stripes, 5 olive or tan stripes, and a blue or blue-gray tail. Adult males are olive or tan and may lose all traces of stripes, or if present the stripes are faded. During the breeding season, the heads of males become reddish and slightly swollen. Scales on the head include postnasal scales, usually 7 supralabial scales, and 2 well-defined and rather large postlabial scales. Examination of 19 specimens (6 males; 6 females; 7 juveniles) in the Drake University Research Collection found no significant difference between the sexes with regard to scale arrangement. The posterior of the head of males was found to be distinctly wider than that of females.

Juvenile common five-lined skink from Jackson County. Photo by Jeff LeClere.

Plestiodon fasciatus, Common Five-Lined Skink  47

Size. Plestiodon fasciatus generally ranges from 5 to 8.75 inches (12.7–22.2 cm)

total body length. The largest specimen in the Drake University collection is a male from Allamakee County measuring 5.5 inches (14 cm) total body length and 2.6 inches (6.6 cm) snout-vent length; the largest female is from Jackson County measuring 4.8 inches (12.2 cm) total body length and 2.4 inches (6.1 cm) snoutvent length. The maximum snout-vent length reported for the species is 3.4 inches (8.6 cm). Similar Species. The northern prairie skink lacks postnasal scales, its dorsal stripe fades as it approaches the head, and if present on the head it is never forked, and the light stripes on its body are similar in width to the dark stripes. The Great Plains skink has diagonal rows of scales on the sides between the front and hind limbs, and its Iowa range does not overlap with that of the common five-lined skink. The prairie racerunner is striped but has small granular scales over most of its body and large rectangular scales on its belly. Distribution. Few vertebrates have ranges that more closely align with the original eastern deciduous forests of North America. Common five-lined skinks are found from the Upper Peninsula of Michigan, southern Ontario, and eastern New York south to northern Florida and the Gulf Coast and west to eastern Wisconsin, Missouri, and eastern Kansas, Oklahoma, and Texas. Isolated populations occur in northeast Iowa, west-central and southern Minnesota, and western Wisconsin. In Iowa, scattered populations are found associated with limestone outcrops in the northeast and east-central part of the state with records from only 10 of Iowa’s 99 counties, 2 (20%) of which have only pre-1960 records. The Lee County rec­ ord (Goodman 1948) suggests that at one time they occurred in southeast Iowa, although LeClere (2013) indicates recent records for 2 additional southeast counties. Because habitat similar to that found in northeast Iowa exists in portions of southeast Iowa, it is unclear why more common five-lined skinks have not been found there. Common five-lined skink distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

48  Common Five-Lined Skink, Plestiodon fasciatus

Habitat. Common five-lined skinks inhabit open moist woodlands and wooded

bluffs, rock outcrops, and rocky hillsides. Ample cover in the form of rocks, downed trees, rotting logs, and brush piles is required, as is an open canopy allowing sunlight to reach the woodland floor. In Iowa, the skink is limited to areas with exposed limestone outcrops with deep crevices or loose flat rocks that provide shelter. Artificial structures such as rock or wood piles, stone walls, and buildings provide good habitat, too, especially when close to good natural habitat. I have found them on the sides of an old limestone mill along the Turkey River in Clayton County, and once while doing reptile and amphibian surveys in Backbone State Park I had someone tell me they had seen “blue-tailed salamanders” on the side of a pit toilet near the Backbone Trail. Knowing that was not suitable salamander habitat, I went there and quickly found several common five-lined skinks. Not only is macrohabitat important, but microhabitat is as well. A lack of suitable woody debris and sufficient rock cover at a specific site can limit the skinks’ distribution or their use of the area. Behavior. The common five-lined skink is secretive and relies on concealment

rather than speed to avoid danger. These skinks spend much of the day hidden in crevices in limestone outcrops, under rocks, or in or under fallen logs or other vegetation. When out basking, they may be seen sitting in the sun on a rock or log with their heads up, keeping an eye out for danger. When they do move, they usually freeze after only a few steps, scan the area around them, and then move another short distance before freezing again. This behavior of moving only a short distance and quickly freezing may help conceal the skinks by causing would-be predators to lose sight of them as they blend into the background. When faced with danger, they may also dart into a crevice, burrow under a log, or climb a tree to escape. If handled they will bite, although due to their small size this is merely a pinch. Similar to other skinks, when grabbed the tail may break off and continue to wriggle for several minutes, distracting the predator as the lizard makes its escape. Tails regenerate over time, although the regenerated tail is shorter than the original. No detailed studies of this skink have been conducted in Iowa. Taylor (1935, Kansas) and Fitch (1954, Kansas) provide details of its life history, and the information in this section is based on their observations except as noted. Common five-lined skinks have the ability to become active and carry on normal activities at relatively low air temperatures, and thus they have a relatively long active season even at northern latitudes such as northern Iowa. The collection/observation dates of 90 Iowa common five-lined skinks show the species has been found in

Plestiodon fasciatus, Common Five-Lined Skink  49

Number of Records

40 30 19

20

18

10 5 0

0

0

0

Jan

Feb

Mar

Apr

May

Jun

4 Jul

4 Aug

Sep

Oct

0

0

Nov

Dec

Month Collection/observation dates of 90 common five-lined skinks in Iowa.

the state from early April to late October with the earliest record from Jackson County on April 6 and the latest on October 19 in Allamakee County. Lack of leaves during spring and fall on the deciduous trees in the woodlands where the skinks live allows more sunlight to reach the ground, providing ample opportunity for them to maintain body temperatures similar to those seen during hot summer weather. They are such efficient thermoregulators, either basking directly in the sunlight or lying under a warm flat rock exposed to the sun, that they are able to raise their body temperatures as much as 32° F (18° C) above the ambient air temperature. Surface activity is more pronounced during the several weeks after they emerge from hibernation, corresponding to the time of breeding. In Kansas the skinks—mostly adult males—were observed much more often in May than at any other time of the year; by June, the number seen in the open declined abruptly. Iowa observation records show a similar pattern. The skinks become much scarcer during midsummer with an increase in surface activity again in late summer and fall prior to hibernation. The decrease in surface activity and retreat underground during midsummer may be tied to availability of water during the height of the summer, as a regular supply of drinking water is a critical ecological requirement of this lizard. Common five-lined skinks do not occupy a fixed home range but instead have a more linear shifting range, moving only some tens to hundreds of feet while returning to the same locations occasionally. The skinks hibernate underground and must get below the frost line to survive the winter. They may be able to sur-

50  Common Five-Lined Skink, Plestiodon fasciatus

vive temperatures a few degrees below freezing but likely cannot survive being frozen solid. Threats. Although many animals may prey on these skinks, few reports of natural

predators exist. They have been found in the diet of opossums in Missouri and some hawks in Kansas (Fitch 1954). In Iowa, birds such as American crows, northern shrikes, American kestrels, and sharp-shinned hawks, along with mammals such as raccoons and skunks, likely eat them as well. Fitch postulated that shrews and eastern moles, along with snakes such as western ratsnakes and eastern milksnakes, may be significant predators. As with most species in Iowa, habitat loss likely poses the most serious concern, and pesticides affecting the lizard’s primary foods also have to be considered a threat along with climate change. Food and Feeding. Common five-lined skinks are active predators that search for prey using both vision and scent. They spend much of their time under rocks or logs where they find prey and from which they make short trips in search of food. When prey is located, the skink lunges, grabs the food in its mouth, and crushes it with its jaws before swallowing it. They eat a variety of insects and insect larvae, spiders, harvestmen—daddy longlegs—and occasionally small snails, and at times they may eat other five-lined skinks or their eggs. Arachnids, such as spiders and harvestmen, appear to be a particular favorite. In Kansas, 92 percent of their diet consisted of arachnids and insects such as crickets, grasshoppers, and cockroaches (Fitch 1954), and in Ontario over 80 percent of food items belonged to four orders—spiders, beetles, harvestmen, and cockroaches—with arachnids making up nearly half the items (Hecnar et al. 2002). Examination of the stomach contents of specimens in the Drake University collection found two beetle larvae in one, a small spider in another, and two harvestmen and two mites in a third. Reproduction. I have used Fitch’s (1954, 1970, Kansas) and Hecnar and Hecnar’s (2019, Ontario) descriptions of P. fasciatus reproduction in this section except as noted. Females reach sexual maturity at snout-vent lengths greater than 2.3 inches (5.8 cm). Mating occurs in the spring several weeks after the skinks emerge from hibernation, likely in May or early June in Iowa. After emergence, males spend much of their time looking for females. At the time of emergence, they lack even a trace of reddish color on their heads; however, slightly more than a month later they have reached their full breeding coloration and are ready to mate. Males find females by both sight and scent, likely initially scent trailing them. When he encounters another skink, the male rushes in with an open mouth. If the other lizard attacks in return, it is a male; if it runs away or stays still, the first reaction

Plestiodon fasciatus, Common Five-Lined Skink  51

Juvenile common five-lined skink from Jackson County. Photo by Jim Scharosch.

of the male as he approaches is to touch her with his tongue, apparently receiving the olfactory stimuli that are essential to initiating mating. If she runs, the male pursues her and upon catching her bites her on the neck or shoulder to hold on. Mating begins soon after and may last several minutes. About 2 weeks after she mates, often with multiple males, hormonal changes cause the female to decrease aboveground activity and prepare a nest cavity. Common five-lined skinks are oviparous with females laying eggs under cover such as a log or rock, inside rock fissures, or inside moderately decayed logs and hollows in trees, with multiple females nesting in close proximity to each other. Jim Christiansen has found nests under flat rocks in cavities about 3 inches (7.6 cm) deep, sometimes with a second nest in another cavity under the same rock. LeClere (2013) reported finding 4 nests under shingles near an abandoned house in Jackson County. Nesting is fairly synchronized in the northern portion of this skink’s range beginning in late June or early July. Females lay a single clutch per year with generally 4 to 16 (average 9) eggs per clutch. Iowa clutch reports include 1 to 9 (average 6) eggs per clutch for 5 Allamakee County clutches and 5 to 12 eggs per clutch for 4 Jackson County clutches

52  Common Five-Lined Skink, Plestiodon fasciatus

found by LeClere (2013). The female remains with the nest brooding the eggs, defending the nest against small predators, maintaining its humidity by urinating on the cavity floor, and keeping the eggs together by encircling them with her body. Jim has observed brooding females encircling their eggs, lying on top of them, or putting a portion of their body under some of them. Females may eat eggs that have spoiled and may leave the nest periodically to feed or rehydrate. The eggs hatch sometime in July or August after approximately 4 to 7 weeks of incubation. Reported Iowa hatching dates range from July 20 through August 21. Hatchlings average approximately 1 inch (2.5 cm) snout-vent length and around 2 inches (5 cm) total body length. The female remains with the young for at least a short period after they hatch. Longevity. A wild-caught adult survived in captivity an additional 2 years, 7  months, and 28 days. A few wild individuals have been reported to reach 10 years of age.

GREAT PLAINS SKINK Plestiodon obsoletus Baird and Girard 1852

Great Plains skink from Fremont County. Photo by Marlowe Wilson.

Iowa Status. Endangered; species of greatest conservation need. Historical Summary. The Great Plains skink has also been called the Sonoran skink. The first confirmed specimens in the state were in 1941 in Waubonsie State Park in Fremont County (Iowa State Natural History Collection; University of Michigan Museum of Zoology). The History of Fremont County, Iowa (Anonymous 1881a) listed the “blue-tailed lizard” along with the former scientific name of the common five-lined skink as common. However, the sightings may well have been juvenile Great Plains skinks because no confirmed common five-lined skink records exist from that portion of the state. Smith (1946) was the first to include a map showing southwest Iowa within the range of the species. Description. Great Plains skinks are light brown to light gray with a black or

dark brown fleck on each body scale; the scales on the back and sides are outlined with black, creating a striking coloration. Although not stripes, the pattern of dark spots creates a striped appearance (obsoletus is Latin meaning “decayed”

54  Great Plains Skink, Plestiodon obsoletus

Great Plains skink from Fremont County showing the diagonal rows of scales on the sides between the front and hind limbs. Photo by Marlowe Wilson.

or “degenerate” in reference to the lack of a distinct pattern on adults although they have a seemingly striped pattern). The scales are smooth and shiny, and those on the sides between the front and hind legs run diagonally upward from front to back instead of parallel to the dorsal scales. The labial scales have dark bars and the legs and tail are relatively short and stubby. Sexual dimorphism is almost lacking, although during the breeding season males have a slightly swollen head and red or orange on the head, neck, and at times the forelimbs. Hatchlings are black with bright white bars on the labial scales, bright blue tails, and red or orange spots on the head. The young change to adult coloration in around two years. Size. Among lizards with legs in Iowa, Great Plains skinks are the largest, gener-

ally ranging from 6.5 to 13.75 inches (16.5–34.9 cm) total body length. Due to the rarity of the species in the state, only one specimen is in the Drake University Research Collection, and it is missing its tail. The largest complete Iowa specimen is a female from Fremont County measured by Reeve Bailey (1943) at 8 inches (20.3  cm) total body length (tail mostly regenerated) and 4.5 inches (11.4 cm) snout-vent length. The maximum snout-vent length reported for the species is 5.6 inches (14.3 cm).

Plestiodon obsoletus, Great Plains Skink  55

Similar Species. No other Iowa lizard has diagonal rows of scales on the sides be-

tween the front and hind limbs. All the other legged lizards in Iowa have parallel rows of scales on the sides and are smaller. The northern prairie skink has thin white stripes on the sides. Distribution. Plestiodon obsoletus is found from southwest Iowa, western Missouri,

and northwest Arkansas west through southern Nebraska to eastern Colorado and most of Kansas, Oklahoma, and West Texas and south into northern Mexico. Scattered populations occur in New Mexico and central Arizona. Records exist from only 3 of Iowa’s 99 counties (Pottawattamie, Mills, and Fremont), and the Great Plains skink is Iowa’s rarest lizard. The few known populations occur in the Loess Hills bordering the Missouri River. Interestingly, the lizard has not been found on the west side of the Missouri River in Nebraska opposite the Iowa locations, although it is found in the southern two tiers of counties farther west in Nebraska. Great Plains skink distribution in Iowa. Yellow = post-1960 Green = both pre- and post-1960

Habitat. Across its broad and diverse geographic range, this skink has adapted

to a wide range of environmental conditions and is found in habitats ranging from mixed woodlands and prairies to deserts. In Iowa, most Great Plains skinks have been found in native loess prairie along Loess Hills ridgetops. Other reports include mixed oak woodland–prairie, an old cemetery, the dead branches of a fallen tree on the edge of a hilltop clearing, and both in the lowland west-facing gentle slopes of a loess bowl and on loess ridges. One of the specimens reported by Reeve Bailey was found under a board near a home on an oak-wooded loess bluff, the other at the base of a loess bluff in Waubonsie State Park. Both areas are now completely wooded and it is unlikely the lizards persist in either location. Great Plains skinks are a southwest species whose range just barely enters Iowa, and it is likely that our long cold winters are a major factor limiting their distribution here.

56  Great Plains Skink, Plestiodon obsoletus

Great Plains skink habitat in the Loess Hills of Fremont County. Note the encroaching eastern red cedar trees.

Behavior. When approached, the Great Plains skink may at first move slowly, slid-

ing its body along the ground with its head slightly raised to watch the intruder for any sign of danger, but if the sense of danger becomes too great it quickly heads for cover in a burrow or under a rock or log with rapid lateral undulations of its body, which aid its short legs in moving along. If handled, it readily bites. In describing the lizards, Smith (1946) stated, “They do not tame well and are likely to snap at almost any time. The bite is rather painful, for the small pointed mouth grabs only a small piece of skin and the jaws are extraordinarily powerful. . . . If they are forcibly removed, they attempt to twist free and cause a very painful laceration.” Similar to other skinks, when the Great Plains skink’s tail is grabbed it may break off and continue to wriggle for several minutes, distracting its predator as the lizard makes its escape. Tails regenerate over time, although the regenerated tail is shorter than the original. No detailed studies of this skink have been conducted in Iowa. Fitch (1955) and Hall (1971) studied the lizard in Kansas, and the information in this section is based on their observations except as noted. The skinks are generally active from late April to early October, although the active season may be shorter in Iowa at the far northeast extent of their range. The collection/observation dates of 8 Iowa Great Plains skinks show the species has been found from May through

Plestiodon obsoletus, Great Plains Skink  57

Number of Records

10

5

5

0

0

0

0

0

Jan

Feb

Mar

Apr

1 May

Jun

2

Jul

0

0

0

0

0

Aug

Sep

Oct

Nov

Dec

Month Collection/observation dates of 8 Great Plains skinks in Iowa.

July with the earliest record from Mills County on May 6 and the latest on July 16 in Fremont County; however, a freshly shed skin was found in Fremont County in September. This skink is fossorial, spending much of its time in burrows it excavates itself or in abandoned small mammal burrows. It is diurnal and will generally not leave its burrow until it has sufficiently warmed up, preferring a body temperature of between 79.5 and 98.2° F (26.4–36.8° C) and becoming inactive below 59° F (15° C) and above 108° F (42° C). Because the air temperature does not always reach its preferred temperature, the skink must bask or use sun-warmed rocks to raise its temperature into the preferred range. Great Plains skinks are sedentary animals, spending days or weeks in the same burrow without leaving. And when they do leave, they make only short movements, generally less than 150 feet (45.7 m). With such a small home range, any woody encroachment into the small loess prairies they use could have serious impacts. The skinks hibernate underground and must get below the frost line to survive the winter. They may be able to survive temperatures a few degrees below freezing but likely cannot survive being frozen solid. Threats. Reported natural predators of the Great Plains skink include North

American racers, bullsnakes, eastern milksnakes, prairie kingsnakes, red-tailed hawks, and eastern moles, and it is likely that raccoons, opossums, and skunks eat them as well. Predators that are able to get into the skinks’ burrows and catch them in the confined spaces or that are able to dig up the burrows may be the most effective; however, predation does not seem to be an important source of

58  Great Plains Skink, Plestiodon obsoletus

mortality in some populations (Hall 1971). It is likely that many die from freezing during hibernation if they have not gotten below the frost line, and the easy digging found in the deep loess soils of the Loess Hills may be critical for their survival this far north. Without question, the greatest threat to these skinks in Iowa is habitat loss. Over time, the native loess prairies the skinks depend on have gradually been lost, and for a species trying to survive at the edge of its range, any loss of suitable habitat may be catastrophic. Grazing, urban and suburban development, fire suppression, and invasive woody plants have all reduced the amount of suitable habitat available. The Great Plains skink is a prairie species that does best in open habitats with low vegetation. Invasive woody plants such as eastern red cedar, smooth sumac, and rough-leaf dogwood have all increased dramatically in the Loess Hills, resulting in the loss of grassland communities and reduced oak regeneration in the bur oak woodlands. As the native grasslands and open oak woodlands have declined, so too has the Great Plains skink. Pesticide use affecting the lizard’s primary foods also has to be considered a threat along with climate change. Food and Feeding. Great Plains skinks are active predators that search for prey

using both scent and vision. Much of their prey is probably found in burrows or other shelters where the lizards spend much of their time. The confined spaces of the burrows likely make it easier for these skinks to catch prey they might otherwise not be able to catch in the open. When prey is located, the skink lunges, grabbing the food in its mouth and crushing it with its powerful jaws. Primarily insectivores whose diet consists chiefly of crickets, grasshoppers, beetles, caterpillars, and spiders, as cold-blooded animals these skinks are highly efficient insect predators because they are inactive and can conserve energy when prey is not available (Hall 1971). Prey preferences change with the season, depending on what insects are available, and with age, with younger and smaller skinks eating smaller prey than older and larger individuals. Reproduction. Fitch (1955, Kansas) and Hall (1971, Kansas) provide the most

complete descriptions of P. obsoletus reproduction, and I have used them in this section except as noted. Both sexes reach sexual maturity in approximately 32 to 34 months at around 4 inches (10.2 cm) snout-vent length. Mating occurs in the spring several weeks after emergence from hibernation, likely in May or early June in Iowa. When a male finds a female, he approaches her using scent and visual cues for sex determination. If she runs, he pursues her and grasps her by the skin on the neck or shoulder. Mating begins soon after and may last several minutes. Females may not breed every year.

Plestiodon obsoletus, Great Plains Skink  59

Great Plains skinks are oviparous with females laying eggs in damp soil in a nest burrow they excavate themselves, usually beneath sunken rocks or logs. Nesting and egg laying occur in late June and early July, with females laying 7 to 21 (average 11) eggs per clutch. The single Iowa clutch report is from Reeve Bailey, who noted a Fremont County female laying 7 eggs between July 10 and 14 averaging 0.63 inch long by 0.44 inch wide (15.9 × 11.2 mm). During incubation, the female guards her clutch, turning and cleaning her eggs daily, moving them to shelter when they are exposed, actively assisting in the hatching of the young, and grooming the hatchlings. The eggs hatch sometime in late July or August after an approximately 7-week incubation period. Hatchlings range from 2.5 to 3 inches (6.4–7.6 cm) total body length. The average survival rate at hatching is almost 1.5 years, fairly high for a small vertebrate, and is the result of this lizard’s relatively large size, fossorial habits, small home range, and the female’s brooding behavior (Hall 1971). Longevity. A wild-caught adult survived in captivity an additional 6 years,

2 months, and 19 days. Wild-marked individuals have been estimated at 5 to 6 years old.

NORTHERN PRAIRIE SKINK Plestiodon septentrionalis septentrionalis Baird 1859

Northern prairie skink from Black Hawk County. Photo by Donald Becker.

Iowa Status. Protected nongame; species of greatest conservation need. Historical Summary. The northern prairie skink has also been called the black-

banded skink and northern blue-tailed skink. The first confirmed specimens in the state appear to be two individuals collected in 1884 near Des Moines in Polk County (National Museum of Natural History–Smithsonian Institution). The History of Fremont County, Iowa (Anonymous 1881a) listed the “northern skink” as common, suggesting that unlike many other species reported in this publication this species may have been seen. Nutting (1892) mentioned a specimen in the Iowa State Natural History Collection, Ruthven (1908a, 1910, 1919) reported the species in prairies in Palo Alto, Clay, and Dickinson Counties, and Somes (1911) listed northern prairie skinks as occurring in Iowa. Three subspecies of the prairie skink, Plestiodon septentrionalis, are currently recognized, only one of which, the northern prairie skink, P. s. septentrionalis, has a range that includes Iowa.

62  Northern Prairie Skink, Plestiodon s. septentrionalis

Northern prairie skink from Bremer County.

Description. Northern prairie skinks have smooth shiny scales with those on

the sides between the front and hind legs running parallel to the dorsal scales. The body is tan or light gray with 3 wide tan stripes extending down the back and onto the tail, black stripes separating the tan stripes that are similar in width to the tan stripes but fade before extending onto the head, and 2 white stripes on each side of the body. The chin is white and the belly is light tan, gray, or slightly bluish and unmarked. Juveniles are patterned like adults but with more intense colors, wider black stripes along the back, and bright blue tails that become duller with age before the blue disappears altogether. During the breeding season, the lower jaw and sides of the head of males become reddish orange. The head lacks postnasal scales. Examination of 14 specimens (7 males; 7 females) in the Drake University Research Collection found no significant difference between the sexes with regard to scale arrangement. Size. Northern prairie skinks generally range from 5.25 to 8.8 inches (13.3–22.4

cm) total body length. The largest specimen in the Drake University collection is a female from Sac County measuring 7.5 inches (19 cm) total body length and 2.8 inches (7.2 cm) snout-vent length; the largest male is also from Sac County measuring 7.4 inches (18.7 cm) total body length and 2.8 inches (7.2 cm) snoutvent length. The maximum snout-vent length reported for P. s. septentrionalis is 3.5 inches (9 cm). Similar Species. The common five-lined skink has postnasal scales, a midback stripe that extends onto the head and is always forked, and light stripes on the body that are narrower in width than the dark stripes. The Great Plains skink

Plestiodon s. septentrionalis, Northern Prairie Skink  63

lacks stripes and has diagonal rows of scales on the sides between the front and hind limbs. The prairie racerunner is striped but has small granular scales over most of the body and large rectangular scales on the belly. Distribution. The northern prairie skink’s specific and subspecific epithet septen­ trionalis is derived from the Latin septentrional meaning “northern” in reference to the northern distribution of this skink, which has a relatively small range and is limited to a patchy distribution in portions of North Dakota, South Dakota, Minnesota, Wisconsin, Iowa, Nebraska, Missouri, and Kansas. This skink is the most widespread Iowa lizard with records from 58 of Iowa’s 99 counties, primarily in the western two-thirds of the state; however, in the mid-1940s it was known from just 10 counties. Three counties (5%) have only pre-1940 records, while 47 counties (81%) have only post-1960 records. The increase in county records since 1960 is likely a reflection of more widespread survey efforts throughout the state since that time along with prairie and wetland restoration efforts that began in the 1980s and have increased habitat for this skink. Northern prairie skink distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

Habitat. Northern prairie skinks inhabit open prairies, hayfields, and other

grasslands, woodland edges, savannas, wetland fringes, and residential yards and gardens that are close to a water source and often contain rocks or other objects that provide cover. Describing the species’ habitat in Clay and Palo Alto Counties, Ruthven (1910) stated, “Its principal habitat is undoubtedly upland prairie.” Although the skinks tend to be associated with sandy or gravelly soils in the northern portion of their range, they are by no means limited to those soil types in Iowa, where they are also found in eroded glacial till in the Southern Iowa Drift Plain and deep prairie soils in the Des Moines Lobe. They are often found under objects such as rocks, logs, or other available debris; however, the presence of these objects is not a prerequisite for their existence in a particular area, as

64  Northern Prairie Skink, Plestiodon s. septentrionalis

many Iowa populations occur in areas devoid of naturally occurring surface rocks or fallen logs. In these areas, the skinks seem just as comfortable under surface leaf litter and are more likely to use habitats with a higher percentage of leaf litter cover. If artificial cover objects such as wooden boards, flat rocks, or tin are placed in areas where the skinks are found, they will serve as attractants and the skinks may be found more often around them. I regularly find northern prairie skinks under cover boards in an upland restored prairie in Bremer County where no naturally occurring cover objects are found. Areas littered with debris such as junkyards, old farmsteads, and lumberyards sometimes have high densities of this lizard. P. s. septentrionalis seems to thrive best in early successional habitats. If a grassland becomes too thick and dense or if woody vegetation invades, their numbers tend to decrease; therefore, a regular disturbance regime such as grazing, fire, or mowing is necessary for them to thrive. In Kansas, they persisted only in mowed areas after invasion of woody vegetation eliminated them from the grasslands they once inhabited (Fitch 2006). Openings in the grass canopy are probably important for thermoregulation and nesting success. Northern prairie skink density has been found to be positively correlated with field age and arthropod density, with density up to 77 percent higher in burned fields than in unburned fields (Pitt 2001). Historically, their populations may have depended on regular disturbance by grazers such as bison to maintain habitat quality, and this condition may be replaced today by moderate grazing of pastures. Burrowing mammals such as pocket gophers, ground squirrels, and badgers enhance the skinks’ habitats as well, and their nests are often found among mounds and burrows dug by mammals. Northern prairie skink population density can be high in the right habitats. Paul Frese (personal communication, 2020) recorded a maximum density of 80 per acre (198/ha) in Adair County, and in Minnesota population density ranged from 23 to 96 per acre (58–238/ha; Pitt 2001). Behavior. Northern prairie skinks are very secretive and rely on concealment

to avoid danger. They spend much of the day hidden in burrows, under rocks or other objects, or under thatch or other vegetation. If they are seen, it is usually just a quick glimpse as they scurry through the foliage before quickly ducking under leaf litter or into a burrow. Using surface leaf litter as cover provides concealment while allowing the skinks to maintain an appropriate body temperature. They are good burrowers that maintain a burrow system used for escaping predators, nesting, and hibernating. If handled, they are usually mild-tempered, although a bite is not out of the question; however, due to their small size it is merely a pinch.

Plestiodon s. septentrionalis, Northern Prairie Skink  65

Number of Records

50

45

40 22

18

20

10

10 0

31

28

30

0

1

0

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

1

0

0

Oct

Nov

Dec

Month Collection/observation dates of 156 northern prairie skinks in Iowa.

Similar to other skinks, this skink’s tail may break off when grabbed, continuing to wriggle for several minutes to distract the predator as the lizard makes its escape. Tails regenerate over time, although the regenerated tail is shorter than the original. The collection/observation dates of 156 Iowa northern prairie skinks show the species is generally active from early April to late September in the state; however, the earliest record is an adult female found under a cover board along the edge of a field in Decatur County on February 23 and the latest an individual found on October 16 in Hancock County. In Minnesota, males were found to emerge from hibernation in late April or early May, while females did not appear until later in May. Paul Frese, who has been observing northern prairie skinks in Adair County for over eighteen years, noted that spring emergence occurs after daytime temperatures have been at least 65° F (18.3° C) for several days, with newly emerged adults found to be lethargic and covered with soil within shallow depressions under rocks. Activity peaks in May and drops off through midsummer. Often the only individuals seen during the heat of the summer are second-season juveniles and females tending nests. A second peak in activity occurs in August as hatchlings begin to appear. The skinks reduce surface activity in September and enter hibernation sometime in October. Northern prairie skinks hibernate underground in burrows they dig themselves or in mammal burrows and must get below the frost line to survive the winter, moving downward in the soil profile ahead of the progression of frost. In

66  Northern Prairie Skink, Plestiodon s. septentrionalis

1937, a football-shaped mass containing 52 hibernating northern prairie skinks was found on February 15 in a Palo Alto County gravel pit beneath a shelf of yellow clay at a depth of 4.5 feet (1.4 m) (Scott and Sheldahl 1937). Most became active after warming in a laboratory, but several were dead. Threats. Known predators include plains hog-nosed snakes, northern harriers,

barred owls, American kestrels, loggerhead shrikes, thirteen-lined ground squirrels, raccoons, and even other northern prairie skinks. American crows, common grackles, North American racers, eastern hog-nosed snakes, both plains and common gartersnakes, opossums, and skunks likely eat them as well if given the opportunity. Paul Frese observed northern prairie skinks impaled on barbed wire in Adair County, victims of a loggerhead shrike, and a blue jay was photographed consuming one in Guthrie County. Domestic cats also pose a threat. A study in Canada found that 50 percent of landowners who owned cats had seen evidence of predation on northern prairie skinks (Krause Danielsen 2012). Many lizards, including these skinks, are often found infested with tiny orange mites that attach to the skin between the scales; the degree to which this parasite affects the lizards’ health is not known. As with most species in Iowa, habitat loss in the past and present poses the most serious concern, with pesticides and climate change jeopardizing the species as well. Food and Feeding. Northern prairie skinks are carnivorous, consuming a wide variety of invertebrates found primarily under rocks, fallen logs, boards, downed vegetation, or other debris. Crickets, grasshoppers, and spiders are preferred, with spiders making up almost 30 percent of the diet and crickets and grasshoppers making up another 27 percent (Breckenridge 1943). Various insects, including butterfly and moth caterpillars, make up the majority of the rest of the diet. Interestingly, these skinks do not eat ants even though they often share space under cover objects. When prey is located, the skink lunges, grabs the food in its mouth, and crushes it with its jaws before swallowing it. Reproduction. Both sexes reach sexual maturity at the beginning of their third season at snout-vent lengths greater than 2.5 inches (6.4 cm). Mating occurs in late May or early June, during which time males are in full breeding coloration and become aggressive toward other males as they search for females. Paul Frese observed Adair County males with breeding colors from May 12 through June 18. When a female is encountered, the male noses and nudges her for several minutes before finally grasping her shoulder with his jaws and curling his tail around hers until their vents meet. Mating may last several minutes.

Plestiodon s. septentrionalis, Northern Prairie Skink  67

Predation of a northern prairie skink by a blue jay in Guthrie County. Photo by John F. Atkins.

Examination of 4 Iowa adult male specimens in the Drake University Research Collection found that testes were largest in April and May and had reduced in size by mid-June; examination of 7 Iowa adult female specimens showed that ovarian follicles grow rapidly in the spring, reaching ovulatory size by late May or early June. Females leave hibernation with large stores of fat that are gone by the time eggs are laid. Northern prairie skinks are oviparous with females laying eggs during the second half of June in burrows or under cover objects in open and sunny well-drained sites. Platt (1975) reported finding their nests in burrows dug inside the soil mounds outside badger burrows in Dickinson County. Nests often consist of burrows 2 to 4 inches (5–10.2 cm) deep within shallow excavations underneath cover objects. Paul Frese found communal nests of up to 5 females under a single cover object, with each female occupying a separate burrow and tending a clutch but all located under the same cover object. Females tend to return to the same location to nest each year. Once the eggs are laid, the female actively broods them, which may reduce egg mortality. In addition, females sometimes move clutches in and out of the nest burrow, presumably to facilitate incubation

68  Northern Prairie Skink, Plestiodon s. septentrionalis

Northern prairie skink female with eggs in Adair County. Photo by Paul Frese.

by providing more favorable temperatures. Females usually stay within the nest burrow even when disturbed and may bite if provoked. Females lay a single clutch per year with generally 4 to 18 (average 11) eggs per clutch. Counts of enlarged ovarian follicles in Iowa female museum specimens resulted in an average clutch size of 9 eggs (range 7–11; n = 5). Similarly, 38 nests from Adair County observed by Paul Frese averaged 9 eggs per clutch (range = 4–15). Eggs begin hatching in July, with July 4 being the earliest recorded hatching date he observed. Hatchlings and their mother abandon the nest burrow within a few days after hatching, and females may eat eggs that have spoiled. Hatchlings average approximately 1 inch (2.5 cm) snout-vent length. Adjustments in posture by the brooding female, such as coiling around the eggs to conserve water in dry soils or having little body contact when water conservation is not a concern, regulate the amount of water exchanged between the eggs and the soil, and studies suggest that neonatal body size increases with increasing soil wetness (Somma 1989, 1990). Longevity. The reported life span of a northern prairie skink in the wild is from

2 to 5 years.

FAMILY TEIIDAE RACERUNNERS AND WHIPTAILS

T

he family Teiidae is entirely New World in distribution. Members of its 18 genera and approximately 150 species range in size from a few inches to 4 feet (1.2 m) long and weigh from a few ounces up to 10 pounds (4.5 kg). Only the genus Aspidoscelis occurs in the United States. Currently 46 species are recognized within Aspidoscelis, of which only the prairie racerunner is native to Iowa. Members of the family usually have non-bony granular scales on the back and sides and large rectangular scales on the belly that are arranged in rows. The body is long and slender with a long tail that will break off if grasped by a predator. Teiid teeth are solid at the base and attached to the jawbones by hard connective tissue, and the tongue is forked and partially retractable. Teiids are oviparous but several species are entirely female with no males in the populations. These all-female species reproduce by parthenogenesis, a form of asexual reproduction in which growth and development of embryos occur without fertilization by sperm. Prairie racerunners, however, require both males and females to reproduce.

PRAIRIE RACERUNNER Aspidoscelis sexlineata viridis (Lowe) 1996

Prairie racerunner from Louisa County. Photo by Ryan D. Rasmussen.

Iowa Status. Protected nongame; species of greatest conservation need. Historical Summary. The prairie racerunner has also been called the six-lined

lizard and six-lined racerunner. The first confirmed specimen in the state appears to be in 1900 near Bellevue in Jackson County (National Museum of Natural History–Smithsonian Institution). The History of Fremont County, Iowa (Anony­ mous 1881a) listed the “six-lined lizard” as occurring in the county, and Cope (1900) listed the National Museum of Natural History specimen as being from Jackson County. Three subspecies of the six-lined racerunner, Aspidoscelis sexlineata, are currently recognized, only one of which, the prairie racerunner, A. s. viridis, has a range that includes Iowa. Description. The prairie racerunner’s scientific name perfectly describes this

graceful slender lizard. Aspidoscelis is derived from the ancient Greek meaning “shield-leg” in reference to the large plates on the front legs; sexlineata comes from

72  Prairie Racerunner, Aspidoscelis s. viridis

the Latin meaning “six-line” in reference to the 3 lines on each side of the body; and viridis is Latin for “green” in reference to the body color. Prairie racerunners are light brown to dark brown with 6 or, more commonly, 7 yellow, white, or greenish stripes extending down the length of the body from the head to the tail—3 on each side—and they may have a vertebral stripe down the midback. During the breeding season, the head and anterior portion of the body of males become bright green and blue. The green color is often more prominent in central and western Iowa than in eastern Iowa, with males along the Mississippi River sometimes having little or no green. Females may also be greenish but the color is more subdued. Unlike other Iowa lizards, the scales on the back and sides are small and granular. The belly has 8 rows of large rectangular plate-like scales and is pale blue on males and cream or white on females. Large scales are also present on the upper surface of the forearm and on the head. The undersurfaces of the thighs have a row of about 15 femoral pores that enlarge in males. The tail is long, comprising almost 70 percent of the total body length, with rings of large scales

Ventral view of a gravid female prairie racerunner from Muscatine County showing the 8 rows of rectangular scales on the belly and a row of femoral pores on each thigh. Photo by James L. Christiansen.

Aspidoscelis s. viridis, Prairie Racerunner  73

Adult prairie racerunner from Muscatine County showing granular dorsal scales on the sides. Photo by Ryan D. Rasmussen.

around it. Males have broader heads; females are heavier-bodied. Juveniles are patterned like adults but with a pale blue tail and vivid yellow stripes. Examination of 51 specimens (17 males; 34 females) in the Drake University Research Collection found no significant difference between the sexes with regard to scale arrangement. The vertebral stripe was found to be more poorly developed on individuals from eastern Iowa than on those from central or western Iowa, while racerunners from western Iowa had fewer ventral plates. Size. Prairie racerunners generally range from 6 to 10.5 inches (15.2–26.7 cm) total

body length. The largest specimen in the Drake University collection is a male from Muscatine County measuring 9.1 inches (23.2 cm) total body length and 3 inches (7.6 cm) snout-vent length; the largest female is from Louisa County measuring 8.6 inches (21.9 cm) total body length and 3.1 inches (7.8 cm) snout-vent length. The maximum snout-vent length reported for A. sexlineata is 3.5 inches (9 cm). Similar Species. This is the only Iowa lizard with granular scales on the back and

sides and large plates on the belly. Northern prairie skinks and common five-lined skinks are striped but are covered with smooth shiny scales.

74  Prairie Racerunner, Aspidoscelis s. viridis

Distribution. The prairie racerunner is primarily found in the southern Great

Plains from southern South Dakota south to Texas and from extreme western Iowa and portions of Missouri and northwest Arkansas west to eastern Colorado and New Mexico. It also occurs along the Mississippi River from Minnesota and Wisconsin south to northeast Missouri and along the Illinois River from the Mississippi River into north-central Illinois. There is a broad zone of intergradation with the eastern six-lined racerunner (A. s. sexlineata) across extreme eastern Texas, Louisiana, southern Arkansas, and southeastern Missouri where racerunner populations have characteristics of both subspecies. In Iowa, this lizard has a disjunct distribution, with scattered populations found in the Loess Hills of western Iowa along the Missouri River as far north as Woodbury County, in eastern Iowa along the Mississippi River, in east-central Iowa, and in southeast Iowa along the Des Moines River, often where remnant sand prairies still exist. Records currently exist from 20 of Iowa’s 99 counties. In the mid-1940s, racerunners were known from just 9 counties. Prairie racerunner distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

Habitat. Prairie racerunners inhabit areas with short or sparse vegetation and

dry sandy or otherwise loose soils. Dryness is essential, and they tend to avoid areas with loamy or wet soils and dense vegetation. While conducting surveys for this species, I have found it effective to use soil survey data to first locate where the sandy soils are in an area in order to focus my search. In Iowa, the lizard is limited to sand prairies and open bluff prairies in eastern Iowa and open dry loess grasslands in western Iowa. Ideal prairie racerunner habitat is also ideal ornate box turtle, hog-nosed snake, and North American racer habitat. The toes of prairie racerunners, especially on the hind feet, are extremely long and perfectly adapted for efficient movement on fine sand.

Aspidoscelis s. viridis, Prairie Racerunner  75

Behavior. As their name implies, prairie racerunners are fast, relying on speed

to avoid danger. They are nervous wary animals with good eyesight that are always on the lookout for threats. When approached, they may first crouch close to the ground hoping to go unnoticed, but if the threat gets too close they will dart off with amazing speed—they have been recorded running 18 miles per hour (29 km/hr) (Hoyt 1941). Breckenridge (1944) concluded that should a good-sized dog run as fast, in comparison to its body length, it would have to run nearly 300 miles per hour (483 km/hr). When they do run, they may quickly take cover under a rock or fallen log or in a burrow, or they may run only a short distance to a clump of vegetation before stopping; if approached again, they will once again dart off, keeping up this behavior while staying just ahead of their would-be predator. The warmer they are, the faster they seem to run. Similar to other lizards, when their tail is grabbed it may break off but continue to wriggle for several minutes, distracting the predator long enough for the lizard to make its escape. Tails regenerate over time, although the regenerated tail is shorter. However, the loss of the tail comes at a cost. The long tail serves as a counterbalance allowing for high running speeds, and the loss of a tail can result in up to a 36 percent decrease in speed (Ballinger et al. 1979). These are diurnal lizards whose daily activity is largely determined by temperature. They are efficient thermoregulators who prefer body temperatures higher than most North American reptiles, near 104° F (40° C), and air temperatures between 66 and 102° F (19–39° C). They are good burrowers; their strong front feet construct burrows that they use as night shelters, to escape predators, or to avoid surface temperatures that are too high or too low. Although they dig well, they just as readily use small mammal burrows. Temperatures below the preferred range cause the lizards to become sluggish. One cool early June morning while trapping turtles in Lee County, I came across a prairie racerunner that was partially buried in the surface sand. Believing it was dead, I reached down and picked it up. Much to my surprise, it was not dead, just lethargic. I kept it for a short time for observation and after warming up it was running around as normal. The collection/observation dates of 172 Iowa prairie racerunners show the species is active from early May to late September in most years, although the earliest record is on April 1 in Louisa County and the latest on October 16 in Johnson County. Surface activity in Iowa is greatest in May and June (61% of records), similar to what has been reported in Kansas where feeding and reproductive activity are concentrated in the spring. During more than thirty years of field studies in Louisa County, Jim Christiansen and Neil Bernstein observed that the period of

76  Prairie Racerunner, Aspidoscelis s. viridis

57

Number of Records

60 48

50 40 30

22

20 10 0

0

0

0

Jan

Feb

Mar

20

20

3 Apr

May

Jun

Jul

Aug

Sep

2

0

0

Oct

Nov

Dec

Month Collection/observation dates of 172 prairie racerunners in Iowa.

greatest activity occurred during the last two weeks of May, with more lizards seen during those two weeks than any other two-week period. As summer progresses, surface temperatures become too hot for the lizard to forage comfortably, and it spends more time underground, restricting surface activity to morning and late afternoon. Beginning in July, surface activity starts to decline and the racerunners spend more time in their burrows. Fitch (1958) observed that they were rarely seen in September even though suitable summer weather might still be present. He went on to conjecture that during this time they probably burrow down to a depth with fairly stable temperatures, but lower than they require for full activity, and lapse into a semitorpid state before eventually entering hibernation. Hibernation sites are located in well-drained, sun-exposed sandy soils. Threats. Due to their good eyesight, wariness, and speed, these racerunners may

be elusive prey for many animals. North American racers may be one of the more common predators as they too have good eyesight, are quick, and are abundant in the Loess Hills as well as in the eastern Iowa sand prairies where the racerunners are found. Other snakes eat them, too; Jim observed a plains hog-nosed snake consuming a racerunner in Louisa County. Predation by hawks and coyotes has been reported, and skunks and raccoons are likely predators as well. Habitat loss probably poses the most serious threat. Prairie racerunners need open and sparsely vegetated habitats. If through succession sand prairies or loess grasslands become overgrown with trees or dense grass, the racerunners disap-

Aspidoscelis s. viridis, Prairie Racerunner  77

pear. A regular disturbance regime, such as grazing or fire, is necessary for them to thrive, and lack of proper management can be detrimental to the lizards and many other sand prairie plants and animals. Several small populations along the Cedar and Iowa Rivers survive only because grazing or other management keeps the vegetation short and controls woody invasion. In Kansas, prairie racerunners in heavily grazed pastures prospered; however, after grazing was eliminated, racerunner numbers dropped due to reduced suitability of the habitat as the vegetation thickened, expanded, and encroached (Fitch 1958). Food and Feeding. Prairie racerunners are active predators that rely primarily

on smell to find food. They search for prey under rocks, logs, or other debris or use their strong front legs to burrow into the soil in search of food. When prey is located, the lizard lunges, grabbing it in its mouth. Fitch (1958) considered prairie racerunners to be “dainty feeders, which spend a long time killing, and worrying their prey, and sometimes reducing it to small morsels, instead of gulping down relatively large objects.” Burt (1928) noted that the prairie racerunner does not detect undesirable food until it is taken into the mouth and that such food is quickly ejected, with the lizard wiping its lips on the ground and displaying great discomfort. Crickets, grasshoppers, spiders, caterpillars, aphids, leafhoppers, and ants are consumed. Jim has often observed prairie racerunners feeding on soft-bodied insect larvae in Louisa County. Adults eat larger prey than juveniles, consuming large jumping planthoppers and grasshoppers, while juveniles eat smaller leafhoppers and jumping spiders. Adult and juvenile prairie racerunners have separate activity seasons, with adults active from May into July and juveniles active in August and September; therefore, in addition to adults being able to handle larger prey, differences in diet between adults and juveniles may be due to different prey being available because of changes in the insect population throughout the year (Paulissen 1987). Reproduction. Examination of 29 Iowa adult female specimens in the Drake

University Research Collection found that Iowa females reach sexual maturity at around 2 inches (5 cm) snout-vent length, many in less than a year, similar to Kansas where females were mature by July of the year after hatching (Fitch 1958). Mating occurs in late May or June, during which time males display their bright coloration to attract females and become aggressive toward other males. When he encounters a female, the male rubs his vent on the ground in a figure-eight pattern before climbing onto her back, biting her neck, and rubbing her back with his femoral pores. If she is receptive, he curls his tail around hers until their vents meet. Mating may last several minutes.

78  Prairie Racerunner, Aspidoscelis s. viridis

Juvenile prairie racerunner from Louisa County. Photo by Ryan D. Rasmussen.

Enlargement of ovarian follicles is well underway by the third week of May, with ovulation in Iowa occurring in late May or early June. Prairie racerunners are oviparous with females laying eggs from mid-June to mid-July a few inches below the surface in burrows or under cover objects in open and sunny well-drained sites. They are the only Iowa female lizards that do not tend their eggs. South of Iowa, a second mating may take place in July, and females have been documented laying 2 clutches per year. A large female from Louisa County collected on June 4 contained oviductal eggs and a second set of enlarged ovarian follicles, indicating that she might have ovulated again in July, but this was unusual among Iowa female museum specimens examined, suggesting that while some females produce a second clutch in Iowa, it is likely not common this far north. Females lay 1 to 8 (average 3) eggs per clutch, with larger females laying more eggs. Counts of enlarged ovarian follicles and shelled oviductal eggs in Iowa females in the Drake University collection resulted in average clutch sizes of 3 eggs (range 2–5; n = 16) and 3.5 eggs (range 3–4; n = 2), respectively. In Kansas, small females in their first year produced clutches averaging only 2 eggs (Fitch 1958). Similarly, none of the Iowa yearling female museum specimens examined produced more than 2 eggs per clutch. Eggs hatch in August and September with

Aspidoscelis s. viridis, Prairie Racerunner  79

hatchlings averaging approximately 1.25 inches (3.2 cm) snout-vent length and 3.7 inches (9.3 cm) total body length. Size of Iowa young-of-the-year specimens in the Drake University collection ranged from 1.3 to 1.4 inches (3.3–3.5 cm; n = 6) snout-vent length. Longevity. A wild-marked individual, estimated to be 6 years old, was recaptured

in Kansas.

PART T WO

SNAKES

Cloaca

Snout-Vent Length

Tail Length Total Body Length Cloaca

Snout-Vent Length Total Body Length

Snake standard measurements.

Tail Length

A

t present, approximately 3,800 snake species are recognized worldwide, ranging in size from the Barbados threadsnake at just 4.1 inches (10.4 cm) long to the reticulated python, which regularly grows to over 20.5 feet (6.25 m) long and can weigh more than 150 pounds (68 kg). About 600 species are venomous, although only about 200 species are able to kill or significantly wound a human, and over 200 species are considered to be medically important. Iowa has 28 species. Snakes are elongated reptiles covered in overlapping scales that lack legs, movable eyelids, and external ear openings. The dry scales covering the body are generally shed in one piece as the snake grows. All snakes are strictly carnivorous and capture prey either by grabbing it and swallowing it alive; grabbing it, wrapping around it, and constricting it to kill it before swallowing it; or biting it and injecting venom into it, then releasing it and using an odor trail to find it once it is dead. Unlike lizards, the two lower jawbones of snakes are separated at the front and are connected by a flexible ligament, enabling a snake to swallow prey much larger than its head. When swallowing large prey, the snake simply “walks” its mouth around it by moving one side of its mouth forward and then the other side forward until the prey is consumed. One snake behavior known to nearly everyone is tongue flicking. The snake senses odors with its long forked tongue. By extending its tongue and moving it around, the snake picks up scent particles in the air, which are transferred to a special organ on the roof of the mouth—Jacobson’s organ—that transmits information to the brain. Snakes use scent to locate prey and to find mates during the breeding season. In addition to scent, pit vipers use heat-sensing facial pits between their eyes and nostrils to locate prey. Young snakes either hatch out of shelled eggs—oviparous species—or are born alive—ovoviviparous and viviparous species. In ovoviviparous species, the young remain in an amniotic sac in the female’s reproductive tract, where they hatch before passing out of the cloaca.

Common gartersnake from Buchanan County showing the lack of a facial pit between the nostril and the eye and the round pupil. Photo by Sarah VanDeWalle.

FAMILY COLUBRIDAE COLUBRIDS (NONVENOMOUS)

T

he family Colubridae is by far the largest and most varied of the snake families and has a nearly worldwide distribution with representatives on every continent except Antarctica. Coluber is Latin meaning “snake” or “serpent,” and much like the general meaning of the family name, the family Colubridae is a mix of species that do not fit elsewhere. They have few traits in common but do lack a pelvic girdle and functioning left lung, have smooth or keeled dorsal scales, large ventral scales, and large plate-like scales on the head. They can range from a few inches to over 11 feet (3.4 m) in length. Most have rounded snouts, but some have a modified rostral scale, such as bullsnakes and hog-nosed snakes, and all Iowa species have round pupils. Most have solid conical teeth; however, some such as prairie ring-necked snakes and eastern and plains hog-nosed snakes have grooved teeth at the rear of the upper jaw that aid in delivering into the wound a mildly toxic saliva—harmless to humans—produced by the Duvernoy’s gland. In a few species with fangs, such as the African boomslang, a bite can be dangerous and possibly fatal, although the vast majority of the members of this family are harmless to humans. The family contains at least 8 subfamilies, 248 genera, and over 1,700 species. Three subfamilies occur in Iowa: Colubrinae, which includes the genera Coluber, Lampropeltis, Opheodrys, Pantherophis, and Pituophis, all of which are oviparous; Dipsadinae, which includes the genera Carphophis, Diadophis, and Heterodon, all of which are oviparous; and Natricinae, which includes the genera Nerodia, Regina, Storeria, Thamnophis, Tropidoclonion, and Virginia, all of which are viviparous with the exception of Tropidoclonion, which is ovoviviparous.

WESTERN WORMSNAKE Carphophis vermis (Kennicott) 1859

Western wormsnake from Van Buren County. Photo by Ryan D. Rasmussen.

Iowa Status. Threatened; species of greatest conservation need. Historical Summary. The western wormsnake has also been called the ground

snake and western twig snake. The first mention in the literature in Iowa appears to be in the History of Fremont County, Iowa (Anonymous 1881a), which considered the species “rare and local,” suggesting the snake may have been seen. Somes (1911) mentioned wormsnakes as occurring in Iowa but provided no evidence for their presence. Guthrie (1926) made no reference to observations of wormsnakes but indicated that the species was likely to occur in the state. The first confirmed specimens are in 1933 from Keosauqua and 1939 from Lacey-Keosauqua State Park (Iowa State Natural History Collection), both in Van Buren County. Description. Western wormsnakes are sharply bicolored: unpatterned brown to black above often with a purplish iridescence and a belly that is salmon pink with the pink ventral coloration extending up the sides to the third lateral scale row. Viewed from above with a flashlight on a rainy night, they can look very similar

88  Western Wormsnake, Carphophis vermis

Belly of a western wormsnake from Van Buren County. Photo by Jeff LeClere.

to earthworms. The head is pointed to aid in burrowing, and the short tail ends in a blunt spinelike scale that feels quite sharp. The body scales are smooth and shiny and in 13 rows at midbody; the anal plate is divided. Males have ridges on the dorsal scales near the cloaca. There are usually 5 supralabial scales, 6 infralabial scales, a large loreal scale between the eyes and the nostrils, and paired prefrontal and internasal scales that are not fused. Hatchlings are similar in appearance to adults but are more sharply bicolored and have an orange-red to bright pink belly. Examination of sexual dimorphism in 14 Iowa adult western wormsnake museum specimens (6 males; 8 females) found the number of ventral scales (male mean 135; female mean 143), the number of subcaudal scales (male mean 34; female mean 28), and tail length as a proportion of total body length (male 16%; female 13%) differed significantly between males and females, with females having more ventral scales and males having a longer tail and more subcaudal scales than females. Size. Western wormsnakes are small snakes generally ranging from 7.5 to 13 inches (19–33 cm) total body length. The largest specimen in the Drake University Research Collection is a female from Lee County measuring 12.6 inches (32 cm) total body length; the largest male is from Decatur County measuring 12.5 inches (31.8 cm) total body length. Reeve Bailey reported the total body length of the

Carphophis vermis, Western Wormsnake  89

first Iowa specimen, a female from Van Buren County, at 13.1 inches (33.3 cm). The record total body length reported for the species is 15.4 inches (39.1 cm). Similar Species. No Iowa snake of similar size has a comparable shape or color. Red-bellied snakes have keeled scales and a red or orange-red belly with the belly coloration not extending up onto the sides. Prairie ring-necked snakes are brown above with a distinct yellow or orange ring around the neck, a bright yellow belly with black dots, and a tail that is bright red below, never pink. Western smooth earthsnakes are light tan above with a white or yellowish belly. Distribution. The western wormsnake is found from southern Iowa and very

southwest Nebraska south through Missouri, the eastern third of Kansas and Oklahoma, and the northwest half of Arkansas, with scattered populations in northeast Texas and northern Louisiana. Southern Iowa is at the northern edge of the species’ range, and the snake is found in widely scattered populations in the southern three tiers of counties. In the mid-1940s, the serpent was known from 7 counties. At present, records exist from only 13 of Iowa’s 99 counties, 4 (31%) of which have only pre-1950 records. Western wormsnake distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

Habitat. This small snake is a jewel whether you find it buried in the ground or in

moist soil under a rock, and it is the wormsnake’s preferred habitat and appearance that give rise to both its common and scientific names. Carphophis vermis describes a litter-dwelling snake the color and size of an earthworm—Carphophis is derived from the Greek words karphos meaning “straw” or “dry twigs,” in reference to the litter in which this species is often buried, and ophios meaning “snake,” and vermis is Latin for “worm.” Western wormsnakes prefer moist rocky woodlands, riparian woodlands, and woodland edges with abundant rocks and logs to provide cover. They are most often found under flat rocks or logs and sometimes even toppled gravestones, where the soil remains moist. In addition to providing cover, the flat rocks also allow for thermoregulation, with the snake using the

90  Western Wormsnake, Carphophis vermis

Western wormsnake from Van Buren County. Photo by Ryan D. Rasmussen.

warmth of the rock instead of basking in the sun on the surface. Adequate soil moisture appears to be a requirement for this species to compensate for evaporative water loss. Kansas western wormsnakes were most often associated with soil moisture levels of 21 to 30 percent (Clark 1967, 1970). These are certainly the most fossorial snakes in Iowa; they are rarely found on the surface. Their narrow heads with tiny eyes, countersunk jaws, smooth scales, and short strong muscular tails to aid in burrowing all reflect adaptations to an underground existence. Klimstra (1950) reported they were found in a freshly plowed field in Davis County, possibly brought to the surface by the soil disturbance. Once, while conducting a drift fence study in Appanoose County, Jim Christiansen removed a buried five-gallon pitfall trap and saw a quick flash of pink. Frantic but careful digging uncovered a western wormsnake in a burrow complex almost 12 inches (30.5 cm) deeper than where he first observed it. This further supports the conclusion that wormsnakes rarely move on the surface, as the pitfall traps and an associated drift fence had been actively catching other snakes for over a month, but no wormsnakes were ever caught. Behavior. These docile snakes never attempt to bite. When frightened, they usually thrash around like an earthworm, and their primary means of defense is to

Carphophis vermis, Western Wormsnake  91

Number of Records

40

34

30 20

0

8

7

10 0

0

0

Jan

Feb

Mar

Apr

May

Jun

3

4

3

2

Jul

Aug

Sep

Oct

0

1

Nov

Dec

Month Collection/observation dates of 62 western wormsnakes in Iowa.

attempt to escape by crawling under the nearest log or rock or burrowing in loose soil. When picked up, the serpent often produces a strong-smelling musk, and it may push its sharply pointed tail into your hand. Although the tail is not sharp enough to penetrate the skin, the sensation can be surprising enough to make you drop the snake. Carphophis vermis is probably largely nocturnal, but some daytime activity likely occurs under leaf litter, fallen logs, or other debris. Its nocturnal and fossorial habits make it difficult to find; nevertheless, the collection/observation dates of 62 Iowa western wormsnakes show the species is active from April through October. The earliest records are from Madison County on April 13. Over 50 percent of the records are from May, often with multiple individuals found on the same day. The snakes become harder to find after May as they move farther underground or remain buried deeper under logs or rocks to avoid the heat during the hottest part of the summer. This activity pattern is consistent with the observations of Clark (1970) in Kansas, who found an activity period of April 1 through October 20 and suggested a relationship between western wormsnake activity and the overturn of soil temperature—that is, the transition from surface soil warmer than subsoil in summer to the reverse in winter and vice versa—and the subsequent upward and downward movement of wormsnake food sources, and Johnson (2000), who reported the snake to be active in Missouri from March through October. The latest Iowa record is the first confirmed western wormsnake in the state, found in Van Buren County on December 16.

92  Western Wormsnake, Carphophis vermis

Western wormsnakes likely hibernate belowground in rodent burrows and rock crevices but may also use rotting stumps and logs. A single individual was reported hibernating in a Missouri cave, but no details were provided about where in the cave it spent the winter. Reeve Bailey found several snakes in April under stones all within 25 feet (7.6 m) of each other along wooded hillsides of the Middle River in Madison County, and another April individual was found in a sawdust pile in Page County, presumably where it spent the winter. Threats. Other snakes, such as eastern milksnakes, eastern copperheads, blue

racers, and speckled kingsnakes, may be the primary natural predators. Small mammals, such as eastern moles and masked shrews, may also eat them. Avian and larger mammalian predators are probably not significant due to the snake’s small size and limited aboveground activity. A coccidian parasite was found in 20 percent of the Iowa western wormsnakes examined (Wacha and Christiansen 1974). Human activities, such as pesticide use and those resulting in habitat loss, also take a toll. Application of chlordane dust to the soil to control insects has been reported to kill wormsnakes and other small snakes (Ernst 1962, 1963). In the 1980s and 1990s, Jim concluded that the species was declining in Iowa and was especially sensitive to the loss of prairie-woodland edges. As with many species, climate change is an emerging threat. Food and Feeding. The small mouth and head of this snake limit the size of the prey it can ingest. Its diet consists almost entirely of earthworms, which are most often eaten headfirst. Soft-bodied insects such as beetle grubs and small salamanders may occasionally be eaten, and a small prairie ring-necked snake was reported to have been eaten when housed with a western wormsnake. Prey is likely consumed underground or under cover of a log or rock. When wormsnakes come into contact with a worm on the surface, they almost seem confused about how to attack it; one individual was observed grabbing a worm on the surface but released it and fled when the worm struggled (Rossi and Rossi 2003). Examination of the stomach contents of specimens in the Drake University Research Collection found only soft material consistent with mostly digested earthworms. Reproduction. Clark (1970, Kansas) and Aldridge and Metter (1973, Missouri)

provide the most complete descriptions of western wormsnake reproduction. Most males reach sexual maturity at 8.5 inches (21.6 cm) snout-vent length, and females mature during their third year at around 9.4 inches (24 cm) snout-vent length. In males, spermatogenesis is initiated in the spring with sperm stored in the vas deferens allowing males to mate throughout the year. In females, en-

Carphophis vermis, Western Wormsnake  93

largement of ovarian follicles begins in late June and continues into October. No growth occurs over the winter, but in April follicles begin enlarging again and reach ovulatory size by May. Courtship and mating occur in both spring (April and May) and fall (September and October), and females are able to store sperm over the winter, allowing it to be available to fertilize the eggs when they are ovulated in the spring. The western wormsnake is oviparous with females using the undersides of rocks, rotting stumps or logs, sawdust piles, and small mammal burrows as nest sites. Nesting and egg laying occur in late June and early July. The eggs hatch from mid-August to early September after a 40- to 50-day incubation period. Hatchlings range from 3 to 4.9 inches (7.6–12.4 cm) total body length. Wright and Wright (1957) cite what is apparently a personal communication with Guthrie, who stated, “It lays a few elongate soft-shelled eggs, from which young 3 ½ inches are hatched.” Iowa records are limited to two reproductive females found by Jeff Parmelee (personal communication, 2011): an 11.2-inch (28.5-cm) snoutvent length female from Madison County that laid 4 eggs on June 16 with the eggs averaging 0.98 inch long by 0.31 inch wide (25 × 8 mm) and an 11-inch (27.8-cm) snout-vent length female from Lee County found on June 6 that contained 5 eggs, the largest of which was 0.79 inch long by 0.28 inch wide (20 × 7 mm). Longevity. Wild females have been reported surviving 10 years and a juvenile

survived in captivity for 3 years and 2 months.

NORTH AMERICAN RACER Coluber constrictor Linnaeus 1758 BLUE RACER, Coluber constrictor foxii (Baird and Girard) 1853 EASTERN YELLOW-BELLIED RACER, Coluber constrictor flaviventris Say 1823

Adult blue racer from Muscatine County. Photo by Ryan D. Rasmussen.

Iowa Status. Protected nongame. Historical Summary. Racers have also been called the blue chaser, yellow-

bellied adder, Fox’s blue racer, olive racer, and green racer. Yarrow (1882) recorded the first confirmed specimen from the state, an eastern yellow-bellied racer from near Quasqueton in Buchanan County (National Museum of Natural History– Smithsonian Institution). Osborn (1892) reported the eastern yellow-bellied racer was common in the vicinity of Ames in Story County and Cope (1900) mentioned specimens from Buchanan and Polk Counties. Wright and Wright (1952) recognized the eastern yellow-bellied racer in Iowa but considered the blue racer problematic, that is, hypothetical, accidental, introduced, puzzling, questionable, unverified, or extinct. Eleven subspecies of the North American racer, Coluber constrictor, are currently recognized, two of which, the blue racer, C. c. foxii, and the eastern yellow-bellied racer, C. c. flaviventris, have ranges that include Iowa.

96  North American Racer, Coluber constrictor

Description. North American racers are elegant slender snakes. Adult blue racers

are unpatterned pale blue to slate gray above; adult eastern yellow-bellied racers are unpatterned bluish gray to olive green above. Blue racers in far southeast Iowa may sometimes be satiny black. The belly of blue racers is bluish white to cream and the throat and chin are white, while the belly of eastern yellow-bellied racers is cream to intensely yellow with the yellow extending onto the throat and chin. The tail is long, the eyes are large, and the heads of adults may be darker than the rest of the body in both subspecies. The body scales are smooth and shiny and in 17 rows at midbody; the anal plate is divided. There are usually 7 to 8 supralabial scales and 8 to 9 infralabial scales.

Right: Adult eastern yellow-bellied racer from Linn County. Below: Adult blue racer from Louisa County showing satiny black coloration.

Coluber constrictor, North American Racer  97

Juvenile eastern yellowbellied racer from Linn County.

Juveniles are strikingly different from adults, with 40 to 50 closely spaced gray or brown dorsal blotches that disappear before they reach the tail, small spots on the sides, and a gray or tan background color. The belly is bluish white in juvenile blue racers and distinctly yellowish in juvenile eastern yellow-bellied racers. Juveniles of both subspecies have small spots, often outlined in red, on the belly that become fewer and confined to the lateral edges of the ventral scales as they near the tail. The tail is brown and unmarked both dorsally and ventrally. The juvenile pattern disappears as the snake ages, with the pattern all or mostly gone by the third year. The solid mature coloration develops from posterior to anterior, with the ventral spotting being the last juvenile pattern to disappear, typically near the end of the snake’s second year. However, third- and even fourth-year snakes may have a few gray spots near the lateral edges of the anterior ventral scales. Reeve Bailey collected a 20.7-inch (52.5-cm) eastern yellow-bellied racer that was uniformly blue-green on the posterior third of the body and tail and still spotted on the anterior two-thirds. Examination of sexual dimorphism without regard to subspecies in 53 Iowa adult racer museum specimens (28 males; 25 females) found that the number of ventral scales (male mean 175; female mean 179), the number of subcaudal scales (male mean 86; female mean 76), and tail length as a proportion of total body

98  North American Racer, Coluber constrictor

length (male 25%; female 22%) differed significantly between males and females, with females having more ventral scales and males having a longer tail and more subcaudal scales than females. Size. North American racers generally range from 23 to 50 inches (58–127 cm) total body length. The largest complete specimen in the Drake University Research Collection is a female blue racer from Louisa County measuring 59 inches (149.9 cm) total body length; the largest complete male is an eastern yellowbellied racer from Davis County measuring 44.9 inches (114.1 cm) total body length. However, several specimens of both subspecies in the collection are missing tails and likely would be the largest if the tail were present—for example, a 42.4-inch (107.7-cm) snout-vent length male from Louisa County. Tail loss in this species appears to be quite common and is correlated with age, with a larger percentage of older snakes missing tails than younger snakes. The record total body length reported for C. constrictor is 75 inches (190.5 cm). Similar Species. Plain-bellied watersnakes have keeled scales and an orange or red belly. Western ratsnakes have weakly keeled scales and a hint of a pattern. The only Iowa smooth-scaled snake with which racers may be confused is the smooth greensnake, which is smaller and has 15 middorsal scale rows; racers of similar size still retain some of their juvenile pattern. Juvenile racers can be distinguished from other small spotted snakes by their smooth scales, divided anal plate, and unmarked tail. Distribution. Blue racers are found from southeast Minnesota, southwest Wis-

consin, and far eastern Iowa south and east through Illinois, Michigan, Indiana, and Ohio. Eastern yellow-bellied racers are found from Montana, the western Dakotas, and much of Iowa south through Nebraska, Kansas, Oklahoma, and eastern Texas. With the exception of northeast Iowa, racers are found primarily south of the U.S. Highway 20 corridor and are most abundant in the southern half of the state, with records from 66 of Iowa’s 99 counties. Even in the 1940s when Reeve Bailey and others were conducting surveys in the state, racers were rare in the northern third of Iowa. Twenty-two counties (33%) have only pre-1950 records, suggesting both subspecies may have declined in the state. Many of these counties include areas where Reeve Bailey found racers in the early 1940s, and the change in distribution may reflect an increase in intensity of agriculture since then. Blue racers are found primarily in eastern and southeast Iowa and are concentrated in counties bordering the Mississippi River. In southern Iowa, they extend westward as far as Lucas County, where they intergrade with the east-

Coluber constrictor, North American Racer  99 North American racer distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

ern yellow-bellied racer. By central Iowa, most individuals are distinctly eastern yellow-bellied racers. Habitat. Racers may be one of the snakes most adapted to prairies in Iowa; they

are found in a variety of grassland habitats, including open prairies, sand prairies, bluff prairies, savannas, old fields, pastures, and road ditches. They also commonly use wetlands and woodland edges. Of 62 racer records where Reeve Bailey took habitat notes, 44 (71%) mentioned pastures, prairies, the Loess Hills, low meadows or marshes, open grassy areas, or stone quarries. The remaining 18 (29%) mentioned wooded areas (but not clearings), cultivated fields, or partially wooded areas. Like most snakes, racers need to be able to retreat to places where they can escape heat or cold and evade predators, such as mammal burrows, rotting stumps or logs, undersides of rocks, and debris piles. When not out hunting or basking, racers are often found under flat rocks or other cover. Behavior. The racer’s first response when approached is to flee or escape down a burrow or under some form of cover. Once while putting in drift fences in Louisa County, I came across a large blue racer that immediately turned and fled. I began the chase but soon realized that I was losing ground; in a last-ditch attempt to catch the snake, I tossed the shovel I was carrying out ahead of it, startling it and causing it to stop and give me time to catch up. When escape is not an option, a racer will often coil, strike vigorously, and spray a foul-smelling musk while thrashing to smear it everywhere. Some individuals will not flee or put up a fight but instead choose to remain in place and coil up with their heads hidden beneath the coils. Like many colubrids, racers vibrate their tails when excited, although the vibration is less vigorous than that of a foxsnake or a bullsnake and therefore sounds less like a rattlesnake. Males may be aggressive toward intruding males during the mating season.

100  North American Racer, Coluber constrictor

As their common name implies, racers are fast snakes, with a reported top speed of up to 3.5 miles per hour (5.6 km/hr); they can often be seen swiftly crawling through the grass with their heads raised searching for prey. They are diurnal predators; their large eyes are well suited to spotting prey or predators during the daytime, and they use vision more than smell to locate prey. While conducting surveys in areas containing racers, I have often seen them looking back at me as they dart away or looking sideways to keep an eye on me as they parallel my movements. Racers are good climbers and may climb low shrubs and trees in search of prey, with males more likely to climb than females. Jim Christiansen observed both subspecies in low trees or shrubs on several occasions over the years, and Neil Bernstein (personal communication, 2020) once observed over a dozen basking on the dead limbs of a fallen eastern red cedar tree in early April. The collection/observation dates of 459 Iowa racers show the snake’s primary activity period is from April through October, with a few stragglers active into November in some years. The earliest record is from Linn County on April 1. In Iowa, racers emerge from hibernation in early April, with a few snakes seen on the surface on warm sunny days. As April progresses, the snakes gradually emerge, and by early May they begin moving to their summer foraging areas, with peak activity occurring in May and lasting into the first two weeks of June (30% of records). This pattern is consistent with Palmer and Braswell (1995, in Ernst and Ernst 2003), who found that most annual activity is in the spring, partly due to males searching for females. The snakes are less commonly seen in July and August in the hottest part of the summer, when they likely spend more time underground in mammal burrows such as those of eastern moles. Activity picks up again from mid-September through mid-October as the snakes move back to hibernacula and young-of-the-year snakes are active. The latest record is from Muscatine County on November 20. Racers hibernate below the frost line in mammal burrows, rock outcrops or crevices, building foundations, or wells, often in communal hibernacula with other snake species such as gartersnakes, foxsnakes, and timber rattlesnakes. Hibernacula are located either within or close to the snakes’ summer activity area, and racers make seasonal movements to and from them in fall and spring. Kansas racers show fidelity for hibernacula, using the same location in successive years (Fitch 1999). In February 1990, Jim received a call from a property owner in Jasper County whose water well was contaminated with bacteria, but the well service contractor would not work on it because it was full of snakes. Jim removed 47 eastern yellow-bellied racers and 34 western foxsnakes from below the waterline of the 4-inch (10.2-cm) diameter well casing. The snakes were all hibernating

Coluber constrictor, North American Racer  101

153

Number of Records

150 100 50 0

66

49

58 30

0

0

0

Jan

Feb

Mar

Apr

May

Jun

Jul

63

36

Aug

Sep

Oct

4

0

Nov

Dec

Month Collection/observation dates of 459 North American racers in Iowa.

underwater in the cold well; although sluggish, all were in good health. With the owner’s permission, Jim and colleagues constructed an artificial hibernaculum nearby and relocated the snakes. Hibernating in wells may be fairly common as illustrated by an Iowa record from Muscatine County, which indicates that a racer, along with a western foxsnake, was removed from a well in November. Threats. Racers have numerous natural predators, including small mammals such

as mice and shrews; larger mammals such as skunks, foxes, and domestic cats; raptors such as red-tailed hawks and great horned owls; other snakes such as prairie kingsnakes and other racers; and even lizards such as the slender glass lizard. Their eggs are consumed by skunks and likely also by coyotes, foxes, and raccoons. Diseases and parasites may also affect the health of racers. A coccidian parasite was found in 17 percent of Iowa eastern yellow-bellied racers examined (Wacha and Christiansen 1974). Examination of the stomach contents of 77 Iowa museum specimens in the Drake University Research Collection found parasitic worms in 12 (15.6%) of the stomachs, 2 of which were distended due to the large number of worms. Racers seem susceptible to an infection that develops in response to excessive wetness and cold, especially immediately after hibernation. During the Iowa floods of 1993, Jim observed two blue racers with pustules on their bodies that were exhibiting lethargic behavior. Similarly, the most common type of affliction Fitch (1963a) observed was an infection of the skin causing cankerlike sores on the ventral scales, head, or tail; these were most often seen in snakes that had recently emerged from hibernation but persisted during exceptionally wet years.

102  North American Racer, Coluber constrictor

Human activities such as pesticide use and those causing habitat loss can also result in mortality or reduced populations. Kansas racer numbers decreased as diverse native prairies were replaced by pastures dominated by a few nonnative grasses, resulting in fewer small mammals and a subsequent decline in racers (Fitch 1999). In addition, in areas where woody vegetation replaced grassland communities, racers almost disappeared. Jim, in the 1980s and 1990s, concluded that both subspecies of racer were declining in Iowa due to the loss of prairie habitat and its replacement with permanent pasture. As with all snakes, cars pose a threat, especially in areas where the remaining suitable habitat is restricted to road ditches; however, because of their good eyesight and speed, racers may see cars coming at a greater distance, allowing them to get off the road before being hit. Food and Feeding. Although the racer’s specific name constrictor is derived from Latin meaning to “compress” or “constrict,” racers do not constrict their prey, although at times they may push it against a solid object to hold it in place while they consume it. Small prey is eaten alive, and large prey is held down and chewed until dead before it is swallowed. Racers are generalists, eating a wide variety of prey, including small mammals, frogs, other snakes, lizards, birds, and insects. At least 29 different invertebrates and 28 vertebrates are eaten by racers, with insects making up much of the diet of young racers and vertebrates becoming increasingly important as they grow. Klimstra (1959a) reported the diet of racers consisted of 39 percent insects, 32 percent small mammals, 11 percent amphibians, 8 percent reptiles, 6 percent birds, and 4 percent miscellaneous material. Guthrie (1926) regarded the racer to be one of the best snakes to encourage on golf courses that are infested with moles, as it enters a burrow and follows the mole until it finds it. Best (1974) reported two instances of blue racer nest predation involving field sparrow nestlings and one involving a field sparrow egg. The nestlings were easily consumed without disturbing the nest, while the snake had more difficulty with the egg. The snake repeatedly returned to the nests after being driven away and continued to return after the nests were empty. Examination of the stomach contents of 77 racer specimens in the Drake University collection found grasshoppers or crickets in 6 specimens, and 2 had unidentified insect parts. Four specimens contained vertebrates: a prairie racerunner, a plains gartersnake, an unidentified bird, and an unidentified reptile vertebra. Other Iowa observations include Guthrie (1926), who reported that both the young and adults feed well on black crickets and adults eat grasshoppers; he found two gartersnakes, each about half the length of the racer, in the gut of a specimen. Klimstra (1950) reported a juvenile cottontail rabbit in the stomach of

Coluber constrictor, North American Racer  103

Adult blue racer from Louisa County eating a bullfrog. Photo by Ryan D. Rasmussen.

a Davis County specimen along with fly larvae, suggesting that it had been eaten as carrion. Reproduction. Courtship and mating of yellow-bellied racers in Kansas have

been described by Fitch (1963a, 1999) and Lillywhite (1985), and I have used them in this section except as noted. Males use scent to locate and trail females. Once he finds a female, the male follows her and courts her by lying alongside her body and writhing; she then raises her tail to signal acceptance. During mating, the female drags the passive male, and when mating is complete the pair separates. A female may be courted by several males at the same time, with mating occurring in May and June. Racers are oviparous with females using mammal burrows, sandy soil, rotting stumps or vegetation, and the underside of logs or other debris as nest sites. Jim once received a photograph of a female racer in Madison County coiled among its 16 eggs under a flat stone. It is unknown how long females remain with the eggs after they are laid, but this observation suggests that some females remain with them at least a short time. Communal nesting is known, and sites may be shared with other snake species.

104  North American Racer, Coluber constrictor

Males mature at an age of 19 months at about 19.7 inches (50 cm) snout-vent length and females in 2 to 3 years at about 23.6 inches (60 cm) snout-vent length. The smallest female in the Drake University collection with distinctly yolking ovarian follicles measured 23.4 inches (59.5 cm) snout-vent length. Examination of 25 Iowa adult female specimens in the Drake University collection found vitellogenesis begins in April and May, with follicles enlarging quickly, and ovulation likely occurs in late May, which is supported by Guthrie’s (1926) May 21 observation of a racer from Story County that contained 15 enlarged ovarian follicles. Eggs were observed in museum specimens found on May 19 (Appanoose County), May 20 (Louisa County), May 28 (Louisa County), and May 31 (Clinton County), and Klimstra (1950) reported a female racer from Davis County that contained 19 eggs on June 3. Egg laying occurs in June and July, with eggs hatching in August and September after an incubation period of 38 to 46 days, as illustrated by an account in Reeve Bailey’s field notes of a female from Story County that laid 20 eggs in his laboratory on June 30, 2 of which hatched on August 9. The eggs of racers differ from those of many other snakes in that they have calcareous concretions scattered over the surface, giving them a rough appearance, and the eggs do not adhere to each other. Females may lay 5 to 25 eggs. Counts of enlarged ovarian follicles and shelled oviductal eggs in Iowa females in the Drake University collection or reported in the literature resulted in average clutch sizes of 13 eggs (range 5–21; n = 9) and 20 eggs (range 17–22; n = 4), respectively. Female size influences egg production, with larger females producing more eggs. Fitch (1999) reported that females completing their third growing season averaged about 8 eggs per clutch, while those that had lived 8 years produced about 14 eggs per clutch. Although the sample size is small, a similar pattern is seen in Iowa racers. When females less than 27.6 inches (70 cm) snout-vent length are separated from those greater than this length, an average clutch size of 7.2 eggs is seen for the smaller snakes compared to an average of 19 eggs for the larger ones, illustrating the danger of eliminating large older females from a population. The removal of these super breeders lowers the overall reproductive potential of the population, lessening its ability to rebound from natural or human-induced disturbances. Hatchlings range from 7 to 9.8 inches (17.8–25 cm) snout-vent length. Longevity. Wild eastern yellow-bellied racers have been reported surviving up

to 11 years, while those in captivity may survive 10 to 20 years.

PRAIRIE RING-NECKED SNAKE Diadophis punctatus arnyi Kennicott 1859

Prairie ring-necked snake from Appanoose County.

Iowa Status. Protected nongame; species of greatest conservation need. Historical Summary. The prairie ring-necked snake has also been called Arny’s

ring neck snake and western ring-necked snake. The first confirmed specimens in the state appear to be in 1878 from Webster City in Hamilton County and in 1884 from Des Moines in Polk County (National Museum of Natural History– Smithsonian Institution). Nutting (1892) reported the species in Greene County, and Osborn (1892) reported its possible presence in Story County and referenced an Iowa State Natural History Collection specimen. Twelve subspecies of the ring-necked snake, Diadophis punctatus, are currently recognized, only one of which, the prairie ring-necked snake, D. p. arnyi, has a range that includes Iowa. Description. The prairie ring-necked snake’s scientific name impeccably describes

this pretty little snake: Diadophis from the Greek diadem meaning “headband” in reference to the bright neck ring and ophis meaning “snake” and punctatus from

106  Prairie Ring-Necked Snake, Diadophis p. arnyi

Belly of a prairie ring-necked snake from Plymouth County. Photo by Ryan D. Rasmussen.

the Latin punct meaning “puncture” or “puncture-like” markings in reference to the rounded spots on the belly; arnyi honors Samuel Arny, who collected the type specimen. Adults are unpatterned reddish brown, brown, dark gray, or black above with a distinct yellow or orange ring behind the head. The neck ring is complete in the majority of Iowa snakes but may occasionally be broken at the midline of the back, and the head is darker than the rest of the body. The belly is bright yellow or orange with a scattering of small black dots extending onto the tail. The underside of the tail is bright red. The ventral spots are sometimes concentrated in an irregular line along the center of the ventral scales, often with 2 side-by-side spots forming a bar. Somewhat more common is an irregular pattern of paired spots, and more often still the pattern alternates among paired spots, bars, and triplicate spots. The body scales are smooth and in 17 rows at midbody; the anal plate is divided. There are usually 7 to 8 supra- and infralabial scales. Some adult males have ridges on the dorsal scales near the cloaca. Hatchlings are similar in appearance to adults. Examination of sexual dimorphism in 68 Iowa adult prairie ring-necked snake museum specimens (35 males; 33 females) found the number of ventral scales

Diadophis p. arnyi, Prairie Ring-Necked Snake  107

Prairie ring-necked snake from Madison County. Photo by Ryan D. Rasmussen.

(male mean 158; female mean 172), the number of subcaudals (male mean 49; female mean 43), and tail length as a proportion of total body length (male 20%; female 16%) differed significantly, with females having more ventral scales and males having a longer tail and more subcaudal scales. Blanchard (1942) suggested that male prairie ring-necked snakes could be distinguished from females by subtracting the number of subcaudal scales from the number of ventral scales. If the difference between the number of ventrals and the number of subcaudals is 119 or less, the snake is a male; if the difference is 120 or more, it is a female. Applied to the 68 Iowa museum specimens, this rule of thumb works for all but a single female. Size. These snakes generally range from 10 to 15 inches (25.4–38 cm) total body

length. Females are generally larger than males. The largest specimen in the Drake University Research Collection is a female from Madison County measuring 15.4 inches (39.1 cm) total body length; the largest male is from Appanoose County measuring 13.5 inches (34.4 cm) total body length. A University of Michigan Museum of Zoology specimen from Warren County examined by Reeve Bailey is a female measured at 16.9 inches (42.8 cm) total body length. The record total body length reported for D. punctatus in the eastern United States (five subspecies) is 27.8 inches (70.6 cm).

108  Prairie Ring-Necked Snake, Diadophis p. arnyi

Similar Species. Prairie ring-necked snakes are the only Iowa snake with an

unpatterned back and a yellow or orange neck ring. Dekay’s brownsnakes and red-bellied snakes often have dorsal spots, lack a yellow or orange neck ring, and have keeled scales. Western smooth earthsnakes and western wormsnakes have an unmarked belly and lack a neck ring. Distribution. Prairie ring-necked snakes are found from southeast South Dakota, eastern Nebraska, and Iowa south through Missouri, Kansas, Oklahoma, Arkansas, and northern Texas. Scattered populations are found in Illinois, Colorado, and New Mexico. With the exception of northeast Iowa, the snakes are found primarily south of the U.S. Highway 18 corridor. In the mid-1940s, they were known from 24 counties. At present, records exist from 54 of Iowa’s 99 counties; 8 (15%) have only pre-1950 records, and 1 (2%) (Hamilton County) has only a pre-1900 record. Prairie ring-necked snakes are abundant in the wooded areas of southern Iowa and occur along the length of the Mississippi River and along the Missouri River with the exception of far northwest Iowa. The snakes are generally absent from or rare in the northern two tiers of counties with the exception of and the wooded unglaciated areas of Allamakee and Clayton Counties. The serpent is rare to absent in much of the Des Moines Lobe in north-central Iowa as is the woodland habitat it requires. Three of the 8 counties that have only pre1950 records are located in the Des Moines Lobe, likely reflecting more intensive agriculture in these counties since the 1950s. Prairie ring-necked snake distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

Habitat. One of the earliest accounts of prairie ring-necked snake habitat is from

Taylor (1892), who reported that in southeast Nebraska they were “rather common and usually found under rocks and in and around old logs and stumps.” This description perfectly depicts this snake’s habitat in Iowa, where most are found in rocky woodland clearings or along woodland edges, most often under loose flat stones or in and under rotting logs, metal, boards, or other debris. These snakes are edge species but may also be commonly found in moist prairies or pastures

Diadophis p. arnyi, Prairie Ring-Necked Snake  109

near woodland edges, and while they are often found near streams or ponds, they are not specifically streamside dwellers. They spend much of their time underground or under leaf litter or rocks and need places to retreat to in order to escape heat or cold and evade predators, such as rotting stumps or logs, undersides of rocks, and debris piles. In good habitat, prairie ring-necked snakes may be found in high densities, including more than a thousand per 2.5 acres (1 ha) (Fitch 1999). Behavior. These docile snakes rarely attempt to bite and do not take the typical

defense posture used by larger snakes. Instead, a snake will often hide its head under a coil and raise its tail in a tightly coiled spiral, exposing its bright red underside. It is unclear whether the purpose of this flash display is to frighten a predator or to direct the attack away from the head and toward the tail. McCallum et al. (2006) concluded tail coiling is a decoy mechanism based on a higher frequency of tail damage in ring-necked snakes compared to species not known to perform this. The tail coiling is often accompanied by the discharge of a foul-smelling secretion from the musk glands that is smeared all over the body, making the snake even less enticing. Death feigning has also been reported in some populations. Prairie ring-necked snakes are secretive and spend much of their time beneath leaf litter, rocks, fallen logs, or other debris. They can be quite social—often several individuals can be found under the same rock. The serpents are most active from 77 to 85° F (25–29.5° C), and they may have some climbing ability. The collection/observation dates of 349 Iowa prairie ring-necked snakes show they Prairie ring-necked snake from Appanoose County displaying tail coiling.

110  Prairie Ring-Necked Snake, Diadophis p. arnyi

97

Number of Records

100

63

54

46

43

50

16 0

0

0

1

Jan

Feb

Mar

Apr

May

Jun

Jul

27

Aug

Sep

Oct

2

0

Nov

Dec

Month Collection/observation dates of 349 prairie ring-necked snakes in Iowa.

have been found from March through November, with the earliest individual found on March 31 in Fremont County. Nevertheless, the primary activity period is from April through October, with peaks in activity in the spring and fall as the snakes make seasonal movements from and to hibernacula. In the spring, they are often found lying in moist soil under rocks, using heat from the rocks to warm themselves instead of basking out in the open. They move farther underground from late June through August during the hottest part of the summer and as the soil dries out. At this time, they enter deep animal burrows where moisture conditions are more favorable. After a second peak of activity in September and early October, the snakes become increasingly less active during the latter part of October, by which time they have presumably reached their hibernacula. The latest records are two individuals found in Polk County on November 21. The snakes hibernate below the frost line in mammal burrows, rock outcrops or crevices, cisterns and wells, stone walls, gravel banks, and buildings. They will use active ant nests, with the ants attacking the snakes only when they are producing eggs or pupae. Sometimes large congregations of ring-necked snakes may use the same hibernaculum. Reeve Bailey noted a group of about fifty uncovered on December 15 in Greene County in a cavity in sandy soil approximately 4 feet (1.2 m) below the surface. Another group of about twenty was uncovered in January in Polk County by construction workers in a wooded area not far from the Des Moines River on the northern edge of Des Moines. In both instances, no other species were observed.

Diadophis p. arnyi, Prairie Ring-Necked Snake  111

Threats. Prairie ring-necked snakes have numerous natural predators, including

small mammals such as mice and shrews, larger mammals such as skunks, foxes, and domestic cats, raptors such as red-tailed hawks and great horned owls, and other snakes such as prairie kingsnakes, eastern milksnakes, and racers. Parasites and diseases may also affect their health. A coccidian parasite was found in 7 percent of Iowa prairie ring-necked snakes examined (Wacha and Christiansen 1974), and Stephenson et al. (2020) found Iowa prairie ring-necked snakes infected with snake fungal disease. Loss of open woodland and woodland edge communities may be the biggest threat. This often occurs directly through the clearing of woodlands for agriculture and urban and rural development or more slowly through succession as the understory of open woodlands fills in with often nonnative shrubs. Fitch (1999) observed that as the woodlands at his study sites became more heavily shaded, he rarely saw prairie ring-necked snakes. Climate change may also affect the suitability of the habitats ring-necked snakes need in order to survive. In areas where rainfall decreases, the soil may become too dry for this snake, which prefers moist soil conditions, whereas an increase in rainfall may lead to an increase in the understory that renders habitats unsuitable. Although prairie ring-necked snakes are not as commonly seen crossing roads as are other snake species, road mortality does occur where roads pass through or adjacent to suitable habitats. Pesticide use may also affect this partially insectivorous snake. Food and Feeding. Prairie ring-necked snakes eat insects, grubs, sow bugs, spiders, salamanders, and other small snakes, though earthworms likely form the bulk of their diet, almost to the exclusion of other prey. These snakes are mildly venomous, using grooved teeth at the rear of their upper jaw to deliver toxic saliva into prey, paralyzing larger prey such as snakes so they can more easily consume them. Fitch (1975) believed the average individual feeds once every eight days. Examination of the stomach contents of more than 70 prairie ring-necked snake specimens in the Drake University Research Collection found earthworms in 2, several with material consistent with slugs or soft-bodied insects, another with a young-of-the-year western smooth earthsnake, and another with what appeared to be snake remains. Reproduction. Mating may occur in spring or fall but is concentrated in the

spring. Males aggregate around females, using scent to locate them. Ernst and Ernst (2003) provide the following description of courtship and mating. When the male is courting the female, he rubs his closed mouth up and down her side as he moves forward along her body. When he reaches the neck ring he bites her there, aligns the lower part of his body against hers, wraps his tail around her tail,

112  Prairie Ring-Necked Snake, Diadophis p. arnyi

and inserts his hemipenis. The female’s neck ring appears to serve as a releaser for male aggressive biting behavior. These snakes are oviparous with females using the underside of rocks or fallen bark, vegetation mounds, rotting logs or stumps, or animal burrows as nest sites, and communal nests are common. Males mature in 2 years and females in 3 years at about 9.25 inches (23.5 cm) snout-vent length. Examination of 21 Iowa adult female museum specimens found the smallest with oviductal eggs to be 10 inches (25.4 cm) snout-vent length, and a 9.76-inch (24.8-cm) snout-vent length June female appeared to have already laid eggs based on the appearance of the ovaries. Two October females measuring 8.9 inches (22.6 cm) and 9.4 inches (24 cm) snout-vent length had enlarged ovarian follicles, suggesting they would have reproduced the following year. These observations suggest Iowa females mature at around 9 to 10 inches (23–25.4 cm), consistent with Fitch’s (1999) findings. Ovarian follicles are heavily yolked and rapidly enlarging by mid-May, and ovulation in Iowa likely occurs in late May. Females are gravid from May into early August, as evidenced by oviductal eggs found in a May 27 specimen and an August 1 specimen. Most egg laying occurs in June and July, although some females likely lay in August. Females lay from 1 to 10 eggs, and embryos are already partly developed at the time the eggs are laid. Counts of enlarged ovarian follicles and shelled oviductal eggs in Iowa female museum specimens resulted in average clutch sizes of 5 eggs (range 2–8; n = 14) and 5.2 eggs (range 3–8; n = 5), respectively. LeClere (2013) reported a clutch of 4 eggs laid by a female from Monroe County. Blanchard (1942) and Fitch (1999) reported larger females produce more eggs than smaller females, with the largest and oldest females producing the most eggs. Although the sample size is small, a similar pattern is seen in Iowa prairie ring-necked snakes, where the largest female museum specimen examined had the largest number of oviductal eggs, illustrating the danger of eliminating large older female snakes from a population. Removal of these super breeders lowers the overall reproductive potential of the population, lessening its ability to rebound from disturbances. Prairie ring-necked snake eggs average about 1 inch long by 0.28 inch wide (25.2 × 7.1 mm). Oviductal eggs measured in Iowa female museum specimens averaged 0.8 inch long by 0.27 inch wide (20.3 × 6.75 mm). Eggs hatch in August and September after a 40- to 50-day incubation period. Hatchlings ranged from 3.9 to 4.76 inches (9.8–12.1 cm) snout-vent length. Iowa young-of-the-year museum specimens measured ranged from 3.8 to 4.7 inches (9.6–12 cm; n = 9) snout-vent length. Longevity. Kansas prairie ring-necked snakes commonly live over 10 years in the

wild, and several individuals have been estimated to be over 20 years old.

PLAINS HOG-NOSED SNAKE Heterodon nasicus Baird and Girard 1852

Plains hog-nosed snake from Louisa County. Photo by Ryan D. Rasmussen.

Iowa Status. Endangered; species of greatest conservation need. Historical Summary. The plains hog-nosed snake has also been called the western hog-nose snake, blowing adder, bluffer, spoonbill snake, blowing viper, prairie hog-nosed snake, and spreadhead snake. The first possible mention in the literature in Iowa is in the History of Fremont County, Iowa (Anonymous 1881a), which listed the “hog-nosed snake” along with the scientific name of the southern hognosed snake (Heterodon simus), a species not found in Iowa. No specimen was referenced, and this may have been a purely hypothetical listing or a misidentified eastern hog-nosed snake. Ruthven (1908a) reported the first confirmed Iowa rec­ ords in Clay (1907, University of Michigan Museum of Zoology) and Palo Alto Counties, and his later publication (1910) provided a further description of the snake’s habitat in those counties. Later, Ruthven (1919) reported a plains hognosed snake specimen from Blue Lake in Monona County that was subsequently determined to be an eastern hog-nosed snake by Reeve Bailey. Dodge (1963) reported a male and a female plains hog-nosed snake collected in Louisa County

114  Plains Hog-Nosed Snake, Heterodon nasicus

in 1961, which represents the first confirmed record of this snake in eastern Iowa; however, a specimen from Muscatine County in the Northern Illinois University BIOS Herpetology Collection (later transferred to the Field Museum of Natural History) may have also been collected in the early 1960s. Description. Plains hog-nosed snakes are thick-bodied snakes with large heads

and sharply upturned snouts as wide as the space between their eyes. The specific name nasicus is derived from the Latin nasus meaning “nose” in reference to the upturned snout. The body is light tan with a series of brown dorsal blotches and 2 alternating rows of dark spots along the sides. A middorsal blotch and 2 elongated dark blotches extend from the forward part of the neck onto the head, and a transverse dark bar between the eyes extends downward behind the eyes to the corners of the mouth. Behind the snout are 2 to 28 small accessory scales called azygous scales. The belly is black with yellow or white blotches, and the underside of the tail is always black. The body scales are keeled and in 21 to 23 rows at midbody; the anal plate is divided and typically lighter than the belly or underside of the tail. There are usually 8 supralabial scales and 10 to 11 infralabial scales. Juveniles are similar in appearance to adults but more brightly colored.

Plains hog-nosed snake from Louisa County showing the tail’s black underside and the light-colored anal plate. Photo by J. Luke Hodges.

Heterodon nasicus, Plains Hog-Nosed Snake  115

Examination of sexual dimorphism in 10 Iowa adult plains hog-nosed snake museum specimens (5 males; 5 females) found snout-vent length, the number of ventral scales (male mean 136; female mean 148), the number of subcaudal scales (male mean 45; female mean 36), and tail length as a proportion of total body length (male 18%; female 12%) differed significantly between males and females. Females are larger and have more ventral scales, while males are smaller and have a longer tail and more subcaudal scales. Size. Plains hog-nosed snakes generally range from 15 to 25 inches (38–63.5 cm) total body length. The largest specimen in the Drake University Research Collection is a female from Louisa County measuring 26.8 inches (68.1 cm) total body length; the largest male is also from Louisa County measuring 21.7 inches (55.2 cm) total body length. An Iowa State Natural History Collection specimen killed on a road in Dickinson County in 1940 measured 31 inches (78.7 cm) total body length. The record total body length reported for the species is 36.1 inches (91.8 cm). Similar Species. Eastern hog-nosed snakes are the only other Iowa snake with an

upturned snout. The eastern hog-nosed snake has a slightly upturned snout and a gray, yellow, or pinkish belly mottled with gray or black, 25 dorsal scale rows at midbody, and an underside of the tail that is always lighter than the belly, never black. In addition, eastern hog-nosed snakes lack small accessory scales behind the snout.

Plains hog-nosed snake from Louisa County showing the sharply upturned snout and accessory scales behind the snout. Photo by Ryan D. Rasmussen.

116  Plains Hog-Nosed Snake, Heterodon nasicus

Distribution. H. nasicus is found in the Great Plains from Saskatchewan, eastern

Montana, and western North Dakota south to the Texas panhandle and eastern New Mexico. Relict populations, holdovers in dry habitats from a post-Pleistocene period of high temperature and aridity, occur in Minnesota, Iowa, Illinois, and Missouri. In Iowa, the plains hog-nosed snake is one of the state’s rarest snakes. Although records exist from 7 of Iowa’s 99 counties, the only remaining populations in the state may now be in Muscatine and Louisa Counties. Searches in Clinton County have been unable to confirm the continued existence of the species there. In the 1920s, Guthrie noted that plains hog-nosed snakes were more common than eastern hog-nosed snakes in western Iowa. As recently as 1940, the species occurred in 4 counties in northwest Iowa, but those populations have been extirpated, similar to many of the populations in Minnesota. In the late 1990s, Jim Christiansen stated that the plains hog-nosed snake is “one of our rarest snakes and continues to decline.” That assessment is still accurate today with the snake continuing to hang on in southeast Iowa in large part due to habitat preservation efforts in Louisa County. Plains hog-nosed snake distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

Habitat. Plains hog-nosed snakes inhabit prairies with sparse vegetation and well-drained sandy or gravelly soils. They are an example of a southwest species that invaded Iowa during the warmer, drier xerothermic period approximately 7,000 to 5,000 years ago. The changes in vegetation that occurred as Iowa’s climate became cooler and wetter likely eliminated these snakes throughout most of the state, leaving only relict populations in the few places where suitable habitat still existed. Today, they survive only in southeast Iowa, exclusively in areas with sparse grasses and shrubs and soils of nearly pure sand that allow for easy burrowing. During his more than thirty years of studies in southeast Iowa, Jim noted the plains hog-nosed snake was more or less equally distributed over sand dunes and moist sandy areas. Where the ranges of the plains and eastern hog-nosed snakes overlap in southeast Iowa, plains hog-nosed snakes prefer habitats that are more

Heterodon nasicus, Plains Hog-Nosed Snake  117

Plains hog-nosed snake from Louisa County. Photo by Ryan D. Rasmussen.

open. The extirpated populations in northwest Iowa occurred in areas with sandy soil as well. In 1910 Ruthven, discussing the plains hog-nosed snake in Clay and Palo Alto Counties, stated, “We found it only on the uplands where the original prairie conditions had not been disturbed.” Behavior. These are shy harmless serpents whose first line of defense is often to remain motionless in an attempt to not be seen. If approached, they may try to flee, but if escape is not possible they will often hide their heads under a body coil, coil their tails into a tight spiral, and hiss loudly. Like the related eastern hog-nosed snake, they may spread their neck and forebody, although they are less likely to do so than the eastern hog-nosed snake. If the attacker is not deterred, the snake may strike; however, the strike is almost always a false strike made with the mouth closed. Human envenomation has been reported, with those who were bitten experiencing pain and swelling. If the threat display does not work, like the eastern hog-nosed snake the plains hog-nosed snake moves on to its next line of defense: playing dead. The snake begins to have convulsive spasms, opens its mouth, lets its tongue hang out, dislocates its lower jaw, discharges feces and musk, and may bleed from its mouth. At some point it turns belly up, twitches a few last times, and then lies perfectly still as if dead. However, again like the eastern hog-nosed snake, there is a shortcoming

118  Plains Hog-Nosed Snake, Heterodon nasicus

in the act. If you turn the snake right side up, it will immediately turn upside down again, spoiling the hoax. Jim related an encounter between his small poodle and a plains hog-nosed snake in southeast Iowa. When approached by the dog, the snake attempted a standard defense of coiling and repeatedly striking, although with its mouth closed. There was some flaring of the neck, but this was minor and did not occur right away. When the dog continued to paw at the snake, the snake suddenly turned upside down, defecated, and released musk while rapidly rubbing its extended cloaca over much of its body. It then remained upside down but still rigidly coiled with its mouth open and its lower jaw out of alignment with its upper jaw. The dog sniffed at the “dead” snake a bit, looked up at Jim, and then walked away. Death feigning is well known among hog-nosed snakes, and Jim’s observation of the encounter with the dog demonstrates that it works with at least one potential mammalian predator. These snakes are diurnal with most activity in the morning and late afternoon or at dusk. They are efficient burrowers and when not out hunting or looking for a mate spend part of the day and much of the night burrowed in loose soil. They use their broad flat heads and pointed snouts to plow through the soil and are better adapted to burrowing than the eastern hog-nosed snake due to their larger and more upturned snouts. Other adaptations to burrowing include a thick body, short tail, and keeled scales, which provide more friction with the burrow wall. Four types of burrows are used: temporary shallow burrows, shelter burrows, nests, and hibernacula. Temporary shallow burrows are only 1 to 2 inches (2.5– 5 cm) below the surface and are used only once, whereas shelter burrows are more permanent and deeper and are used frequently over a period of weeks or months. The snakes also burrow in search of prey. Unlike many snakes, plains hog-nosed snakes are not commonly found under rocks, rotting logs, bark, boards, or other debris, although the first one I found was a juvenile under an old board in Louisa County. The collection/observation dates of 67 Iowa plains hog-nosed snakes occur between late April and early October. Platt (1969) reported average first and last sighting dates of May 9 and October 18 in Kansas, and none was caught in the spring until the soil temperature remained above 60° F (15.5° C) for a few days. The earliest Iowa record is an individual found on April 30 in Louisa County. Jim commonly found adults through mid-July during his studies in southeast Iowa, but they became less common after July. In Kansas, late August is a period of inactivity and molting, with only limited resumption of activity in the fall, and the last captures in fall usually occur immediately before the soil temperature drops below 60° F (15.5° C) (Platt 1969). Similarly, in late August in southeast Iowa adults

Heterodon nasicus, Plains Hog-Nosed Snake  119

Number of Records

20

18 15

15 11

11

10 6

5

5 0

0

0

0

Jan

Feb

Mar

1 Apr

May

Jun

Jul

Aug

Sep

Oct

0

0

Nov

Dec

Month Collection/observation dates of 67 plains hog-nosed snakes in Iowa.

are rarely found, but young-of-the-year snakes are frequently found, particularly in September. By late September, the snakes have settled into their overwintering sites, typically mammal burrows or burrows they excavate themselves, and surface activity drops off dramatically after September 30. The latest Iowa record is an individual found in Louisa County on October 9. Threats. Hog-nosed snakes may not be common prey for any predator due to

their secretive nature. Nevertheless, known predators include hawks such as redtailed hawks, American crows, and coyotes. Road mortality and pesticides pose threats as well; however, the primary threat to the Iowa populations is the loss of habitat in the few remaining places in the state where they still exist. Climate change may have serious long-term consequences for this rare snake by accelerating succession of the dry and sparsely vegetated habitats they require to wetter and more densely vegetated habitats. Food and Feeding. Although plains hog-nosed snakes eat frogs and toads, they

do not rely on amphibian prey as heavily as the eastern hog-nosed snake and regularly consume other reptiles, small mammals, birds, and some insects (although insects may not be primary prey items) as well as the eggs of turtles, lizards, and birds. Jim observed the snakes eating prairie racerunners in Louisa County. Plains hog-nosed snakes have been reported to use the scent trails of female turtles to find their nests (Iverson 1990), and one was found 4.9 feet (1.5 m) up in a bush consuming lark sparrow eggs (Langford and Janovy 2011). Illinois data suggest a change in diet over the life span of an individual from a juvenile diet composed

120  Plains Hog-Nosed Snake, Heterodon nasicus

primarily of prairie racerunners and their eggs to an adult diet composed primarily of aquatic turtle eggs, with toads consumed during the adolescent years. Iowa diet records are limited. Examination of the stomach contents of 10 plains hog-nosed snake specimens in the Drake University Research Collection found mammal hair in the intestine of a large female from Louisa County, and LeClere (2013) reported a male from Louisa County had consumed two turtle eggs. The snakes locate prey by both sight and smell, either by encountering it by chance during their daily travels or by burrowing in search of lizards and toads. When prey is located, the snake goes after it with a wide-open mouth, never actually striking, grabs it, and eats it alive. When prey is seized, the snake maneuvers it to the back of its mouth where specialized enlarged grooved teeth are used to hold it (Heterodon comes from the Greek hetero meaning “different” and odont meaning “tooth”). Some have postulated these teeth are used to “pop” toads that have expanded with air as a defense mechanism, though this has not been confirmed, and Kroll (1976) concluded the snakes deflate toads by crushing them with their jaws and not by puncturing them with their teeth. The enlarged teeth may assist in working toxic saliva into prey. Like the eastern hog-nosed snake, the plains hog-nosed snake has enlarged adrenal glands that provide resistance to the strong toxins produced by the parotoid glands of toads, allowing them to eat toads without suffering the severe illness or death experienced by other vertebrates. Reproduction. Information regarding plains hog-nosed snake reproduction

comes primarily from the superb field studies of Platt (1969, Kansas) and Iverson (2019, Nebraska), which I have used in this section except as noted. Female plains hog-nosed snakes mature in approximately 2 to 3 years at around 14 to 15 inches (35.8–38 cm) snout-vent length, and males mature in 1 to 2 years at around 12 inches (30.5 cm) snout-vent length. Mating occurs in spring, likely May to June, although fall mating has also been reported. After they emerge from hibernation, males begin looking for females by following scent trails to locate them. Plains hog-nosed snakes are oviparous, with females laying eggs primarily in June or July—although Ruthven (1910) reported an Iowa female laying on August 4—in excavated nest chambers 4 to 6 inches (10.2–15.2 cm) deep. Females likely reproduce every other year; however, Iverson (2019) suggested that reproduction may frequently be less than biennial because reproductive frequency increases with female body size and extremely hot and dry conditions during the year prior to the nesting season may reduce reproductive frequency that summer. Clutch size is proportional to female size, with larger females producing more eggs than smaller females. Across the range of the species, clutch size has been

Heterodon nasicus, Plains Hog-Nosed Snake  121

reported at 2 to 24 eggs (average 10.5), though Iverson (2019) questioned the possibility of actual deposited clutches of 23 or 24 eggs and suggested an average clutch size of 8 to 9 eggs based on his studies in Nebraska and those of others across this snake’s range. Counts of enlarged ovarian follicles and oviductal eggs in Iowa females in the Drake University collection included 17 enlarged ovarian follicles in a Louisa County female found on May 17 and 10 unshelled oviductal eggs in a Louisa County female found on June 6, suggesting ovulation in Iowa occurs in late May. Other Iowa records include a Dickinson County female that had 17 shelled oviductal eggs on July 6 (Iowa State Natural History Collection specimen) and a Clay County female that laid 5 eggs on August 4 (Ruthven 1910). Eggs hatch in August and September after an approximately 50- to 64-day incubation period, with hatchlings ranging from 5.5 to 8 inches (14–20.3 cm) total body length. Longevity. A wild-caught male survived in captivity an additional 19 years, 10

months, and 28 days.

EASTERN HOG-NOSED SNAKE Heterodon platirhinos Latreille 1801

Eastern hog-nosed snake from Linn County.

Iowa Status. Protected nongame; species of greatest conservation need. Historical Summary. The eastern hog-nosed snake has been known by at least 47

common names over time, including spreading adder, chunk head, hog-nosed rattler, bastard rattlesnake, blowing adder, black adder, black blowing viper, hissing adder, black hog-nosed snake, deaf adder, sand viper, and spread-head moccasin. The first confirmed specimens in the state appear to be in 1855 from Delaware County (National Museum of Natural History–Smithsonian Institution). The first mention in the literature in Iowa appears to be in the History of Fremont County, Iowa (Anonymous 1881a), which referred to the eastern hog-nosed snake as the “blowing viper” and listed the southern hog-nosed snake (Heterodon simus), a species not found in Iowa, as occurring in the county as well. Yarrow (1882)

124  Eastern Hog-Nosed Snake, Heterodon platirhinos

reported eastern hog-nosed snake specimens in the National Museum of Natural History from Brookville in Jefferson County and Quasqueton in Buchanan County. Ruthven (1919) reported a plains hog-nosed snake specimen from Blue Lake in Monona County that was incorrectly identified and later determined to be an eastern hog-nosed snake by Reeve Bailey. Description. Eastern hog-nosed snakes are thick-bodied snakes with large heads and slightly upturned snouts. The specific name platirhinos is derived from the Greek plati meaning “flat” or “broad” and rhinos meaning “nose” in reference to the broad flat upturned snout. The body is gray, tan, yellow, brown to olive, or less commonly uniformly black with a series of 20 to 30 brown dorsal blotches and 8 to 12 bands that sometimes appear to form rings around the tail. Rows of dark spots are found along the sides. Two large dark spots are present on the forward part of the neck even on uniformly dark individuals, and a transverse dark bar between the eyes extends downward through the eyes to the corners of the mouth. The skin between the scales is yellow, red, or orange and becomes visible when the snake spreads its neck. The belly is gray, yellow, or pinkish and mottled with gray or black. The underside of the tail is always lighter than the belly. The body scales are keeled and in 25 rows at midbody; the anal plate is divided. There are usually 8 supralabial scales and 10 to 11 infralabial scales. Juveniles are more brightly colored and have a bolder pattern than adults. Examination of sexual dimorphism in 27 Iowa adult eastern hog-nosed snake museum specimens (15 males; 12 females) found snout-vent length, the number of ventral scales (male mean 130; female mean 141), the number of subcaudal scales (male mean 51; female mean 42), and tail length as a proportion of total body length (male 20%; female 14%) differed significantly between males and females. Females are larger and have more ventral scales, while males have a longer tail and more subcaudal scales. Size. Eastern hog-nosed snakes generally range from 20 to 33 inches (51–84 cm)

total body length. The largest specimen in the Drake University Research Collection is a female from Linn County measuring 33.3 inches (84.5 cm) total body length; the largest male is from Henry County measuring 31.3 inches (79.4 cm) total body length. Reeve Bailey recorded a 32.6-inch (82.7-cm) total body length male from Dallas County in his field notes. The record total body length reported for the species is 49.9 inches (126.8 cm). Similar Species. Plains hog-nosed snakes are the only other Iowa snake with an

upturned snout. In contrast to the eastern hog-nosed snake, plains hog-nosed

Heterodon platirhinos, Eastern Hog-Nosed Snake  125

Eastern hog-nosed snake from Linn County showing the slightly upturned snout.

snakes have a sharply upturned snout, a black belly, 23 or fewer dorsal scale rows at midbody, and an underside of the tail that is always black. Bullsnakes have a bluntly pointed snout that does not turn up and a yellow background color with distinct brown spots, and they are much larger. Both eastern and prairie massasaugas have a rattle at the end of the tail, a facial pit between the eye and nostril, and a vertically elliptical pupil. Distribution. Eastern hog-nosed snakes are widely distributed throughout the eastern United States with the exception of some New England states and are found in scattered populations in Nebraska, Kansas, western Oklahoma, and the panhandle of Texas. In Iowa, they are found in eastern, southern, and western portions of the state. They are absent from much of northern Iowa with the exception of areas along the Mississippi and Missouri Rivers. In the mid-1940s, the species was known from 24 counties. At present, records exist from 41 of Iowa’s 99 counties, of which 10 (24%) have only pre-1960 records. In the mid-1980s, Jim Christiansen and Catherine Mabry (1985) postulated an increase in eastern hognosed snakes in the Loess Hills due to an expansion of woodlands throughout the region.

126  Eastern Hog-Nosed Snake, Heterodon platirhinos Eastern hog-nosed snake distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

Habitat. These snakes inhabit open woodlands, rocky wooded hillsides, woodland edges, blufflands, sand prairies, pastures, other grasslands, and the edges of cultivated fields, and they are more likely to be found in close proximity to coarse woody debris and in microhabitats with denser vegetation. They prefer welldrained loose or sandy soil for easy burrowing but at times may be found close to moist areas, especially during late spring when amphibians are abundant. Among the eastern hog-nosed snake records in Reeve Bailey’s field notes where he included habitat, he recorded streams, sloughs, or other moist areas as being present 76 percent of the time. Jim, during his studies in Muscatine and Louisa Counties, noted eastern hog-nosed snakes were commonly found along pond edges where amphibians were abundant. Where the ranges of the eastern and plains hog-nosed snakes overlap in southeast Iowa, eastern hog-nosed snakes prefer more cluttered habitats than do plains hog-nosed snakes. Behavior. Eastern hog-nosed snakes are shy harmless serpents whose first line

of defense is their cryptic coloration. If approached, they may try to flee, but their heavy bodies prevent efficient or quick escape. If escape is not possible, their second line of defense is to put on an impressive and at times intimidating threat display, giving rise to such common names as spreading adder and blowing viper; it was at one time thought they blew a poisonous powder or breath from their mouth. The snake raises its forebody off the ground and flattens and spreads its neck like that of a cobra, revealing the brightly colored skin between the scales, all the while inhaling and exhaling deeply, producing a loud hiss, sometimes with the mouth wide open. If the attacker is not deterred, the snake will often strike repeatedly; this is all a bluff and is almost always a false strike made with the mouth closed. However, the saliva of eastern hog-nosed snakes has been shown to be mildly venomous to humans, causing burning, pain, swelling, discoloration, and bleeding from the puncture wounds. The threat display is so innate that even

Heterodon platirhinos, Eastern Hog-Nosed Snake  127

Eastern hog-nosed snake from Monroe County death feigning. Photo by Ryan D. Rasmussen.

newborns exhibit such behavior. I was checking drift fences one summer in Lee County, and as I walked along I felt something hit my boot. When I turned around, a large eastern hog-nosed snake was raised up cobra-style and swaying back and forth. I assume I stepped a little too close and it struck and hit my boot as I passed. If the threat display does not work, the snake moves on to its third line of defense: playing dead. It begins to have convulsive spasms, opens its mouth with its tongue out, discharges feces and musk, and may even bleed from around the teeth and lining of the mouth and regurgitate a meal if it has recently eaten. At some point, the snake turns belly up, twitches a few last times, and then lies perfectly still. The function of death feigning is to try to convince a predator to move on and find something more appealing to eat. However, eastern hog-nosed snakes do have a chink in their armor. If you turn them right side up, they usually will immediately turn upside down again, spoiling the ruse. If handled enough, the snakes lose this death-feigning behavior. While working as a naturalist for the Clayton County Conservation Board, I would use an eastern hog-nosed snake for programs with school groups. When I first started using the snake, I would get it out and begin discussing hog-nosed snakes and just as I was starting to describe how the species plays dead, right on cue the snake would start convulsing and flip

128  Eastern Hog-Nosed Snake, Heterodon platirhinos

upside down in my hands with its tongue hanging out. I would flip it right side up and it would turn right back over. The kids got quite a kick out of watching the routine. After I handled the snake for a while, though, it no longer played dead. H. platirhinos is primarily diurnal with most activity occurring in the morning and less activity in the late afternoon or at dusk. Both sexes roam quite a bit during the day with an average home range encompassing 87.5 to 124 acres (35.4–50.2 ha). The snakes are efficient burrowers; when not out hunting or looking for a mate, they spend part of the day and much of the night burrowed in loose soil. They use their broad flat heads and pointed snouts to plow through the soil, moving their heads from side to side while pushing their snouts into the soil until they are completely covered. They use four types of burrows: temporary shallow burrows, shelter burrows, nests, and hibernacula. Temporary shallow burrows are only 1 to 2 inches (2.5–5 cm) below the surface and are used only once, whereas shelter burrows are more permanent and deeper and are used frequently over a period of weeks or months. In areas where the soil is too rocky or hard for burrowing, the snakes use the burrows of other animals. They also burrow in search of prey. Unlike many other snakes, eastern hog-nosed snakes are not commonly found under rocks, rotting logs, bark, boards, or other debris. The collection/observation dates of 265 Iowa eastern hog-nosed snakes show the activity period to be April through October. Interestingly, the earliest Iowa records are 3 individuals found in March 2012, 2 in Davis County and another in Linn County. The winter of 2011–12 was exceptionally warm, and snakes of several species were observed throughout the state as early as January 2012; while this explains the early emergence of these individuals, it also illustrates how a changing climate has the potential to affect a species’ activity period. Activity in Iowa appears to be bimodal with the highest peak in April through June (69% of records) and a second peak in September and October (20% of rec­ ords). Klimstra (1958) recorded a similar seasonal activity period for eastern hog-nosed snakes during a study of snake populations in Davis County. Although eastern hog-nosed snakes are found throughout the summer in Iowa, surface activity declines during the hottest part of the summer, during which time the snakes become inactive for up to a few weeks. By October, the snakes have returned to their overwintering sites. The latest Iowa record is an individual found in Wapello County on October 19. Unlike many snake species, eastern hog-nosed snakes hibernate individually, either in mammal burrows or in tunnels they excavate themselves, with some showing fidelity for overwintering sites by using the same site in successive years. Anderson (1965) stated that the eastern hog-nosed snake usually hibernates in

Heterodon platirhinos, Eastern Hog-Nosed Snake  129

77

Number of Records

80 70

62

60 50

43

37

40 30 20 10 0

0

0

3

Jan

Feb

Mar

11

Apr

May

Jun

Jul

16

Aug

16

Sep

Oct

0

0

Nov

Dec

Month Collection/observation dates of 265 eastern hog-nosed snakes in Iowa.

rodent burrows in open fields and is conspicuously absent from the limestone ledges that most snakes select for hibernating. In contrast, Reeve Bailey observed 3 eastern hog-nosed snakes on April 13 basking together near a rocky crevice in Madison County; he found another on that same date in a different year also near a rock outcrop, suggesting outcrops may at times be used. Nevertheless, most hibernation in Iowa probably occurs in mammal burrows, as was likely the case with an individual found by Jim on April 7 in the Eddyville Dunes of Wapello County. Threats. Eastern hog-nosed snakes may not be common prey for any predator

due to their secretive habits. Nevertheless, known predators include North American racers, speckled kingsnakes, western ratsnakes, red-tailed hawks, American crows, and barred owls. Disease may be a concern as infections of snake fungal disease have been confirmed in some populations. Road mortality does occur, although studies have shown a reluctance of eastern hog-nosed snakes to cross paved roads but not unpaved roads. Pesticides, loss of habitat, and climate change also pose threats to Iowa populations. Food and Feeding. These snakes eat primarily toads along with frogs and salamanders. Although they feed mainly on amphibians, they consume small snakes, shrews, mice, voles, and invertebrates such as earthworms and insects as well. Insects have been reported to make up a significant percentage of the diet (e.g., Platt 1969, 35%), though some believe the insects found in the stomachs of eastern hognosed snakes do not represent primary prey items but are secondary items that were first eaten by the amphibians that were subsequently eaten by the snakes.

130  Eastern Hog-Nosed Snake, Heterodon platirhinos

Eastern hog-nosed snakes have poor eyesight and primarily find prey by smell, either by encountering it by chance during their daily travels or by burrowing in search of it. Once prey is located, the snake goes after it with mouth wide open, never actually striking, and grabs it and eats it alive. It has long been speculated that the toxic saliva of the snake subdues prey; however, instances of eastern hognosed snakes regurgitating toads that were still alive and survived being eaten bring this into question. These snakes possess several adaptations that make them particularly well suited to eating toads, including a heavy body, large head, wide flexible mouth, and enlarged grooved back teeth (Heterodon comes from the Greek hetero meaning “different” and odont meaning “tooth”). When prey is seized, the snake maneuvers it to the back of the mouth and holds it with its enlarged teeth. Some have suggested that the snake uses these teeth to “pop” toads that have expanded with air as a defense mechanism. This has not been confirmed, and Kroll (1976) concluded toads are deflated when the snakes crush them with their jaws, not by puncturing them. Enlarged adrenal glands are an additional and possibly the most important adaptation, providing resistance to the strong toxins produced by the parotoid glands of toads, secretions so toxic that most vertebrates cannot consume toads without suffering severe illness or death. Examination of the stomach contents of 38 eastern hog-nosed snake specimens in the Drake University Research Collection found toads ranging from 0.8 to 2.4 inches (2–6.1 cm) snout-vent length in 4 specimens. Other Iowa records include a large eastern hog-nosed snake picked up by Jim in Muscatine County that immediately regurgitated two large adult tiger salamanders and an individual found by Reeve Bailey in a hollow tree in Madison County that regurgitated an American toad. Reproduction. Both sexes mature in approximately 21 months at around 19

inches (48.5 cm) snout-vent length for males and 20 to 22 inches (51–56 cm) snoutvent length for females. Mating occurs in spring, likely late April into early June in Iowa, although fall mating has been reported in Wisconsin. After they emerge from hibernation, males begin looking for females, following scent trails to locate them. When males and females meet, the male investigates the female with tongue flicking, crawls beside her until his head is even with her neck, coils his tail over hers, and performs undulating head-to-tail body pulsations as he attempts to insert his hemipenis into her vent. While mating, the female may remain still or may slowly crawl away, dragging the male by his hemipenis. Copulation may last several hours to a few days, and females may mate with several males during the course of the mating period.

Heterodon platirhinos, Eastern Hog-Nosed Snake  131

Juvenile eastern hog-nosed snake from Davis County. Photo by Ryan D. Rasmussen.

Eastern hog-nosed snakes are oviparous with females laying eggs in June or July in excavated nest chambers 4 to 6 inches (10.2–15.2 cm) deep in loose soil in open grassy areas with little shrub cover, under rocks, or in mammal burrows. Females may spend several days probing the ground digging test burrows before finally selecting a nest site, and multiple females may nest in the same area. Clutch size is proportional to female size, with larger females producing more eggs than smaller females. Across the range of the species, clutch size has been reported at 4 to 61 eggs. In the Midwest, clutches of 61 eggs (Breckenridge 1944, Minnesota), 24 eggs (Johnson 2000, Missouri), and 8 to 38 eggs (Vogt 1981, Wisconsin) have been reported. Iowa records include Guthrie (1926), who shows a photograph of an Iowa snake containing 18 eggs nearly ready to be laid; Reeve Bailey’s notes, which list an eastern hog-nosed snake collected by Guthrie that laid 6 eggs on June 26; and an eastern hog-nosed snake collected by Bailey on June 16 that laid 41 eggs between July 6 and 8. Eggs hatch in August and September after an approximately 39- to 65-day incubation period. Hatchlings range from 5.1 to 11.6 inches (13–29.4 cm) total body length. Longevity. A captive-born male survived 7 years, 8 months, and 15 days, while a

wild-caught male survived in captivity an additional 9 years and 40 days.

PRAIRIE KINGSNAKE Lampropeltis calligaster (Harlan) 1827

Prairie kingsnake from Wapello County. Photo by Ryan D. Rasmussen.

Iowa Status. Protected nongame; species of greatest conservation need. Historical Summary. The prairie kingsnake has also been called Kennicott’s chain snake, milk snake, blotched king snake, Kansas king snake, brown king snake, and Say’s chain snake. The first mention in the literature in Iowa appears to be in the History of Fremont County, Iowa (Anonymous 1881a), which referred to the species as “Kennicott’s chain snake.” Osborn (1892) referenced an Iowa State Natural History Collection specimen believed to be from Ames in Story County, but that specimen appears to be missing, and Somes (1911) stated the species was found in Iowa but did not reference a specimen. Blanchard (1921) stated that “there is no record from Iowa or Nebraska.” Guthrie (1926) did not include the species as occurring in the state due to the lack of a reliable record. Reeve Bailey (1939) questioned Anonymous (1881a) and Somes (1911) because they did not provide “descriptions, substantiating specimens, or evidence that the lists are more than hypothetical enumerations selected from general accounts.” However,

134  Prairie Kingsnake, Lampropeltis calligaster

he went on to conclude the prairie kingsnake not only occurs in Iowa but is “one of the commonest species in the southern part of the state,” and he provided records for seventeen Iowa locations. The first confirmed specimen in the state appears to be in 1938 from Rose Hill in Mahaska County (Iowa State Natural History Collection). Description. Prairie kingsnakes are shiny tan, light brown, or gray with 41 to 60 dark brown, black, or reddish dorsal blotches alternating with smaller lateral blotches along the length of the body. The tail has an additional 11 to 22 blotches that may form nearly complete rings near the end. The neck has 2 broad stripes that barely extend onto the back of the head, and the head has a dark line extending from the eyes to the angle of the jaw, a stripe extending downward from each eye onto the supralabials, and a bar immediately anterior to the eyes. A backward-facing arrowhead-shaped mark is usually on top of the head. The belly is cream with scattered gray to black rectangles that are bold on young snakes and become diffuse and ragged on old snakes. The belly pattern gives rise to the name calligaster from the Greek kallos meaning “beautiful” and gaster meaning “belly” or “stomach.” The body scales are smooth and in 25 to 27 rows at midbody; the anal plate is single. There are usually 7 supralabial scales and 8 to 9 infralabial scales.

Prairie kingsnake from Wapello County. Photo by Ryan D. Rasmussen.

Lampropeltis calligaster, Prairie Kingsnake  135

Juveniles are more brightly colored and have a bolder pattern than adults, consisting of very dark blotches on a light gray or brown background. The bold pattern of juveniles fades with age. As the snakes age, there may be a darkening of the background color accompanied by an alternate lengthwise lightening and intensification of pigment, producing a prominent striped effect (Blanchard 1921). Examination of specimens in the Drake University Research Collection revealed a large female from Davis County with this pattern of faint diffused stripes, although not as prominent as suggested by Blanchard. Atypical individuals are occasionally found. An aberrant striped juvenile was found in Louisa County with a unique pattern of dot and dash stripes, a brown spot centered in each scale, and a somewhat shorter than normal head. The belly was cream-colored with scattered stippled dark rectangles. Examination of sexual dimorphism in 40 Iowa adult prairie kingsnake museum specimens (24 males; 16 females) found the number of subcaudal scales (male mean 52; female mean 47) and tail length as a proportion of total body length (male 15%; female 13%) differed significantly between males and females, with males having more subcaudal scales and a longer tail, although the difference in tail length between males and females is not as pronounced as in other snakes. Size. Prairie kingsnakes generally range from 30 to 42 inches (76–106.7 cm) total

body length. Males are larger than females. The largest specimen in the Drake University collection is a male from Louisa County measuring 47.5 inches (120.6 cm) total body length; the largest female is from Van Buren County measuring 45.8 inches (116.3 cm) total body length. The record total body length reported for the species is 56.25 inches (142.8 cm). Similar Species. Eastern milksnakes have red dorsal blotches that extend down the sides of the body, reduced lateral blotches, and usually 21 dorsal scale rows at midbody. Western foxsnakes have weakly keeled scales and a divided anal plate. Bullsnakes have keeled scales and a pointed snout with an enlarged rostral scale. Distribution. Prairie kingsnakes are found from southeast Nebraska, southern Iowa, the middle of Illinois, and western Indiana south through Missouri and portions of Kansas, Oklahoma, Arkansas, Texas, and Louisiana. Scattered populations are also found in Kentucky, Tennessee, and Mississippi, where they intergrade with the mole kingsnake. In Iowa, prairie kingsnakes are found primarily in the southern three tiers of counties. In the mid-1940s, they were known from 24 counties. At present, records exist from 32 of Iowa’s 99 counties. Two literature records are from north of U.S. Highway 30 in Story (Osborn 1892) and

136  Prairie Kingsnake, Lampropeltis calligaster

Hardin (Carlander and Moorman 1950c) Counties. In eastern Iowa, the snakes can be found along the Iowa River as far north as Johnson and Iowa Counties. Nine of the 32 counties (28%) have only pre-1950 records, and Story County has only a pre-1900 record. Reeve Bailey concluded the prairie kingsnake was one of the most common snake species in southern Iowa in the 1930s, and it can still be quite common in portions of south-central and southeast Iowa; however, it appears to have declined in southwest Iowa. Of the 11 counties in southwest Iowa with prairie kingsnake records, only 4 (36%) have post-1960 records, and 87 percent of the total records from these 11 counties are pre-1960. Pottawattamie County is the only county in southwest Iowa that does not have a pre-1960 record, but it does have a post-1960 record. In the mid-1980s, Jim Christiansen and Catherine Mabry (1985) concluded prairie kingsnakes had declined in the Loess Hills along with other prairie species as a result of expansion of woodlands and agriculture. While they are still present in southwest Iowa, it seems apparent that they are not as common as they once were. Although records exist from more counties now than did at the time of Reeve Bailey’s work, even with increased survey efforts since 1970 there are fewer records after 1960 (44% of total) than before (56% of total), suggesting that prairie kingsnakes have been declining over time. Prairie kingsnake distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

Habitat. These snakes are prairie to prairie-woodland edge dwellers that have a preference for grasslands over woodlands. In Iowa, they are found in sand and tallgrass prairies, along woodland edges, in pastures, hayfields, grassed waterways, and other grassland habitats, and in road ditches and railroad rights-of-way. Of 32 prairie kingsnake records in Reeve Bailey’s field notes, mostly snakes found dead on the road, 11 were near grasslands or pastures, 5 were near both pastures and streams, 6 were near woodlands, 2 were near savannas, 4 were near open crop fields, and 4 mentioned only ponds or streams. Jim noted that during his field

Lampropeltis calligaster, Prairie Kingsnake  137

Prairie kingsnake from Lee County.

studies in southeast Iowa, he commonly found prairie kingsnakes in sand prairies but nearly always within 100 feet (30.5 m) of a woodland edge. He also found the snakes in a restored prairie near Rathbun Lake in Appanoose County, suggesting they will move into restored habitats in areas that have been intensively row-cropped. Behavior. Generally mild-tempered, prairie kingsnakes use cryptic coloration as their first line of defense, remaining motionless in an attempt to not be seen. If alarmed, they often make every effort to escape; however, if escape is not possible, they may take a defensive position: coiling, twitching their heads from side to side or up and down, vibrating their tails, making the occasional short strike, and spraying musk or feces. Fitch (1999) noted that the defensive coiling, tail vibrating, and head twitching resembled the behavior of the massasauga and might involve Batesian mimicry—where a harmless species evolves to mimic the appearance of a species that is harmful to potential predators. The defensive behavior is temperature-dependent: the colder the snake, the more passive the defense.

138  Prairie Kingsnake, Lampropeltis calligaster

This secretive snake spends much of its time underground in mammal burrows, beneath rocks, or under matted vegetation. As a result, little is known about its life history. Prairie kingsnakes followed via radiotelemetry in Illinois were found underground at least 73 percent of the time yet changed sites frequently between relocations, suggesting they move primarily at night (Richardson et al. 2006). The serpent has a fairly wide temperature tolerance and is primarily active at air temperatures between approximately 40 and 95° F (4.4–35° C). LeClere (2013) reported finding a large male beneath a sheet of tin in Monroe County on April 21 at an air temperature of 37° F (2.8° C). Home range sizes of up to 27.4 acres (11.1 ha) for males and 6.2 acres (2.5 ha) for females have been reported in Illinois; a range of 24.4 acres (9.86 ha) has been reported in Kansas. The collection/observation dates of 113 Iowa prairie kingsnakes show the species has been found from March through October, with the earliest individual found on March 20 in Henry County. The primary activity period, however, is from April through October. Richardson et al. (2006) reported use of underground locations increases throughout the active season, with the lowest use in April and May and a steady increase to the highest use in October. They surmised that aboveground temperatures become more conducive to nocturnal activity as the season progressed, leading to fewer aboveground observations. This pattern of increased underground use and fewer direct aboveground sightings may be reflected in Iowa collection/observation data, which show the largest number of observations early in the active season and a decrease through the remainder of the active season. By October, the snakes have presumably reached their overwintering locations and aboveground sightings cease. In Illinois, movement toward hibernacula occurs between mid-September and mid-October, with most activity stopping by mid-October. The latest Iowa record is an individual found in Henry County on October 23. Little is known of the overwintering ecology of prairie kingsnakes. They occasionally use road embankments as overwintering sites in Illinois and both rock outcrops and floodplains in Kansas. Richardson et al. (2006) provide the best data regarding hibernacula. In Illinois they found radio-tracked prairie kingsnakes hibernating in a creek bank, along a woodland-grassland edge, and in grasslands often close to creek banks. All hibernacula were mammal burrows indistinguishable from burrows used during the active months. Although no overwintering records are known for Iowa, it is suspected the snakes use fissures in rock outcrops or even house foundations when available but likely rely primarily on mammal burrows.

Lampropeltis calligaster, Prairie Kingsnake  139

40 Number of Records

32 30 20

20

20 12

10 0

0

0

Jan

Feb

5

3 Mar

Apr

May

Jun

Jul

Aug

13 8

Sep

Oct

0

0

Nov

Dec

Month Collection/observation dates of 113 prairie kingsnakes in Iowa.

Threats. Predators include other kingsnakes, small mammals such as ground

squirrels, and larger mammals such as raccoons, badgers, skunks, and foxes as well as raptors such as red-tailed hawks. Jim and Catherine Mabry (1985) reported a prairie kingsnake being dropped at their feet by a hawk while they conducted amphibian and reptile surveys in the Loess Hills in the 1980s. Loss and fragmentation of grassland and woodland edge communities resulting from the conversion to row crops and urban and rural development may be the biggest threat. Climate change may also affect the suitability of the habitats prairie kingsnakes need to survive. Road mortality does occur, and both live and dead prairie kingsnakes are occasionally found on roads in Iowa. However, Illinois radiotelemetry data suggest roads may be a barrier to movement and show prairie kingsnakes are reluctant to cross them (Richardson et al. 2006). Food and Feeding. Prairie kingsnakes are powerful and efficient constrictors consuming primarily small mammals such as voles, mice, shrews, chipmunks, moles, and small rabbits along with lizards, other snakes, and amphibians. Birds and their eggs are also eaten, and in some locations prairie kingsnakes can be a significant predator of grassland birds. Like many kingsnakes, they will eat venomous snakes and are resistant to timber rattlesnake and other pit viper venoms. Young-of-the-year prairie kingsnakes may eat relatively large meals, up to 58 percent of the snake’s body mass. Three studies provide the most complete information regarding the prairie kingsnake’s diet. In southern Illinois, Klimstra

140  Prairie Kingsnake, Lampropeltis calligaster

(1959b) reported the diet as 68.6 percent mammals dominated by white-footed mice and voles, 11.2 percent amphibians, 6.8 percent reptiles, 6.8 percent birds, and 6.4 percent insects. Two studies by Fitch (1978, 1982) reported voles making up the largest proportion of the diet in Kansas and listed a variety of shrews and mice, moles, prairie racerunners, Great Plains skinks, slender glass lizards, prairie ring-necked snakes, milksnakes, wormsnakes, and newborn timber rattlesnakes as food items. All three studies mentioned northern bobwhites and their eggs being eaten. Examination of the stomach contents of 47 Iowa prairie kingsnake specimens in the Drake University Research Collection found identifiable items in only 2. One contained three newborn shrews, and the other contained short black hair, also consistent with a shrew. A captive prairie kingsnake kept in Jim’s lab at Drake University ate gartersnakes. LeClere (2013) reported a prairie kingsnake from Louisa County regurgitated a southern bog lemming, and a juvenile from Decatur County was observed attempting to consume a juvenile common gartersnake. Reproduction. Mating occurs in spring shortly after the snakes emerge from hibernation, likely May into early June in Iowa. After they emerge, males begin looking for females, following scent trails to locate them, during which time males may engage in ritualized combat for access to females. Moehn (1967) provided an excellent account of one such male-male encounter in Missouri, where he observed two males raising their forebodies off the ground, holding their necks in a tense loop, and pushing their necks together in an effort to throw the other off balance. Although this “dance” may last for some time, neither participant is seriously injured. When males and females meet, they position their bodies alongside each other with occasional jerking and tongue flicking as they prepare to mate, and the female may rub her cloacal vent along the male’s tail region. When copulating, the male lies either alongside or on top of the female and places his head on her neck, occasionally waves or pulsates his tail, and may bite her neck or body. Mating may last over an hour. Prairie kingsnakes are oviparous, with females using rodent burrows, loose soil, and undersides of rocks, rotting logs, or stumps as nest sites. Males and females mature in 2 to 3 years at about 27.6 inches (70 cm) snout-vent length. Examination of 14 Iowa adult female museum specimens found the smallest female prairie kingsnake with oviductal eggs to be 28.9 inches (73.4 cm) snout-vent length. A female from Lee County containing 3 oviductal eggs measured 24.6 inches (62.6 cm) snout-vent length, although the snake was not well preserved and therefore likely was longer but still less than 27.6 inches (70 cm) snout-vent length.

Lampropeltis calligaster, Prairie Kingsnake  141

These observations suggest Iowa females mature at around 26 to 28 inches (66– 71 cm) snout-vent length, consistent with observations elsewhere. Ovarian follicles are heavily yolked and rapidly enlarging by mid-May, and ovulation in Iowa likely occurs in late May or early June. Sometime in late June or July, the female lays her eggs. Females may not lay eggs every year and up to 33 percent of females may not breed in any given year, although this is highly variable and depends on the health of the female, abundance of food, and weather conditions (Fitch 1999). Although limited, evidence of nonbreeding females is found in Iowa museum specimens. A 30.9-inch (78.4-cm) snout-vent length female found in Van Buren County on May 19 contained only small unyolked ovarian follicles, suggesting she would not have reproduced that year. All other adult female specimens examined that were collected during that same time frame contained enlarged ovarian follicles. Cagle (1942) and Smith (1961) estimated 9 eggs per clutch in Illinois, Trauth et al. (1994) estimated 14 eggs per clutch in Arkansas, and Carpenter (1985) found a clutch of 21 eggs in a road-killed female in Oklahoma. Clutch size is proportional to female size, with larger females producing more eggs than smaller females. Counts of enlarged ovarian follicles and shelled oviductal eggs in Iowa female museum specimens resulted in average clutch sizes of 10 eggs (range 5–15; n = 6) and 8.5 eggs (range 8–9; n = 2), respectively. Prairie kingsnake eggs are white, elongated, and adherent, averaging 1.7 inches long by 0.77 inch wide (43.2 × 19.6 mm). Oviductal eggs measured in Iowa females averaged 1.4 inches long by 0.85 inch wide (35.7 × 21.6 mm). Eggs hatch in August and September after a 45- to 75-day incubation period with hatchlings averaging 10.4 inches (26.4 cm) snout-vent length and weighing an average of 0.3 ounce (8.26 g). Iowa young-of-the-year museum specimens averaged 10.6 inches (26.9 cm; n = 6) snout-vent length. Longevity. A wild-caught adult male survived in captivity an additional 23 years, 8 months, and 23 days and survival of at least 10 years in the wild has been confirmed.

SPECKLED KINGSNAKE Lampropeltis holbrooki Stejneger 1903

Speckled kingsnake from Jefferson County. Photo by Jeff LeClere.

Iowa Status. Threatened; species of greatest conservation need. Historical Summary. The speckled kingsnake has also been called the chicken snake, Holbrook’s king snake, salt-and-pepper king snake, dotted black snake, chain snake, yellow spotted black snake, speckled adder, and spotted king snake. The first mention in the literature in Iowa appears to be in the History of Fremont County, Iowa (Anonymous 1881a); however, the lack of notes suggests this was a hypothetical listing. Osborn (1892) referred to the species as common and referenced an Iowa State Natural History Collection specimen. The first confirmed specimen in the state appears to be in 1895 from Keokuk in Lee County (Iowa State Natural History Collection), although it is possible an earlier specimen was collected from the same area (Goodman 1948). Guthrie (1926) considered the species to be “somewhat rare” in the state. Description. Adult speckled kingsnakes are a gorgeous glossy black with one or more white or yellowish spots in the center of most dorsal and lateral scales that

144  Speckled Kingsnake, Lampropeltis holbrooki

Belly of a speckled kingsnake from Ringgold County. Photo by Casey Trine.

produce a salt-and-pepper effect. The shiny appearance of this snake’s body is reflected in the genus name Lampropeltis, derived from the Greek lampros meaning “shining” and the Latin pelta meaning “shield” (the species name holbrooki honors physician and naturalist John Edwards Holbrook, often regarded as the father of American herpetology). On some individuals, the spots may form irregular white lines across the back, which may be solid or speckled. The head is similarly patterned with black bars on the lips. The belly is white to yellowish with scattered irregular black rectangles that become more numerous toward the tail. The posterior half of the belly may be nearly black, as was the case with an individual from Clarke County (Schmidt and Davis 1941). The body is more uniformly cylindrical than that of most snakes, giving it an almost pipe-like appearance, with even the head and neck being nearly the same diameter. The body scales are smooth and in 21 to 23 rows at midbody; the anal plate is single. There are usually 6 to 8 supralabial scales and 9 to 10 infralabial scales. Juveniles are much less speckled than adults with white bands about 3 scales wide separating dark dorsal blotches, little or no spotting between the bands, and some spotting on the lateral scale rows. The spots on the dorsal scales develop with age. The overall impression of the juveniles is of a blotched yellowish snake, while that of the adults is of a glossy black snake with white spots.

Lampropeltis holbrooki, Speckled Kingsnake  145

Ventral scales number 197 to 222 in both sexes, subcaudal scales range from 46 to 59 on males and 37 to 51 on females, and tail length as a proportion of total body length averages 13 percent for males and 12 percent for females (Blanchard 1921; Blaney 1977). Only 2 complete speckled kingsnake specimens are found in the Drake University Research Collection, a male 29.4 inches (74.8 cm) snoutvent length with 211 ventral scales, 47 subcaudal scales, and tail length 13 percent of total body length and a female 33.5 inches (85 cm) snout-vent length with 208 ventral scales, 43 subcaudal scales, and tail length 12 percent of total body length. Size. Speckled kingsnakes generally range from 36 to 48 inches (91.4–122 cm) total body length. The largest specimen in the Drake University collection is a female from Davis County measuring 38 inches (96.6 cm) total body length; the largest male is also from Davis County measuring 34 inches (86.2 cm) total body length. The record total body length reported for the species is 72 inches (182.9 cm) total body length. Similar Species. No other Iowa snake can be confused with the distinctive speckled kingsnake. The other Lampropeltis species in Iowa, the prairie kingsnake and the eastern milksnake, are both strongly blotched dorsally. The western ratsnake has keeled scales and a divided anal plate.

Speckled kingsnake from Ringgold County. Photo by Casey Trine.

146  Speckled Kingsnake, Lampropeltis holbrooki

Distribution. The speckled kingsnake is found west of the Mississippi River from

southern Iowa south through Kansas, Missouri, Oklahoma, Arkansas, Texas, and Louisiana. Widely scattered populations are also found in southern Nebraska. Iowa is at the very northern limit of this snake’s range and the serpent may be one of the rarest snakes in the state; it is certainly one of the rarest to be seen. It occurs in scattered populations primarily in the southern three tiers of counties, although pre-1940 records also exist for Johnson and Poweshiek Counties. In the mid-1940s, the species was known from 12 counties. At present, it is known from 16 of Iowa’s 99 counties; however, 10 of the 16 (63%) have only pre-1950 records, and 57 percent of all records in the state are pre-1950. Only 4 counties have both pre- and post1960 records, and 3 additional counties have only post-1960 records. In the late 1970s, Jim Christiansen and Russ Burken (1978) stated the speckled kingsnake was possibly one of Iowa’s most endangered species. In the early 1980s, Jim concluded the snake was one of Iowa’s most severely endangered species due to loss of woodland and woodland-prairie edges, and in 1998 he stated speckled kingsnakes were still exceedingly rare. The snakes are still occasionally found in southern Iowa and new populations may yet be discovered. Nevertheless, Jim’s 1998 statement holds true: speckled kingsnakes are still exceedingly rare in the state. Speckled kingsnake distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

Habitat. Lampropeltis holbrooki prefers open prairies, pastures, or other grass-

lands, lowlands, moist areas around ponds and streams, rocky hillsides, and woodland edges. Little is known about habitat use in Iowa as very few speckled kingsnake records exist for the state. When the snakes have been found in Iowa, most have been in grasslands or along woodland edges and often near water. Reeve Bailey described in his field notes an encounter with a speckled kingsnake in an open pasture dominated by little bluestem with no trees for at least 100 yards (91.4  m). Radio tracking of speckled kingsnakes in Arkansas showed a strong preference for vegetated shrubby microhabitats and an avoidance of active agri-

Lampropeltis holbrooki, Speckled Kingsnake  147

cultural fields (Plummer 2010). In addition, there was no evidence showing more natural habitats were preferred over agricultural edge habitats. The presence of sufficient ground vegetation, leaf litter, or other ground cover appears to be necessary; because the snakes spend a large amount of time concealed, burning grasslands too frequently may have a negative effect on them as they appear to prefer an intermediate burn frequency of every four years (Wilgers and Horne 2006). Behavior. Speckled kingsnakes are generally mild-tempered, although some will

bite when handled, and like most kingsnakes they vigorously vibrate their tails and release musk and feces in an attempt to dissuade their attacker. Some may stand their ground, raise the forebody into an elevated S coil, and strike vigorously when approached. Most can be handled with time, and this along with their spectacular appearance and ease of care in captivity has made them favorites of the pet trade, which may have contributed to the decline of the species in some locations. One of the first snakes I handled was a speckled kingsnake when I was a high school student in the early 1980s in Cedar Rapids. The snake had been wildcaught by one of the biology teachers at his family farm in southern Iowa. It was a beautiful snake and very calm, and we used it for environmental education programs with elementary students. And while I hope that snake helped hundreds of kids gain a greater appreciation for snakes, snakes should not be taken out of the wild and kept as pets. These secretive snakes spend much of their time underground in mammal burrows or beneath rocks, logs, leaf litter, or matted vegetation. Speckled kingsnakes followed using radiotelemetry were found underground or concealed approximately 80 percent of the time, and in many ecological respects they are similar to the closely related prairie kingsnake, specifically in the amount of time spent underground and sexual differences in movement and home range size (Plummer 2010). Home range sizes averaging 49.4 acres (20 ha) for males and 6.9 acres (2.8 ha) for females have been reported, with males moving longer distances than females. They are typical ambush predators, remaining in the same location from a few days up to a week or more before moving to a new location. Although primarily terrestrial, they will occasionally climb into shrubs and trees and have been reported in dead trees up to 6 feet (1.8 m) above the ground (Hubbs 2009). The collection/observation dates of 20 Iowa speckled kingsnakes show the species has been found from late March through October, with the earliest individual found on March 29 in Ringgold County. The primary activity period, however, is likely from April through October. In Missouri, Hurter (in Wright and Wright 1957) reported spring emergence dates throughout April and into mid-May. The

148  Speckled Kingsnake, Lampropeltis holbrooki

Number of Records

5 4

4

4

4 3

3

3

2 1

1 0

0

0

Jan

Feb

1 0

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

0

0

Nov

Dec

Month Collection/observation dates of 20 speckled kingsnakes in Iowa.

snakes are active during the day in spring and summer and become more crepuscular and nocturnal during the warmest portions of the summer. Although the sample size is small, collection/observation data from Iowa support this pattern, showing a decrease in observations during July. By mid- to late October, the snakes have reached their overwintering sites. The latest Iowa record is an individual killed and carried up to the porch of a house by a domestic cat in Davis County on October 25. Little is known of the overwintering ecology of speckled kingsnakes, but they have been reported to use small mammal burrows, rock outcrops, and building foundations, and one was found hibernating in a cave in Missouri. Although no overwintering records are known for Iowa, it is suspected the snakes may use fissures in rock outcrops or even building foundations but likely rely primarily on mammal burrows, given the lack of rocky terrain or outcrops in the vicinity of most Iowa observations. Threats. Predators include other speckled kingsnakes, which are known to eat

smaller members of their own species, mammals such as foxes and coyotes, and raptors such as great horned owls and Cooper’s hawks. Loss and fragmentation of grassland and woodland edge communities resulting from the conversion to row crops and urban and rural development may be the biggest threat. Reeve Bailey found a speckled kingsnake in a pasture in Union County in 1941 and Jim revisited the location in the 1990s, at which time he found the pasture had been converted to row crops. Other threats include pesticides, vehicles, and collection for the pet

Lampropeltis holbrooki, Speckled Kingsnake  149

trade. Climate change may be particularly significant for populations living at the edge of a species’ range, such as Iowa’s speckled kingsnake populations. Even a slight change in weather may be enough to push the range farther south and out of Iowa or allow it to expand farther north, assuming suitable habitats are present. Food and Feeding. A dietary generalist, this snake seems to prefer reptiles,

particularly snakes, including members of its own species; however, amphibians, birds, small mammals, lizards, and turtles and their eggs are also eagerly consumed. Many early writers regarded speckled kingsnakes as an enemy to all snakes due to their preference for eating snakes of all kinds and sizes, including those much larger than themselves. Blanchard (1921) reported a captive speckled kingsnake swallowing other snakes up to 18 inches (45.7 cm) longer than itself, a process that took up to three days. Speckled kingsnakes are able to subdue much larger snakes, including other strong constrictors, because they are powerful constrictors that exert significantly higher pressure on their prey than do other constricting snakes. They win in predatory encounters because of their superior constriction performance, a result of their consistent and distinctive coil posture, typically consisting of multiple loops forming a tight coil like that of a spring (Penning and Moon 2017). In addition to preying on other constrictors, speckled kingsnakes readily consume venomous snakes and are resistant to pit viper venom, particularly timber rattlesnake, prairie rattlesnake, and eastern copperhead venom. Steen et al. (2014) hypothesized that speckled kingsnakes regulate eastern copperhead abundance; as speckled kingsnake abundance declines, copperhead abundance increases and vice versa. The combination of superior constriction performance and immunity to snake venom makes the speckled kingsnake a formidable predator and, aptly, the king snake. Reproduction. Mating occurs in spring shortly after the snakes emerge from hibernation, in Iowa likely in late April or May as in Missouri (Johnson 2000). After they emerge, males begin looking for females, following scent trails to locate them, during which time they may engage in ritualized combat for access to females. During these dominance encounters, two males begin by lying stretched out with the posterior portions of their bodies intertwined and the rest of their bodies in contact but not as tightly twisted. As the combat proceeds, using his body for leverage, each male seeks to gain the dominant position by attempting to force his opponent’s head and forebody to the ground. The larger male is usually successful, crawling on top of the smaller male and holding him down. The smaller male may try to flee, but he is aggressively pursued by the dominant male. When they come into contact once again, the smaller male jerks his body

150  Speckled Kingsnake, Lampropeltis holbrooki

spasmodically, and the dominant male responds with powerful jerks of his own. The two continue wrestling for the superior position, biting each other during the later stages. This series of interactions goes on over and over, possibly for more than an hour, until one of the snakes (usually the smaller) leaves the area in defeat. When males and females meet, the male examines her with tongue flicking and then crawls alongside and on top of her, holds her still by biting her neck while searching with his tail for her vent, and orients his body into position for insertion of his hemipenis. The female remains passive, and mating may last over an hour. Females may mate with more than one male. Both male and female speckled kingsnakes mature in 2 to 4 years. Ovarian follicular growth begins in early May with greatly enlarged follicles present by late May (Trauth et al. 1994), suggesting ovulation likely occurs in late May or early June. The females are oviparous, laying 6 to 15 white adherent eggs in June or July using abandoned mammal burrows, rotting logs or vegetation, or possibly rock crevices as nest sites. The only Iowa reproductive data come from a 33.5-inch (85-cm) snout-vent length female in the Drake University Research Collection found on May 21 in Davis County that contained 18 enlarged ovarian follicles. Eggs hatch in August and September after an incubation period of about 59 days. However, temperature influences the incubation period and hatchling fitness; hatchlings incubated at 82º F (28° C) have better escape and strike development than those incubated above or below that temperature, and those incubated at a temperature of 71.6º F (22° C) or less fail to hatch. Hatchlings average 9 to 10.6 inches (23–27 cm) total body length. Meade (in Wright and Wright 1957) stated that “young speckled kingsnakes are agile and slender, about the size of a lead pencil, and as brilliantly colored as green and gold enamel.” Longevity. A wild-caught adult male survived in captivity an additional 14 years,

5 months, and 22 days.

EASTERN MILKSNAKE Lampropeltis triangulum (Lacépède) 1789

Adult eastern milksnake from Cedar County. Photo by James L. Christiansen.

Iowa Status. Protected nongame. Historical Summary. The eastern milksnake has also been called the milksucker, cow-sucker, corn snake, calico snake, house moccasin, painted king snake, spotted adder, and thunder-and-lightning snake. The first mention in the literature in Iowa appears to be in the History of Fremont County, Iowa (Anonymous 1881a), which referred to two formerly recognized subspecies as the “spotted adder” and the “corn snake,” respectively. The first confirmed specimens appear to be in 1881 from Keokuk in Lee County (Goodman 1948) and 1884 from Des Moines in Polk County (National Museum of Natural History–Smithsonian Institution). Osborn (1892) mentioned a specimen in the Iowa State Natural History Collection and Somes (1911) listed eastern milksnakes as occurring in Iowa. Formerly, twenty-five subspecies of milksnake were recognized, two of which, the eastern milksnake, L. t. triangulum, and the red milksnake, L. t. syspila, had ranges that included Iowa. Ruane et al. (2014) used genetic evidence to show the

152  Eastern Milksnake, Lampropeltis triangulum

milksnake species complex was derived from distinct lineages that do not correspond to the formerly recognized subspecies and proposed the eastern milksnake as a distinct species that includes the former two subspecies. As a result, only the eastern milksnake is currently recognized in Iowa. Description. Eastern milksnakes are slender snakes with 20 to 30 brown, gray, or-

ange, or red dorsal blotches or bands bordered in black on a white, gray, or brown background. Smaller black lateral blotches may be present along the length of the body or may be virtually absent. The western variant is distinguished by a light collar and lateral blotches that are reduced or absent. The head is not distinctly larger than the neck, the nose is blunt, and a Y- or V-shaped mark near the back of the head connects to the first body blotch or to a light-colored collar on the nape of the neck. The mark on the head gives rise to the specific name triangulum from the Latin meaning “triangle.” The belly is white or cream with an irregular black checkerboard pattern. The body scales are smooth and in 21 rows at midbody; the anal plate is single. There are usually 7 supralabial scales and 8 to 9 infralabial scales. Juveniles are more brightly colored and have a bolder pattern—deep red blotches on a white or gray background—than adults. The bold pattern of juveniles fades with age.

Juvenile western variant eastern milksnake from Linn County.

Lampropeltis triangulum, Eastern Milksnake  153

Examination of sexual dimorphism in 45 Iowa adult eastern milksnake museum specimens (24 males; 21 females) found the number of subcaudal scales (male mean 49; female mean 44) and tail length as a proportion of total body length (male 14%; female 13%) differed significantly between males and females, with males having more subcaudal scales and a longer tail. Size. Lampropeltis triangulum generally ranges from 24 to 36 inches (61–91.8 cm)

total body length. The largest specimen in the Drake University Research Collection is a female from Jefferson County measuring 38.6 inches (98 cm) total body length; the largest male is from Webster County measuring 35.9 inches (91.1 cm) total body length. The record total body length reported for the species is 52 inches (132.1 cm). Similar Species. Prairie kingsnakes have brown, black, or reddish dorsal blotches, 2 broad stripes that barely extend onto the back of the head, a cream belly with scattered rectangles, and 25 dorsal scale rows at midbody. Western foxsnakes, northern watersnakes, and juvenile western ratsnakes have keeled scales and divided anal plates. Eastern copperheads have unmarked heads, hourglass-shaped dorsal blotches, keeled scales, and a facial pit between the nostril and eye.

Adult western variant eastern milksnake from Ringgold County showing light-colored collar. Photo by Ryan D. Rasmussen.

154  Eastern Milksnake, Lampropeltis triangulum

Distribution. Eastern milksnakes are found from southeast Minnesota, Iowa,

Missouri, Arkansas, and Louisiana north and east through New England and southern Canada. In Iowa, they are found essentially statewide. In the mid-1940s, the species was known from 26 counties. At present, records exist from 62 of Iowa’s 99 counties. The exception is in north-central Iowa in the Des Moines Lobe region along the Minnesota border, where no records exist (Oldfield and Moriarty 1994). The snakes also appear to be rare in northwest Iowa, where they are found in scattered populations. Milksnakes are commonly found in northeast and central Iowa. Six of the 62 counties (10%) have only pre-1950 records, while 35 of the 62 (57%) have only post-1960 records and another 21 (34%) have both pre- and post-1960 records, suggesting the snakes are still quite common in the state. Eastern milksnake distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

Habitat. These snakes inhabit rocky woodlands, blufflands, woodland edges, wooded stream valleys, old quarries, pastures, and other grasslands adjacent to woodlands and are often found associated with farmsteads and other buildings. I have found them in a hole in a limestone outcrop in Backbone State Park in Delaware County and under a cattle tank in Mills County, and once I found a brightly colored juvenile coiled up on the steps into the house in my mother’s garage in Linn County. Of 19 eastern milksnake observations where Reeve Bailey took habitat notes, 15 were found in or adjacent to woodlands, 2 were in the city of Ames, another was along a wooded river, and yet another was in a field. Numerous Iowa records report the observation location as “under a flat rock on a grassy hillside.” Behavior. Eastern milksnakes are generally mild-tempered, but if alarmed they

may take a defensive position—coiling, vibrating their tails, striking, and spraying musk or feces. Others may just coil up and hide their heads beneath the coils. If they do bite, they often hold on and chew. The first snake I was ever bitten by was a small eastern milksnake in the Clayton County Conservation Board’s wildlife

Lampropeltis triangulum, Eastern Milksnake  155

exhibit. I was working as a naturalist for the county and was showing the snake to a group of senior citizens from a local care facility. During the presentation, the snake bit me on the little finger and began chewing a bit. It was no more than a pinprick, and I continued talking while removing the snake from my finger and using the teachable moment to discuss snakebites. When the program was over and the visitors were getting back on the bus, an elderly lady was asked how she enjoyed her day. She excitedly responded, “It was great! I have never seen anyone get bit by a snake before.” Although eastern milksnakes may bite, they often calm down and become docile in captivity; this along with their striking coloration has made the species a favorite of the pet trade. These secretive snakes, when not out hunting, spend much of their time under rocks, rotting logs, bark, boards, or other debris or underground in small mammal burrows. They are primarily nocturnal but may be active during the day, especially in the spring or fall, preferring air temperatures between approximately 50 and 84° F (10–29° C). They do not normally bask in direct sunlight but instead get heat through contact with the undersides of sun-warmed objects. In Illinois, most were found under cover early in the morning or late in the afternoon, with only one individual found active during midday, and most roadkills occurred at night (Dyrkacz 1977). Eastern milksnakes show greater fidelity to individual shelters than do other snakes, with some individuals returning to the same shelter multiple times in a year and others using the same shelter over multiple years. Several gravid females may use the same shelter, presumably because sites with optimal temperatures for gestation are limited. Home range sizes may vary from 17.5 to 49.4 acres (7.07–20 ha), with males moving farther distances than females. The collection/observation dates of 547 Iowa eastern milksnakes show the species has been found in every month of the year with the exception of February and December, with the earliest individual found on January 13 in Linn County. The primary activity period is from April through late October or early November. Activity in Iowa appears to be bimodal with the highest peak in April through June (69% of records) and a second peak in September and October (21% of records). Missouri eastern milksnakes are often found under deeply embedded rocks and are seldom near enough to the surface to be discovered except in early spring (Anderson 1965). Although the snakes can be found throughout the summer in Iowa, observation records suggest a similar pattern of high spring and early summer surface activity that decreases during the rest of the activity season, with 44 percent of records in May alone. After spring emergence, the snakes bask near their hibernacula for a period of time before dispersing to summer feeding areas,

156  Eastern Milksnake, Lampropeltis triangulum

238

Number of Records

250 200 150

91

100 47

50 0

1

0

1

Jan

Feb

Mar

Apr

67 31

May

Jun

Jul

47

19 Aug

Sep

Oct

5

0

Nov

Dec

Month Collection/observation dates of 547 eastern milksnakes in Iowa.

which may also explain the large number of spring observations. By October, the snakes have returned to their overwintering sites. The latest Iowa record is an individual found in Linn County on November 20. Eastern milksnakes may use old wells and cisterns, crevices in rock outcrops, gravel and dirt banks, and building foundations as hibernacula, and they may overwinter with other species such as timber rattlesnakes. In Minnesota, they hibernated in dry hills and moved to moister valleys during the warmer months (Breckenridge 1958). Late fall and early spring Iowa records provide clues to likely overwintering sites. Eastern milksnakes have been found on rocky hillsides and in the basements of houses in October, in a basement in March, and in an old quarry and under the porch of a house in April. Given the lack of rocky terrain or outcrops in the vicinity of some late fall and early spring observations in Iowa, it is likely that mammal burrows are used in these locations. Threats. Little is known about the predators of this snake, although reported

predators include bullfrogs, brown thrashers, hawks, and other milksnakes. Its secretive habits may protect it from many raptorial and mammalian predators, although raccoons and domestic cats likely pose a threat to snakes residing near farmsteads or residential houses. Disease may be a concern for some populations. A coccidian parasite was found in Iowa eastern milksnakes (Wacha and Christiansen 1974), and infections of snake fungal disease have been confirmed in some populations within the species’ range. Loss of habitat due to the clearing of open woodlands and woodland edge communities for agriculture and urban

Lampropeltis triangulum, Eastern Milksnake  157

and rural development likely poses the biggest threat in Iowa. In the early 1980s, Jim Christiansen concluded eastern milksnakes are especially sensitive to the loss of woodland-meadow edges and have been reduced as a result of the loss of natural woodlands and prairies. Many eastern milksnakes die each year in Iowa due to road mortality, most often in the spring and fall as they move from and to overwintering sites. Climate change may also affect the suitability of the habitats these snakes need in order to survive. Food and Feeding. The common name milk snake, along with the older milksucker and cow-sucker, comes from the myth that these snakes steal milk from the udders of cows. In reality, eastern milksnakes are constrictors that consume small mammals, birds and bird eggs, other snakes including their own species, lizards, and insects; small mammals such as mice, voles, and shrews are their preferred prey and the snake frequently raids small mammal nests. Brown (1979) reported the diet of eastern milksnakes to be 79 percent small mammals, 12.7 percent birds, and 8.1 percent reptiles by volume. Like many kingsnakes, eastern milksnakes may eat venomous snakes and are resistant to the venom of timber rattlesnakes, prairie rattlesnakes, and eastern copperheads. The milk-drinking myth likely comes from the common occurrence of finding these serpents in barns and milking parlors where their rodent prey is abundant. The benefits of these snakes as a hunter of small mammals have been recognized by some. Guthrie (1926) stated, “The milk-snake is often found around farm buildings, where it feeds on rats and mice. It fearlessly follows them into any place where they are able to penetrate, destroying their entire broods of young, so it is exceedingly valuable. There are some farmers who appreciate its value as an ally in the war on rodents.” Examination of the stomach contents of 50 eastern milksnake specimens in the Drake University Research Collection found identifiable items in only 3. One contained a shrew, one contained a naked apparently newborn vole, and the third, a juvenile from Dubuque County, contained an almost complete shed snakeskin (no bones or teeth present) about the same size as the preserved snake. It is unknown whether the snake ate its own shed skin or that of another snake. LeClere (2013) reported an adult from Mills County consumed a juvenile prairie vole and a hatchling from western Iowa ate a lined snake. Another Iowa record noted an eastern milksnake from Winneshiek County regurgitated a red-bellied snake. Reproduction. Both sexes mature in approximately 3 to 4 years at around 16 to

20 inches (40.6–51 cm) total body length. Mating occurs in spring, likely April into early June in Iowa. After emergence from hibernation, males begin looking for females, following scent trails to locate them. When males and females meet,

158  Eastern Milksnake, Lampropeltis triangulum

the male investigates the female with tongue flicking, places several loops of his body over her back, grasps her neck with his mouth, and vigorously undulates his body while using his tail to search for her vent. Once his hemipenis is inserted, he straightens out his tail so that it lies beside the female’s tail. The entire courtship and mating sequence may last approximately an hour. Examination of 10 Iowa adult female museum specimens found females with enlarged ovarian follicles in mid-May and oviductal eggs in mid-June, suggesting ovulation in Iowa likely occurs in late May or early June. Sometime in late June or July, the female lays her eggs. Eastern milksnakes are oviparous with females using rodent burrows, loose soil, and the undersides of rocks, rotting logs, or stumps as nest sites, and several females may lay their eggs at the same site. Clutch size is proportional to female size, with larger females producing more eggs than smaller females. Across the range of the species, clutch size has been reported at 6 to 24 eggs. In the Midwest, clutches of 5 to 11 eggs (Dyrkacz 1977, Illinois), 1 to 13 eggs (Johnson 2000, Missouri), and 8 to 12 eggs (Vogt 1981, Wisconsin) have been reported. Counts of enlarged ovarian follicles and shelled oviductal eggs in Iowa female museum specimens resulted in average clutch sizes of 12.5 eggs (range 10–15; n = 2) and 8.5 eggs (range 8–9; n = 2), respectively. Loomis (1948) reported a 32-inch (81.3-cm) total body length female from Adams County that laid 8 eggs.

Eastern milksnake eggs laid by a Decatur County female hatched in Jim Christiansen’s lab. Photo by James L. Christiansen.

Lampropeltis triangulum, Eastern Milksnake  159

Eggs hatch in August and September after an approximately 50- to 70-day incubation period with hatchlings ranging from 7.5 to 11 inches (19–28 cm) total body length. Iowa young-of-the-year museum specimens average 9.5 inches (24.2 cm; n = 4) total body length. In 1984, Jim picked up a female eastern milksnake in Decatur County on June 3 that laid 11 eggs a few days later. He noted the eggs were more elongated— approximately 1.3 inches long by 0.8 inch wide (34 × 20.5 mm)—than those of larger snakes and varied surprisingly in shape, with some nearly teardrop-shaped (one end much smaller than the other), others oval (both ends almost pointed), and still others evenly elliptical. He incubated the eggs in his lab at Drake University until August 26 when they began hatching. Each hatchling cut a slit in the shell with its egg tooth, a sharp calcified point on the end of the snout that drops off after hatching. The hatchlings did not extend their heads out of the slit for 1 to 2 days after piercing the egg, and it was 4 days from the time the first hatchling emerged until all hatchlings had emerged. Longevity. A wild-caught adult male survived in captivity an additional 21 years,

4 months, and 14 days, and survival in the wild of up to 14 years has been reported. Jim maintained one of the eastern milksnake hatchlings from Decatur County in his lab for 21 years and 3 months.

PLAIN-BELLIED WATERSNAKE Nerodia erythrogaster (Forster) 1771

Adult plain-bellied watersnake from Louisa County. Photo by Jeff LeClere.

Iowa Status. Endangered; species of greatest conservation need. Historical Summary. The plain-bellied watersnake has also been called the

copperbelly water snake, yellowbelly water snake, copper-bellied moccasin, orange-bellied moccasin, Mississippi Valley copper belly, and red-bellied black snake. The History of Fremont County, Iowa (Anonymous 1881a) referred to it as the “red-bellied water snake”; however, this was likely a northern watersnake that was misidentified based on the reddish half-moons on the bellies of those watersnakes, as there is no other indication that plain-bellied watersnakes have occurred in southwest Iowa. The first confirmed specimen in the state was a snake collected in the 1920s “in the vicinity of Mt. Pleasant” in Henry County (exact date unknown) and deposited in the collection of the Chicago Academy of Sciences and its Peggy Notebaert Nature Museum. The specimen is now missing; however, museum staff examined it in the 1980s at the request of Jim Christiansen and confirmed that it was a plain-bellied watersnake. Wright and Wright (1952)

162  Plain-Bellied Watersnake, Nerodia erythrogaster

listed the plain-bellied watersnake as “problematic” in Iowa—that is, hypothetical, accidental, introduced, puzzling, questionable, unverified, or extinct—and Conant (1958) included a map showing an isolated population in Henry County based on the museum specimen. Formerly, six subspecies of plain-bellied watersnake were recognized, two of which, the yellow-bellied watersnake, N. e. flavigaster, and the copperbelly watersnake, N. e. neglecta, had ranges that included Iowa. In 2010, Makowsky et al. used genetic evidence to show the plain-bellied watersnake complex represents a single widespread species that does not correspond to the formerly recognized subspecies. As a result, the subspecies are no longer recognized. Description. Adult plain-bellied watersnakes are large and heavy-bodied uniformly gray, dark brown, or black snakes with no trace of a pattern. The belly is orange to orange-red and mostly unpatterned (erythrogaster comes from the Greek erythros meaning “red” and gaster meaning “belly” or “stomach”; the genus Nerodia honors Nereis, a Greek sea nymph), although black pigment may spread onto the ventrals from the lateral scales and is most dense on the posterior twothirds of the belly. The eyes are large and the labial scales range from pale yellow to orange with dark bars on the supralabials. The chin and throat are white to yellow. The body scales are strongly keeled and in 23 to 25 rows at midbody; the anal plate is divided. There are usually 8 supralabial scales and 10 infralabial scales.

Juvenile plain-bellied watersnake from Louisa County. Photo by Jeff LeClere.

Nerodia erythrogaster, Plain-Bellied Watersnake  163

Juveniles are light brown and strongly patterned with brown dorsal and lateral blotches that may fuse to form transverse bars. The belly is light yellow to very light orange with less black pigment than adults. As the snake ages, the black pigment increases, the belly becomes orange to orange-red, and the dorsal pattern disappears, usually between eight to twelve months after birth (Christiansen and LeClere 2002). Ventral scales number 132 to 161 in both sexes, subcaudal scales range from 67 to 90 in males and 46 to 79 in females, and tail length as a proportion of total body length averages 25 percent for males and 21 percent for females (Ernst and Ernst 2003). Only 3 complete adult plain-bellied watersnake specimens are found in the Drake University Research Collection: a male 26.7 inches (67.8 cm) snout-vent length with 147 ventral scales, 80 subcaudal scales, and tail length 26 percent of total body length and 2 females 31.7 inches (80.4 cm) and 32.2 inches (81.7 cm) snout-vent length averaging 149 ventral scales, 64 subcaudal scales, and tail length 21 percent of total body length. Size. Nerodia erythrogaster generally ranges from 30 to 48 inches (76–122 cm) total

body length. Females are larger than males. The largest specimen in the Drake University Research Collection is a female from Muscatine County measuring 40.6 inches (103.1 cm) total body length; the largest male is from Louisa County measuring 35.9 inches (91.3 cm) total body length. Several records in the Iowa Department of Natural Resources Natural Areas Inventory Database indicate plain-bellied watersnakes over 40 inches (101.6 cm) total body length, including a record from Louisa County that reported the snake at “about 49 inches” (124.5 cm). The record total body length reported for the species is 64.4 inches (163.6 cm). Similar Species. Plain-bellied watersnakes can be separated from Iowa’s other

watersnakes by the lack of a pattern on the belly, although the black pigment on the lateral scales may extend onto the ventrals. Northern watersnakes and diamond-backed watersnakes both have a dorsal pattern and half-moons on the belly. Graham’s crayfish snake is solid brown above with a cream or tan lateral stripe on the sides and a cream, tan, light yellow, or white belly without black pigment. North American racers have smooth scales, a single anal plate, and a white to yellow belly. Juvenile plain-bellied watersnakes can be difficult to identify, but the combination of keeled scales, a divided anal plate, a light yellow to very light orange belly, and bands on the anterior third of the body that become alternating dorsal and lateral blotches posteriorly separates them from other patterned small snakes.

164  Plain-Bellied Watersnake, Nerodia erythrogaster

Distribution. The plain-bellied watersnake is found from southeast Kansas,

Oklahoma, and east Texas east to Georgia and North and South Carolina. A finger of the range extends north along the Mississippi River to southeast Iowa. Iowa is near the northern edge of the species’ range and the snake is restricted to southeast Iowa, predominantly along the Mississippi River. In spite of the Henry County specimen, the serpent was not thought to occur in the state in the 1940s and at present is known only from 4 of Iowa’s 99 counties, though Henry County is represented by only the single specimen collected in the 1920s, and no additional observations have been reported in that county despite searches since the early 1970s. In 1981, Jim concluded the snake was one of Iowa’s most severely endangered species due to its position at the northern periphery of its range. Plain-bellied watersnake distribution in Iowa. Blue = pre-1960 Yellow = post-1960

Habitat. Plain-bellied watersnakes inhabit large rivers, streams, backwater

sloughs, and floodplain woodlands and pools and prefer habitats with abundant emergent vegetation, brushy banks, and slow-moving water. In Iowa, they are primarily associated with the Mississippi River and its islands and backwaters. They can be quite terrestrial at times and range farther from water than other watersnakes. Roe et al. (2003) found them in uplands nearly 30 percent of the time, sometimes over 328 feet (100 m) from the nearest wetland. In addition, they found plain-bellied watersnakes used twice as many wetlands, moved between wetlands three times more often, and moved to small wetlands seven times more often than do northern watersnakes. Jim noted that most of the adults he found over the years were on dry land, and one was feeding in dense emergent vegetation in 6 inches (15.2 cm) of water. Of the young-of-the-year and juveniles he found, most were under rotting logs in open floodplain woodlands with a good mix of grasses and other herbaceous vegetation along with many small pools and interconnected shallow oxbows. They have also been found in Iowa basking on levees and partially flooded roads, in brush along the shoreline, under logs in floodplain

Nerodia erythrogaster, Plain-Bellied Watersnake  165

Adult plain-bellied watersnake basking in Louisa County. Photo by Jessica Bolser.

woodlands, and even in a residential yard in the city of Muscatine approximately 0.25 mile (402 m) from the Mississippi River. Behavior. Like most watersnakes, plain-bellied watersnakes are quick-tempered.

When first approached, they will almost always head for cover in the nearest underbrush, dive into the water and swim away, or hide on the bottom where they can remain submerged for up to thirty to sixty minutes (Ernst and Ernst 2003). Encountered in the water, they often head for land to escape, a behavior very different from that of other watersnakes. If escape is not possible, they become a formidable adversary, flattening the head and stiffening the body, ready to strike. If grabbed, the serpent thrashes frantically, sprays foul-smelling musk and liquid feces, and bites hard and repeatedly all in an attempt to convince the attacker to let go, which often works. The collection/observation dates of 50 Iowa plain-bellied watersnakes show the species has been found from May through October; however, it is likely the snake is active by late April in most years. Just to the south in Missouri, activity has been reported from March through October (Johnson 2000). The earliest Iowa record

166  Plain-Bellied Watersnake, Nerodia erythrogaster

is from Louisa County on May 15. Plain-bellied watersnakes are primarily nocturnal and spend much of the day under rotting logs, bark, or other debris or basking on branches over the water or on partially submerged logs. The snakes begin basking and hunting during the day in the spring when the temperature is above 60° F (15.6° C) and return to shelter at night as the temperature drops (Diener 1957). As the days grow longer and warmer throughout the summer, they bask or hide during the daylight hours and forage for food at night. As cooler weather returns in the fall, they once again bask and forage during the warmer daylight hours. Iowa observation records are consistent with this pattern, showing a decreasing number of observations from May through September, possibly reflecting the nocturnal habits of the snake during this time, with a slight uptick in observations in October as they become somewhat more diurnal just prior to hibernation. Both wetland and upland hibernation sites may be used, suggesting both wetlands and adjacent uplands are equally important for this species. They hibernate individually and prefer inactive crayfish burrows, although other animal burrows, rotting stumps, and beaver and muskrat lodges or bank burrows are also used. The sites may be close to water and the wetlands they use during the summer or located in upland areas some distance from the nearest wetland, and individuals often return to the same hibernation site in multiple years. The latest Iowa record is an individual found in Louisa County on October 30. Threats. The aggressive nature of large adults may provide some defense against

predators, but larger mammals such as raccoons likely eat them when the opportunity arises. Juveniles are easier prey and are eaten by snapping turtles, large­mouth

Number of Records

20 15

15

12 9

10

8

5 0

0

0

0

0

Jan

Feb

Mar

Apr

2 May

Jun

Jul

Aug

Sep

Month Collection/observation dates of 50 plain-bellied watersnakes in Iowa.

4

Oct

0

0

Nov

Dec

Nerodia erythrogaster, Plain-Bellied Watersnake  167

bass, loggerhead shrikes, predatory aquatic birds, and other snakes. Raptors may prey on both adults and juveniles, and plain-bellied watersnakes may be more susceptible to raptor predation than other watersnakes due to their more terrestrial habits. Disease may be a concern as parasite infestations and snake fungal disease have been confirmed in some populations. Habitat loss and fragmentation, road mortality, water pollution, and climate change likely pose the biggest threats in Iowa. Food and Feeding. Plain-bellied watersnakes are active hunters that forage both

in the water and on land and primarily consume amphibians, such as salamanders, frogs, toads, and their tadpoles, along with various species of fish. Crayfish and aquatic insects may also be eaten. They consume a higher proportion of frogs and toads than do other watersnakes and undergo an abrupt change in diet from fish to frogs and toads as they grow (Mushinsky and Hebrard 1977; Mushinsky et al. 1982). Byrd et al. (1988) reported 65 percent frogs and toads and 35 percent fish in the diet in Arkansas, and Diener (1957) reported 92 percent frogs and 5.5 percent fish in the Kansas diet. One individual in Oklahoma regurgitated a large meal consisting of 56 young green sunfish, 16 goldstripe darters, 5 central newt larvae, and 2 gray treefrog tadpoles (McKnight et al. 2014). In Iowa, LeClere (2013) watched a plain-bellied watersnake feeding on young bullheads in a nearly dry pool in Louisa County by loosely coiling around the fish to trap them for easy capture. Jim recounted a time in Louisa County when he heard a bullfrog distress call and found a plain-bellied watersnake in the process of consuming a large subadult bullfrog legs first. As he watched, the last of the frog disappeared into the snake’s mouth. The snake took off underwater and was lost for several minutes until the distress call of the frog was again heard, this time from inside the stomach of the snake. Using the call of the frog, Jim was able to locate and capture the snake. After photographing it, he released it. After release, while the snake lay coiled on the edge of the water, it regurgitated the frog. The frog righted itself, looked around, and hopped into the water after having resided in the stomach of the snake for at least thirty minutes. Reproduction. Both sexes mature in approximately 3 years at around 27 to 30 inches (68.6–76 cm) total body length for females and 28 to 30 inches (72–76 cm) total body length for males. Mating occurs in spring, likely May into early June in Iowa, either in shallow water or in brush along the shoreline. LeClere (2013) observed a courting pair in Louisa County on May 27. During courtship, males follow scent trails to find females; when they meet, the male crawls alongside her, places several loops of his body over hers, uses his head to press her head to the

168  Plain-Bellied Watersnake, Nerodia erythrogaster

Adult plain-bellied watersnake in Louisa County. Photo by Jessica Bolser.

ground, and aligns his vent with hers. If receptive, the female will raise her tail and the pair will remain intertwined during copulation. Females may store sperm for almost 2 years after mating (Ernst and Ernst 2003). Plain-bellied watersnakes are viviparous with females giving birth to live young in August and September. Iowa young-of-the-year museum specimens have been found as early as August 12. Litters generally range from 10 to 20 young (over 30 are possible), with newborns ranging from 7.1 to 11.8 inches (18–30 cm) total body length. Litter size is proportional to female size, with larger females producing more young than smaller females. LeClere (2013) reported a Louisa County female giving birth to 25 young. Examination of the 2 adult females in the Drake University Research Collection found the one collected on July 15 had 17 recently ovulated ova, 5 of which were smaller than the rest and might not have produced an embryo, consistent with Laposha et al. (1985), who reported stillborn young or unfertilized eggs are often passed by this species at the time of birth. Minton (1972) suggested that this might indicate that the female reproductive cycle is not well adapted to a northern climate. The second female, collected on June 24, contained no enlarged follicles or ova and would not have had young that year, suggesting that Iowa females may not reproduce every year. Longevity. A wild-caught juvenile survived in captivity an additional 14 years, 11 months, and 17 days.

DIAMOND-BACKED WATERSNAKE Nerodia rhombifer (Hallowell) 1852

Adult diamond-backed watersnake from Louisa County. Photo by Ryan D. Rasmussen.

Iowa Status. Threatened; species of greatest conservation need. Historical Summary. The diamond-backed watersnake has also been called

Holbrook’s water snake, diamond-back moccasin, and North American rhombmarked snake. The History of Fremont County, Iowa (Anonymous 1881a) listed “Holbrook’s water snake” as occurring in the county, but this may have been a hypothetical listing. The first confirmed specimens in the state appear to be two snakes collected in the late 1800s near Burlington in Des Moines County (Museum of Comparative Zoology–Harvard University). Somes (1911) stated the species was found in Iowa but indicated the record was uncertain. Conant (1958) indicated the species was found in extreme southeast Iowa. Description. Diamond-backed watersnakes are heavy-bodied olive, gray, or most

often light brown snakes with a series of dark dorsal blotches that are often attached to lateral blotches by a thin dark line. The dark borders of the blotches connect in a chainlike pattern down the midline of the back (rhombifer is New

170  Diamond-Backed Watersnake, Nerodia rhombifer

Belly of an adult diamond-backed watersnake from Lee County. Photo by Jeff LeClere.

Latin meaning “rhomb bearer” in reference to the rhomboid dorsal pattern; the genus Nerodia honors Nereis, a Greek sea nymph). The head is darker brown with dark bars on the yellow supralabials, the eyes are rotated toward the top of the head enabling the snake to see above the water surface when its head is submerged, and males have prominent tubercles on the chin. The belly is cream to yellow with black half-moons. The body scales are strongly keeled and in 25 to 31 rows at midbody; the anal plate is divided. There are usually 8 supralabial scales and 11 infralabial scales. Juveniles are patterned like adults but the pattern is more noticeable and the belly often has an orangish tint. Ventral scales number 132 to 152 with no obvious sexual dimorphism, subcaudal scales range from 68 to 88 on males and 56 to 73 on females, and males have a longer tail (Ernst and Ernst 2003). Examination of sexual dimorphism in 8 Iowa adult diamond-backed watersnake museum specimens (5 males; 3 females) found tail length as a proportion of total body length (male 25%; female 20%) differed significantly between males and females. Size. Diamond-backed watersnakes generally range from 30 to 48 inches (76–122

cm) total body length. Females are larger than males. The largest specimen in the Drake University Research Collection is a male from Louisa County measuring

Nerodia rhombifer, Diamond-Backed Watersnake  171

40.6 inches (103 cm) total body length; the largest female is from Lee County measuring 34.9 inches (88.7 cm) total body length. The record total body length reported for the species is 69 inches (175.3 cm). Similar Species. The northern watersnake is the Iowa snake most similar in appearance to diamond-backed watersnakes. Northern watersnakes have dark gray to brown bands extending across the anterior third of the body breaking into rectangular dorsal blotches over the remainder of the body and extending onto the tail, a belly with reddish brown half-moons, and 21 to 25 scale rows at midbody. Both northern and diamond-backed watersnakes can become dark with age, nearly obscuring the pattern; therefore, it is sometimes easiest to check the belly for the presence of reddish brown or black half-moons. Distribution. This watersnake is found from southwest Indiana, southeast Iowa, and southeast Kansas south to the Gulf of Mexico and from western Alabama to eastern Texas; it is mostly absent from the central highlands of Missouri, Arkansas, and eastern Oklahoma. Iowa is at the extreme northern edge of the species’ range and the snake is restricted to southeast Iowa, predominantly along the Mississippi and Chariton Rivers. The serpent was known from only a single county in the 1940s; at present, records exist from only 6 of Iowa’s 99 counties. In 1981, Jim Christiansen concluded the snake was one of Iowa’s most severely endangered species due to its position at the northern periphery of its range. Diamond-backed watersnake distribution in Iowa. Yellow = post-1960 Green = both pre- and post-1960

Habitat. Diamond-backed watersnakes inhabit rivers, backwater sloughs, ox-

bows, and ponds, preferring gently sloping and sparsely vegetated banks with overhanging trees, logs, stumps, or large rocks for basking and hiding. In Iowa, they may be locally abundant, especially in places with many fallen trees and good sun exposure for at least part of the day. In Appanoose County, Jim found them in ponds up to 0.25 mile (0.4 km) from the Chariton River. Juveniles prefer vegetated areas or rock crevices and avoid open water. The serpents are highly aquatic,

172  Diamond-Backed Watersnake, Nerodia rhombifer

using a wide range of water depths and distances from the shore, and do not travel as far from water as do plain-bellied watersnakes. Behavior. Few other Iowa snakes are as belligerent as the diamond-backed watersnake. They are often seen basking on dead branches of overhanging trees and are quick to flee into the water when approached, swimming underwater for some distance before reappearing with just the top of the head above the surface. They may voluntarily stay submerged for up to fifteen to thirty minutes (Gratz 1978). If escape is not possible, they strike viciously, readily biting while violently thrashing their body, leaving behind a wound consisting of several razor-like cuts made by their sharp needle-like teeth. Along with fiercely biting, they release foul-smelling feces and musk, with an odor that has a surprising lasting power, which it smears on the would-be predator. If the predator grasps the snake in its mouth, this glutinous discharge is smeared all over its face including the eyes and nose. This combination of aggressiveness and offensive discharge is an effective deterrent and often results in a quick release. The collection/observation dates of 50 Iowa diamond-backed watersnakes show the species has been found from April through October. The earliest Iowa record is from Appanoose County on April 16. Just to the south of Iowa in Missouri, they are active from late March through October (Johnson 2000). They are primarily nocturnal and spend much of the day basking coiled or straight on streambanks or riverbanks, overhanging branches, or partially submerged logs. They may be more diurnal in the spring, but as the days become longer and the temperatures increase throughout the summer, nocturnal activity increases and the snakes become more arboreal. As cooler weather returns in the fall, they once again bask and forage during the warmer daylight hours. By sometime in October, the snakes have found their overwintering sites. Hibernation occurs in crayfish burrows, muskrat or beaver lodges or bank burrows, or other retreats below the frost line. The latest Iowa record is an individual found in Appanoose County on October 10. Threats. This snake’s aggressive nature along with its behavior of quickly retreat-

ing into the water when danger appears provides a good defense against predators, and few reports of predation exist in the literature. Juveniles are easier prey and are eaten by large predatory fish, bullfrogs, snapping turtles, other snakes, loggerhead shrikes, predatory aquatic birds, raptors, and carnivorous mammals. Disease may be a concern as parasite infestations have been confirmed in some populations, including some in Iowa. The snakes become infected by eating intermediate hosts such as fish and tadpoles. Humans, however, are the biggest threat. Like other

Nerodia rhombifer, Diamond-Backed Watersnake  173

Number of Records

30

20

17 9

10

0

0

0

0

Jan

Feb

Mar

5

3 Apr

May

Jun

8

6 2

Jul

Aug

Sep

Oct

0

0

Nov

Dec

Month Collection/observation dates of 50 diamond-backed watersnakes in Iowa.

watersnakes, diamond-backed watersnakes are often killed by people believing them to be either the venomous water moccasin or the cottonmouth; however, despite rumors to the contrary, neither water moccasins nor cottonmouths occur in Iowa. Many more are killed due to habitat loss and fragmentation, road mortality, and water pollution. Death from DDT and heptachlor poisoning has been reported (Ernst and Ernst 2003), and exposure to high concentrations of the commonly used pesticide carbaryl has been shown to reduce swimming performance in newborns (Hopkins and Winne 2006). The effects of climate change on this species are likely to become increasingly significant as time goes on. Food and Feeding. Some of the information in this section is based on the

literature review presented in Gibbons and Dorcas (2004). Diamond-backed watersnakes are active hunters that find prey by both sight and smell. They primarily eat fish but will also consume frogs, toads, and salamanders and at least occasionally small turtles and mammals. In some places, fish constitute up to 98 percent of their diet, including various eels, minnows, mosquitofish, sunfish, and catfish. Small fish such as mosquitofish are important prey until the snakes reach a snout-vent length of more than 31.5 inches (80 cm), at which time the gape of the mouth is large enough that they can switch to larger fish such as catfish. Fish with pectoral and dorsal spines, which are a deterrent to some predators, are readily consumed, although sometimes not without difficulty. Cases have been reported where the spines of swallowed catfish penetrated the snake’s body wall and were observed projecting through the skin. Dead fish, fish heads, and other body parts

174  Diamond-Backed Watersnake, Nerodia rhombifer

left by anglers may be scavenged, but the serpents appear to have a preference for live fish. The snakes forage from the water, not the shore, with prey captured, handled, and ingested underwater. Specialization on fish by a predator with no limbs presents challenges to foraging for and handling prey. Adults generally employ openmouthed searching, with the snake stationary and moving its submerged head from side to side, grabbing any fish that touches its mouth, or swimming slowly in a figure-eight pattern to catch any fish its mouth touches. The snake may encircle small fish with its body, trapping them for easier capture. In flowing water, it may anchor its tail to a rock, face upstream with its mouth open, and grab any fish that contacts its mouth. In contrast, newborns attack from the surface with very little openmouthed searching, instead using a sit-and-wait approach at the surface. As the young snakes age, they gradually shift from hunting in dense aquatic vegetation to hunting in open water and spend more time foraging underwater and less time on the surface. Reproduction. Both sexes mature in approximately 2.5 to 3 years at around 27

to 31.5 inches (68.6–80 cm) snout-vent length. Mating occurs in spring soon after emergence from hibernation, likely late April into May in Iowa, either in shallow water or along the shoreline. Multiple males may court a single female. While

Juvenile diamond-backed watersnake from Appanoose County. Photo by Ryan D. Rasmussen.

Nerodia rhombifer, Diamond-Backed Watersnake  175

mating, the snakes intertwine with the male on top, and he may rub his chin tubercles on the female or touch her neck with his tongue. If the female is receptive, mating may last up to an hour. Diamond-backed watersnakes are viviparous with females giving birth to live young from late August to early October. Litters generally range from 8 to 62 young with newborns ranging from 7.9 to 13 inches (20–33 cm) total body length. Litter size is proportional to female size, with larger females producing more young than smaller females. Examination of 2 adult females in the Drake University Research Collection found a female collected in Muscatine County on May 17 had a distinct set of 18 elongated enlarging ovarian follicles, suggesting ovulation would have occurred in late May or early June, consistent with Missouri females who ovulated between May 15 and June 15 followed by a 3-month gestation period (Betz 1963). A 28.6-inch (72.7-cm) snout-vent length female from Lee County collected on August 19 contained 14 embryos, half of which had internalized nearly all their external yolk sacs with the other half still retaining small yolk sacs, suggesting this female would likely have given birth by early September. LeClere (2013) reported a gravid Louisa County female found on May 8 that gave birth to 24 young on September 8 averaging 11.4 inches (29 cm) total body length. Longevity. A wild-caught juvenile survived in captivity an additional 4 years and

11 months.

NORTHERN WATERSNAKE Nerodia sipedon sipedon (Linnaeus) 1758

Adult northern watersnake from Linn County. Photo by Joshua G. Otten.

Iowa Status. Protected nongame; species of greatest conservation need. Historical Summary. The northern watersnake has also been called the banded watersnake, spotted watersnake, mud moccasin, water moccasin, North American water snake, and spotted water adder. The History of Fremont County, Iowa (Anonymous 1881a) lists the “red-bellied water snake”—the plain-bellied watersnake—as occurring in the county; however, this was likely a northern watersnake misidentified due to the reddish brown half-moons on the bellies of these snakes. The first confirmed specimen in the state appears to be one collected in 1868 near Keokuk in Lee County (Goodman 1948). Osborn (1892) reported the species was common in Iowa. Cope (1900) reported the species near Des Moines in Polk County, and Somes (1911) listed northern watersnakes as occurring in Iowa. Four subspecies of the common watersnake, Nerodia sipedon, are currently recognized, only one of which, the northern watersnake, N. s. sipedon, has a range that includes Iowa.

178  Northern Watersnake, Nerodia s. sipedon

Juvenile northern watersnake from Davis County. Photo by Ryan D. Rasmussen.

Description. Northern watersnakes are heavy-bodied gray to tan snakes with 8 to 16 wide dark gray to brown bands extending across the anterior third of the body that break into 20 to 30 rectangular blotches that alternate along the back and sides over the remainder of the body and extend onto the tail. There is a great deal of variation in dorsal coloration and pattern with a few individuals almost black and others banded all the way to the tail. The eyes are large, and black bars are present on the supralabials. The chin, throat, and belly are cream to yellow with irregularly spaced reddish brown half-moons with black borders on the belly that continue to the tip of the tail. Some individuals may have an orange to light red stripe down the belly. The body scales are strongly keeled and in 21 to 25 rows at midbody; the anal plate is divided. There are usually 8 supralabial scales and 10 infralabial scales. Juveniles are more strikingly marked than adults with a light gray or tan background color contrasting with black blotches. As the snakes age, they become darker and the dorsal pattern is obscured. Examination of sexual dimorphism in 51 Iowa adult northern watersnake museum specimens (21 males; 30 females) found snout-vent length, the number of subcaudal scales (male mean 74; female mean 63), and tail length as a proportion of total body length (male 25%; female 21%) differed significantly between males and females. Females are larger and heavier than males, while males have more subcaudal scales and a longer tail than females.

Nerodia s. sipedon, Northern Watersnake  179

Size. Northern watersnakes generally range from 22 to 42 inches (56–106.7 cm)

total body length. The largest specimen in the Drake University Research Collection is a female from Wayne County measuring 53.8 inches (136.7 cm) total body length; the largest male is from Polk County measuring 35.8 inches (90.9 cm) total body length. The record total body length reported for N. sipedon is 59 inches (149.9 cm). Similar Species. No other Iowa snake has anterior bands that break into blotches

posteriorly. Diamond-backed watersnakes have a series of dark dorsal blotches that are often attached to lateral blotches by a thin dark line forming a chainlike pattern down the midline of the back, a belly with black half-moons, and 25 to 31 scale rows at midbody. Plain-bellied watersnakes are dark brown or black with no trace of a pattern and an orange to orange-red mostly unpatterned belly. Older watersnakes are often darker and can be confusing; the ventrals are the key to distinguishing them. Plain-bellied watersnakes lack half-moons on the belly, diamond-backed watersnakes have scattered black half-moons on the belly, and northern watersnakes have reddish brown half-moons on the belly. Distribution. The northern watersnake is found from Maine to eastern Minnesota and eastern Colorado to the Atlantic coast with the exception of southeast Missouri, southern Illinois, southwest Indiana, and points to the south where it is replaced by the midland watersnake (N. s. pleuralis). In Iowa, northern watersnakes are the most widely distributed watersnake in the state. Found across the southeast two-thirds, they follow the Des Moines River drainage northwestward but become progressively less common in north-central Iowa and are absent from far northwest Iowa. The snake is rare in western portions of the state, with scattered populations along the Missouri River as far north as Harrison County. A single road-killed specimen from 1987 exists from Dickinson County in an area where Reeve Bailey and other early herpetologists did extensive work. The species was not found by the early workers or during the more recent surveys conducted by researchers at Iowa Lakeside Laboratory. It is currently believed this specimen does not represent an extant population but is instead a single individual brought in as a stowaway on a boat (Neil Bernstein, personal communication, 2020). Although still considered common in the state and abundant in some locations, northern watersnakes have nonetheless declined. In the 1920s, Guthrie (1926) stated they were found “practically everywhere” in the state. By the mid1940s, they were known from 37 counties. During the 1970s, the serpent could be seen in large numbers on nearly every pile of debris along the banks of the state’s

180  Northern Watersnake, Nerodia s. sipedon Northern watersnake distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

larger rivers. By the late 1980s, they were much less common in these areas and were rarely seen in some places during the 1990s. At present, records exist for 73 of Iowa’s 99 counties, 3 of which (4%) have only pre-1945 records. Habitat. These watersnakes can be found in nearly any body of water, including

natural and artificial lakes and ponds, large and small streams, river backwaters, marshes and other wetlands, drainage ditches, and even urban parks. Vegetated banks with overhanging trees, logs, stumps, or large rocks for basking and hiding are important components of their habitats. They are often seen basking in trees that overhang the water or on rocks along the shore. In Wisconsin, clumps of dead cattails were the most used substrate for basking, followed by water and grass (Tiebout and Cary 1987). They do well in disturbed habitats and do not seem to mind human presence, often being found in popular fishing spots. Both upland and wetland characteristics influence the abundance of northern watersnakes; when wetland size and connectivity to other wetlands increase, the snakes increase in abundance (Attum et al. 2007). Although they may use multiple wetlands throughout the year, they use fewer wetlands and travel less between them than do plain-bellied watersnakes. In late August and early September, one of the best places to find young-of-the-year northern watersnakes is under flat rocks not far from a pool in a partially dry stream where they have easy access to stranded minnows. Behavior. Like other watersnakes, northern watersnakes are quick-tempered and pugnacious. Their first response is to flee under nearby cover or into the water when approached, diving to the bottom to hide for a few minutes before returning to the surface or swimming on the surface a short distance before returning to shore. If escape is not possible, they flatten their head and body, strike viciously and repeatedly, and readily bite—often holding on and chewing, leaving behind razor-like cuts made by their sharp needle-like teeth. Although not venomous,

Nerodia s. sipedon, Northern Watersnake  181

their bite can be painful. Linnaeus, who was not fond of snakes and who first named the species, may not have been so sure about the effect of the bite, as the specific epithet he chose, sipedon, comes from the Greek sepedon meaning “rottenness, decay; a serpent whose bite causes mortification”; the genus Nerodia honors the Greek sea nymph Nereis. In concert with fierce biting, these snakes release foul-smelling feces and musk that are smeared on the attacker. Once while I was looking for snakes with Jim Christiansen in Lee County, Jim found a large female northern watersnake under a piece of tin in a junkyard. After a brief struggle, he captured the snake. While he was holding her, the snake let go an explosive release of putrid feces and musk that thoroughly covered his chest and belly. As was often the case, Jim was wearing dress clothes in the field; nevertheless, like the true teacher he is, he calmly put the snake into a bag while giving me a lesson on the defensive behavior of the northern watersnake. While he may have been undaunted, I had to spend the next two hours in the car with him. These snakes are primarily nocturnal and forage mostly from twilight to midnight. They spend much of the day basking on shores, on beaver lodges, or on branches overhanging the water, sometimes in large groups several snakes deep and at times mixed with other species such as diamond-backed watersnakes. They prefer air temperatures between approximately 60 and 102° F (15.5–39° C) with most activity between 70 and 90° F (21–32° C). During the hottest parts of the day they move in and out of direct sunlight, often resting with only parts of their body exposed. Wisconsin northern watersnakes use an average home range of 13.3 acres (5.4 ha) throughout the year; however, they spend 50 percent of their time in an area of about 1 acre (0.4 ha) (Tiebout and Cary 1987). The collection/observation dates of 739 Iowa northern watersnakes show the species has been found from February through November, with the earliest individual found on February 18 in Linn County. In most years, the snakes emerge from hibernation in April and remain active through October. Observations decline during the hottest part of the summer, likely as the snakes become more nocturnal, leading to fewer observations. By October, the snakes have reached their overwintering sites and aboveground sightings generally cease. The latest Iowa record is an individual found in Linn County on November 20. Northern watersnakes hibernate individually or in groups and use a variety of overwintering sites, including earthen and rock dams, beaver and muskrat lodges and bank burrows, crayfish burrows, levees, and upland rock ledges. Reeve Bailey found a northern watersnake on April 13 under rocks on a rocky bluff overlooking the Middle River in Madison County approximately 150 to 200 feet (45.7–61 m) from the stream. He found another on April 17 under a rock in Van Buren County

182  Northern Watersnake, Nerodia s. sipedon

231

Number of Records

250 200 150

122

100

89

76

46

50 0

126

0

1

6

Jan

Feb

Mar

Apr

May

Jun

Jul

39

Aug

Sep

Oct

3

0

Nov

Dec

Month Collection/observation dates of 739 northern watersnakes in Iowa.

on a southwest-facing slope that was also a considerable distance from water. These observations support the possibility that when rocky habitat is available, the snakes may hibernate terrestrially as was suggested by Breckenridge (1944) in Minnesota. Threats. Northern watersnakes have many predators including predatory fish,

snapping turtles, wading birds, raptors, and mammals such as river otters and mink. Young snakes are most vulnerable, but adults may be taken by larger predators. Human predation can be significant—over 6,000 northern watersnakes were killed at a Missouri fish hatchery in a single year (Ernst and Ernst 2003). Many northern watersnakes are killed by people believing they are either venomous water moccasins or cottonmouths. This myth has been perpetuated from very early on. As an example, nine northern watersnakes collected around Keokuk in Lee County during the late 1800s and displayed at the Fairfield Public Library Museum for many years were labeled “water moccasin” complete with the water moccasin’s scientific name (Goodman 1948). However, despite popular belief, neither the water moccasin nor the cottonmouth is found in Iowa. Disease may be a concern as parasite infestations and snake fungal disease have been confirmed in some populations. Habitat loss and fragmentation, road mortality, water pollution, and climate change likely pose the biggest threats in Iowa. Food and Feeding. Active hunters, these watersnakes find prey by both sight and smell. Young snakes may be imprinted with prey species odors resulting in

Nerodia s. sipedon, Northern Watersnake  183

Adult northern watersnake eating an American toad in Buchanan County. Photo by Riggs Wilson.

chemical food preferences later in life. They primarily eat fish but will also consume frogs, toads, salamanders, small mammals, and invertebrates such as insects, earthworms, leeches, and crayfish. More than 80 species of fish and 30 species of amphibian have been confirmed as prey (Gibbons and Dorcas 2004). Although game fish may be eaten, the snakes chiefly eat rough fish along with many dead or dying fish. While it is often believed that northern watersnakes along with other watersnakes are bad for fish populations or reduce fishing opportunities, in fact fish-eating watersnakes do not significantly reduce fish populations; instead they can promote healthy populations by removing sick or injured individuals and scavenging dead fish. The snakes forage both on land and in the water, and captured prey is ingested either on the shore or in shallow water. Juveniles use both sit-and-wait and active foraging strategies. Older snakes may employ four modes of foraging: tongue flicking while searching around the bottom, swimming in a relatively straight line

184  Northern Watersnake, Nerodia s. sipedon

with minimal tongue flicking, remaining motionless with the head above the surface, or traveling along the surface in search of prey (Gibbons and Dorcas 2004). They may also employ a method known as fly casting: the snake floats while flicking its tongue so that it barely breaks the surface, thereby serving as a lure, and then captures the fish attracted to its tongue (Czaplicki and Porter 1974). Examination of the stomach contents of 38 northern watersnake specimens in the Drake University Research Collection found identifiable items in 3. One contained a plains leopard frog, another a bullfrog tadpole, and the third fish eggs, a grasshopper, and a minnow. The museum tag of a fourth specimen indicated the snake was consuming a juvenile white sucker at the time of capture. I observed a northern watersnake ingesting a yellow bullhead on the shore of the Wapsipinicon River in Buchanan County, and in Buchanan County one was photographed struggling with a large American toad (Riggs Wilson and Sarah VanDeWalle, personal communication, 2020). LeClere (2013) reported a northern watersnake from Johnson County eating a catfish. Reproduction. Females mature in approximately 2 to 3 years at around 20 to 26 inches (51–66 cm) snout-vent length and males in 21 to 24 months at around 15 to 18 inches (38–46 cm) snout-vent length. Examination of 21 Iowa adult female museum specimens found the smallest female with oviductal eggs was 21.7 inches (55.2 cm) snout-vent length. When adult females emerge from hibernation, most have a single set of enlarged ovarian follicles that grow quickly in the spring and are ovulated in May

Mating northern watersnakes in Muscatine County. Photo by Ryan D. Rasmussen.

Nerodia s. sipedon, Northern Watersnake  185

or June. Mating occurs in spring, usually during the day, either in shallow water or along the shoreline. Jim noted that his observations of northern watersnake mating were always in May and June in shallow water strewn with branches and fallen logs. Males search for females using scent trails, and when a female is found the male investigates her with tongue flicks, aligns himself next to her, places his head on her back, and rubs her back with his chin while spasmodically jerking his body and using his tail to search for her vent, with the whole courtship-mating sequence lasting up to 2 to 3 hours. Females may mate with more than one male. Northern watersnakes are viviparous with females giving birth to live young from late July to September in Iowa after a 2- to 3-month gestation period, often in the shelter of a rotten log near the shore. Litters can range from 6 to 99 young (average 27) with newborns measuring about 6.25 to 12 inches (16–30.5 cm) total body length. Litter size is proportional to female size, with larger females producing more young than smaller females. Counts of enlarged ovarian follicles and oviductal eggs or embryos in Iowa female museum specimens or based on Iowa literature accounts (Guthrie 1926; Loomis 1948) resulted in average litter sizes of 18 young (range 1–38; n = 3) and 21 young (range 2–39; n = 8), respectively. Litter size based on young born to captives in Jim’s lab at Drake University averaged 22 young (range 11–40; n = 5), consistent with the 20 to 25 young per litter estimated for Missouri (Johnson 2000). Longevity. A captive-born male survived for 9 years, 7 months, and 24 days and a

wild-caught Michigan male survived a minimum of 21 years in captivity. Survival of 7 to 10 years in the wild has been estimated.

SMOOTH GREENSNAKE Opheodrys vernalis (Harlan) 1827

Smooth greensnake from Bremer County.

Iowa Status. Special concern; species of greatest conservation need. Historical Summary. The smooth greensnake has also been called the American

smooth green snake, common green snake, northern grass snake, spring snake, summer snake, and smooth-coated green snake. The first confirmed specimens in the state appear to be in 1855 from Delaware County (National Museum of Natural History–Smithsonian Institution). Additional specimens were collected in the 1870s in Buchanan, Hamilton, and Lee Counties and in Polk and Lee Counties in the 1880s (National Museum of Natural History–Smithsonian Institution; Goodman 1948), and Osborn (1892) stated the species was common around Ames in Story County.

188  Smooth Greensnake, Opheodrys vernalis

Newly hatched smooth greensnake from Bremer County showing the bluish gray color of hatchlings.

Description. Smooth greensnakes are slender, uniformly green, and unpatterned

on the back and sides with a white to cream belly and white or yellow supralabials. Buff or tan individuals are occasionally found in Iowa (Hollander and Barnhart 1976) but are uncommon. Reeve Bailey noted that a smooth greensnake he found in Carroll County was “brown in life.” Interestingly, soon after death, this bright green snake turns blue. Blue and yellow pigments combine to make the snake green, and after death the yellow fades quickly, leaving only the blue behind. The body scales are smooth and in 15 rows at midbody; the anal plate is divided. There are usually 7 supralabial scales and 7 to 8 infralabial scales. Hatchlings are bluish gray or olive brown and juveniles are darker green than adults. Examination of sexual dimorphism in 24 Iowa adult smooth greensnake museum specimens (10 males; 14 females) found snout-vent length, the number of ventral scales (male mean 134; female mean 141), the number of subcaudal scales (male mean 88; female mean 76), and tail length as a proportion of total body length (male 33%; female 29%) differed significantly between males and females. Females are larger and have more ventral scales, while males have more subcaudal scales and a longer tail than females. Size. Opheodrys vernalis generally ranges from 12 to 20 inches (30.5–50.8 cm) total

body length. Females are larger than males. The largest specimen in the Drake University Research Collection is a male from Clay County measuring 20.7 inches

Opheodrys vernalis, Smooth Greensnake  189

(52.5 cm) total body length; the largest female is from Clinton County measuring 20.2 inches (51.4 cm) total body length. Reeve Bailey recorded a 20.4-inch (51.9-cm) total body length female from Jefferson County in his field notes. The record total body length reported for the species is 31.4 inches (79.7 cm). Similar Species. No other Iowa snake is vivid green with an unmarked white to

cream belly. The western smooth earthsnake may be confused with buff-colored smooth greensnakes; however, western smooth earthsnakes have an elongated loreal scale that touches the orbit of the eye. Smooth greensnakes who have died turn blue and may resemble blue racers, but racers of similar size retain their blotched juvenile pattern. Adult racers are unmarked and sometimes have a greenish color but are much larger. Distribution. Smooth greensnakes are found from southeast Canada, New England, and Virginia westward in scattered populations to Saskatchewan, North and South Dakota, Nebraska, and Kansas and southwestward into Wyoming, Colorado, Utah, and New Mexico. An isolated population occurs in southeast Texas. In Iowa, they are found in scattered populations across most of the state and seem to be missing only from the very northeast and northwest corners. During the mid-1940s, they were known from 22 counties; at present, records exist from 67 of Iowa’s 99 counties. Of the 67 counties with records, 5 (7%) have only pre-1950 records, and Delaware County has only a pre-1900 record. The increase in counties since the 1940s does not indicate the species has increased in the state but, rather, reflects more intensive searches since 1970. Smooth greensnake distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

Historically, it is likely these snakes were abundant statewide wherever moist prairies were present prior to farming. It is possible the species was underrepresented in early collections for two reasons. First, their cryptic coloration makes them almost invisible in green grass and therefore difficult to spot, so they may

190  Smooth Greensnake, Opheodrys vernalis

have just been missed; second, they are much less frequently killed on roads than some other snake species and as a result were not commonly found by Reeve Bailey and others, who collected a large share of the specimens they found as roadkills. Smooth greensnakes were at one time listed as threatened in Iowa, but the confirmation of more populations across the state resulted in the downlisting of the species to special concern. Habitat. These are cool-climate snakes that prefer moist habitats such as wet

meadows, wet prairies, and other wet grasslands as well as the edges of shrubby marshes, ponds, and lakes, but they can also be found in upland grasslands adjacent to these areas. Their green color is a perfect match for a blade of grass, and they are nearly invisible in the field. In many places in Iowa’s highly agricultural landscape, they may be restricted to road ditches and grassed waterways when other suitable habitat is no longer available. In my long-term study of snake ecology in Bremer County, I routinely find large numbers of smooth greensnakes in a wet prairie, a restored upland prairie, and road ditches. Behavior. Smooth greensnakes are gentle serpents that never attempt to bite.

When they are approached, their first response is to dart away using their camouflage to disappear into the grass. If cornered or handled, they may open their mouth in a threatening manner, but it is all bluff and never followed by a bite. At most, they release a mix of smelly feces and musk, twisting the tail and using it to smear the discharge on their assailant. The snakes are primarily diurnal, spending their days basking or searching for food, although they have been found in Wisconsin crossing roads at night during warm summer and fall rains (Vogt 1981). At night, they retreat under logs, rocks, piles of dead vegetation, or objects such as boards and tin. During more than twenty years of snake surveys in Bremer County, I have consistently found them under boards early in the morning and again late in the day, especially during the spring and fall. Cox and his coworkers (2009) found smooth greensnakes in northwest Iowa used smaller cover objects than 3 other snakes they studied and showed a preference for nonmetal cover objects. Although they are primarily terrestrial, the snakes will climb into low bushes and shrubs. The collection/observation dates of 295 Iowa smooth greensnakes, along with my own field observations over more than twenty years, show the species is typically active from early April through late October; however, the earliest record is from February 4 in Woodbury County. In most years, smooth greensnakes emerge from hibernation in early April, and they are often referred to as the spring snake (vernalis is Latin for “spring”). Because they prefer air temperatures

Opheodrys vernalis, Smooth Greensnake  191

Number of Records

100

87

80 60 40

48 25

20 0

43

42

32 12

0

3

0

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

3

0

Nov

Dec

Month Collection/observation dates of 295 smooth greensnakes in Iowa.

between approximately 70 and 86° F (21–30° C), they remain active throughout the summer. This is in contrast to many of Iowa’s snakes, whose surface activity declines during July and August. Females may be generally more active during the summer than males due to the high energy requirements associated with reproduction in northern climates (Gregory 2009). Although smooth greensnakes remain active all summer, they are harder to find once the vegetation gets thick and tall. On warm sunny days in late September and early October, they can sometimes be found in large numbers. I once caught 5 large adults within 10 feet (3 m) of each other in the course of approximately two minutes. By the end of October, the snakes have reached their overwintering sites and aboveground sightings generally cease. The latest Iowa record is an individual found in Polk County on November 8. The smooth greensnake often hibernates communally, sometimes with other species, in places such as road embankments and mammal burrows but show a preference for ant mounds. In northern Minnesota, the snakes were found hibernating with red-bellied snakes and common gartersnakes in large inactive ant mounds that were extensively channeled with tunnels extending 5 to 10 feet (1.5–3 m) below the surface; they were evenly distributed in the tunnels to a depth of 8.5 feet (2.6 m) (Lang 1969). In Manitoba, 148 were dug out of an anthill, with those in the lowest tunnels in contact with the groundwater (Criddle 1937). Winter mortality can occur depending on the location and structure of the ant mound and in years when the frost line extends deep into the soil. One November 11, I picked up a smooth greensnake at a temporary cement plant in Poweshiek County

192  Smooth Greensnake, Opheodrys vernalis

found by construction workers removing a sandpile that the snake was attempting to hibernate in. I overwintered the snake and released it the following spring near where it was found. Threats. Even with the near-perfect camouflage of smooth greensnakes, raccoons, weasels, and other predatory mammals, hawks, and other snakes all prey on them. I have observed young-of-the-year smooth greensnakes being eaten by young-ofthe-year eastern massasaugas, and they serve as an important food source for the young rattlesnakes. As with most snake species, however, their greatest threat comes from humans through habitat loss, pesticide use, lawn mowers, and climate change. The smooth greensnake’s diet of insects and other arthropods makes it highly susceptible to the effects of insecticides. Minton (1972) reported the death of two smooth greensnakes in Indiana due to insecticide poisoning after heavy spraying. At the time of Iowa’s settlement, smooth greensnake habitats probably occurred across much of the state. As the prairies were lost to the plow, the snakes’ habitats were lost as well. Certain farm programs, such as the Conservation Reserve and Wetlands Reserve Programs (now the Agricultural Conservation Easement Program) and those implementing buffer strips and grassed waterways, promote the restoration of grasslands and wetlands, thereby increasing habitats for a whole host of species, including smooth greensnakes. Knoot and Best (2011) suggested that the replacement of areas that are not currently in perennial grassland cover with grassed waterways may be of conservation value to these snakes. It is important that we maintain these programs and increase grassland cover and wetlands where possible. Food and Feeding. Smooth greensnakes are active hunters that move through

the grass in search of prey. When captured, prey is either chewed or eaten whole. The snakes eat arthropods almost exclusively, including ants, grasshoppers, crickets, beetles, butterfly and moth caterpillars, centipedes, millipedes, and spiders, but at times they may eat worms, slugs, and snails. Examination of the stomachs of specimens in the Drake University Research Collection found insect legs, mouth parts, and miscellaneous exoskeletons along with unidentifiable soft material consistent with a diet of soft-bodied invertebrates and insects. Reproduction. Females mature at around 11 inches (27.8 cm) total body length

and males at around 11.8 inches (30 cm) total body length. Mating occurs in the spring, although fall mating has been reported in southern Canada. Examination of 14 Iowa adult female museum specimens showed distinct sets of enlarging

Opheodrys vernalis, Smooth Greensnake  193

Clutch of 5 smooth greensnake eggs in Bremer County.

follicles in May, and by the last week of June follicles had enlarged to ovulatory size, with some females having already ovulated. Smooth greensnakes are oviparous; however, it has been suggested that northern populations may be evolving toward ovoviviparity because the eggs are often retained in the female for extended periods, are well developed at the time of laying, and typically hatch more quickly than those of most oviparous snakes (Vogt 1981; Shine 1983; Ernst and Ernst 2003). Egg laying in Iowa occurs in July and August with females using rotting stumps, logs, or vegetation, mammal burrows, or quite commonly the undersides of boards and other debris as nest sites. Several females may share the same nest site, and communal nests may contain over 30 eggs. I have observed smooth greensnake nests under boards in Bremer County on multiple occasions. I found 5 eggs on August 11 under a rotting board that had been in place in a restored upland prairie for 3 years. I checked on them every few days until the first egg began hatching on August 30, at which time the posterior third of one hatchling was protruding from an egg, and the eggs had swelled and lost their earlier wrinkled appearance. I took them back to my lab where all 5 hatched by September 2. I found another nest on July 12 under a board in the same restored prairie containing 24 eggs averaging 0.87 inch long by 0.44 inch wide (22.2 × 11.3 mm) and weighing an average of 0.06 ounce (1.6 g). I once

194  Smooth Greensnake, Opheodrys vernalis

Hatching smooth greensnake from Bremer County.

again brought them back to my lab and incubated them at 80º F (26.7º C). Hatching began on August 4, and 19 eggs had hatched by the morning of August 6. The remaining eggs were not viable and had shriveled by the time of hatching. Given the number of eggs in this nest, in all likelihood it was a communal nest. Hatching occurs in August or September after a short 4- to 25-day incubation period. Several females in the Drake University collection had laid their eggs by mid-July, and Reeve Bailey noted a female from Humboldt County that laid 11 eggs on July 18. One female in the Drake collection still had oviductal eggs on September 7. Clutch size ranges from 2 to 18 eggs (average 6.9). Counts of oviductal eggs in Iowa female museum specimens or based on eggs hatched in my lab (excluding the clutch of 24 eggs) and those noted by Reeve Bailey resulted in an average clutch size of 5 eggs (range 3–7; n = 3) and 8 eggs (range 5–11; n = 2), respectively. Hatchlings range from 3.3 to 6.6 inches (8.3–16.7 cm) total body length. Nineteen hatchlings from Bremer County that I measured ranged from 4.8 to 5.75 inches (12.2–14.6 cm) total body length and weighed an average of 0.07 ounce (2 g). Longevity. A wild-caught adult female survived in captivity for an additional

6 years, 1 month, and 9 days.

WESTERN RATSNAKE Pantherophis obsoletus (Say) 1823

Adult western ratsnake from Davis County. Photo by Ryan D. Rasmussen.

Iowa Status. Protected nongame; species of greatest conservation need. Historical Summary. The western ratsnake has also been called the black pilot

snake, pilot, black rat snake, chicken snake, sleepy John, white-throated racer, black racer, and scaly black snake. The names black pilot snake and pilot come from the myth that these snakes move ahead of rattlesnakes to warn them of the approach of danger. Say (in James 1823) provided the original description of the western ratsnake based on a specimen collected along the Missouri River: “It is not an uncommon species on the Missouri River from the vicinity of Isle au Vache (Cow Island, Kansas) to Council Bluff.” However, it is likely the first specimens were collected well south of Iowa (Dundee 1996). The History of Fremont County, Iowa (Anonymous 1881a) referred to the western ratsnake as a “racer” and noted it is “one of the largest snakes.” The first confirmed specimens appear to be two collected near Keokuk in Lee County sometime between 1863 and 1895 (Goodman 1948).

196  Western Ratsnake, Pantherophis obsoletus

Adult western ratsnake from Mills County with red pigment on its skin between the scales. Photo by Ryan D. Rasmussen.

Description. Adult western ratsnakes are shiny black with some dorsal blotching

and white, orange, or red pigment on the skin between the scales or on the scales themselves. The snout is shortened, not rounded, and the black head is wider behind the eyes. The labial scales, chin, and neck are white and the belly is white to cream with faded gray, brown, or black rectangles, often in pairs, forming a crude checkerboard pattern. The belly rectangles tend to merge near the tail, making the underside of the tail nearly black. The sides of the body are straight with sharp corners where the lateral and ventral scales meet, giving the snake a loaf of bread, not rounded, appearance in cross section. This unique body shape contributes to the western ratsnake’s superior ability to climb. The body scales are weakly keeled dorsally and may be unkeeled laterally and in 23 to 27 middorsal rows; the anal plate is divided. There are usually 8 supralabial scales and 11 infralabial scales. Hatchlings and juveniles are light gray with 25 to 40 distinct brown or black blotches on the back and sides, a dark bar between the eyes, and a dark stripe from each eye to the corner of the mouth. The dorsal blotches become progressively darker with age, eventually mostly disappearing, resulting in an evenly black snake in approximately two to three years (obsoletus is from the Latin meaning “dim” or “faded” referring to the fading of the juvenile pattern).

Pantherophis obsoletus, Western Ratsnake  197

Juvenile western ratsnake from Jones County. Photo by Jeff LeClere.

Examination of sexual dimorphism in 16 Iowa adult western ratsnake museum specimens (10 males; 6 females) found snout-vent length, total body length, the number of ventral scales (male mean 231; female mean 233), and the number of subcaudal scales (male mean 80; female mean 73) differed significantly between males and females, with males being larger and having more subcaudal scales and females having more ventral scales. Unlike many Iowa snakes, no significant difference was seen between the sexes in tail length as a proportion of total body length (male 17%; female 16%). Size. Western ratsnakes are one of Iowa’s largest snakes, generally ranging from

42 to 72 inches (106.7–183 cm) total body length. The largest specimen in the Drake University Research Collection is a male from Madison County measuring 63.5 inches (161.3 cm) total body length; the largest female is from Wapello County measuring 56.8 inches (144.2 cm) total body length. Klimstra (1950) measured a western ratsnake in Davis County at 73 inches (185.4 cm) total body length and eight others at between 60 and 66 inches (152.4–167.6 cm). The record total body length reported for the species is 86 inches (218.4 cm). Similar Species. The western ratsnake’s large size, overall black coloration, solidly black head, and distinctly flat checkered belly distinguish it from other Iowa snakes. Racers have smooth scales and a single anal plate and are round in cross section. Watersnakes may be entirely black above but have strongly keeled scales

198  Western Ratsnake, Pantherophis obsoletus

and bellies that are plain white, yellow, or red or have a pattern of half-moons. Bullsnakes have black blotches with a distinctly yellow background color, a single anal plate, and 4 prefrontal scales; western ratsnakes have only 2. Western foxsnakes are the most difficult to distinguish from juvenile western ratsnakes. Both have a series of dorsal blotches, a dark bar between the eyes, and a checkerboard pattern on the belly; however, western foxsnakes have fewer than 217 ventral scales, whereas western ratsnakes have more than 220. Distribution. Western ratsnakes are found west of the Mississippi River in southeast Minnesota and portions of Iowa and from Missouri, Arkansas, and Louisiana west to southeast Nebraska and approximately the middle of Kansas, Oklahoma, and Texas. They are found in scattered populations in eastern Iowa and throughout the southern third of the state. In the mid-1940s, the species was known from 20 counties; at present, records exist for 35 of Iowa’s 99 counties, 3 (9%) of which have only pre-1940 records. Jim Christiansen (1981, 1998) considered the western ratsnake threatened due to a decline in woodland-meadow edges and a reduction in abundance compared to collections prior to 1950. Current indications are that the species continues to decline in some locations in the state. Western ratsnake distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

Habitat. Pantherophis obsoletus is a woodland snake that can be found climbing trees, hiding in hollows, or basking in the sun in open rocky woodlands, on wooded hillsides and bluffs, and in heavily wooded river valleys. It is also fond of houses, barns, and other buildings with abundant mice. While working in Clayton County, I frequently found western ratsnakes along with their shed skins in an abandoned mill along the Turkey River. Often the shed skins were inside the old equipment or hanging high in the rafters. Of eighteen western ratsnakes found by Reeve Bailey, he listed woodlands, woods, or dense shrubs for all but one in the habitat descriptions. The exception was a snake he found in a pasture in Van Buren County. In Ontario, the serpents preferred old field or grassland-woodland

Pantherophis obsoletus, Western Ratsnake  199

Adult western ratsnake scaling a dead tree in Keokuk County. Photo by Sarah VanDeWalle.

edges during the breeding bird season but showed no preference for edge habitat following the season (Weatherhead and Charland 1985). In contrast, Illinois western ratsnakes showed no consistent association with forest edges (Keller and Heske 2000). Behavior. When encountered, western ratsnakes first respond by remaining motionless and waiting passively for the intruder to leave or by simply crawling away. However, if they feel threatened, they take up a defensive position—coiling, striking, and vibrating their tails. If handled, they release a strong musk and readily bite, often without warning, and may wrap around and constrict their attacker. A high school biology teacher of mine recounted the following story. As a child growing up in southern Iowa, he often picked raspberries with his mother. Once as he reached into a berry patch, a large western ratsnake struck from inside the vines, biting and coiling around his neck. The snake was quickly removed and killed by his mother, but his fear of snakes continued into adulthood.

200  Western Ratsnake, Pantherophis obsoletus

These snakes are excellent climbers that are perfectly adapted for an arboreal lifestyle. With their slender muscular bodies, flat bellies allowing for more surface contact, and ventral scales forming 90° angles at the sides of the body that are readily able to grip rough surfaces, they can effortlessly scale up the side of a tree, rock outcrop, or building. The serpents are primarily diurnal or crepuscular but become more nocturnal during the hottest part of the summer. They spend their days basking outstretched on a tree limb or with part of the body sticking out of a hole in a tree, and when not basking they patrol the trees and woodland floor in search of food. They have a preference for air temperatures between approximately 59 and 86° F (15–30° C) but can survive temperatures as low as 32° F (0° C) for short periods. Males have larger home ranges and move greater distances than females, and an individual may use the same home range for years or possibly for life. The collection/observation dates of 150 Iowa western ratsnakes show the species has been found from February through October. The earliest record is from Lucas County on February 3, 2017, when a red-tailed hawk was observed catching and flying off with a western ratsnake approximately 5 feet (152.4 cm) long. Review of weather data around that date shows the air temperature on February 3 was 23° F (–5° C); however, it had been about 30° F (17° C) warmer two days earlier. It is likely the brief warm-up caused the snake to emerge from its winter retreat; it was then caught off guard by the drop in temperature, making it easy prey for the hawk. In most years, however, western ratsnake activity in Iowa begins in late March or April with a few snakes seen on the surface on warm sunny days. Observations peak in May and June and then drop off and remain relatively steady the remainder of the active season. A second peak of activity may occur in September as snakes make their way back to overwintering sites and young-of-the-year snakes are active. The latest Iowa record is an individual found in Scott County on October 29. Western ratsnakes hibernate communally, sometimes with other species such as eastern milksnakes, North American racers, and timber rattlesnakes, in mammal burrows, rock outcrops, building foundations, cisterns or wells, old dump sites, and rock quarries. Individuals make seasonal movements to and from overwintering sites that may or may not be within their home range. Kansas western ratsnakes showed no fidelity to hibernation sites, using different sites in different years (Fitch 1999). Reeve Bailey found one under a rock high on the Devil’s Backbone in Van Buren County on April 18, probably not far from where it overwintered.

Pantherophis obsoletus, Western Ratsnake  201

46

Number of Records

50 40

35

30 19

20

13

10 0

0

1

Jan

Feb

5

6

Mar

Apr

May

Jun

Jul

13

12

Aug

Sep

Oct

0

0

Nov

Dec

Month Collection/observation dates of 150 western ratsnakes in Iowa.

Threats. Large adult western ratsnakes likely have few natural predators with

the exception of hawks. Fitch (1963b) recorded 577 instances of red-tailed hawk predation on western ratsnakes in Kansas, and hawk predation has been reported in Iowa as well as recounted above. Fitch (1999) also noted that songbirds loudly scold or harass western ratsnakes, a frequent predator of birds and their nests, in an attempt to drive them away. He went on to postulate that hawks might cue in on the scolding as a way to find snakes in the trees. Juveniles and small adults are more likely to be preyed upon by other animals, such as other snakes, raccoons, and other predatory mammals. Humans, however, are the primary threat through automobiles, habitat loss, and climate change. It seems western ratsnakes have decided that the best defense is a good offense. When attacked by a predator, the snake may wrap itself around the legs or body of its assailant to constrict it. Two accounts describe attempted western ratsnake predation by a hawk during which the snake wrapped around the neck and chest of the bird (Meshaka et al. 1988; Vandermast 1999). In both cases, the hawk was clearly fatigued and not struggling when the observer arrived and in one case it appeared to have died, although the snake retained its hold for ten minutes after the hawk seemed to be dead. Food and Feeding. The western ratsnake is a strong constrictor who locates prey

by sight or smell and shows a preference for mammals, such as mice, voles, chipmunks, squirrels, and rabbits, and for birds, including nestlings and eggs. Fitch

202  Western Ratsnake, Pantherophis obsoletus

(1963b, 1999) reported the diet consisted of up to 76 percent mammals and up to 23 percent birds. Bats, such as the big brown bat, tricolored bat, and the federally endangered Indiana bat, may be eaten as well (Ernst and Ernst 2003). The snake may ambush prey, seizing it with the mouth and quickly constricting it, or in a bird or small mammal nest the snake may just simply eat the young alive. It has been known to take up residence near colony-nesting birds to exploit the abundant and continuous food supply. An observation reported to Jim involved a western ratsnake in southeast Minnesota that was lying motionless on the ground with its head raised approximately 1.5 feet (45.7 cm) high. A small bird hopped to progressively lower branches to investigate. The snake struck and captured the bird when it reached the bottom branch, only a few inches from the snake’s head. It is possible that the bird was attracted to the continual movement of the snake’s tongue, thinking it to be an insect. Reeve Bailey found an overstuffed 13-inch (33-cm) western ratsnake in Wapello County that contained two deer mice, quite a large meal for a small snake. Examination of specimens in the Drake University Research Collection found unidentified birds in the stomachs of specimens from Madison and Van Buren Counties and mammal fur in the stomachs of specimens from Marion and Van Buren Counties. Reproduction. Females mature in their fourth year at around 35 inches (88.9 cm)

snout-vent length and males a year earlier at around 32.5 inches (82.6 cm) snoutvent length. Mating occurs in the spring from late April into June, although fall mating has also been suggested. During the mating season, males engage in combat for access to females, during which they try to pin each other to the ground. When males and females come together, the male crawls onto the female’s back, bites her neck to hold her still, and positions his tail under hers, aligning their vents while undulating his body. Mating may take place on the ground or in trees. Examination of 6 Iowa adult female specimens in the Drake University collection showed a female found on May 25 had a set of enlarged ovarian follicles. A female found by Reeve Bailey on July 3 had oviductal eggs. Although limited, these two observations suggest that ovulation occurs in June. Western ratsnakes are oviparous with females laying their eggs sometime in June or July using hollow logs or stumps, tree holes, rodent burrows, rotting vegetation, or the undersides of rocks or other debris as nest sites, and several females may lay eggs at the same site. Not all females breed each year—somewhere between 33 and 72 percent reproduce each year—and larger females are more likely to reproduce than smaller females (Fitch 1999). From 4 to 44 eggs are laid with clutch size proportional to female size—larger females produce more eggs than smaller females. A female

Pantherophis obsoletus, Western Ratsnake  203

specimen in the Drake University collection contained 17 enlarged ovarian follicles, suggesting a clutch size of around that number. LeClere (2013) reported 2 Iowa clutches of 16 and 18 eggs per clutch. Eggs hatch in August and September after a 42- to 70-day incubation period with hatchlings averaging 15.2 inches (38.6 cm) total body length, large compared to hatchlings of most Iowa snakes. The size of Iowa young-of-the-year specimens in the Drake collection found in September and October ranged from 11.5 to 15.6 inches (29.3–39.7 cm; n = 4) total body length. Hatchlings from 2 Iowa clutches reported by LeClere (2013) averaged 7.4 inches (18.7 cm) and 14 inches (35.8 cm) total body length. Longevity. A wild-caught adult male survived in captivity an additional 22 years,

11 months, and 30 days. Jim captured an adult western ratsnake in Fremont County in 1986 that lived in his lab at Drake University until 2006. Western ratsnake survival in the wild has been estimated at over 20 years.

WESTERN FOXSNAKE Pantherophis ramspotti (Crother, White, Savage, Eckstut, Graham, and Gardner 2011)

Adult western foxsnake from Linn County.

Iowa Status. Protected nongame; species of greatest conservation need. Historical Summary. The western foxsnake has also been called the prairie fox snake, bull snake, copperhead, Fox’s black snake, corn snake, fox racer, hardwood rattler, timber snake, and spotted adder. The first confirmed specimen in the state appears to be in 1878 from Webster City in Hamilton County (National Museum of Natural History–Smithsonian Institution). Yarrow (1882) referenced the National Museum of Natural History specimen and Osborn (1892) stated the snakes were common near Ames in Story County. Wright and Wright (1957) based their color description on a snake from Cedar Falls in Black Hawk County collected in May 1936. Conant (1940) described a new subspecies of foxsnake and designated the Iowa form as the western foxsnake, Elaphe vulpina vulpina. In 2011, Crother et al. proposed Pantherophis ramspotti (Pantherophis from the Greek panther meaning “panther” and ophis meaning “snake,” likely referring to the spotted and colorful pattern of the type specimen; ramspotti honors the late aspiring herpetologist Joseph Ramspott) as the new name for the species west of the Mississippi River. They cited the holotype—a single specimen upon which the description and

206  Western Foxsnake, Pantherophis ramspotti

name of a new species are based—as an Iowa adult female pregnant with seven eggs from Warren County, with paratypes—specimens cited along with the holotype in the original description—from Marion, Warren, and Madison Counties. Description. The body color of western foxsnakes varies from a faint yellow or tan to a light gray, with 28 to 60 dark brown or black dorsal blotches. Twenty-two to 60 smaller round spots in a series along each side of the body alternate with the dorsal blotches. The snout is square or rounded and the head of adults is tan to copper-colored (sometimes reddish) and usually unmarked except for a somewhat faded black mask. The belly is yellow or cream with bold black rectangles often forming a checkerboard pattern. The body scales are weakly keeled dorsally and unkeeled laterally and in 24 rows at midbody; the anal plate is divided. There are usually 8 supralabial scales and 11 infralabial scales. The pattern of juveniles is bolder, consisting of very dark blotches on a very light gray background. The head has a prominent bar between the eyes and another diagonally from each eye to the angle of the mouth and large black spots on the upper lips. In most cases, the dark head markings of juveniles disappear as they age. Atypical individuals have been reported in Iowa. Keegan (1944) reported an albino snake from Wapello County; in 2003, Jim Christiansen photographed an adult male in Muscatine County with a distinct vertebral stripe on the first half of the body; and LeClere et al. (2012) reported a bullsnake and western foxsnake hybrid from Madison County. Examination of sexual dimorphism in 74 Iowa adult western foxsnake museum specimens (42 males; 32 females) found the number of ventral scales (male mean 197; female mean 204), the number of subcaudal scales (male mean 63; female mean 55), and tail length as a proportion of total body length (male 16%; female 14%) differed significantly between males and females, with females having more ventral scales and males having a longer tail and more subcaudal scales. Size. Western foxsnakes generally range from 24 to 54 inches (61–137 cm) total body length. The largest specimen in the Drake University Research Collection is a male from Polk County measuring 49.7 inches (126.3 cm) total body length; the largest female is from Muscatine County measuring 48.7 inches (123.7 cm) total body length. The record total body length reported for the species is 61 inches (155 cm). Similar Species. Prairie kingsnakes are similar in color and size but have smooth scales, a single anal plate, and a much less distinct belly pattern. Bullsnakes have distinct brown spots on a yellow background, a single anal plate, and a pointed

Belly of an adult western foxsnake from Linn County showing its checkerboard pattern.

Young-of-the-year western foxsnake from Buchanan County.

208  Western Foxsnake, Pantherophis ramspotti

snout. Northern watersnakes have reddish brown half-moons on the belly. Eastern and prairie massasaugas have strongly keeled scales and an obvious rattle at the end of the tail. Juvenile western ratsnakes are the most difficult to distinguish from western foxsnakes. Both have a series of dorsal blotches, a dark bar between the eyes, and a checkerboard pattern on the belly; however, western foxsnakes have fewer than 217 ventral scales, whereas western ratsnakes have more than 220. Distribution. Western foxsnakes are found west of the Mississippi River from

southern Minnesota, Iowa, and northeast Missouri west into the eastern quarter of Nebraska, southeast South Dakota, and northwest Missouri. They may intergrade with the eastern foxsnake (P. vulpinus), found east of the Mississippi River, along the river, although some uncertainty exists. Iowa forms the heart of the range of this species. In the mid-1940s, western foxsnakes were known from 68 counties; at present, records exist for 88 of Iowa’s 99 counties, 9 (10%) of which have only pre-1940 records. The serpent is rare in the northern tier of counties and seems to be lacking from some south-central counties along the Iowa-Missouri border. While this snake is certainly less common than it was when Reeve Bailey conducted his studies in Iowa, it is still found throughout the range he established at that time. Western foxsnake distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

Habitat. Unlike bullsnakes, with which they are often confused, western foxsnakes use woodland edges extensively. They are also commonly found associated with marshes and other wetlands, as well as in grasslands and farm fields and along fencerows, and are often seen crossing roads even in heavily cropped areas. In the past, when corncribs with their ever-present rat and mouse populations were part of every farmstead in Iowa, western foxsnakes were often found associated with farm buildings, and they are still one of the species most often associated with buildings. I removed an adult from my mother’s basement in Linn County where

Pantherophis ramspotti, Western Foxsnake  209

it was lying across the washer and dryer. Permanent pasture with a few fallen trees is prime habitat for these snakes, but these too have declined as farms have shifted more toward row-crop production and feedlots. Approximately 80 percent of the collection notes made by Reeve Bailey where he described habitats for the western foxsnake mention some aspect of a farm. Behavior. Because these mild-tempered snakes rarely bite, they are commonly used for environmental education. However, when encountered in the wild, they often put on an impressive display, coiling, striking, and vibrating their tails, creating a convincing loud rattling sound that mimics a rattlesnake. I have been fooled by this while searching for eastern massasaugas. I once spent several minutes searching through the grass convinced I had found a massasauga only to discover it was an angry foxsnake. This mimicry often results in people insisting foxsnakes are rattlesnakes, usually to the detriment of the foxsnakes. Over the years Jim and I have received many calls from individuals convinced they have found a rattlesnake. Jim remembers that nearly 90 percent of the rattlesnake calls he answered during his more than thirty years at Drake University concerned western foxsnakes; the remainder concerned bullsnakes. When frightened, western foxsnakes secrete a musky substance from their anal glands, which has an odor similar to that of foxes and may have contributed to the origin of the common name. The collection/observation dates of 927 Iowa western foxsnakes show the species has been found every month of the year in the state with the exception of January. The earliest record is from Washington County on February 9. In most years, activity in Iowa begins in early April with a few snakes seen on the surface on warm sunny days. By early May, most have emerged from hibernation with a peak of activity lasting into June (48% of observations). The snakes are less commonly seen in July and August during the hottest part of the summer. A second peak of activity occurs in September and October (27% of observations) as snakes make their way back to their overwintering sites and young-of-the-year snakes are active. Each year during September and October, I see many young-of-the-year foxsnakes crossing the gravel road near my home in Buchanan County. A number of November and December records exist; the latest records include 3 snakes in Jones County on December 12. P. ramspotti often hibernates communally, sometimes with other species, in muskrat and beaver lodges and burrows, other mammal burrows, foundations, rock outcrops, and wells. One February, Jim received a call from a property owner in Jasper County; her water well was contaminated with coliform bacteria but

210  Western Foxsnake, Pantherophis ramspotti

Number of Records

300

274

250 200

191

174

150 100 50 0

58 0

1

3

Jan

Feb

Mar

Apr

53

May

Jun

Jul

92

61

Aug

Sep

Oct

16

4

Nov

Dec

Month Collection/observation dates of 927 western foxsnakes in Iowa.

the well service contractor would not work on it because it was full of snakes. That day, Jim removed 34 western foxsnakes and 47 eastern yellow-bellied racers from the well and the foundation of the well house. Some snakes were at least 60 inches (152.4 cm) underwater, and those at the bottom were chocolate brown with feces from the snakes above. All appeared to be healthy. With the owner’s permission, Jim and colleagues relocated the snakes to an artificial hibernaculum they constructed nearby. Hibernating in wells may be fairly common in both western and eastern foxsnakes. LeClere (2013) reported two instances of western foxsnakes hibernating in wells in Iowa; a HerpMapper record indicates a western foxsnake, along with a racer, was removed in November from a well in Muscatine County; Vogt (1981) found 166 eastern foxsnakes in an old well in Wisconsin, 68 of which were underwater; and Smith (1961) found 16 eastern foxsnakes hibernating in wells in Illinois. Threats. Natural predators include raptors and mammals such as coyotes,

weasels, and raccoons, and small mammals such as deer mice prey on the eggs. Stephenson et al. (2020) found Iowa western foxsnakes infected with snake fungal disease. Humans, however, are the primary threat. Hundreds of western foxsnakes are killed each year in Iowa while crossing roads, especially in the fall. As early as the 1930s, Scott (1938) reported road mortality of western foxsnakes in Fayette, Guthrie, and Webster Counties, and they are still one of the most common snake species found dead on the road in many locations. Many others are killed by lawn mowers. Habitat loss has been and continues to be a threat, and climate change is an emerging threat.

Pantherophis ramspotti, Western Foxsnake  211

Adult western foxsnake from Buchanan County eating an egg in a chicken coop. Photo by Michael G. Fisher.

Food and Feeding. Adult foxsnakes are strong constrictors who primarily prey

on young rabbits, chipmunks, ground squirrels, and a variety of small mammals such as shrews, mice, and voles. Juveniles may eat frogs and insects, small mice, and earthworms until they are big enough to consume larger prey, and captives have been observed eating snakes of other species. Western foxsnakes are good climbers and will also eat adult birds and nestlings and sometimes their eggs. I once observed an adult entering a bluebird house and eating nestlings in my backyard, and one was found eating eggs in a chicken coop in Buchanan County (Mike Fisher, personal communication, 2020). Western foxsnakes locate prey primarily by scent while actively searching or by remaining motionless and ambushing prey. Examination of specimens in the Drake University Research Collection found meadow voles in the stomachs of specimens from Warren and Cass Counties, and the stomach of a specimen from Muscatine County contained two unidentified birds. Reproduction. Courtship and mating of western foxsnakes follow a typical colubrid pattern involving an initial chasing of the female by the male, a tactile and mounting phase, and a biting of the female by the male during mating.

212  Western Foxsnake, Pantherophis ramspotti

Courtship and mating in Iowa likely occur in May. Western foxsnakes are oviparous with females using loose soil, rotting stumps or vegetation, and the underside of logs or other cover objects as nest sites. Several females may lay eggs in the same place. LeClere (2013) reported eggs under a railroad tie and an old door in Iowa. Little data exist in the literature on the size at sexual maturity of western foxsnakes. Examination of 27 Iowa adult female specimens in the Drake University collection found the smallest gravid female was 29.5 inches (75 cm) snout-vent length and the largest immature female was 30 inches (76 cm) snout-vent length, suggesting that female maturity in Iowa occurs at snout-vent lengths of approximately 29 to 30 inches (74–76 cm). Examination of fall female specimens found no distinct sets of enlarged ovarian follicles, and the first spring specimens suggest that very little follicular growth occurs over the winter. Vitellogenesis begins in April and May with follicles enlarging quickly. Reeve Bailey noted that a specimen collected by Guthrie on May 31 contained 8 enlarged ovarian follicles. Shelled oviductal eggs were observed in Drake University specimens dated May 30 through the end of June. By late July, specimens no longer contained shelled oviductal eggs, suggesting that egg laying in Iowa occurs from late June through July. Iowa observations of egg laying support this as well. One of the western foxsnakes that Reeve Bailey maintained in captivity laid eggs between June 28 and 30 with eggs averaging 1.6 inches long by 0.92 inch wide (39.7 × 23.4 mm), and the other laid eggs on July 2 and 3 with eggs averaging 1.9 inches long by 0.89 inch wide (47.4 × 22.5 mm). Other Iowa reports include July 3 and July 5, respectively, for 2 clutches (LeClere 2013), July 20 (Wright and Wright 1957), and July 24 (Guthrie 1926). By September, females have used much of their fat reserves and contain only pre­ vitellogenic follicles. Clutch size ranges from 7 to 29 eggs. Iowa western foxsnake clutch size reports are limited but include 11 eggs (Reeve Bailey’s field notes), 13 eggs (Guthrie 1926), 9 eggs (Wright and Wright 1957), and 8, 12, and 25 eggs (LeClere 2013). Counts of enlarged ovarian follicles and shelled oviductal eggs in females in the Drake collection resulted in average clutch sizes of 9 eggs (range 6–10; n = 7) and 8 eggs (range 3–14; n = 5), respectively. Incubation in Iowa has been reported at 38 to 54 days (Guthrie 1926), 38 to 42 days (Reeve Bailey’s field notes), and 40 to 42 days (LeClere 2013). Given egg laying in July, these data suggest that eggs in Iowa typically hatch in August or early September, consistent with my annual field observations of young-of-the-year western foxsnakes in late August and September. Hatchlings range from 9 to 13.8 inches (23–35 cm) total body length. Five young measured by Reeve Bailey ranged from 10.3 to 11.4 inches (26.2–29 cm) total body length. Size of Iowa young-of-the-year specimens in the Drake collection found in

Pantherophis ramspotti, Western Foxsnake  213

September ranged from 10.8 to 13.9 inches (27.5–35.3 cm; n = 9) total body length and in October from 11.1 to 16.4 inches (28.2–41.7 cm; n = 11) total body length. Young from 2 clutches reported by LeClere (2013) ranged from 10.7 to 13.5 inches (27.3–34.3 cm; n = 20) total body length. Longevity. Given the frequency with which western foxsnakes are kept as educa-

tional display animals, it is interesting that longevity has not been reported for the species. A wild-caught adult of the related eastern foxsnake survived in captivity an additional 7 years, 5 months, and 18 days.

BULLSNAKE Pituophis catenifer sayi (Schlegel) 1837

Adult bullsnake from Linn County.

Iowa Status. Special concern; species of greatest conservation need. Historical Summary. The bullsnake has also been called the prairie bull snake,

common bull snake, Say’s bullsnake, pilot snake, gopher snake, western pine snake, yellow bull snake, and speckled chain adder. The first confirmed specimens in the state appear to be in 1881 from near Davenport in Scott County and in 1883 from near Sioux City in Woodbury County (National Museum of Natural History–Smithsonian Institution). The first mention of bullsnakes in the literature in Iowa appears to be in the History of Fremont County, Iowa (Anonymous 1881a), which referred to the species as the “western pine snake” with the note “seventy inches long,” in Yarrow (1882), who referenced the 1881 National Museum of Natural History specimen, and in Osborn (1892), who made reference to the possible occurrence of bullsnakes near Ames in Story County.

216  Bullsnake, Pituophis c. sayi

Six subspecies of the gophersnake, Pituophis catenifer, are currently recognized, only one of which, the bullsnake, P. c. sayi, has a range that includes Iowa. Description. Bullsnakes are whitish on the forebody, faint yellow or tan at midbody, and yellow near the tail with 41 to 60 black, brown, or reddish unconnected dorsal blotches and 9 to 19 dark brown or black tail bands. The dorsal pattern gives rise to the name catenifer from the Latin catena meaning “chain” and -ifera meaning “bearing.” A series of smaller round spots that alternate with the dorsal blotches is located along each side of the body. The dorsal and lateral blotches are usually darker on both ends of the snake than in the middle. The head is yellow or brown with small black spots on top forming no consistent pattern, a black line extending from the back of each eye to the corner of the mouth, a dark band between the eyes, black bars on the labial scales, 4 prefrontal scales, and a prominent pointed snout formed by a high keeled rostral scale that is about twice as long as it is broad. The chin and throat are white and the belly is yellow and checkered with dark brown rectangles. The body scales are keeled and in 30 to 33 rows at midbody; the anal plate is single. There are usually 8 to 9 supralabial scales and 9 to 13 infralabial scales. Hatchlings are patterned like adults. A bullsnake and western foxsnake hybrid was found in Madison County (LeClere et al. 2012). Juvenile bullsnake from Linn County.

Pituophis c. sayi, Bullsnake  217

Examination of sexual dimorphism in 39 Iowa adult bullsnake museum specimens (24 males; 15 females) found the number of ventral scales (male mean 220; female mean 225), the number of subcaudal scales (male mean 57; female mean 50), and tail length as a proportion of total body length (male 13%; female 12%) differed significantly between males and females, with females having more ventral scales and males having more subcaudal scales and a longer tail. Size. Bullsnakes are one of Iowa’s largest snakes, generally ranging from 37 to 72

inches (94–183 cm) total body length. The largest specimen in the Drake University Research Collection is a male from Black Hawk County measuring 75.8 inches (192.5 cm) total body length; the largest female is from Polk County measuring 60.6 inches (154 cm) total body length. The record total body length reported for P. catenifer in the eastern United States (two subspecies) is 105 inches (266.7 cm). Similar Species. Western foxsnakes and prairie kingsnakes are the species most

often confused with bullsnakes. Western foxsnakes have divided anal plates, blunt or rounded snouts, 2 prefrontal scales, and a more intense checkerboard pattern on the belly. Prairie kingsnakes have brown dorsal blotches on a sometimes yellowish background, a single anal plate, smooth scales, and 2 broad stripes on the neck. Distribution. Bullsnakes are found primarily in the Great Plains from Alberta, Saskatchewan, eastern Montana, and western North Dakota south to Texas and into Mexico. In the United States, the western extent of their range is the foothills of the Rocky Mountains. East of the Great Plains, scattered populations are found Adult bullsnake from Linn County showing its prominent pointed snout.

218  Bullsnake, Pituophis c. sayi

in Minnesota, Wisconsin, Iowa, Illinois, and Missouri. In Iowa, bullsnakes may still be found nearly statewide with the exception of north-central Iowa, where no records exist, although their populations are widely scattered and their numbers are certainly reduced, with the number of new records declining over time. In the mid-1940s, the serpent was known from 63 counties. In the 1940s, Loomis (1948) considered the bullsnake to be the most common snake in Adams County. At present, records exist for 70 of Iowa’s 99 counties; however, 19 (27%) counties have only pre-1950 records. Based on records collected by Reeve Bailey and others in the 1940s and those collected after 1970, Jim Christiansen (1998) suggested bullsnakes had declined by 91 percent in Iowa between the 1940s and 1990s. Bullsnake distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

Habitat. A prairie-adapted snake, bullsnakes are most commonly found in bluff

prairies, sand prairies, open meadows, pastures, and oak savannas, and although they primarily prefer dry habitats, they will at times venture into wetter areas in search of food. Loose soil for easy digging and an abundant supply of small mammals are necessary components of their habitats. The serpents avoid closed-canopy woodlands and generally tend to avoid agricultural lands but may occasionally use them. They can also be found around farmsteads and in urban areas. Each spring while in high school in Cedar Rapids, I was asked to move several bullsnakes from the school’s football field back into an adjacent grassland. Nearly forty years later, I suspect that grassland is no longer there. Behavior. When it is encountered in the field, often the bullsnake’s first response is to slowly crawl away and avoid conflict. However, if escape is not possible, the snake puts on an impressive and often frightening display. This large snake will raise its forebody a foot or more off the ground into a tight S-shaped coil poised for a quick strike. At the same time, it flattens its head, inflates its neck, opens its mouth at an angle, vibrates its tail to create a convincing loud rattling sound that mimics a rattlesnake, and may strike repeatedly. But perhaps the most ominous of all is the loud sustained hissing that accompanies the defensive posture, created

Pituophis c. sayi, Bullsnake  219

when the snake forces air from its lungs past thin cartilage near the entrance of its windpipe. Garman (1892) described the loud hissing as “bearing a very remote resemblance to the bellow of a bull.” Carlander and Moorman (1950c) likened it to an “engine blowing off steam.” This loud hissing can be heard from quite a distance away. Once while checking drift fences in Wapello County, I heard a loud hiss coming from behind me. A quick scan of the area revealed a bullsnake raising up and hissing at least 20 feet (6.1 m) from me. Had it not hissed, I would have walked right on past without noticing it. Despite the frightful display, much of the behavior is bluff, although some individuals are more prone to biting than others and the bite of a large bullsnake can be painful. Bullsnakes spend a fair amount of time underground escaping the heat, taking refuge during dry periods, or excavating prey. They are excellent burrowers, using their pointed snouts and enlarged rostral scales to tunnel through loose soil. The snout first spades the soil, after which the head and neck scoop the excavated material and move it out of the burrow. An excavating bullsnake can move as much as 207.5 cubic inches of soil per hour (3,400 cm3/hr) (Carpenter 1982). When not underground, they crawl slowly on the surface in search of food and may at times climb trees. They are not able to climb directly up the trunk of a tree as western ratsnakes do but instead use branches as a ladder, which allows them to move up the tree with surprising speed. In the Midwest, home range size varies from 3.7 to 100.8 acres (1.5 to 40.8 ha). Males have larger home ranges and make longer daily movements than females, and individual snakes use the same significant areas within their home range year after year. The collection/observation dates of 659 Iowa bullsnakes show the snake has been found from March through December. The earliest record is from Lee County on March 10. In most years, however, bullsnakes emerge from hibernation by mid- to late April. Peak spring emergence in Wisconsin was found to be April 7 to 15 (Kapfer et al. 2008). Surface activity decreases during the hottest and driest portions of the summer, when the snakes are likely spending more time underground to escape the heat. Surface activity begins to pick up again in mid-August with a steady rise into early October as snakes make their way back toward overwintering sites and young-of-the-year snakes appear. In Wisconsin, bullsnakes enter hibernation in late September and early October (Vogt 1981), and the sharp drop-off in activity in Iowa during the last two weeks of October suggests a similar pattern. The latest Iowa record is an individual found in Muscatine County on December 13. The bullsnake hibernates communally with other snakes, including rattlesnakes, deep in limestone outcrops or mammal burrows, with snakes traveling 0.3 to 2.5 miles (0.5–4 km) from their summer ranges to reach suitable overwintering

220  Bullsnake, Pituophis c. sayi

187

Number of Records

200 134

150

102

100

41

50 0

0

0

2

Jan

Feb

Mar

Apr

May

Jun

Jul

50

Aug

72

Sep

63

Oct

6

2

Nov

Dec

Month Collection/observation dates of 659 bullsnakes in Iowa.

sites. Despite having mammal burrows available for hibernacula in adjacent prairie habitat, nearly all radio-tracked Wisconsin bullsnakes overwintered along south-facing rock outcrops of bluff slopes (Kapfer et al. 2008). The researchers went on to surmise that rock fissures may extend farther below the frost line than available mammal burrows, thereby reducing winter mortality. Threats. Natural predators include badgers, coyotes, great horned owls, and

red-tailed hawks, and raccoon predation on bullsnakes was documented in eastern Iowa (Giles 1940). Strecker (1908, in Stull 1940) described an aerial combat between a bullsnake and a large hawk during which the snake “squirmed so vigorously and struck at its captor so furiously that the bird was forced to relinquish its hold.” Unfortunately, the impressive defensive display of bullsnakes has little effect on automobiles, and in Iowa roads are one of the primary threats these snakes face. As early as the 1930s, road mortality of bullsnakes in Iowa was reported (Stoner 1936; Scott 1938), and Reeve Bailey picked up most of the specimens he collected as roadkills. The largest specimen in the Drake University Research Collection, a huge 75.8-inch (192.5-cm) Black Hawk County male, was intentionally run over. Agricultural equipment also likely takes a toll. Wisconsin bullsnakes using agricultural lands are often killed by farm equipment (Kapfer et al. 2008). In Iowa, the primary threat to this prairie snake has been and continues to be the loss of its grassland habitat due to increasingly intensive row-crop produc-

Pituophis c. sayi, Bullsnake  221

tion. In the 1940s, Reeve Bailey recorded eighty-one instances where he found bullsnakes in pastures, but as pastures have disappeared from the state, so has the bullsnake. In many places, permanent pastures have been replaced by row crops, and the only grassland habitat that remains is in road ditches, placing the snakes in close proximity to their other major threat, automobiles. Food and Feeding. Bullsnakes are slow-moving active hunters who locate prey by smell or sight. They may hunt either on the surface, underground in mammal burrows, or occasionally in shrubs or small trees. Jim once watched a bullsnake for nearly thirty minutes as it moved through a sedge marsh following meadow vole trails and continually flicking its tongue. Obvious food lumps in the snake indicated that the hunt had already been successful. The snakes may push through pocket gopher mounds to enter the burrows in search of prey. Once bullsnakes capture small prey, such as mice and voles, or prey captured in the confined space of a burrow, they pin it to the ground or against the side of the burrow to hold it until it can be eaten; larger prey is fully encircled by coils and constricted. The bullsnake does not always come out unscathed, however, and many adults have scars inflicted by their prey. These large and powerful constrictors are tremendous consumers of pocket gophers, mice, and other mammals. Wooster (1925, in Stull 1940) noted that “the bull snake is a much more effective ratter than most cats, and a good-sized one about the barn pays for itself many times over, provided it does not have access to the chicken nests, for it eats eggs and sometimes small chickens.” Guthrie (1926) stressed the value of this snake to agriculture and noted that it was common to find these (then common) snakes with stomachs filled with ground squirrels, gray squirrels, young rabbits, pocket gophers, rats, or mice. Examination of the stomach contents of specimens in the Drake University Research Collection found small mammals in the stomachs of several specimens, including three voles in the stomach of a female from Muscatine County. Although mammals are the primary prey, amphibians, other reptiles, birds, and bird eggs may be eaten. Rattlesnakes may be consumed as well, and it is believed by some that bullsnakes can survive a rattlesnake bite; however, it has not been shown that bullsnake serum provides protection against pit viper venom. Reproduction. Females mature in approximately 3 years at around 35 inches (88.9 cm) snout-vent length and males slightly earlier and at a smaller size. Examination of 15 Iowa adult female specimens in the Drake University collection found the smallest mature female was 39.5 inches (100.4 cm) snout-vent length

222  Bullsnake, Pituophis c. sayi

and the largest immature female was 34.9 inches (88.7 cm) snout-vent length, suggesting that female maturity in Iowa occurs at snout-vent lengths of approximately 35 to 39 inches (89–99.1 cm), similar to that reported in Nebraska (Iverson et al. 2012). Courtship and mating occur in the spring from late April into May in the vicinity of the overwintering sites. In the mating season, males engage in combat for access to females during which they try to pin each other to the ground. When males and females come together, the male crawls onto the female’s back, bites her neck to hold her still, undulates his body, curls his tail underneath hers, and inserts his hemipenis. Mating may last over an hour. Loomis (1948) provided an account of bullsnake courtship he observed on May 26 in Adams County during which the male grasped the female behind the head and rapidly undulated his body over hers with his tail moving under hers. This continued for 20 minutes with the seemingly “annoyed” female attempting to move away. Examination of 10 Iowa female specimens in the Drake University collection found no distinct sets of enlarged ovarian follicles in the fall, and the first spring specimens suggest that very little follicular growth occurs over the winter. Follicular growth resumes in April and May with follicles growing quickly. Among 2 female specimens, each found on May 24 but a year apart, one had enlarged

Mating bullsnakes from Black Hawk County showing the male biting the female’s neck. Photo by Ryan D. Rasmussen.

Pituophis c. sayi, Bullsnake  223

ovarian follicles and the other contained oviductal eggs, suggesting ovulation in Iowa likely occurs in late May or early June. By mid-June, oviductal eggs were no longer found, suggesting that egg laying in Iowa occurs in mid-June and likely extends into early July. Bullsnakes are oviparous with females using animal burrows, burrows they dig themselves, or the undersides of rocks or other debris as nest sites, and several females may lay eggs at the same site. Not all females may breed each year, with the proportion of females reproducing a function of body size and warmth of the previous summer (Iverson et al. 2012). From 2 to 24 large eggs 2.4 inches long by 1.2 inches wide (61 × 30.2 mm) are laid with clutch size proportional to female size—larger females produce more eggs than smaller females. Counts of enlarged ovarian follicles in females in the Drake University collection resulted in an average clutch size of 12 eggs (range 6–15; n = 6). A Louisa County specimen found on May 24 contained 13 oviductal eggs. Best (1977) reported 14 oviductal eggs in a Story County female dissected on June 17, and LeClere (2013) reported a Linn County female that laid 13 eggs. Eggs hatch in August and September after a 51- to 70-day incubation period with hatchlings averaging 14.8 inches (37.5 cm) total body length. Size of Iowa young-of-the-year specimens in the Drake collection ranged from 14.2 to 16.5 inches (36–42 cm; n = 10) total body length. Longevity. A wild-caught adult survived in captivity an additional 22 years, 5

months, and 1 day, and survival in the wild of least 8 years has been reported.

GRAHAM’S CRAYFISH SNAKE Regina grahamii Baird and Girard 1853

Graham’s crayfish snake from Woodbury County. Photo by Ryan D. Rasmussen.

Iowa Status. Protected nongame; species of greatest conservation need. Historical Summary. Graham’s crayfish snake has also been called Graham’s queen snake (regina is Latin for “queen”), Graham’s leather snake, Graham’s snake, striped moccasin, prairie water snake, and prairie water adder. The snake is named in honor of James D. Graham, founder of the Corps of Topographical Engineers, who collected the first specimen of the species. Osborn (1892) reported the species was common in Iowa and Somes (1911) listed it as occurring in the state. The first confirmed specimen in the state appears to be in 1894 from Ames in Story County (University of Illinois Museum of Natural History), although it is possible an earlier specimen was collected near Keokuk in Lee County (Goodman 1948). Description. Graham’s crayfish snakes are slender brown to dark brown snakes

with a cream, tan, light yellow, or white lateral stripe on scale rows 1 to 3. A thin black line forming a zigzag pattern is present where the ventral scales meet the

226  Graham’s Crayfish Snake, Regina grahamii

Belly of a melanistic Graham’s crayfish snake from Polk County.

first lateral scale row, and a faint vertebral stripe may be present. The chin and throat are cream to yellow and the belly is cream, tan, light yellow, or white and unmarked, although old individuals may have some gray spotting down the center. The body scales are keeled, with the exception of the first scale row, which may be smooth, and in 19 rows at midbody; the anal plate is divided. There are usually 7 supralabial scales and 9 to 10 infralabial scales. Juveniles are marked like adults but with more vivid stripes. Guthrie (1930a, b, c) reported a melanistic female found in a city park in Des Moines that gave birth to 10 young, 4 of which were also melanistic. The melanistic individuals were so dark that the lateral stripe was nearly obscured. Reeve Bailey collected a similarly dark individual in Kossuth County and noted that its lateral stripe was completely obscured and that dark pigment extended onto the ventral scales. Melanistic individuals can still be found in central Iowa. Examination of sexual dimorphism in 27 Iowa adult Graham’s crayfish snake museum specimens (16 males; 11 females) found snout-vent length, the number of ventral scales (male mean 169; female mean 158), the number of subcaudal scales (male mean 65; female mean 55), and tail length as a proportion of total body length (male 19%; female 17%) differed significantly between males and females.

Regina grahamii, Graham’s Crayfish Snake  227

Melanistic Graham’s crayfish snake from Polk County lacking the lateral stripe on scale rows 1 to 3.

Females are larger, while males have more ventral and subcaudal scales and a longer tail than females. Size. Graham’s crayfish snakes generally range from 18 to 28 inches (46–71 cm) total body length. The largest specimen in the Drake University Research Collection is a male from Louisa County measuring 30.8 inches (78.3 cm) total body length; the largest female is from Warren County measuring 28.2 inches (71.6 cm) total body length. The record total body length reported for the species is 47 inches (119.4 cm). Similar Species. No other Iowa snake has a dark zigzag line where the ventral

scales meet the lateral scales. Among Iowa’s other striped snakes, gartersnakes and the orange-striped ribbonsnake have a bright vertebral stripe, an unpatterned belly, and a single anal plate, and lined snakes have a single anal plate and 2 rows of dark half-moons on the belly. No other Iowa watersnake has a lateral stripe. Distribution. Regina grahamii is found from southeast Nebraska, Iowa, and

Illinois south to the Gulf of Mexico through portions of Missouri, Kansas, Oklahoma, Arkansas, Texas, and Louisiana, with most of the range occurring west of the Mississippi River. Iowa is at the northern edge of the range, and these snakes

228  Graham’s Crayfish Snake, Regina grahamii

are found in scattered populations along major rivers extending into central Iowa, across southern Iowa, and northward along the Missouri River into Woodbury County. During the mid-1940s, they were known from 16 counties; at present, records exist from 32 of Iowa’s 99 counties. The increase in counties does not indicate that the species has increased in the state but, rather, reflects more intensive searches since 1970. Distribution records suggest in fact that the species has declined in Iowa. In the late 1970s, Jim Christiansen and Russ Burken (1978) stated Graham’s crayfish snakes were once common but had disappeared from many parts of the state, and in 1981 Jim concluded the snake had declined as a direct result of the loss of shallow marsh habitats. Of the 32 counties with records, 8 (25%) have only pre-1960 records. The majority of the counties with only pre-1960 records are from the Des Moines Lobe region where Reeve Bailey and others collected specimens in the 1930s and 1940s. More recent searches in these counties have failed to find the species, likely due to the drainage of wetlands associated with increasingly intensive agriculture in that region. Graham’s crayfish snake distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

Habitat. This slender snake is a prairie or woodland edge inhabitant that can be

found in marshes and other wetlands, ponds, lakes, sloughs, wet road ditches, urban parks, and slow-moving streams with soft muddy bottoms and plentiful shoreline vegetation. Along with sluggish shallow water, the primary habitat requirement is the presence of crayfish. The snake is typically found in areas with a variety of aquatic or emergent vegetation and abundant crayfish burrows and can often be found in leaf litter or under rocks, logs, or other debris adjacent to aquatic habitats. Behavior. Unlike Iowa’s other watersnakes, Graham’s crayfish snakes are shy docile creatures that rarely bite even when handled. Their first response is to flee into the water when approached. If harassed, they may flatten their head and body and freely release a slimy mix of foul-smelling feces and musk while twisting their

Regina grahamii, Graham’s Crayfish Snake  229

Graham’s crayfish snake habitat in Bremer County.

tail around their attacker to smear the discharge on the assailant. They are secretive snakes and when not out hunting spend much of their time under logs, bark, or rocks, in crayfish burrows or burrows they construct themselves, or on branches over the water. They are more arboreal than other watersnakes and are good burrowers, excavating tunnels ending in chambers in which they lie with just the tip of their snout and eyes out of the water. The only information concerning movement comes from Hall (1969), who marked and released 14 Graham’s crayfish snakes. One was found three days later in the same pond and 2 others were recaptured eight to nine weeks later in adjacent ponds, with no snake moving more than 328 feet (100 m) from where it was first captured. The collection/observation dates of 136 Iowa Graham’s crayfish snakes show the species is active in Iowa primarily from April through October, consistent with what has been reported in Missouri (Seigel 1992; Johnson 2000). The earliest Iowa record is from Woodbury County on January 22. Reeve Bailey found a male in Lee County on March 22. In most years, activity in Iowa begins in mid-April on warm sunny days, and by early May all have emerged from hibernation. At more northern latitudes such as Iowa, the snake is primarily active during the day in the spring and fall and becomes more nocturnal during the hot days of summer, preferring air temperatures between approximately 81 and 89° F (27–31.5° C). In

230  Graham’s Crayfish Snake, Regina grahamii

Number of Records

50

42

40 30

30 20 10 0

23

21

11 1

0

1

Jan

Feb

Mar

4

3 Apr

May

Jun

Jul

Aug

Sep

Oct

0

0

Nov

Dec

Month Collection/observation dates of 136 Graham’s crayfish snakes in Iowa.

northwest Missouri, 70 percent of individuals were found in April, May, and October, with a lower percentage being found during the summer months (Seigel 1992). Iowa observation records indicate a similar pattern with a peak in observations in spring (46% in April and May), a decrease in observations from June through August, and a slight uptick in September (8% of observations), about a month earlier than in northwest Missouri. In contrast, farther south in Louisiana, Mushinsky and his coworkers (1980) found a significant decline in activity after May and concluded Graham’s crayfish snake is diurnal early in spring and gradually becomes nocturnal before disappearing altogether later in the summer. By late October in Iowa, the snakes have reached their overwintering sites, likely primarily crayfish burrows, and aboveground sightings cease. The latest Iowa record is an individual found in Muscatine County on October 18. Threats. Predation or at least attempted predation of these snakes may be high.

Mushinsky and Miller (1993) found 44 percent of the snakes they examined had wounds from predator attacks. They surmised the serpents’ diurnal basking behavior, especially early in the year, may lead to high rates of attempted predation, with larger snakes having a greater chance of survival than smaller ones. Natural predators may include mammals such as raccoons and weasels, large wading birds, raptors, and other snakes. The tag of a Clinton County specimen in the Drake University Research Collection indicated the snake was killed by a hawk. Humans are likely the biggest threat in Iowa through habitat loss and fragmentation, road mortality, water pollution, and climate change.

Regina grahamii, Graham’s Crayfish Snake  231

Food and Feeding. Graham’s crayfish snakes are active hunters that roam around

the wetlands, ponds, and streams they inhabit in search of prey. Jim has seen the snakes at night moving seemingly randomly underwater, presumably in search of food. They eat primarily crayfish, with a preference for those that have recently molted, but may resort to fish and amphibians when crayfish are not available. Crayfish that have recently molted are more easily digested and are eaten either head or tail first; although adults eat larger crayfish than juveniles, the minimum prey size does not change as the snake grows. Newborns show a greater response (more tongue flicking) to soft-shelled than to hard-shelled crayfish and a greater response to the smell of crayfish than to that of frogs or fish (Burghardt 1968). In Iowa, Graham’s crayfish snakes are frequently found in minnow traps, presumably entering the traps to get at the crayfish inside. Reeve Bailey forced a crayfish out of the stomach of an individual from Pottawattamie County, and Graham’s crayfish snakes in Monona County fed exclusively on crayfish (Godley et al. 1984). Reproduction. Females mature in approximately 3 years at around 16.5 to

19 inches (42–48.5 cm) snout-vent length and males in approximately 1 year at around 12.6 to 15.75 inches (32–40 cm) snout-vent length. Examination of 11 Iowa adult female specimens in the Drake University Research Collection found the smallest reproductive female measured 18.4 inches (46.8 cm) snout-vent length. Ovarian follicles start increasing in size in early May, enlarged follicles were observed in specimens through the end of May, and embryos were observed in late June, suggesting that ovulation in Iowa takes place from late May into June. Mating takes place in the water in April and May, and often several males are attracted to the same female by her scent. In such cases, the males swim around excitedly searching for a female; when they find one, they all gather around her, wrapping their bodies around her and around each other in an intermingled ball as each attempts to mate with her. The males push and prod the female’s body until finally the successful suitor intertwines with her and copulates. Reeve Bailey found an apparently confused male Graham’s crayfish snake on March 22 in Lee County that was intertwined in a ball with 12 common gartersnakes, and on April 15 he encountered 3 Graham’s crayfish snakes in an aggregation in a marshy pool in Lucas County that were possibly trying to mate. Graham’s crayfish snakes are viviparous with females giving birth to live young in August and September. Iowa birth dates include August 12 (Reeve Bailey’s field notes), August 27 and 30 (Jim’s lab), September 12 (Guthrie 1930b), and September 18 (LeClere 2013). Litters can range from 4 to 39 young (average 15) with litter size proportional to female size, with larger females producing more

232  Graham’s Crayfish Snake, Regina grahamii

young than smaller females. Counts of enlarged ovarian follicles in Iowa female museum specimens resulted in an average litter size of 13.3 young (range 10–16; n = 6). Similarly, results based on young born to captives in Jim’s lab at Drake University, Reeve Bailey’s captives, and those reported in the literature (Guthrie 1930b; LeClere 2013) showed an average litter size of 13.2 young (range 7–25; n = 5). Newborns range from 6 to 11.5 inches (15.2–29.3 cm) total body length. Size of Iowa young-of-the-year specimens in the Drake University collection ranged from 7.3 to 8.9 inches (18.5–22.5 cm; n = 10) total body length. Ten living young from Polk County measured by Guthrie (1930b) ranged from 8 to 9 inches (20.3– 23 cm) total body length, and a Louisa County litter measured by LeClere (2013) ranged from 7.7 to 8.5 inches (19.5–21.5 cm) total body length. Longevity. No longevity records are known for Graham’s crayfish snakes.

DEK AY’S BROWNSNAKE Storeria dekayi (Holbrook) 1839

Dekay’s brownsnake from Linn County. Photo by Donald Becker.

Iowa Status. Protected nongame. Historical Summary. Dekay’s brownsnake has been called the brown snake, little

brown snake, house snake, ground snake, and rock snake. The snake is named in honor of James Ellsworth DeKay, a New York naturalist who collected the first specimen of the species. The first mention of this snake in the literature in Iowa appears to be Osborn (1892), who referenced two specimens in the Iowa State Natural History Collection from near Ames in Story County. The first confirmed specimen in the state appears to be one collected sometime between 1863 and 1895 near Keokuk in Lee County (Goodman 1948). Formerly, at least eight subspecies of Storeria dekayi were recognized, two of which, the Texas brown snake, S. d. texana, and the midland brown snake, S. d. wrightorum, had ranges that included Iowa. Pyron et al. (2016) used genetic and morphological evidence to show that Storeria dekayi is a single polymorphic species—a species occurring in several different forms—and concluded against the recognition of subspecies. As a result, only Dekay’s brownsnake is currently recognized in Iowa.

234  Dekay’s Brownsnake, Storeria dekayi

Description. Dekay’s brownsnakes are gray, reddish brown, or brown with 2 par-

allel rows of dark spots along the back separated by a pale stripe down the middle of the back. The paired spots alternate with less distinct small blotches on the sides of the body, and the pairs may be connected by a thin dark line forming a ladder over the pale dorsal stripe. Some individuals have bold dorsal blotches that give more of a checkered appearance and a bold jagged line connecting the dots, while others lack the line connecting the paired spots altogether. All the markings tend to be better developed over the first two-thirds of the body, with the last third of the snake being nearly plain light brown. The head lacks loreal scales and usually has a conspicuous downward stripe or dark spot under each eye. Dark spots behind the head on the nape of the neck often reach down the sides to the belly line, each forming half of a dark collar. The belly is cream to pinkish, often with 2 rows of somewhat scattered small black dots. The body scales are keeled and in 17 rows at midbody; the anal plate is divided. There are usually 7 supra- and infra­ labial scales. Newborns are darker than adults with a light yellow collar. Examination of sexual dimorphism in 114 Iowa adult Dekay’s brownsnake museum specimens (33 males; 81 females) found snout-vent length, the number of ventral scales (male mean 126; female mean 133), the number of subcaudal scales Belly of a Dekay’s brownsnake from Buchanan County.

Storeria dekayi, Dekay’s Brownsnake  235

Dekay’s brownsnake from Buchanan County. Photo by Nicole VanDeWalle.

(male mean 54; female mean 47), and tail length as a proportion of total body length (male 24%; female 20%) differed significantly between males and females. Females are larger and have more ventral scales, while males have more subcaudal scales and a longer tail than females. Size. Dekay’s brownsnakes generally range from 9 to 13 inches (23–33 cm) total

body length. The largest specimen in the Drake University Research Collection is a female from Clayton County measuring 16.7 inches (42.4 cm) total body length; the largest male is also from Clayton County measuring 13.9 inches (35.4 cm) total body length. The record total body length reported for the species is 20.75 inches (52.7 cm). Similar Species. Red-bellied snakes have a pale dorsal stripe but lack paired dor-

sal spots; they have a distinctly red belly and 15 scale rows at midbody. Western smooth earthsnakes lack a dorsal pattern and have both smooth scales and loreal scales. Distribution. S. dekayi is widespread throughout the eastern United States from

Maine south to the Florida panhandle and west to the Great Plains. In Iowa, these snakes are common where suitable habitat exists in the southeast two-thirds of

236  Dekay’s Brownsnake, Storeria dekayi

the state but largely absent from north-central and northwest Iowa. During the mid-1940s, they were known from just 24 counties, only 3 of which were in western Iowa. At present, records exist from 81 of Iowa’s 99 counties, with numerous records throughout much of southwest Iowa. The increase in counties since the 1940s does not necessarily indicate the species has increased in the state but reflects more intensive searches since 1970, although growth of woody vegetation in the Loess Hills over time may have added to the amount of habitat available for this little snake in that part of the state. Many of the post-1960 locations are in urban areas, suggesting Dekay’s brownsnakes may do better with urbanization than many other snake species. Dekay’s brownsnake distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

Habitat. Dekay’s brownsnakes can be found in nearly any terrestrial or wetland

habitat that contains abundant surface litter for hiding, including grasslands and the edges of ponds, wetlands, streams, and rivers as well as residential yards, city parks, and other urban areas, but they are particularly common in open woodlands and wooded river valleys and along woodland edges. In Kansas, they show a clear pattern of using woodland edges during early March, moving into grasslands from mid- to late March to fall, then moving back to woodlands and woodland edges in the fall (Pisani 2009b). They are quite fond of cover objects and are commonly found under rotting logs, bark, flat rocks, boards, and other debris. They are the most commonly seen snake on woodland bike trails during the fall. Often twenty or more can be seen during a single trip on a warm September or October day. Behavior. These gentle little snakes rarely, if ever, attempt to bite. When first found, they may freeze for a moment, sometimes hiding their head beneath their body, before attempting to escape. If escape is not possible, they often assume a threatening posture while spreading their neck and quickly inflating their body to expose the white skin between the scales. This quick flash is intended to startle

Storeria dekayi, Dekay’s Brownsnake  237

Threat display of a Dekay’s brownsnake from Buchanan County showing the white skin between the scales.

and deter would-be predators. Some snakes may also open their mouths in a threatening manner, but it is all bluff and rarely followed by a strike. If handled, they squirm trying to get away while releasing a mix of feces and musk and spraying it on their assailant. They are a cold-tolerant species, illustrated by the collection/observation dates of 869 Iowa Dekay’s brownsnakes, which show they have been found every month of the year in Iowa. The earliest record is from Linn County on January 10. Although they may be seen on the surface on warm sunny winter days, the active season usually begins in late March or early April shortly after the spring thaw when the snakes emerge from hibernation. During cold periods in early spring and again in late fall, the snakes take refuge under logs or other debris or in animal burrows where they wait out the cold. Sudden drops in temperature that catch them off guard may kill those that cannot find shelter. Activity in Iowa is bimodal with a spring peak in late April and May (25% of records) and a second peak in September and October (50% of records). Like many snakes, Dekay’s brownsnakes are primarily diurnal during the spring, become more crepuscular or nocturnal during the heat of the summer, and then return to diurnal activity again in the fall.

238  Dekay’s Brownsnake, Storeria dekayi

322

Number of Records

350 300 250 200 150

104

100 50 0

2

6

Jan

Feb

58

33 Mar

115

109

Apr

May

Jun

39

47

Jul

Aug

30 Sep

Oct

Nov

4 Dec

Month Collection/observation dates of 869 Dekay’s brownsnakes in Iowa.

As September and October progress and the serpents begin moving back to their overwintering locations, large numbers are sometimes found on roadways as the snakes seek warmth. I observed a great example of this one October 18 while working on a road project in Shimek State Forest in Lee County. Because the road corridor was heavily wooded, the road was shaded most of the day. At that time of the year, the road only received direct sunlight for an hour a day. Prior to 12:00 p.m., when the road was shaded, I observed no snakes on it. From 12:00 p.m. to 1:00 p.m., when sunlight hit the road, my coworker Stacey Parks and I removed more than 30 Dekay’s brownsnakes, 1 common gartersnake, and 1 prairie ringnecked snake from the half-mile (0.8-km) stretch. After 1:00 p.m., the road was again shaded and we saw no more snakes. By the end of October, the snakes have reached their overwintering sites and aboveground sightings generally cease. However, November and even December sightings are not unusual. The latest Iowa record is an individual found in Linn County on December 19. The snakes hibernate below the frost line, sometimes in large groups with other species, in anthills, old wells, building foundations, mammal burrows, decaying logs, rotting stumps, and compost piles. One April I received a call from a neighbor who said he had found “a bunch of baby snakes” while removing a stump from his yard. When I arrived, several adult Dekay’s brownsnakes were on the surface near the stump. After we carefully finished removing the stump, I relocated 15 to 20 Dekay’s brownsnakes from around the root ball to an adjacent woodland. Apparently they had been hibernating among the roots.

Storeria dekayi, Dekay’s Brownsnake  239

Winter kill can be a concern for those that do not get below the frost line. Reeve Bailey (1948) discovered Dekay’s brownsnakes leaving a hibernaculum in Lee County on March 22. The snakes were seen emerging from burrows that formed a labyrinth of subterranean galleries in a roadway embankment. Excavation of the burrows revealed 12 living snakes between the surface and a depth of 18 inches (46 cm) and 20 dead adults and juveniles, in various stages of decomposition, all within 10 inches (25.4 cm) of the surface. Many had been dead for some time, suggesting the mortality was due to winter kill during hibernation. In addition to the 32 snakes in the burrows, about a dozen live snakes were found on the surface near the burrows, suggesting that the complex may have contained approximately 50 snakes. Threats. Natural predators include mammals such as shrews, opossums, skunks, raccoons, and domestic cats; birds such as shrikes, songbirds, and hawks; and other snakes such as prairie kingsnakes, eastern milksnakes, North American racers, and common gartersnakes. I once watched an American robin kill an earthworm-sized Dekay’s brownsnake in my yard in Buchanan County. As is the case with so many snake species, however, humans pose the biggest threat through habitat loss, pesticide use, lawn mowers, climate change, and automobiles. Road mortality is a particular concern for these little snakes, which especially in the fall are fond of crawling out onto warm roads that pass through or along the edges of woodlands. Of 422 Iowa September and October observations, the largest percentage were found either alive or dead on a road. Food and Feeding. Dekay’s brownsnakes are active hunters that search for

prey primarily by smell. When prey is located, the snake quickly moves toward it, grasps it with its jaws, and works it into a position to be swallowed. They feed primarily on slugs, earthworms, and snails, but insects, mites, and small amphibians may also be eaten. Rossman and Myer (1990) suggested the teeth of Dekay’s brownsnakes may be adapted to feeding on slugs, and they showed the snake was able to wedge a snail against an immovable object and apply force to its soft body to extract it from its shell. Examination of specimens in the Drake University Research Collection found three slugs in the stomach of a female from Muscatine County and partially digested material consistent with slugs or snails in several other specimens. Virgin and King (2019) noted that the two most abundant prey types consumed in Illinois, slugs and earthworms, were nonnative species; they hypothesized that the availability of abundant nonnative prey might improve competitive interactions with other snake species, such as red-bellied snakes, and promote coexistence.

240  Dekay’s Brownsnake, Storeria dekayi

Reproduction. Both males and females mature in 2 to 3 years at around 7 inches

(17.8 cm) snout-vent length for females and around 6.3 inches (16 cm) snout-vent length for males. The smallest reproductive female in the Drake University Research Collection measured 9.1 inches (23.1 cm) snout-vent length. Mating occurs in the spring, with males using scent trails to find females. When a male encounters a female, he first uses scent to confirm she is a female, then slides alongside her by moving his chin along her back until he reaches her head, encircles her with the posterior portion of his body, and inserts his hemipenis, after which the female may crawl away dragging the male with her. Several males may court a single female at the same time, each wrestling with the others for position. Mating may last up to 30 minutes. Examination of 81 Iowa adult female museum specimens found enlarged ovarian follicles from early April to early June, oviductal eggs from late May to June, early embryos from mid-June to mid-July, and near-full-term embryos from late July to early August. Dekay’s brownsnakes are viviparous with females giving birth from late July to September after an approximately 75-day gestation period. The young are born surrounded by a transparent membrane that ruptures soon after birth. Iowa birth dates are limited. Jim found a mother with 6 newborns in Van Buren County on August 11, and he had a record of 11 young born to a captive female from August 20 to 22; Guthrie (1926) reported a litter of 11 young born in his laboratory from September 1 to 2. Females may produce from 3 to 41 young (average = 13). In the Midwest, litters of 4 to 24 young have been reported. Counts of enlarged ovarian follicles and oviductal eggs or embryos in Iowa females in the Drake University collection resulted in average litter sizes of 16 (range 3–38; n = 11) and 15 (range 3–23; n = 17) young, respectively. An average count of 9 young (range 6–11; n = 3) is based on Iowa litter reports (Guthrie 1926; Jim Christiansen, personal communication, 2019). Newborns range from 3.5 to 4.5 inches (9–11.4 cm) total body length. Guthrie (1926) reported size at birth as 3.5 inches (9 cm) total body length for a litter born in his laboratory. Size of young from a Van Buren County litter in the Drake collection ranged from 3.4 to 4 inches (8.7–10.1 cm; n = 4) total body length. Fitch (1999) reported rapid growth of newborns during September and October with the largest young reaching 5.5 inches (13.9 cm) snout-vent length by their first hibernation. Similarly, first-year October specimens in the Drake collection ranged from 4.1 to 5.5 inches (10.5–13.9 cm) snout-vent length. Longevity. A wild-caught adult of unknown sex survived in captivity an addi-

tional 7 years and 13 days.

RED-BELLIED SNAKE Storeria occipitomaculata (Storer) 1839

Red-bellied snake from Bremer County. Photo by Jim Scharosch.

Iowa Status. Protected nongame; species of greatest conservation need. Historical Summary. The red-bellied snake has also been called Storer’s snake,

little brown snake, red-bellied Dekay’s snake, little red-bellied snake, red-bellied brown snake, copper snake, spot-necked snake, and Storer’s grass snake. The genus Storeria honors the herpetological contributions of physician and naturalist David Humphreys Storer. The first confirmed specimen in the state appears to be one collected sometime between 1863 and 1895 near Keokuk in Lee County (Goodman 1948). Formerly, three subspecies of Storeria occipitomaculata were recognized, two of which, the northern red-bellied snake, S. o. occipitomaculata, and the Black Hills red-bellied snake, S. o. pahasapae, had ranges that included Iowa. Pyron et al. (2016) used genetic and morphological evidence to show that Storeria occipitoma­ culata is a single monotypic polymorphic species—a species that occurs in several different forms—and concluded against the recognition of subspecies. As a result, only the red-bellied snake is currently recognized in Iowa.

242  Red-Bellied Snake, Storeria occipitomaculata

Red-bellied snakes from Cherokee County showing color variation. Photo by Ryan D. Rasmussen.

Description. Red-bellied snakes are light to dark brown, coppery brown, olive

black, or grayish with 3 small light spots on the nape of the neck, 1 dorsal and 1 on each side—the specific epithet occipitomaculata is from the Latin occipit referring to the back of the head and maculata meaning “spotted”—and either 4 narrow dark stripes along the sides and back or a single wide pale vertebral stripe. The dorsal stripes may be quite indistinct on some individuals. Color is highly variable with light (gray) and dark (brown) individuals often found in the same population. The belly is bright red, orange, or pale yellow. The light spots on the nape of the neck may fuse to form a complete collar, or any of the 3 may be missing to form a broken collar. The head lacks loreal scales, has 2 (occasionally more) preocular scales anterior to each eye, is darker behind the eyes than in front of the eyes, and usually has a light spot on the fifth supralabial scale. The body scales are keeled and in 15 rows at midbody; the anal plate is divided. There are usually 6 supralabial scales and 7 infralabial scales. Newborns are similar in color to adults but may be darker with a light collar and sometimes a brighter belly. Examination of sexual dimorphism in 37 Iowa adult red-bellied snake museum specimens (18 males; 19 females) found the number of ventral scales (male mean

Storeria occipitomaculata, Red-Bellied Snake  243

Red-bellied snakes from Bremer County showing color variation.

126; female mean 130), the number of subcaudal scales (male mean 52; female mean 46), and tail length as a proportion of total body length (male 24%; female 21%) differed significantly between males and females. Females have more ventral scales, while males have more subcaudal scales and a longer tail. Size. S. occipitomaculata, Iowa’s smallest snake, generally ranges from 8 to 10

inches (20.3–25.4 cm) total body length. The largest specimen in the Drake University Research Collection is a male from Dickinson County measuring 12.4 inches (31.4 cm) total body length; the largest female is from Cherokee County measuring 11.5 inches (29.3 cm) total body length. The record total body length reported for the species is 16.6 inches (42.2 cm). Similar Species. Dekay’s brownsnakes have a pale dorsal stripe with paired dorsal spots, a cream to pinkish belly often with 2 rows of somewhat scattered small black dots, and 17 scale rows at midbody. Western smooth earthsnakes lack a dorsal pattern and have both smooth scales and loreal scales. Prairie ring-necked

244  Red-Bellied Snake, Storeria occipitomaculata

snakes have smooth scales, a yellow to orange ring around the neck, a bright red underside to the tail, and a bright yellow or orange belly with a scattering of small black dots extending onto the tail. Western wormsnakes have smooth scales and a salmon pink belly with the pink color extending up the sides to the third lateral scale row. Distribution. Red-bellied snakes are found from Nova Scotia to eastern North

Dakota south to Georgia and west to northern Arkansas, with widely scattered populations over much of their range. They are found in most of northern and southeast Iowa but are absent from southwest Iowa. During the mid-1940s, they were known from just 12 counties. At present, records exist from 56 of Iowa’s 99 counties, with the increase in counties since the 1940s largely reflecting the more intensive searches for this species conducted after 1970. Two counties (Greene and Story) have only a single pre-1960 record each. These counties are heavily tiled and intensely cropped, which has resulted in a loss of habitat for this little snake. Wright and Wright (1957) noted red-bellied snakes occur “rarely in plowed fields.” Red-bellied snake distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

Habitat. Most often associated with moist woodlands, these snakes may also use

wetland and pond edges, wet prairies, and dry grasslands. During a long-term study of snake ecology in Bremer County, I have found them to be abundant in sedge meadows, wet prairies, and an upland restored prairie. In northeast and southeast Iowa they are frequently found in open woodlands, whereas in northwest Iowa where trees are scarce they use prairies. Ideal habitat consists of riparian woodlands or grasslands with abundant prey, suitable overwintering sites, and plentiful cover objects such as rotting logs, bark, flat rocks, boards, or other debris. Busby and Pisani (2014) concluded that available data strongly suggest that established populations of slugs and snails in a habitat can serve as a reliable indicator of the value of that habitat to red-bellied snakes.

Storeria occipitomaculata, Red-Bellied Snake  245

Number of Records

50

45

40 34

34

21

25

15

0

0

1

2

Jan

Feb

Mar

7

Apr

May

Jun

Jul

Aug

Sep

Oct

2

4

Nov

Dec

Month Collection/observation dates of 205 red-bellied snakes in Iowa.

Behavior. These secretive little snakes rarely, if ever, attempt to bite. When found, they most often lie motionless or simply try to get under the nearest cover. If you handle them, they may flatten their head and body, release a mix of feces and musk, and curl their upper lip to expose their teeth, seeming to grin while rubbing the side of their head against your hand. Others may roll onto their back and play dead or extend their body straight out and become rigid. Reeve Bailey once observed a red-bellied snake basking on a rock ledge with a timber rattlesnake in Madison County. With friends like that, who needs a defense? Red-bellied snakes are a cold-tolerant species, and the collection/observation dates of 205 Iowa red-bellied snakes show the species has been found every month of the year in the state with the exception of January. The earliest record is from Louisa County on February 15. The active season usually begins in late March or early April, and I commonly find them at this time under cover boards in Bremer County, often when ice is still present around the margins of the wetlands. Activity in Iowa is bimodal with a spring peak in May and June (41% of records) and a second peak in September and October (33% of records). Like many snakes, red-bellied snakes are primarily diurnal during the spring, appear to be more crepuscular or nocturnal during the heat of the summer, and then return to diurnal activity in the fall. Sometime in late September or early October the serpents begin moving back to their overwintering locations, with 75 percent of Iowa fall observations occurring between September 15 and October 15. In Minnesota, most red-bellied snakes were recorded moving from 500 to 1,000 feet (152–305 m) between summer foraging areas and hibernacula (Lang 1969).

246  Red-Bellied Snake, Storeria occipitomaculata

Red-bellied snake from Bremer County with an opaque eye prior to shedding.

By the end of October, the snakes have reached their overwintering sites and aboveground sightings generally cease. The latest Iowa records, however, are 4 individuals found in Cherokee County on December 10 and 11 after several warm days. Red-bellied snakes hibernate below the frost line in rock crevices, mammal burrows, rotting stumps, and the foundations of houses. Mound-building ants may play a critical role in providing suitable hibernacula in some locations (Busby and Pisani 2014). In northern Minnesota, the snakes were found hibernating with smooth greensnakes and common gartersnakes in large inactive ant mounds that were extensively channeled with tunnels extending 5 to 10 feet (1.5–3 m) below the surface, with snakes being evenly distributed in the tunnels to a depth of 8.5 feet (2.6 m) (Lang 1969). In Manitoba, 101 were dug out of an anthill, with those snakes in the lowest tunnels in contact with the groundwater (Criddle 1937). Red-bellied snakes show a strong fidelity to overwintering sites, with individual snakes returning to the same site in successive years. Winter kill can be a concern for those that do not get below the frost line. Threats. Natural predators include mammals such as thirteen-lined ground

squirrels and chipmunks; birds such as chickens, American crows, red-tailed hawks, and American kestrels; and other snakes such as eastern milksnakes, racers, and prairie kingsnakes. Domestic cats also take a toll. Neil Bernstein (personal communication, 2020) witnessed an American robin killing a 13.3-inch (33.8-cm)

Storeria occipitomaculata, Red-Bellied Snake  247

red-bellied snake in Dickinson County, and a record from Winneshiek County noted that a red-bellied snake had been regurgitated by an eastern milksnake. Humans pose the greatest threat, however, through habitat loss, pesticide use, lawn mowers, climate change, and automobiles. Conversion of woodlands or wet grasslands to intensive agriculture will eliminate this snake. Some areas in Kansas with a history of intensive agriculture did not support red-bellied snakes more than thirty years after the end of agricultural use (Busby and Pisani 2014). Pesticides may indirectly affect red-bellied snakes by reducing the slug and snail prey they depend on, thereby diminishing snake activity. Road mortality is a particular concern during the fall for these little snakes that often must cross roadways to reach overwintering sites or that crawl out onto warm roads as the days grow shorter and the temperatures drop. Food and Feeding. The foraging behavior of red-bellied snakes has not been

described; however, when prey is encountered the snake simply grasps it and swallows it. Red-bellied snakes are diet specialists that feed principally on slugs, but at times they may also eat earthworms and the occasional soft-bodied insect. Guthrie (1926) reported that their diet consists of slugs, grubs, and earthworms. Rossman and Myer (1990) suggested the teeth of these snakes may be adapted to feeding on slugs, and they showed the snake could wedge a snail against an immovable object and apply force to its soft body to extract it from its shell. A high overlap in diet was noted between red-bellied snakes and Dekay’s brownsnakes in Illinois; the most commonly consumed prey by both species was nonnative slugs and earthworms (Virgin and King 2019). The researchers went on to hypothesize that the availability of abundant nonnative prey may improve competitive interactions between the two snake species and promote coexistence. Reproduction. These snakes mature in 18 to 24 months, females at around 6.3 inches (16 cm) snout-vent length and males at around 5.5 inches (14 cm) snoutvent length. Examination of 24 Iowa adult female museum specimens in the Drake University Research Collection found the largest immature female was 5.8 inches (14.7 cm) snout-vent length and the smallest mature female was 7.2 inches (18.3 cm) snout-vent length, suggesting that female maturity in Iowa occurs at snout-vent lengths of about 6 to 7 inches (15.2–17.8 cm). Likewise, examination of 22 Iowa adult male specimens found the largest immature male was 5.4 inches (13.6 cm) snout-vent length and the smallest mature male was 5.8 inches (14.8 cm) snout-vent length, suggesting that male maturity in Iowa occurs at snout-vent lengths of about 5.5 to 6 inches (14–15.2 cm). Mating, during which the male coils around the female with his tail beneath

248  Red-Bellied Snake, Storeria occipitomaculata

hers, occurs in both spring and fall. Females may store sperm, even over the winter months, allowing for delayed fertilization, with sperm remaining viable for up to 4 months. Examination of 19 Iowa adult female museum specimens showed ovarian follicles nearly doubled in size between early April and the end of May or early June. Enlarged ovarian follicles were present in specimens in April and oviductal eggs were found in late May and early June. A May 30 female from Lee County with early oviductal eggs and a June 2 female from Worth County that appeared to have just ovulated suggest ovulation in Iowa occurs in late May or early June. Red-bellied snakes are viviparous with females aggregating at suitable sites from late July to September to give birth. A female specimen in the Drake University collection found in Cherokee County on October 13 contained a single fully developed embryo, suggesting that some females may not give birth until well into October. The young are born surrounded by a transparent membrane that ruptures soon after birth, and many are stillborn. Half an hour may pass between births, and several days may be needed to pass an entire litter (Ernst and Ernst 2003). Litter size has been reported at 1 to 23 young; however, litters from the northern part of the species’ range are generally smaller, averaging 7 young per litter. Litter size in the Midwest has been reported as 2 to 14 (Vogt 1981, Wisconsin), 14 (Smith 1961, Illinois), 18 (Breckenridge 1944, Minnesota), 1 to 13 (Blanchard 1937, Michigan), and 4 to 13 young (Busby and Pisani 2014, Kansas). No Iowa birth dates or litter sizes are known, but counts of enlarged ovarian follicles and oviductal eggs or embryos in Iowa females in the Drake University collection resulted in average litter sizes of 13 (range 8–16; n = 7) and 11 (range 10–12; n = 3) young, respectively. Red-bellied snakes give birth to relatively small young, with newborns ranging from 2.5 to 4.5 inches (6.4–11.4 cm) total body length. Large females produce more but smaller young. Litter size and total litter mass are correlated with female size but average offspring size is not, indicating that larger females invest more in total reproduction but partition it into more rather than larger offspring (Brodie and Ducey 1989). Newborns grow very quickly, increasing about an inch (2.5 cm) in size by their first hibernation. Longevity. A wild-caught adult female lived in captivity an additional 4 years

and 7 months.

ORANGE-STRIPED RIBBONSNAKE Thamnophis proximus proximus (Say) 1823

Orange-striped ribbonsnake from Muscatine County. Photo by Ryan D. Rasmussen.

Iowa Status. Protected nongame; species of greatest conservation need. Historical Summary. The western ribbonsnake has also been called Long’s ribbon snake, Fairie’s ribbon snake, Fairie’s garter snake, slender garter snake, swift striped snake, Say’s garter snake, and plains ribbon snake. The History of Fremont County, Iowa (Anonymous 1881a) listed three species as present—the riband snake (the eastern ribbonsnake, Thamnophis saurita, not found in Iowa), Fairie’s garter snake, and Say’s garter snake—along with scientific names that are synonyms for the western ribbonsnake. The first confirmed specimens in the state appear to be in 1889 from Des Moines in Polk County (National Museum of Natural History–Smithsonian Institution) and four specimens collected near Riverton in Fremont County in 1890 by Iowa naturalist Bohumil Shimek (Iowa State Natural History Collection), although it is possible an earlier specimen was collected from near Keokuk in Lee County (Goodman 1948). Nutting (1892) listed a specimen from Johnson County and Cope (1900) included Iowa within the range of the species.

250  Orange-Striped Ribbonsnake, Thamnophis p. proximus

Four subspecies of the western ribbonsnake, Thamnophis proximus, are currently recognized, only one of which, the orange-striped ribbonsnake, T. p. proximus, has a range that includes Iowa. Description. Orange-striped ribbonsnakes are long and slender with a dark

brown to black back with a narrow orange dorsal stripe, yellow lateral stripes on scale rows 3 and 4, and a long narrow tail measuring approximately one-third or more of the total body length. When threatened, the snake may fill its lungs with air, stretching the skin and exposing the white to light green skin between the scales, which gives the appearance of dashes on the dark background color. The head is brown or black with no dark bars on the labial scales, is distinct from the neck, and has 2 large fused yellow spots on top. The neck and belly are white, cream, or green and unpatterned. The body scales are keeled and in 19 rows at midbody; the anal plate is single. There are usually 8 supralabial scales and 10 infralabial scales. The young are similar in appearance to adults. Examination of sexual dimorphism in 33 Iowa adult orange-striped ribbonsnake museum specimens (13 males; 20 females) found the number of subcaudal scales (male mean 107; female mean 95) and tail length as a proportion of total body length (male 30%; female 28%) differed significantly between males and females. Females are larger, while males have more subcaudal scales and longer tails.

Shedding orange-striped ribbonsnake from Muscatine County showing the paired spots on the head. Note the spectacles—scales covering the eyes—in the shed skin. Photo by Ryan D. Rasmussen.

Thamnophis p. proximus, Orange-Striped Ribbonsnake  251

Size. Western ribbonsnakes generally range from 20 to 30 inches (51–76 cm)

total body length. The largest specimen in the Drake University Research Collection is a female from Clinton County measuring 37 inches (94 cm) total body length; the largest male is from Louisa County measuring 30 inches (76 cm) total body length. The record total body length reported for T. proximus is 49.9 inches (126.8 cm). Similar Species. Plains gartersnakes also have lateral stripes on scale rows 3 and

4, but they have distinct checkering between the dorsal stripe and the lateral stripes, black bars on the labial scales, and light spots on top of the head that are most often not fused. Common gartersnakes have lateral stripes on scale rows 2 and 3. Both plains and common gartersnakes tend to have a yellow dorsal stripe and have tails that are usually less than one-fourth of the total body length. Distribution. The orange-striped ribbonsnake is found in scattered populations

in Indiana, southern Wisconsin, and Illinois and from southern Iowa south along the Mississippi River to Louisiana and west to parts of Nebraska, Kansas, Oklahoma, and Texas. In Iowa, orange-striped ribbonsnakes are more abundant in the south and east than in the western portions of the state and are absent from the northwest. A few widely scattered populations are found in the north-central part of the state. During the mid-1940s, the serpent was known from 15 counties. At present, records exist from 37 of Iowa’s 99 counties, 2 (5%) of which have only pre-1945 records (Montgomery and Pottawattamie). In the early 1980s, Jim Christiansen considered the snake to be declining in the state due to the loss of open native marshy habitat, which is probably still the case over much of its Iowa range with the exception of portions of south-central and southeast Iowa, where it remains abundant. Orange-striped ribbonsnake distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

252  Orange-Striped Ribbonsnake, Thamnophis p. proximus

Orange-striped ribbonsnake from Bremer County.

Habitat. Orange-striped ribbonsnakes are most often found in grassy or shrubby

habitats (Thamnophis comes from the Greek thamnos meaning “shrub” or “bush” and ophis meaning “snake”; proximus is Latin for “nearest”) associated with marshes, woodland pools, ponds, lakes, streams, and less commonly rivers. Water is an important component of the habitats of these semi-aquatic snakes. However, they will use drier habitats in some locations. I have often found these snakes, including gravid females, under cover boards in an upland restored prairie in Bremer County up to 656 feet (200 m) from open water, and Minton (1972) reported similar observations in Indiana. Jim has found the snake as far as 984 feet (300 m) from open water but always in moist grassy or shrubby wetlands. Among seven records in Reeve Bailey’s field notes where he recorded habitat, six mentioned water. Behavior. When approached, this fast snake first responds by darting quickly

away to disappear into the surrounding vegetation. If near water, it will readily dive in, either hiding in the shoreline vegetation or quickly skimming across the surface to escape. When escape is not an option, it often assumes a defensive posture—coiling, flattening the body, opening the mouth in a threatening manner, spraying a foul-smelling musk, and sometimes striking—however, it is less likely to bite than other gartersnakes.

Thamnophis p. proximus, Orange-Striped Ribbonsnake  253

Number of Records

40

35 24

20

20

23 12

9 0

0

0

Jan

Feb

8

4 Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

1

1

Nov

Dec

Month Collection/observation dates of 137 orange-striped ribbonsnakes in Iowa.

This cold-tolerant snake has one of the longer activity periods among Iowa snakes. The collection/observation dates of 137 Iowa orange-striped ribbonsnakes show the snake has been found from March through December. The earliest record is from Appanoose County on March 20 when Jim observed a male swimming slowly across a frigid pond filled with calling chorus frogs and spring peepers. Ice had been present on the pond a week earlier. During the early spring, the serpent emerges during the day to bask or hunt and returns to shelter at night as the temperature drops. Surface activity begins to increase in April and peaks in May and early June (43% of records). Rainfall during this time and again in the fall has been shown to stimulate activity, likely because the wet weather also increases amphibian activity, and the availability of water throughout the year, including soil moisture, affects their activity and in some cases their survival. This snake is primarily diurnal but is just as comfortable being out on warm nights in search of food. When not out hunting, it can be found under logs, rocks, boards, tin, or other debris or climbing into shrubs to bask. Activity in Iowa appears to be bimodal with a second peak in August and September (26% of records) corresponding to the appearance of young-of-the-year snakes. As air and water temperatures drop throughout September and October, the snakes become less active, and by the end of October aboveground sightings generally cease. They hibernate below the frost line, sometimes with other species, in anthills and small mammal burrows, rocky banks near water, or deep in rock crevices. It is likely they use crayfish burrows in some locations. Winter kill

254  Orange-Striped Ribbonsnake, Thamnophis p. proximus

can be a concern for those that do not get below the frost line. The latest Iowa record is an individual found in Story County on December 5. Threats. Natural predators include those species commonly found in the semi-

aquatic habitats of this snake, such as large wading birds like great blue herons and mammals like raccoons and foxes. The tag of an adult male specimen from Appanoose County in the Drake University Research Collection notes that it was “dropped by a hawk.” Predation by domestic cats and by large frogs and fish on juveniles may also occur. In Iowa, bullfrogs would have to be considered a threat to juveniles along with other small snakes. Drought can pose a serious threat to this moisture-dependent snake. A lack of rainfall may reduce its amphibian prey, leading to starvation; prolonged dry periods can result in desiccation or, over the winter, winter kill. Humans also pose a threat through habitat loss, pesticide use, lawn mowers, climate change, and automobiles. Food and Feeding. The snake’s diet consists primarily of amphibians and fish,

with adult and tadpole frogs and toads making up the largest percentage of the food eaten, although invertebrates such as crayfish and the occasional earthworm may also be consumed. A large individual in Illinois was observed eating two smaller snakes of its own kind (Smith 1961), but this appears to be rare. Clark (1974) found frogs and toads or their tadpoles in 92 percent of the stomachs he examined. Iowa diet reports are limited but include an individual captured in Lucas County by Reeve Bailey on April 15 that regurgitated two chorus frogs; Jim’s observations of an individual in Appanoose County in May eating a large tadpole and captives in his lab at Drake University readily consuming minnows and earthworms; a specimen in the Drake University collection from Davis County that was found in June with a tadpole in its mouth; and LeClere’s (2013) reports of an individual in Louisa County on May 27 eating a chorus frog and a gravid female in Muscatine County swallowing a young bullfrog. These snakes are active hunters; their long sleek bodies and quick speed allow them to chase down fleeing frogs. The snake appears to seek out high-density patches of prey such as ephemeral pools full of tadpoles or calling frogs. When hunting, it prowls wetlands where frogs are calling, looking for prey and probing potential hiding places with a series of three short thrusts of its forebody across a semicircular arc (Wendelken 1978). When a startled frog moves, the snake quickly chases it, grasps it in its mouth, and swallows it alive. If the frog gets away, the snake freezes with its head raised off the ground and remains motionless waiting for the frog to move again. If no further movement is seen, the snake resumes the

Thamnophis p. proximus, Orange-Striped Ribbonsnake  255

hunt. They often consume more than one prey item per meal with larger snakes eating larger prey. The prey type consumed may change throughout the year depending on availability, with tadpoles available in the spring, newly metamorphosed frogs and toads in the late spring and summer, and adults in all seasons. Reproduction. Females generally mature in 3 years at around 19 to 20 inches

(48.5–51 cm) snout-vent length and males in 1 to 2 years at around 14.5 inches (36.8 cm) snout-vent length. Two Iowa records indicate that at least some females mature at a smaller size. A 17.9-inch (45.5-cm) snout-vent length female from Story County with oviductal eggs was examined by Reeve Bailey, and an 18.6inch (47.2-cm) snout-vent length female from Lee County in the Drake University collection gave birth to 12 young. Mating occurs in the spring soon after the snakes emerge from hibernation, with males likely using scent trails to find females. Several males may be attracted to a single female, resulting in a mating ball such as one I observed one April 6 evening under a piece of aluminum in Bremer County. Examination of 20 Iowa adult female museum specimens caught in early spring showed ovarian follicles

Orange-striped ribbonsnake mating ball in Bremer County.

256  Orange-Striped Ribbonsnake, Thamnophis p. proximus

were still small ovoid structures averaging 0.2 inch (4.6 mm) long. By early June, the follicles had increased to three times this length. The first early oviductal eggs were found in a June 22 Louisa County female, suggesting ovulation occurs sometime in June. I have found large gravid orange-striped ribbonsnakes under cover boards in Bremer County in June and July along with gravid red-sided and plains gartersnakes, all presumably using the warmth of the boards to gestate young. Not all females may reproduce each year. In Missouri, 81 percent of adult females contained eggs or embryos in any one year (Seigel and Ford 1987). Although the sample size is small, examination of Iowa female museum specimens suggests some females may skip a reproductive year as well. Among 8 adult females examined that were found in May and June, 7 (87%) contained enlarged ovarian follicles or oviductal eggs. One 22-inch (55.8-cm) snout-vent length female found in Louisa County on May 18 had no enlarged ovarian follicles or embryos. These snakes are viviparous with most females giving birth to 10 to 15 young from late July to September. In Missouri, Anderson (1965) reported 9 young born on July 21 and Johnson (2000) reported an average of 10 young for 10 females. Counts of enlarged ovarian follicles and oviductal eggs or embryos in Iowa females in the Drake University collection resulted in average litter sizes of 13.5 (range 10–17; n = 4) and 9 (range 5–12; n = 2) young, respectively. A wild-caught female from Lee County kept in Jim’s lab gave birth to 12 young on August 19, and 18 young in the Drake collection were born to a Polk County female on August 22. Newborns average 8.7 inches (22 cm) total body length. The 18 young born to the Polk County female averaged 8.1 inches (20.7 cm) total body length. Longevity. A wild-caught adult of unknown sex lived in captivity an additional

3 years, 7 months, and 1 day.

PLAINS GARTERSNAKE Thamnophis radix (Baird and Girard) 1853

Plains gartersnake from Benton County. Photo by Jim Scharosch.

Iowa Status. Protected nongame; species of greatest conservation need. Historical Summary. The plains gartersnake has also been called the prairie

garter snake, transition garter snake, common garter snake, Hay’s garter snake, ribbon snake, Say’s garter snake, striped snake, and western garter snake. The History of Fremont County, Iowa (Anonymous 1881a) listed “Hoy’s garter snake” along with the note “determination doubtful.” The first confirmed specimens in the state appear to be one collected sometime between 1863 and 1895 near Keokuk in Lee County (Goodman 1948) and one in 1889 from Des Moines in Polk County

258  Plains Gartersnake, Thamnophis radix

(National Museum of Natural History–Smithsonian Institution). Osborn (1892) reported a specimen in the Iowa State Natural History Collection believed to be from near Ames in Story County. Description. Plains gartersnakes are the stockiest of the gartersnakes with a tan to dark brown, black, greenish, or red back with a prominent and usually yellow dorsal stripe that often becomes more orange toward the head, cream to yellow lateral stripes on scale rows 3 and 4, rows of black spots above and below the lateral stripes, and a tail measuring slightly less than one-fourth of the total body length. The head is brown or black with dark bars on the labial scales, is not distinct from the neck, and has 2 small white spots on top just in front of the dorsal stripe. The neck and belly are white, yellowish, greenish, or bluish with a row of small dark spots along the edges of the ventral scales. The body scales are keeled and in 19 to 21 rows at midbody; the anal plate is single. There are usually 7 supralabial scales and 9 to 10 infralabial scales. The young are similar in appearance to adults. Several color variations have been reported in Iowa. Albinos and amelanistic— lacking black pigment—individuals appear fairly frequently with this species. Reeve Bailey found what he called an albino in Hardin County in 1940, Jeff LeClere (2013) reported albinos from several central Iowa counties, and several reports of presumed albinos exist from around the state. Populations of bright red plains gartersnakes are found in various locations across the state. I have seen them in Bremer County, Jim Christiansen found them in northwest Iowa, and Jeff LeClere (2013) reported observations of red individuals in several counties. Jim (1961) reported a possible plains gartersnake and common gartersnake hybrid in Buena Vista County that had extensive red bars on the sides and lateral stripes on scale rows 3 and 4. Over the years, Jim took note of very dark plains gartersnakes in several locations in northeast Iowa, and LeClere (2013) reported “unusually dark” individuals found in Des Moines in Polk County. Although this was not a color variation, Guthrie (1929) reported a young partial double-headed plains gartersnake found at one of the Iowa State University farms near Ames in Story County. The snake attempted to eat an earthworm “but got it badly tangled and finally failed in the attempt and died of starvation.” A young double-headed plains gartersnake found in Polk County also died soon after capture (LeClere 2013). Examination of sexual dimorphism in 46 Iowa adult plains gartersnake museum specimens (14 males; 32 females) found the number of ventral scales (male mean 159; female mean 155), the number of subcaudal scales (male mean 74; female mean 64), and tail length as a proportion of total body length (male 24%; female 21%) differed significantly between males and females. Females are larger; males have more ventral and subcaudal scales and a longer tail.

Thamnophis radix, Plains Gartersnake  259

Red phase plains gartersnake from Bremer County before shedding.

Size. This gartersnake generally ranges from 15 to 28 inches (38–71 cm) total body

length. The largest specimen in the Drake University Research Collection is a female from Fremont County measuring 29.7 inches (75.5 cm) total body length; the largest male is from Mills County measuring 26.6 inches (67.5 cm) total body length. The record total body length reported for the species is 43 inches (109.3 cm). Similar Species. Orange-striped ribbonsnakes also have lateral stripes on scale

rows 3 and 4 but lack black spots above and below the lateral stripes and black bars on the labial scales, have 2 large fused yellow spots on top of the head, and tails that are one-third or more of the total body length. Common gartersnakes have lateral stripes on scale rows 2 and 3. Lined snakes have a double row of black half-moons down the middle of the ventral scales in contrast to the smaller and less regular dark spots on the edges of the ventral scales of plains gartersnakes. Distribution. Plains gartersnakes are found throughout the Great Plains from

southern Alberta, Saskatchewan, and Manitoba south to northeast New Mexico and the panhandles of Oklahoma and Texas and east through Minnesota, Iowa, southern Wisconsin (radix is Latin for “root” in reference to the Root River near Racine, Wisconsin, where the type specimen for the species was thought to have been collected), and northern Illinois. Scattered populations also occur in Missouri, Indiana, and Ohio. In Iowa, they are found statewide but are more common in the north. During the mid-1940s, the species was known from 70 counties. In 1950, Moorman and Carlander (1950a) stated the plains gartersnake was the most common and widely distributed snake in the state. At present, records exist from

260  Plains Gartersnake, Thamnophis radix

Plains gartersnake from Bremer County.

93 of Iowa’s 99 counties, 7 (8%) of which have only pre-1960 records. In 1981, Jim concluded plains gartersnake abundance was unchanged since the time of Reeve Bailey’s surveys in the 1940s. Later, Jim and Catherine Mabry (1985) reported the species had decreased in the Loess Hills since the time of Bailey’s surveys due to the loss of prairie habitat. Although records exist from more counties now than at the time of Bailey’s work, even with increased survey effort since 1970 there are fewer records after 1960 (49% of total) than before (51% of total), suggesting that although plains gartersnakes are still common in many places, they may be declining over time. Plains gartersnake distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

Thamnophis radix, Plains Gartersnake  261

Plains gartersnake from Cherokee County. Photo by Ryan D. Rasmussen.

Habitat. Thamnophis radix is found in open grasslands such as prairies, mead-

ows, and old fields with easy access to ponds, marshes, and streams. It will also use city parks and residential yards. I once found several individuals, including a gravid female, under an overturned canoe next to a garage in a rural residential area in Black Hawk County. Reeve Bailey recorded habitat data in his field notes for 89 plains gartersnakes; although some notes contained more than one habitat type, 77 percent mentioned prairie, hayfield, stubble, or grassland, 58 percent mentioned marsh, river, stream, pool, or lake, 10 percent mentioned woodland (likely woodland edge or nearby woodland), 7 percent mentioned only farmstead or cultivated field, and 6 percent mentioned city. Blanchard (1923) found these snakes rarely in woodlands in Dickinson County but frequently along roads, near marshes, in tallgrass and shortgrass prairies, and along lakeshores. Habitat partitioning may occur in places where both plains gartersnakes and common gartersnakes live, with common gartersnakes found in wetter areas and plains gartersnakes found in open drier areas (Ernst and Ernst 2003). I have observed this in Bremer County where plains gartersnakes are most abundant in an upland restored prairie and become less abundant closer to the marsh, whereas common gartersnakes show the opposite pattern, although both species occur throughout the site.

262  Plains Gartersnake, Thamnophis radix

Behavior. Like other gartersnakes, when it is approached the plains gartersnake’s

first response is to flee by quickly disappearing into the surrounding vegetation. When escape is not possible, it often assumes a defensive posture. Nine antipredator displays have been described for newborn plains gartersnakes including simply hiding the head beneath one or more loops of the body, rolling the body into a loose ball, coiling the body and vibrating the tail, and striking with the mouth open or closed, with the most frequently used behaviors being an openmouthed strike from a coil and a body extend with a tail shake (Arnold and Bennet 1984, in Ernst and Ernst 2003). Plains gartersnakes are not as quick-tempered as common gartersnakes but may still bite if handled, and like many snakes they release a foul-smelling combination of musk and liquid feces that they smear on their captor. Females have significantly larger cloacal glands than males, allowing them to produce more musk, which may serve an important antipredator function for gravid females (Kissneras et al. 1988, in Ernst and Ernst 2003). The collection/observation dates of 723 Iowa plains gartersnakes show the species has been found from March through December in the state. The earliest record is from Story County on March 19. The primary activity period in Iowa is from late March through October and extends into early November in warm years. Surface activity begins to increase in April as the snakes emerge from hibernation and peaks from May into early July (47% of records). These gartersnakes are diurnal, crepuscular, or nocturnal depending on temperature and may spend only three to five hours a day on the surface (Ernst and Ernst 2003). Air temperatures of 70 to 84º F (21–29º C) are preferred and activity usually ceases below 45º F (7.2º C). When not out hunting, the snakes can often be found under logs, boards, tin, or other debris or underground. Surface activity in Iowa decreases from late July through mid-September during the hottest part of the summer. Beginning in mid-September and continuing through mid-October, the snakes are active on the surface again (21% of records) as they make their way to overwintering sites and young-of-the-year snakes are out and about. The latest Iowa records are 2 individuals found dead on the road in Cherokee County on December 10. Plains gartersnakes hibernate in mammal burrows, anthills, rock crevices, wells, and crayfish burrows. Jim found a group of approximately 20 in April around a partially filled abandoned well in Cherokee County that was being used as a hibernaculum. Reeve Bailey found a dead individual underwater on March 14 in Little Wall Lake in Hamilton County and a live individual on April 1 on the edge of an icy Wright County farm pond with its tail in a hole and the rest of its body underwater, suggesting that the serpent will sometimes hibernate under­water or at least in crayfish burrows where it may be below the water table.

Thamnophis radix, Plains Gartersnake  263

139

Number of Records

150 117 100

113

111 90

76

63

50

0

0

0

4

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

8

2

Nov

Dec

Month Collection/observation dates of 723 plains gartersnakes in Iowa.

Murphy (1997, in Ernst and Ernst 2003) made similar observations of plains gartersnakes hibernating underwater under the ice. In Manitoba, 8 juveniles were dug out of an anthill at a depth of 1 to 3 feet (30.5–91.4 cm) (Criddle 1937). Reeve Bailey (1949) studied temperature toleration in hibernating plains gartersnakes in Story County and found that snakes hibernating at a depth of 18 inches (45.7 cm) above the frost line survived, demonstrating their ability to withstand a minimum temperature of approximately –4º F (–20º C) and to resist subfreezing temperatures for eighteen to twenty-eight continuous days. Those snakes that hibernated at a soil depth shallower than 18 inches (45.7 cm) did not survive. Threats. Natural predators include various hawks and owls, predatory mammals such as opossums, skunks, coyotes, mink, and domestic cats, and other snakes such as the eastern milksnake. Raccoons can almost certainly be added to the list. Largemouth bass were reported as predators in Nebraska (Lundgren et al. 2012). The introduction of bullfrogs into northern Iowa, the historic stronghold of the plains gartersnake, from the 1930s to about 1960 likely provided an additional predator as bullfrogs will eat anything they can catch, including gartersnakes. Snake fungal disease is an emerging threat and infected plains gartersnakes have been found in Iowa (Stephenson et al. 2020). Humans likely pose the biggest threat, however, through habitat loss, pesticide use, lawn mowers, climate change, and automobiles. As early as the 1930s, road mortality of plains gartersnakes in Iowa was reported (Scott 1938), and it continues to be a major source of mortality, especially in the fall.

264  Plains Gartersnake, Thamnophis radix

Food and Feeding. This gartersnake is an active hunter that feeds on adult and

larval frogs, toads, and salamanders, fish, earthworms, leeches, small mammals, and insects. In Missouri, there is strong seasonal variation in prey selection, with the snakes eating primarily earthworms in the spring and fall and frogs in the summer (Seigel 1984, in Rossman et al. 1996). When prey is found, it is quickly captured and swallowed alive. Iowa diet reports are limited. Reeve Bailey observed a plains gartersnake eating small fish in a creek in Audubon County and recorded five instances of the snake eating frogs or large tadpoles that were developing legs, all during daylight hours between May 14 and July 10. On two other occasions he found tiger salamanders in the stomachs of plains gartersnakes, one of which had ingested two. Other reports include Guthrie (1926), who reported that young plains gartersnakes lived entirely upon earthworms, which also made up a large part of the diet of adults, and who observed a snake swallowing a toad at Little Wall Lake in Hamilton County, and Jim’s multiple observations of plains gartersnakes eating leopard frog tadpoles and a captive in his lab at Drake University that ate live minnows and occasionally earthworms. Reproduction. Males and females generally mature in 2 to 3 years at around 15

to 15.75 inches (38–40 cm) snout-vent length for females and 13.8 to 14.6 inches (35–37 cm) snout-vent length for males. Examination of 35 Iowa adult female specimens in the Drake University Research Collection found the largest immature female was 13.3 inches (33.9 cm) snout-vent length and the smallest mature female was 14 inches (35.6 cm) snout-vent length, suggesting that female maturity in Iowa occurs at snout-vent lengths of about 13 to 14 inches (33–35.6 cm). Mating occurs in the spring soon after the snakes emerge from hibernation, with males likely using scent trails to find females. Several males may court a female at one time, crawling alongside her poking her with their snouts and touching her with their tongues until one male successfully positions himself and inserts his hemipenis. More than one male may mate with a female, but often a male will place a seminal plug in the female’s cloaca after mating to prevent other males from mating with her. Examination of 32 Iowa adult female museum specimens indicated ovarian follicular growth occurs rapidly in the spring with follicles measuring 0.4 to 0.8 inch (10–21 mm) by mid-May. The first early oviductal eggs were seen in a June 2 female from Monona County, and a July 1 Bremer County female had 3 recently ovulated eggs in the upper oviduct and 11 similarly sized follicles that had not yet been ovulated in the ovary, suggesting ovulation in Iowa occurs sometime in

Thamnophis radix, Plains Gartersnake  265

June. Not all eggs that are ovulated are eventually fertilized. Among the females with oviductal eggs or embryos, an average of 17.6 percent (0–33%; n = 5) of eggs were not fertilized. Plains gartersnakes are viviparous with females giving birth to 5 to 60 (frequently 10–20) young from mid-July to September. Breckenridge (1944) reported an amazing litter of 92 young in Minnesota. Counts of enlarged ovarian follicles and oviductal eggs or embryos in Iowa females in the Drake University Research Collection resulted in average litter sizes of 19 (range 11–24; n = 3) and 15 (range 3–30; n = 8) young, respectively. An average litter size of 25 (range 2–53) was obtained based on 15 Iowa litters in the Drake University collection, the University of Michigan Museum of Zoology collection, and LeClere (2013), comparable to the 25 young per litter reported in Wisconsin (Vogt 1981). Litter size is proportional to female size, with larger females producing more young than smaller females. In Illinois, average female fertility increased from 6.4 in year-old females to 21 in 6-year-old females (Stanford and King 2004), illustrating the importance of older and larger females in maintaining a population. Newborns range from 4.7 to 9.4 inches (12–24 cm) total body length and may grow to over 17 inches (43 cm) their first year. The average weight of newborns weighed by Reeve Bailey ranged from 0.05 to 0.07 ounce (1.46–2 g). Longevity. A wild-caught juvenile lived in captivity an additional 8 years, 5

months, and 3 days, and survival in the wild has been estimated at 6 to 7 years.

COMMON GARTERSNAKE Thamnophis sirtalis (Linnaeus) 1758 CHICAGO GARTERSNAKE, Thamnophis sirtalis semifasciatus Cope 1892 EASTERN GARTERSNAKE, Thamnophis sirtalis sirtalis (Linnaeus) 1758 RED-SIDED GARTERSNAKE, Thamnophis sirtalis parietalis (Say) 1823

Eastern gartersnake from Muscatine County.

Iowa Status. Not protected. Historical Summary. The common gartersnake has been known by over forty common names, including adder, common streaked snake, blue spotted snake, common striped snake, garden snake, swamp garter, three-striped adder, redbacked garter snake, red-spotted garter snake, and prairie garter snake. The first confirmed specimen in the state appears to be from near Keokuk in Lee County in 1868 (Goodman 1948). Osborn (1892) reported a specimen in the Iowa State Natural History Collection that was probably from near Ames in Story County. Ruthven (1908b) reported red-sided gartersnakes were rare in northern Iowa, and Guthrie (1926) reported eastern gartersnakes were not common in the state.

268  Common Gartersnake, Thamnophis sirtalis

Twelve subspecies of the common gartersnake, Thamnophis sirtalis, are currently recognized, three of which, the Chicago gartersnake, T. s. semifasciatus, eastern gartersnake, T. s. sirtalis, and red-sided gartersnake, T. s. parietalis, have ranges that include Iowa. Description. The common gartersnake is a long striped snake with highly vari-

able coloration. The species name sirtalis is Latin meaning “like a garter,” referring to the striped pattern that resembles garters men used to wear to hold up their socks. The back may be greenish, gray, dark brown, or black with a cream or yellow vertebral stripe along the midback. A white, yellow, or greenish lateral stripe is present on each side of the body, and there may or may not be red along the sides or black bars crossing the lateral stripes anteriorly. The lateral stripes are always confined to scale rows 2 and 3, and the vertebral stripe may be intensely colored, may disappear before reaching the tail, or may be absent altogether. The head is distinct from the neck with a light-colored throat. The belly may be gray, green, cream, or yellow and unpatterned; some individuals may have 2 rows of black spots that are often partially hidden by the ventral scales. The body scales are keeled and in 19 middorsal rows; the anal plate is single. There are usually 7 supralabial scales and 10 infralabial scales. A partial albino from Pine Lake in Hardin County is in the University of Michigan Museum of Zoology collection, and other albinos have been reported in Iowa as well. The young are similar in appearance to the adults. Eastern gartersnakes often have a nearly black background color, especially in northern Iowa, and most individuals lack red along the sides. Red-sided gartersnakes have red or reddish orange along the sides of the body between the lateral and vertebral stripes. The red, which may form bars that are separated by black bars on some individuals, is located on the skin between the scales and is normally concealed unless the snake is threatened. It is more extensive and prominent on western Iowa snakes than on those from the eastern half of the state. The degree of red may differ slightly between the sexes, with males lacking red more often than females. Chicago gartersnakes are similar in color to eastern gartersnakes, except that they have distinct broad black bars on the sides of the body that interrupt the lateral stripes (semifasciatus is from the Latin semi meaning “half ” and fasciatus meaning “banded,” referring to the black bars on the forebody). These black bars are found mainly on the anterior one-third of the body on Iowa snakes and may consist of only a series of 2 to 3 bars on some individuals. The bars may be present on both sides of the body or only on one side and may completely or only partially interrupt the lateral stripes on intergrades with other subspecies.

Red-sided gartersnake from Chickasaw County in defensive display.

Chicago gartersnake from Louisa County. Photo by Joshua G. Otten.

270  Common Gartersnake, Thamnophis sirtalis

Examination of sexual dimorphism without regard to subspecies in 108 Iowa adult common gartersnake museum specimens (48 males; 60 females) found snout-vent length, the number of ventral scales (male mean 158; female mean 155), the number of subcaudal scales (male mean 75; female mean 70), and tail length as a proportion of total body length (male 24%; female 22%) differed significantly between males and females. Females are larger while males have more ventral scales, longer tails, and more subcaudal scales. Males over 18.5 inches (47 cm) snout-vent length usually have knobs on the keels of the dorsal scales near the vent, a secondary sex feature that appears at reproductive age (Harrison 1933). Size. Common gartersnakes generally range from 18 to 26 inches (46–66 cm) total

body length. The largest specimen in the Drake University Research Collection is a male from Allamakee County measuring 40.4 inches (102.5 cm) total body length; the largest female is also from Allamakee County measuring 36.2 inches (92 cm) total body length. A female in the Iowa State Natural History Collection from Marion County examined by Reeve Bailey measured 44.3 inches (112.5 cm) total body length. The record total body length for T. sirtalis in the eastern United States (7 subspecies) is 54 inches (137.2 cm). Similar Species. The plains gartersnake and the orange-striped ribbonsnake have

lateral stripes on scale rows 3 and 4. The lined snake has stripes on scale rows 2 and 3 but has a double row of black half-moons extending down the ventral scales. Dekay’s brownsnake and the red-bellied snake have only faint stripes and a divided anal plate; in addition, the red-bellied snake has a red belly. Graham’s crayfish snake has nearly black lateral stripes that touch the ventral scales and a divided anal plate. Distribution. The common gartersnake has one of the largest natural ranges of

any snake species in North America; it is found from the Atlantic coast to the Pacific coast and from northern Canada to southern California and Florida. Of the three subspecies in Iowa, the eastern gartersnake occurs from northern Canada to the Gulf Coast and from eastern Iowa to the Atlantic coast; red-sided gartersnakes occur from northern Canada to the Gulf Coast and from Iowa west to Colorado and Wyoming; and Chicago gartersnakes occur from the Chicago region in Illinois west in scattered populations through northern Illinois and southern Wisconsin to extreme eastern Iowa. Common gartersnakes are found statewide, with records from 98 of Iowa’s 99 counties. Three counties (3%) have only pre-1945 records. In the 1980s, Jim Christiansen concluded that both eastern and red-sided gartersnakes were maintaining

Thamnophis sirtalis, Common Gartersnake  271

the distribution patterns established by Reeve Bailey in the 1940s, and a review by me of more than 1,200 post-1960 records indicates that has not changed. The following discussion of the distribution of subspecies in Iowa is based on my examination of 401 specimens in the Drake University Research Collection. Common gartersnake distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

Eastern gartersnakes are found primarily in the eastern quarter of the state from Mitchell, Floyd, Black Hawk, and Jefferson Counties east to the Mississippi River, where they intergrade with both red-sided and Chicago gartersnakes. Small remnant populations of eastern gartersnakes may exist farther west in the state. Jim (1961) observed two eastern gartersnake populations in Buena Vista County with no trace of red, and Reeve Bailey collected a possible eastern gartersnake roadkill in Crawford County. Red-sided gartersnakes are found statewide, although those in extreme eastern Iowa intergrade with eastern gartersnakes and less commonly with Chicago gartersnakes. They become the dominant subspecies from Bremer, Black Hawk, Linn, and Van Buren Counties west to the Missouri River. Although not previously reported as occurring in Iowa, scattered populations of snakes with classic Chicago gartersnake traits—lateral stripes regularly interrupted anteriorly by vertical black bars—have been found in Allamakee, Clinton, Scott, Muscatine, Louisa, Washington, Des Moines, and Lee Counties in eastern Iowa. The Drake University collection includes ten specimens of this subspecies. Common gartersnakes from several counties with black spots along the neck that extend through the lateral stripe are mentioned by LeClere (2013), but he did not specify the counties they were found in. Habitat. The common gartersnake, probably the most frequently observed snake

in the state, is a habitat generalist with a strong affinity for water. It can be found along the banks of lakes, rivers, marshes, and streams as well as in road ditches,

272  Common Gartersnake, Thamnophis sirtalis

pastures, cultivated fields, native prairies, woodland edges, and residential yards and on farmsteads, golf courses, and urban lots. Young snakes tend to be more closely tied to moist habitats than are older and larger snakes, which are more likely to use drier upland habitats. Common gartersnakes are often seen swimming or darting through vegetation and are good climbers. Reeve Bailey listed the following habitats in his field notes: water and timber, prairie without water, prairie or open pasture with water, timber without water, and cultivated field. In the mid-1980s, Jim and Catherine Mabry (1985) observed that the plains gartersnake had declined in the Loess Hills of western Iowa due to woodland invasion but not the red-sided gartersnake, possibly reflecting the latter’s greater tolerance for woodlands. Nevertheless, when woodlands are used by common gartersnakes, they prefer open woodlands that provide abundant basking sites over closedcanopy woodlands. Behavior. The common gartersnake’s first response when approached is to flee or escape down a burrow or under some form of cover. When escape is not an option, it often coils, flattens its head and body, releases liquid feces and sprays a foul-smelling musk, strikes vigorously, bites, and seems to chew its attacker. The red-sided gartersnake, when threatened, fills its lungs to inflate its body and stretch its skin to expose the red between the scales as a warning display. The serpents are primarily diurnal but may be crepuscular or nocturnal to coincide with frog and toad breeding. Most daily movements are short, with most individuals moving less than 328 feet (100 m) in a day. Gravid females move less often and a shorter distance than nongravid females; however, after they give birth, their movement is similar to nongravid females. The collection/observation dates of 1,473 Iowa common gartersnakes show the species has been found every month of the year in Iowa. The earliest records are 2 snakes found in Palo Alto County on January 2. Common gartersnakes are very cold-tolerant and have one of the longest activity seasons of any Iowa snake, at least 227 days in Bremer County based on my over twenty years of surveys in that county, and the season is likely slightly longer in southern Iowa. They are one of the first snakes to emerge from hibernation in the spring, usually by mid- to late March, and one of the last to enter hibernation in the fall, usually in late October or early November, and they can often be seen aboveground and active on warm winter days. As with many snake species, activity drops off during the hot dry days of July and August. A number of individuals have been found across the state in December, with the latest a snake found in Clayton County on December 30. Common gartersnakes hibernate communally with other gartersnakes or with other snake species. Hibernacula include rock crevices, earthen dams, beaver

Thamnophis sirtalis, Common Gartersnake  273

341

Number of Records

350 300

253

250

267 222

200

164

150

105

100 50 0

2

1

Jan

Feb

70

21 Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

19

8

Nov

Dec

Month Collection/observation dates of 1,473 common gartersnakes in Iowa.

and muskrat burrows or lodges, wells, and crayfish burrows. In addition, they are commonly found hibernating in the basements and foundations of old homes throughout the state. Juveniles will use active ant nests; the ants attack the snakes only when the ants are producing eggs or pupae (Pisani 2009a). Reeve Bailey collected red-sided gartersnakes along with blue racers and a bullsnake on April 13 approximately 2 feet (61 cm) below the surface in a hibernaculum on a southfacing slope in Madison County. For a short time after emerging from hibernation, common gartersnakes spend their days aboveground basking and return to the hibernacula at night. I have observed red-sided gartersnakes in Bremer County investigating crayfish burrows during the late afternoon in late March, presumably looking for a night shelter. Threats. Common gartersnakes, particularly juveniles, are preyed upon by

many animals, including both small and large mammals and birds, reptiles such as turtles and other snakes, amphibians such as bullfrogs, fish, and even spiders and crayfish. Jim has observed predation of red-sided gartersnakes by prairie kingsnakes and a captive speckled kingsnake. Fitch (1999) proposed that certain avian predators, such as hawks and herons, might be affected by the warning display of red markings by red-sided gartersnakes. Gartersnakes, like some other snakes and many lizards, use caudal autotomy— voluntary self-amputation of the tail—to escape predation. If the snake is grabbed by the tail, the tail breaks off and wriggles. The predator focuses on the squirming tail, giving the snake time to escape. Unlike many lizards, the gartersnake’s tail does not grow back. Fitch (1999) found that females, whose larger mass allows

274  Common Gartersnake, Thamnophis sirtalis

them to break off their tails more easily, are more likely to use this method of escape than males. Consistent with this, 15 percent of Iowa subadult and adult museum specimens examined had incomplete tails, and 69 percent of these were females. Parasites may affect the health of common gartersnakes. A coccidian parasite was found in 4 percent of Iowa red-sided gartersnakes examined (Wacha and Christiansen 1974). However, cars and loss of habitat are the primary threats to the species. Large numbers are killed on roads each year in Iowa. The roads warm up first in the morning, hold the heat, and cool down slowly in the evening, making them attractive basking sites. Gartersnakes are often found living close to humans in places such as residential yards, golf courses, and parks. As a result, they often fall prey to lawn mowers and domestic cats. Food and Feeding. Active hunters, common gartersnakes locate prey primarily

by smell. When hunting, they crawl slowly through an area and actively search with side-to-side head movements and rapid tongue flicking. Prey is grasped in the jaws and eaten alive. It has been suggested that the saliva of the common gartersnake has venomous properties and may help immobilize prey. The snakes do not have fangs like true venomous snakes but instead have small grooves on the rear teeth of the upper jaw. Secretions from the Duvernoy’s gland run down these grooves and into the prey as the teeth pierce the skin. Common gartersnakes frequently seem to chew their prey before ingesting it. This chewing action may promote injection of saliva into prey. One case of mild human envenomation has been reported (Hayes and Hayes 1985). A thirteen-year-old boy was bitten on the index finger by a large eastern gartersnake, which chewed on his finger for about ten minutes. His hand swelled over several hours and was bluish and cold the next morning. The boy was admitted to the hospital, responded to treatment, and was released the next day. In addition to being habitat generalists, common gartersnakes are also prey generalists. The list of prey species is long and includes aquatic and terrestrial invertebrates, earthworms, insects, fish, larval and adult frogs, toads and salamanders, small snakes including other gartersnakes, the eggs and young of birds, and small mammals such as shrews, mice, and voles. A Chickasaw County snake collected by Reeve Bailey disgorged a small tiger salamander. Other prey that Reeve Bailey, Jim, or I observed in common gartersnake stomachs included leopard frogs, American toads, tadpoles, and cricket frogs. Klimstra (1950) reported a 13-inch (33-cm) red-sided gartersnake in Davis County attempting to swallow a gray treefrog. Earthworms form a large proportion of the diet of young snakes.

Thamnophis sirtalis, Common Gartersnake  275

Red-sided gartersnake from Monroe County eating a bullfrog. Photo by Ryan D. Rasmussen.

A fifty-year study in Kansas noted that first- or second-year snakes ate mostly earthworms, while adults ate primarily small mammals (Fitch 1999). Although live prey is preferred, carrion feeding on amphibians and birds may also occur. Reproduction. Both spring and fall mating may occur, with spring being more

common. Several researchers have reported that exposure to cold during hibernation followed by a rapid rise in body temperature triggers spring mating in males. Males emerge from hibernation first and wait near the entrance of their hibernacula for females to emerge. Sexually receptive females secrete species-specific pheromones that serve to attract males. Males may also visually search for females after first being attracted to their location by the pheromones. Several males may court a single female, resulting in a writhing ball of snakes. Reeve Bailey reported a mating ball that consisted of 12 red-sided and eastern gartersnakes on March 22 in Lee County. The ball also included a single Graham’s crayfish snake. I observed a mating ball in a wet road ditch one spring while growing up in Linn County; the other neighborhood kids and I watched in fascination. Once semen has been deposited, the male places a copulatory plug in the cloaca of the female, possibly restricting insemination by another male. However, DNA studies on newborn common gartersnakes indicate that multiple matings with different males can occur.

276  Common Gartersnake, Thamnophis sirtalis

Examination of 60 Iowa adult female specimens in the Drake University Research Collection found the smallest mature female was 17.8 inches (45.3 cm) snout-vent length, and the largest immature female was 17.3 inches (44 cm) snoutvent length, suggesting that female maturity in Iowa occurs at a snout-vent length of 17 to 18 inches (43–46 cm). This is consistent with Rossman et al. (1996), who reported that on average males reach sexual maturity in 1 to 2 years at a snout-vent length of 14.2 to 14.6 inches (36–37 cm) and females in 2 to 3 years at a snout-vent length of 16.5 to 17.7 inches (42–45 cm). Examination of 44 Iowa adult female museum specimens indicates vitellogenesis begins in April and May, with follicles enlarging quickly. Ovulation occurs in late May or early June at maximum follicle sizes of 0.7 to 0.75 inch (17–19 mm). The first oviductal eggs were seen in a June 10 specimen, and these contained visible embryos, suggesting that these ova were ovulated more than a week earlier. Oviductal eggs or embryos were found in specimens through the end of July; by September, most specimens no longer contained embryos, but some had ovulation scars, indicating that they had given birth that year. These females had used much of their fat reserves and contained only previtellogenic follicles. Only 3 of the 44 specimens examined that were collected during the reproductive season did not contain enlarged follicles or oviductal eggs or embryos, suggesting that most of Iowa’s common gartersnakes reproduce annually. Common gartersnakes are viviparous and give birth to live young. In Iowa, most give birth in August. Ruthven (1908b), however, reported a Palo Alto County female that gave birth on September 30. Litter size ranges from 1 to 101 young (average 27). A large female from Palo Alto County gave birth to 73 young (Ruthven 1908b), and Reeve Bailey received a large female from Marion County that also contained 73 embryos. Counts of enlarged ovarian follicles, oviductal eggs, and embryos in Iowa females in the Drake University collection or reported by Reeve Bailey, as well as litters observed by Jim or reported by Ruthven (1908b), resulted in average litter sizes of 23 young (range 12–45; n = 15), 17 young (range 7–32; n = 4), 41 young (range 2–73; n = 3), and 36 young (range 17–73; n = 3), respectively. Based on these data, Iowa litter size may range from 2 to 73 young (mean 26). It is interesting to note that the 2 largest litters are both prior to 1940 (Ruthven 1908b; Bailey 1939). Given all the threats snakes presently face, it is unclear how many females capable of producing these very large litters are still present in Iowa—out of the 401 museum specimens I examined, the largest number of embryos found in a single female was 49. In any case, this illustrates the danger of eliminating large older female snakes from a population. Removal of these super breeders lowers the

Thamnophis sirtalis, Common Gartersnake  277

overall reproductive potential of the population, lessening its ability to rebound from natural or human-induced disturbances. The brightly colored newborns range from 4.7 to 11 inches (12–28 cm) total body length. A litter of 19 eastern gartersnakes from Allamakee County in the Drake University collection ranged from 7.3 to 7.6 inches (18.5–19.3 cm) total body length. Longevity. Common gartersnakes are arguably the most studied snake in North

America, yet few longevity records exist. A wild-caught female of unknown age survived in captivity another 14 years, and wild red-sided gartersnakes have been estimated to be up to 11 years old.

LINED SNAKE Tropidoclonion lineatum (Hallowell) 1856

Lined snake from O’Brien County. Photo by Ryan D. Rasmussen.

Iowa Status. Protected nongame; species of greatest conservation need. Historical Summary. The lined snake has also been called the dwarf garter snake, striped swamp snake, common snake, grass snake, ribbon snake, striped snake, and swamp snake. The first confirmed specimens in the state appear to be in 1883 from Keokuk in Lee County (Goodman 1948) and 1884 from Des Moines in Polk County (National Museum of Natural History–Smithsonian Institution). Call (1891) provided a description of a new subspecies from Iowa—Tropidoclonion lineatum iowae—based on four specimens collected around Des Moines in Polk County and Ames in Story County; however, Stejneger (1891) failed to find any differences between Iowa specimens and those found elsewhere and questioned the legitimacy of the subspecies. Osborn (1892) listed a specimen in the Iowa State Natural History Collection probably from near Ames, and Somes (1911) listed the species as occurring in the state. Smith and Smith (1963) synonymized T. l. iowae with T. l. lineatum, now T. lineatum. At present, no subspecies are recognized.

280  Lined Snake, Tropidoclonion lineatum

Belly of a lined snake from O’Brien County. Photo by Ryan D. Rasmussen.

Description. The lined snake’s appearance gives rise to both its common and

scientific names. Tropidoclonion lineatum describes a snake that resembles a twig with lines: Tropidoclonion is Greek meaning “keeled twig”; lineatum is Latin meaning “marked with lines.” Lined snakes are slender gray to brown with white to cream lateral stripes on scale rows 2 and 3 and a white, yellow, or light brown dorsal stripe. A row of dark spots is present on either side of the dorsal stripe and another row is present just above the lateral stripes. The head is small and barely wider than the neck and body. The belly is white or yellowish with a double row of black half-moons down the middle of the ventral scales. The body scales are keeled and in 19 rows at midbody; the anal plate is single. There are usually 5 supralabial scales and 6 infralabial scales. The young are grayish with poorly defined stripes and bold ventral spots. As they age, their body becomes darker and the stripes more pronounced. Examination of sexual dimorphism in 32 Iowa adult lined snake museum specimens (4 males; 28 females) found the number of subcaudal scales (male mean 42; female mean 34) and tail length as a proportion of total body length (male 17%; female 14%) differed significantly between males and females, with males having more subcaudal scales and a longer tail.

Tropidoclonion lineatum, Lined Snake  281

Size. Lined snakes generally range from 8.75 to 15 inches (22.2–38 cm) total body

length. The largest specimen in the Drake University Research Collection is a female from Madison County measuring 16 inches (40.6 cm) total body length; the largest male is from Cherokee County measuring 13.5 inches (34.3 cm) total body length. The record total body length reported for the species is 21.5 inches (54.6 cm). Similar Species. Common gartersnakes have lateral stripes on scale rows 2 and

3 but lack a distinct double row of black half-moons on the ventral scales; they have a distinct neck with the head wider than the neck. Plains gartersnakes and orange-striped ribbonsnakes have lateral stripes on scale rows 3 and 4. Graham’s crayfish snake has a generally unmarked cream, tan, light yellow, or white belly and a divided anal plate. Distribution. Lined snakes are found in scattered populations from southern

Wisconsin and Illinois west to southeast South Dakota and southwest through Nebraska to New Mexico and Texas. In Iowa, they are found in widely scattered populations south of U.S. Highway 30, with the exception of northwest Iowa where they occur in several counties. During the mid-1940s, the species was known from 10 counties. At present, records exist from 36 of Iowa’s 99 counties. The increase in records since the 1940s is the result of more intensive searches for the species since 1970. The presence of lined snakes in southeast South Dakota and eastern Nebraska suggests that the ancestral Iowa population may have covered much of western Iowa. The reason for the current apparent rarity of the species in western Iowa is unknown but is likely due to loss of habitat resulting from intensive agriculture. Lined snake distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

282  Lined Snake, Tropidoclonion lineatum

Lined snake habitat in Cherokee County. Photo by Ryan D. Rasmussen.

Habitat. These snakes inhabit woodland edges and open grasslands such as prairies, meadows, and pastures that are often associated with wetlands of some sort; however, they are not restricted to wet habitats and may at times be found in drier areas. In either case, they prefer areas with abundant cover in the form of flat rocks, rotting logs, boards, or other debris where they can hide from predators and escape bad weather. They may also use city parks and residential yards, and although frequent urban use has been reported elsewhere, very few Iowa records are from urban areas, and those that do exist are mostly prior to 1945. The arid conditions over much of the lined snake’s range suggests adaptations to warmer soils and less rainfall, and it has been suggested that environmental conditions during the warmer and drier xerothermic period approximately 7,000 to 5,000 years ago created favorable conditions that allowed this species to expand its range northward into places like Iowa. Behavior. The docile lined snake generally relies on camouflage to go unnoticed.

When handled, it rarely attempts to bite but often releases an unpleasant-smelling musk that is smeared on its captor. They are secretive and semifossorial creatures that spend much of the day underground or under leaf litter, fallen logs, flat rocks,

Tropidoclonion lineatum, Lined Snake  283

or other debris, coming out primarily at night or during a warm rain shower in search of food. Because they are so secretive, they may appear to be less abundant than they really are. For example, in Kansas 47 were found under rocks on a single hillside, and 72 were found in just three hours at another location (Taggart 1992, in Ernst and Ernst 2003). They tend to be crepuscular in the spring and fall and more nocturnal during the summer, preferring air temperatures of approximately 63 to 81° F (17–27° C). Although lined snakes do not bask, they are nonetheless efficient thermoregulators able to raise their body temperature significantly above both air and substrate temperatures. In the early spring, they are typically found under a thin layer of debris exposed to direct sunlight; this microclimate allows snakes to raise their body temperature compared to both air and substrate temperatures. As air temperatures rise in early summer, the snakes switch from thin sun-warmed cover to the thicker cover found under large rocks or in underground burrows, which allows them to remain within a specific temperature range by selecting microhabitats with higher air temperatures and cooler substrate temperatures. The collection/observation dates of 113 Iowa lined snakes show the species has been found in the state every month of the year with the exception of February. The earliest record is from Davis County on January 5 when a lined snake was brought up to a farmhouse by a domestic cat. In most years, however, the snakes are active from April through October. Activity in Iowa appears to be bimodal, with one peak from April through June (43% of records) and another peak in September and October (46% of records). Surface observations decline in July and August as the snakes are likely spending more time underground and become more nocturnal during the heat of the summer. A gradual increase in surface activity begins in September and peaks in October (35% of records), with most individuals found at this time reported as roadkills as the snakes are out and about looking for mates or moving to overwintering sites. Lined snakes hibernate singly or in groups in burrows they dig themselves, in those dug by other animals, or in some instances in rock crevices. South of Iowa they may find winter shelter in rotting stumps and logs or burrows just a few inches belowground, but with Iowa’s harsh winters it is likely they must go deeper to get below the frost line. The latest Iowa record is an individual found as roadkill in Cherokee County on December 11. Threats. Diurnal predators may not be significant consumers of lined snakes due

to the serpents’ secretive and nocturnal habits. However, a large variety of crepuscular and nocturnal animals likely do eat the snakes, such as raccoons, weasels, foxes, domestic cats (as evidenced by the Davis County record), and raptors such

284  Lined Snake, Tropidoclonion lineatum

Number of Records

50 40

40 30

23

20 10 0

18 12

8 1

0

2

Jan

Feb

Mar

Apr

May

Jun

2

4

Jul

Aug

Sep

Oct

2

1

Nov

Dec

Month Collection/observation dates of 113 lined snakes in Iowa.

as great horned owls, which have been shown to feed heavily on lined snakes in Oklahoma (Black 1985). Snakes such as racers and even other lined snakes are known to prey on them as well. Habitat loss, climate change, and automobiles all pose threats, with roadkill a major source of fall mortality in Iowa. Pesticide use has to be considered a threat to the lined snake’s chief prey and therefore at least indirectly to the lined snake itself. Food and Feeding. These snakes feed almost exclusively on earthworms, coming

out mostly at night or after a rain when worms are abundant on the surface. They hunt primarily by smell and taste with vision playing a minor role. I used the feeding behavior of the lined snake described by Ramsey (1947) for the following. When an earthworm is encountered the snake moves cautiously toward it, carefully examining it with tongue flicking. When satisfied about its identity, the snake quickly grabs the worm near its midbody, recoils, and begins swallowing it from both sides, forcing the worm into a U shape as it is swallowed. Unlike most snakes, lined snakes rarely swallow prey endwise. If an earthworm is grabbed by the tail, it often escapes by rolling and twisting to break off its tail, leaving it in the snake’s mouth as the worm makes its getaway. When seized, the earthworm begins to wriggle, secretes a copious amount of slime, and sometimes wraps itself around the head of the snake. When the snake has finished eating, the slime may be so irritating that the snake may rub its head against the ground or other objects or may go into water to remove it. When consuming a large earthworm, the snake

Tropidoclonion lineatum, Lined Snake  285

may wrap its tail around a rock or other object in order to anchor itself. Ramsey concluded that grabbing the earthworm at midbody and wrapping the tail around an object are unique adaptations to feeding on earthworms, specifically those worms lying just outside their burrows with their tails firmly anchored inside them. Seizing the earthworm at midbody prevents it from getting its forebody into the burrow, and anchoring the tail gives the snake leverage to help extract the worm from the burrow. Reproduction. Males mature faster than females, maturing in approximately a year at around 7.3 to 8 inches (18.5–20.3 cm) snout-vent length; females take a bit longer and mature in 18 to 24 months at around 8.7 inches (22 cm) snoutvent length. Examination of 28 Iowa female specimens in the Drake University Research Collection found the smallest mature female was 9.6 inches (24.5 cm) snout-vent length. A 7.6-inch (19.4-cm) female from Adair County found on September 21 had a set of 0.16-inch (4-mm) ovarian follicles. Krohmer and Aldridge (1985b) reported the threshold size of committed follicles—those follicles that will be ovulated or become atretic or degenerate—in the lined snake was 0.12 inch (3.1 mm), suggesting the Adair County female may have reproduced the following year had she lived. Mating occurs in late summer soon after females give birth; the sperm remains viable in the female until ovulation and fertilization occur the following spring. Courtship has not been described, but Ramsey (1946) reported copulation lasting 6.5 hours for a captive pair, during which time they lay calmly together. Ovarian follicular growth begins after birth with follicles reaching 0.2 inch (5 mm) by hibernation (Krohmer and Aldridge 1985b). Examination of 14 Iowa adult female museum specimens found that by September or early October a distinct set of follicles was distinguishable, with most measuring 0.16 inch (4 mm) long. Folli­ cular growth resumes in the spring with follicles in Iowa females measuring 0.35 to 0.6 inch (9–14 mm) by the end of May, consistent with Krohmer and Aldridge (1985b), who reported eggs were ovulated in June at an average of 0.6 inch (14 mm) long. The first oviductal eggs were seen in a June 24 female from Madison County. Lined snakes are ovoviviparous with females giving birth to 2 to 17 (average 8) young in August or early September. Litter size is proportional to female size, with larger females producing more young than smaller females. Counts of enlarged ovarian follicles and oviductal eggs or embryos in Iowa females in the Drake University collection resulted in average litter sizes of 9 (range 5–20; n = 11) and 6 (range 4–8; n = 3) young, respectively. Five young were born between August 29 and 30 to a Davis County female.

286  Lined Snake, Tropidoclonion lineatum

Birth of young is rapid—10 seconds to 3 minutes—with intervals between births varying from less than 2 minutes to more than 45 minutes (Force 1931). Newborns range from 2.75 to 5.7 inches (7–14.5 cm) total body length. The 5 young born to the Davis County female averaged 4.1 inches (10.5 cm) total body length. Both sexes grow at a rate of approximately 0.6 inch (1.4 cm) per month (Ernst and Ernst 2003). Longevity. Lined snake longevity has not been reported.

WESTERN SMOOTH EARTHSNAKE Virginia valeriae elegans Kennicott 1859

Western smooth earthsnake from Monroe County.

Iowa Status. Protected nongame; species of greatest conservation need. Historical Summary. The western smooth earthsnake has also been called Vir-

ginia’s snake (the genus Virginia refers to the state of Virginia although no type specimens were collected there; valeriae honors Valeria Blaney, who collected a type specimen for Baird and Girard; elegans is Latin meaning “fine” or “elegant”), western ground snake, elegant snake, brown snake, gray snake, Kennicott’s brown snake, Valeria’s snake, and worm snake. The first confirmed specimens in the state appear to be from Keosauqua in Van Buren County (Guthrie 1929), and although no collection date is given, Guthrie reported two specimens in the museum at the State Historical Society of Iowa that were labeled “Dekay’s brownsnake.” After examining them, he was able to correctly identify them as western smooth earthsnakes and provided a complete description including scale counts. In his earlier publication, Guthrie (1926) acknowledged the existence of the Keosauqua specimens and reported that the two specimens of “Virginia’s snake” were the only ones known from the state and that he had never seen one alive. Three subspecies of the smooth earthsnake, Virginia valeriae, are currently recognized, only one of which, the western smooth earthsnake, V. v. elegans, has a range that includes Iowa.

288  Western Smooth Earthsnake, Virginia v. elegans

Western smooth earthsnake from Wayne County. Photo by Ryan D. Rasmussen.

Description. The western smooth earthsnake is a slender brown, reddish brown,

or tan snake with a generally unmarked back, although a faint light dorsal stripe may be present on some individuals. The head is somewhat flattened with a pointed snout and is approximately the same diameter as the neck. Tiny black flecks are present on the back of the head and neck on some individuals, and the labial scales are light-colored. A loreal scale is present between the eye and the nostril that touches the orbit of the eye. The belly is cream to light yellow and unmarked. The body scales are smooth anteriorly, giving the snake a shiny appearance, weakly keeled posteriorly, and in 17 rows at midbody; the anal plate is divided. There are usually 6 supra- and infralabial scales. Newborns look like miniature adults but are opalescent charcoal gray. Examination of sexual dimorphism in 22 Iowa adult western smooth earthsnake museum specimens (13 males; 9 females) and a live adult female found the number of ventral scales (male mean 124; female mean 132), the number of subcaudal scales (male mean 42; female mean 34), and tail length as a proportion of total body length (male 20%; female 15%) differed significantly between males and females, with females having more ventral scales and males having more subcaudal scales and longer tails.

Virginia v. elegans, Western Smooth Earthsnake  289

Western smooth earthsnake from Monroe County.

Size. Western smooth earthsnakes generally range from 7 to 10 inches (17.8–25.4

cm) total body length. The largest specimen in the Drake University Research Collection is a female from Appanoose County measuring 12.9 inches (32.8 cm) total body length; the largest male is also from Appanoose County measuring 10.6 inches (26.9 cm) total body length. A male in the Iowa State Natural History Collection from Van Buren County measured 11 inches (27.9 cm) total body length. The record total body length reported for V. valeriae is 15.4 inches (39.1 cm). Similar Species. Dekay’s brownsnakes lack a loreal scale and have strongly keeled

scales and dark spots behind the head on the nape of the neck that form two halves of a dark collar. Western wormsnakes have 13 scale rows at midbody and a salmon pink belly with the pink extending up the sides to the third lateral scale row. Distribution. Western smooth earthsnakes are found from Iowa, Illinois, and Indiana southward through Kentucky, Tennessee, and Mississippi to the Gulf of Mexico and westward to eastern Kansas, Oklahoma, and Texas. Iowa is at the northern edge of the subspecies’ range with the northernmost known population found in northern Polk County. In Iowa, they are found in scattered populations from Guthrie, Dallas, Polk, and Poweshiek Counties south to the Missouri border and from Washington and Van Buren Counties west to Adams County, with

290  Western Smooth Earthsnake, Virginia v. elegans

populations concentrated along the Grand, Chariton, Des Moines, and Raccoon Rivers. During the mid-1940s, they were known from just 2 counties (Polk and Van Buren). At present, records exist from 19 of Iowa’s 99 counties. The increase in records since the 1940s is the result of more intensive searches since 1970, and it is likely that earlier workers in the state just missed this snake due to its secretive habits. Western smooth earthsnake distribution in Iowa. Yellow = post-1960 Green = both pre- and post-1960

Habitat. These snakes have been most often reported as inhabiting open moist

woodlands and grasslands near woodlands. In Iowa, Jim Christiansen (1973) reported the habitat as rocky woodland riparian areas or rocky woodland-meadow edges. Eleven of twelve snakes he found were in or near dense woodlands, six were within 50 feet (15.25 m) of a stream, and nine were within 1,000 feet (305 m) of a stream. Jim reported the serpents were most frequently found under stones in wet or poorly drained places, one was found in a wet rotten log, and another was found on a woodland trail. I have found them crossing the road at night in Monroe County where small patches of grasslands adjacent to woodlands were present on both sides of the road. Hurter (1911, Missouri) reported that all the western smooth earthsnakes he found were under rocks, although he also caught one on a narrow path in heavily timbered bottomlands. Smith (1961, Illinois), Anderson (1965, Missouri), and LeClere (2013, Iowa) also mentioned rocky timbered hillsides as habitat. Pisani (2009b) found far more frequent overall use of grasslands than was predicted from earlier published accounts. He found habitat use was highly seasonal, with the snakes using woodlands and woodland-grassland edges soon after spring emergence, followed by dispersal into grasslands by mid-April and a return to woodlands or woodland-grassland edges in September to October. He concluded that his results indicated considerably more complex habitat use than previously recognized. Behavior. The docile western smooth earthsnake rarely, if ever, attempts to bite.

When found under a stone or board, it may remain motionless for only a few sec-

Virginia v. elegans, Western Smooth Earthsnake  291

Western smooth earthsnake habitat in Monroe County.

onds before attempting to escape under vegetation or into a rodent burrow. When handled, it squirms and smears a smelly mix of musk and feces on its captor. Other defensive behaviors include playing dead, curling the lips to expose the inner surface of the lips and teeth (the purpose or effectiveness of which is unknown), and forming a loop knot with the body—making itself larger to avoid being swallowed by another snake (Ernst and Ernst 2003). This small snake is secretive and semifossorial, spending much of the day underground or under leaf litter, fallen logs, flat rocks, or other debris, coming out primarily at night or during a warm rain shower in search of food. It tends to be crepuscular or nocturnal with occasional daytime activity. Across its range, the activity period has been reported as from April through October or November. The collection/observation dates of 115 Iowa western smooth earthsnakes show an activity period consistent with this, with the earliest records being 3 individuals found in Madison County on April 5. Activity in Iowa appears to be bimodal, with a spring and early summer peak in May and June (48% of records) and a second peak in September and October (25% of records). Surface observations decline in July and August, consistent with observations in eastern Kansas that suggest the serpent moves beneath grass thatch, where relative humidity is higher, during

292  Western Smooth Earthsnake, Virginia v. elegans

40 Number of Records

32 30

23

20

17

16 8

10 0

0

0

0

Jan

Feb

Mar

Apr

May

Jun

Jul

12 7

Aug

Sep

Oct

0

0

Nov

Dec

Month Collection/observation dates of 115 western smooth earthsnakes in Iowa.

the heat of the summer (Pisani 2009b). A gradual increase in surface activity begins in September with activity extending into October, when the snake enters hibernation. The latest Iowa record is an individual found in Davis County on October 18. Western smooth earthsnakes hibernate singly or in groups in rock crevices, rodent burrows, or ant nests. In more southern parts of their range, they may find winter shelter in rotting stumps or logs, but with Iowa’s harsh winters it is likely they must go deeper. However, observations have shown the snakes to be more cold-tolerant than other small snake species, and at times they can even survive being frozen solid. Fitch (1956b) reported a western smooth earthsnake housed with 2 prairie ring-necked snakes that survived when the container in which they were hiding turned slushy after a particularly cold night (the prairie ring-necked snakes did not survive) and approximately a week later froze solid with the western smooth earthsnake inside it. In spite of the seemingly grave situation, when the ice melted the snake appeared to be unharmed. Threats. Larger diurnal predators may not be significant consumers due to this

serpent’s secretive and nocturnal habits; however, small mammals such as whitefooted mice, which have been shown to prey on other small snakes, may eat them. A variety of crepuscular and nocturnal animals such as raccoons, weasels, foxes, domestic cats, and raptors probably eat them, too, if the opportunity arises. Other snakes such as racers and kingsnakes are known to prey on the western smooth earthsnake. Jim found a western smooth earthsnake in the stomach of a juvenile

Virginia v. elegans, Western Smooth Earthsnake  293

prairie ring-necked snake from Madison County. Humans pose threats as well through habitat loss, climate change, automobiles, and pesticide use, which has to be considered a threat to the snake’s chief prey and therefore at least indirectly to the snake. Food and Feeding. As early as the late 1800s, Hay (1892) surmised that western

smooth earthsnakes “must live on the smallest insects and worm-like creatures.” Indeed, many studies since then have shown they feed almost exclusively on earthworms, although soft-bodied insects, insect larvae, and slugs may also be consumed. Examination of the stomachs of specimens in the Drake University Research Collection found significant material in only three, none of which had insect parts or other identifiable matter, but the contents were consistent with a diet of earthworms, caterpillars, or other soft-bodied invertebrates. Jim maintained a captive western smooth earthsnake in his lab at Drake University for a while that readily ate earthworms. Reproduction. Both sexes likely mature in their second year at approximately 7 inches (17.8 cm) total body length. In Virginia, the smallest mature females of the eastern smooth earthsnake (V. v. valeriae) were 7.2 to 7.3 inches (18.3–18.5 cm) snout-vent length and the smallest mature male was 6 inches (15.3 cm) snout-vent length (Blem and Blem 1985; Mitchell 1994, in Ernst and Ernst 2003). Examination of 22 Iowa adult western smooth earthsnakes (13 males; 9 females) in the Drake University collection found the smallest mature female was 5.9 inches (15.1 cm) snout-vent length and 7.1 inches (18 cm) total body length and the smallest mature male was 5.5 inches (14 cm) snout-vent length and 6.9 inches (17.4 cm) total body length. The reproductive cycle has not been described for either sex; however, examination of Iowa museum specimens provides some insight although it is based on a small sample size (n = 9). October females showed no indication of distinct sets of enlarging ovarian follicles, suggesting that follicular growth occurs primarily in spring. Spring growth and yolking of follicles appear to occur rapidly with follicles measuring 0.35 inch (8.9 mm) by late May and 0.45 inch (11.4 mm) by early June. Interestingly, the largest female in the Drake University collection, an 11.3-inch (28.8-cm) snout-vent length individual found on June 19 in Appanoose County, contained no enlarged follicles or embryos, suggesting she may not have reproduced the year she died. Mating occurs in the spring soon after the snakes emerge from hibernation, though some fall mating may also occur. Courtship has not been described. Western smooth earthsnakes are viviparous with females giving birth to 2 to 14

294  Western Smooth Earthsnake, Virginia v. elegans

(average 6 or 7) young in August or early September after a gestation period of around 88 days. Counts of enlarged ovarian follicles and embryos in Iowa female museum specimens resulted in average litter sizes of 6 (range 3–8; n = 3) and 15 (n = 1) young, respectively. A Van Buren County female gave birth to a litter of 7 young (Christiansen 1973) and a Dallas County female in the Drake collection gave birth to 9 young on September 11, 4 of which were stillborn. Newborns range in size from 2.5 to 4.8 inches (6.4–12.3 cm) total body length. The 4 stillborn young born to the Dallas County female ranged from 2.9 to 3.8 inches (7.4–9.6 cm) total body length. Three additional young-of-the-year museum specimens found in September and October ranged from 4 to 5 inches (10.2–12.6 cm) total body length. Longevity. Longevity has not been reported for the western smooth earthsnake.

A wild-caught juvenile eastern smooth earthsnake survived in captivity an additional 6 years, 1 month, and 17 days.

FAMILY VIPERIDAE VIPERS AND PIT VIPERS (VENOMOUS)

T

he Viperidae is a family of venomous snakes found nearly worldwide with the exception of Antarctica, Australia, Hawaii, and Madagascar; it is divided into three subfamilies, only one of which, the Crotalinae, the pit vipers, occurs in Iowa. Worldwide, the Crotalinae includes about 252 species. Iowa has 3 genera—Sistrurus, Crotalus, and Agkistrodon—and 5 species. Pit vipers have a wide, somewhat triangular head, vertically elliptical pupils, and hollow fangs. One feature separating pit vipers from all other Iowa snake species is the presence of infrared- or heat-sensing pits on either side of the head between the eyes and the nostrils. The facial pits allow the snakes to locate warmblooded prey and judge the distance to it as well as its size and shape even in total darkness. Historically, it has been thought that vertical pupils were an adaptation to a nocturnal lifestyle, but research suggests that they increase the sharpness of the snake’s vision, allowing it to see more clearly over a wide range of light conditions, and when combined with the heat-sensing facial pits make for an effective ambush predator (Brischoux et al. 2010). All snakes have teeth, but not all snakes have fangs. Fangs are hollow teeth connected via ducts to venom glands—modified salivary glands—that are just behind and below the eyes. Fangs work like a hypodermic needle—when the snake strikes, its muscles squeeze venom from the glands through the ducts and hollow teeth into the prey. Viper fangs rotate through an arc of approximately 90 degrees, allowing them to range from lying horizontally against the roof of the mouth to being fully extended and ready to strike, and broken or damaged fangs are shed and replenished throughout a snake’s life. Most vipers are ovoviviparous: Viperidae comes from the Latin vipera meaning “viper, snake, serpent” and “alive, living” and parire meaning “bring forth, bear” in reference to the development of embryos inside the body. Snake venom is a complex mixture of components that can cause severe tissue and muscle damage; it affects the nervous system, heart, and kidneys, acts as an anticoagulant, and can result in low blood pressure, difficulty breathing, and death. Larger snakes can deliver much more venom than smaller snakes, or they may not inject venom at all. Defensive strikes are often dry bites, those in which

296  Family Viperidae

Eastern massasauga showing the heat-sensing pit between the nostril and the eye and the vertically elliptical pupil.

no venom is injected, and are more common in older snakes. Estimates are that up to 50 percent of venomous snake defensive bites are dry bites. The problem is that you do not know. Therefore, if you are bitten by a venomous snake, seek medical treatment immediately. First aid can be administered, but remember the first rule of first aid is do no harm, and many snakebite remedies suggested in the past have not followed this rule. In the late 1800s and early 1900s, the commonly accepted snakebite treatment was to administer copious amounts of whiskey—often several quarts—to counteract the venom. Of course, the whiskey had no effect on the venom but often had dire effects on the victim. An 1883 story in the Toledo Chronicle told of a little boy living on a farm south of Creston in Union County who was bitten by a rattlesnake. The boy was given a quart of whiskey as an antidote but nevertheless died. The doctor who treated the boy thought it was the whiskey, not the snakebite, that caused his death. Other accepted antidotes included applying coal oil, saltpeter, baking soda, chicken blood or raw meat, sweet olive oil, raw onions, iodine, or a mixture of gunpowder, egg yolk, and salt to the bite. Strychnine—rat poison— was even prescribed by some doctors. More recent hazardous first aid methods include incision of the bite, suction by mouth, tourniquets, vigorous exercise, and electric shock treatment. These should all be avoided. At present, the universally

Family Viperidae  297

accepted first aid treatment for snakebite is immobilization and elevation of the bitten limb using a splint; it is important to keep the victim as calm and inactive as possible while seeking medical help. The nation’s health protection agency, the Centers for Disease Control and Prevention, estimates that 7,000 to 8,000 people are bitten by venomous snakes in the United States each year, and about 5 of those people die. The number of deaths would be much higher if not for medical treatment with antivenom. Bites by venomous snakes are uncommon in Iowa today, as are venomous snakes, but at one time they were quite common and often fatal. A review of Iowa newspapers and county histories shows that during the 1800s and early 1900s rattlesnakes were distributed nearly statewide. While not all the newspaper reports may actually have been about rattlesnakes, those that reported symptoms consistent with rattlesnake bites—for example, extreme swelling, severe pain, blackening of the skin, and death—and those that reported rattles being cut off and saved undoubtedly were about rattlesnakes. Based on my admittedly not exhaustive review, at one time rattlesnakes occurred in at least 82 of Iowa’s 99 counties and likely more. Bites were reported in at least 63 counties and deaths in 33 counties. Humans were major threats to rattlesnakes as Iowa was being settled. Rattlesnake bites were common and the snakes were feared, leading to the killing of every rattlesnake found. The History of Kossuth County (Reed 1913) stated, “Present day settlers often ask why there are so few such deadly snakes in the county now when they were so numerous in early days. One of the principal reasons is the fact that the unwritten law of the settlements in those days permitted no one to discover a rattler and allow it to escape. It was considered an offense, at least in the southern part of the county, not to kill one at all hazards when once located. Boys have been known to get off their horses, take them by the foretops with their left hands and then beat the snakes to death with the bridles. This practice was strictly adhered to for a long term of years and no doubt had much to do with thinning Bites and deaths due to rattlesnakes by county based on newspaper accounts and county histories. White = no rattlesnakes reported Yellow = rattlesnakes reported Green = rattlesnake bites reported Peach = rattlesnake fatalities reported

298  Family Viperidae

out the rattlers.” In addition to killing them outright, in the early 1900s counties began paying a bounty on rattlesnakes. This relentless persecution, along with loss of habitat, has been effective. Where at one time rattlesnakes were found in at least 82 Iowa counties, at present small and often isolated populations are known from just 23 counties.

EASTERN COPPERHEAD Agkistrodon contortrix (Linnaeus) 1766 Venomous

Eastern copperhead from Van Buren County. Photo by Jeff LeClere.

Iowa Status. Endangered; species of greatest conservation need. Historical Summary. The eastern copperhead has also been called the highland

moccasin, copperhead moccasin, chunk head, deaf adder, copper-bell, copper belly, hazel head, thunder snake, red viper, northern copperhead, rattlesnake pilot, upland moccasin, red eye, and dumb rattlesnake. The first confirmed specimens in the state appear to be six collected near Keokuk in Lee County in 1879 (Goodman 1948). The specimens were housed at the Fairfield Public Library Museum and were not examined until the 1940s, leading some earlier workers such as Guthrie (1926) to conclude the species did not occur in the state; however, Somes (1911) did list it as being found in Iowa. Four specimens collected in Lee and Van Buren Counties in 1939 led Reeve Bailey (1940) to conclude the species’ range extended into southeast Iowa (presumably he was not aware of the Fairfield specimens).

300  Eastern Copperhead, Agkistrodon contortrix

Description. Eastern copperheads are heavy-bodied light coppery brown, orang-

ish, pinkish, or tan snakes with distinct hourglass-shaped brown blotches across the back that are narrowest at the midback. The unpatterned head is pinkish to coppery, often lighter below the eyes than above them, and has thin dark lines extending from the eyes to the angles of the jaw. Heat-sensing pits are present below and in front of the eyes, and the pupils are vertically elliptical. The belly is cream or pink with dark spots along the edges that may extend up onto the sides. The tail lacks a rattle, may be lightly banded, and has a greenish tip. The body scales are keeled and in 23 rows at midbody; the anal plate is single. As with Iowa’s other vipers, the subcaudal scales are single although some may become double near the end of the tail. There are usually 8 supralabial scales and 10 infralabial scales. Newborns look like miniature adults but are paler and have yellow tails. Examination of sexual dimorphism in 9 Iowa adult eastern copperhead museum specimens (6 males; 3 females) found no significant difference in the number of ventral scales (male mean 151; female mean 151), the number of subcaudal scales (male mean 47; female mean 43), or tail length as a proportion of total body length (male 13%; female 13%) between males and females. Size. Agkistrodon contortrix generally ranges from 24 to 36 inches (61–91.8 cm)

total body length. The largest specimen in the Drake University Research Collection is a male from Van Buren County measuring 30.8 inches (78.3 cm) total body length; the largest female is also from Van Buren County measuring 26.3 inches (66.7 cm) total body length. The largest Iowa specimens, however, are both in the Iowa State Natural History Collection and were measured by Reeve Bailey: a male from Lee County measured 31.5 inches (80.1 cm) total body length and a female from Van Buren County measured 31.26 inches (79.4 cm) total body length. The record total body length reported for the species is 53 inches (134.6 cm). Similar Species. No other Iowa snake has hourglass-shaped dorsal blotches, an

overall coppery color, vertically elliptical pupils, and facial pits. Eastern milksnakes are sometimes killed by those confusing them with copperheads, but eastern milksnakes have smooth scales, round pupils, and brown, gray, orange, or red dorsal blotches bordered in black on a white, gray, or brown background and lack facial pits. Western foxsnakes, eastern hog-nosed snakes, and all Iowa’s watersnakes lack facial pits, have round pupils, and may have patterned heads. Distribution. Eastern copperheads are found throughout much of the midAtlantic and southeast United States with the exception of Florida, ranging from eastern Kansas, Oklahoma, and Texas eastward to the Atlantic coast. Southeast

Agkistrodon contortrix, Eastern Copperhead  301

Head of an eastern copperhead from Van Buren County. Photo by Jeff LeClere.

Iowa, where records exist from just 4 counties, is at the very northern edge of the species’ range in the Midwest, and eastern copperheads are one of Iowa’s rarest snakes. Interestingly, they are found in northwest Missouri as far north as Atchison County on the Iowa-Missouri border; however, despite extensive surveys conducted by many searchers over the years, none has been found just to the north in Fremont County, Iowa. Davis County is represented by a single specimen collected in 1948 (Iowa State Natural History Collection; Klimstra 1950). Jim Christiansen and others have searched this area, but even though the habitat appears to be relatively undisturbed, no copperheads have been found. Eastern copperhead distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

302  Eastern Copperhead, Agkistrodon contortrix

Habitat. Over much of its range, the eastern copperhead inhabits rocky hillsides

in open-canopy woodlands with plentiful downed trees, hollow logs, and brush piles; it tends to use relatively open areas with a higher rock density and less surface vegetation than do timber rattlesnakes, with which it often coexists. In Missouri, it is found on rocky hillsides, along woodland edges and creeks, and near abandoned farm buildings (Johnson 2000). Most Iowa records are from habitats that fit these descriptions well, with the exception of Davis County, where Klimstra (1950) made no mention of rock outcrops in his note on the discovery of an eastern copperhead, and Jim’s surveys of the area failed to find any. Behavior. These snakes rely on camouflage and remaining motionless to go un-

detected and are not aggressive unless disturbed. If they are disturbed, in most cases they simply try to flee. A study of eastern copperhead antipredator behavior found that 93 percent of the snakes fled when approached or when physical contact was made with them, while only 3 percent struck (Adams et al. 2020). If escape is not possible, they may take up a defensive posture, often vibrating their tails, and they are able to strike from either a coiled or an uncoiled position. They may be more likely to strike when the air temperature is above 81° F (27° C), and males are more easily agitated than females, with gravid females being especially quiet. In northern portions of its range, the eastern copperhead is active from March or April to October or early November. The collection/observation dates of 18 Iowa eastern copperheads show the snake has been found from April through September in the state, with the earliest record on April 17 in Van Buren County. After emergence from hibernation, the snakes may stay around their hibernacula for up to a month, basking nearby during the day and retreating underground at night as the temperature drops. By sometime in May, males and nongravid females leave their hibernacula and head for summer foraging areas. Gravid females remain close to their overwintering sites. Much of the eastern copperhead’s time is spent coiled in leaf litter or near downed trees, hollow logs, or brush piles with the snake being active in the morning and afternoon during spring and fall and more crepuscular and nocturnal during the summer. Throughout the active season, males have larger ranges, make greater annual movements, and move farther from hibernacula than do females. Connecticut males showed more than a seventeenfold increase in activity range size and a fivefold increase in movement distance in August and September, likely due to searching for mates at this time (Smith et al. 2009). Interestingly, 72 percent of Iowa’s records occur during this time, many as roadkills.

Agkistrodon contortrix, Eastern Copperhead  303

Number of Records

10 8

7

6

6

4 2 0

0

0

0

Jan

Feb

Mar

1 Apr

2

2

0 May

Jun

Jul

Aug

Sep

0

0

0

Oct

Nov

Dec

Month

Collection/observation dates of 18 eastern copperheads in Iowa.

By late September, the snakes begin moving back to their hibernacula. The latest Iowa record is September 13 in Lee County, although LeClere (2013) reported finding one on September 17 in Van Buren County. In any case, it is likely they remain active near their overwintering sites well into October in most years. Eastern copperheads hibernate in groups in communal hibernacula, often with timber rattlesnakes, western ratsnakes, and racers, in rock crevices, caves, and other areas below the frost line. They show high fidelity for hibernacula, returning to the same sites year after year. Venom and Bites. It is the eastern copperhead’s cryptic coloration and behavior

that make it dangerous. Bites often occur when someone steps or places a hand on an unseen snake. Such was the case in 2007 when a resident of Lee County was bitten on the finger by an eastern copperhead while clearing wood. The Cedar Rapids Gazette reported that within a few hours the hand became painful, swollen, and numb. The pain eventually became unbearable, and the person was admitted to the hospital where he spent two days before recovering. Adults have fangs up to about 0.28 inch (7.2 mm) long, with larger snakes having longer fangs (Ernst and Ernst 2011). Agkistrodon comes from the Greek ankistron meaning “fishhook” and odontos meaning “tooth,” referring to the curved fangs; contortrix is Latin meaning “female contortionist,” possibly referring to the condition of a specimen or the dorsal pattern. Young copperheads are born with functional fangs and are able to inject venom right from the start. Eastern copperhead venom is the least toxic of that of Iowa’s five venomous snakes and

304  Eastern Copperhead, Agkistrodon contortrix

is about one-fifth as toxic as that of many rattlesnakes (Russell 1983). Although eastern copperhead bites make up the largest proportion of reported envenomations across the mid-Atlantic and southeast United States, death from their bites is uncommon. A typical bite yields 40 to 75 milligrams of dry venom, and it is likely that 100 milligrams or more would be needed to kill an adult human (Ernst and Ernst 2011). Although not often fatal, the venom is hemolytic and typically causes pain and swelling at the bite site along with discoloration of the skin and some death of tissue as well as difficulty breathing, fever, chills or sweating, headaches, increased or weakened pulse, nausea and vomiting, and shock. Infection and gangrene are a concern if the wound is not treated. Threats. A number of animals prey on these snakes, particularly on juveniles,

including coyotes, opossums, domestic cats, moles, American crows, great horned owls, red-tailed hawks, and even bullfrogs for those unfortunate young snakes that enter the water. Other snakes, such as racers, prairie kingsnakes, eastern milksnakes, and speckled kingsnakes, also eat them, and in some cases they can be significant predators. Steen et al. (2014) hypothesized that speckled kingsnakes regulate eastern copperhead abundance; as speckled kingsnake abundance declines, eastern copperhead abundance increases and vice versa. Humans pose threats as well through habitat loss, climate change, automobiles, and collecting. A road separating the presumed overwintering and summer foraging areas of the Van Buren County eastern copperhead population poses a serious threat. Many of the records from that area are snakes that were picked up as roadkills. In addition, the woodlands in the area have become denser over time, which may be detrimental to the snakes by limiting opportunities for thermoregulation. A changing climate can have serious implications for populations living at the edges of their species’ range, where conditions are likely near the limits of the species’ environmental tolerance. Even a slight change in climate, with an area becoming hotter or colder or wetter or drier, may make an area uninhabitable for a species, resulting in the loss of those populations on the fringes. A long-term study of eastern copperheads showed that five consecutive years of drought effectively ended the snakes’ reproductive output, with none of the dozens of females that were monitored producing young the year after the drought ended (Smith et al. 2019). Food and Feeding. Eastern copperheads have a diverse diet of amphibians, insects, small mammals, and birds and reptiles and their eggs. A sampling of reported prey items includes cicadas, green frogs, western slender glass lizards, prairie ring-necked snakes, red-winged blackbirds, and various shrews, mice,

Agkistrodon contortrix, Eastern Copperhead  305

and young squirrels and rabbits (see Ernst and Ernst 2011 for a complete list). Examination of the stomachs of specimens in the Drake University Research Collection found adult short-tailed shrews along with other mammal fur in two specimens and a large vole in another. Adults are primarily ambush predators, while juveniles actively stalk prey. Newborns slowly undulate their yellow tails, using them as lures to bring prey in close. When prey comes into range, the snake strikes, bites, injects venom, and most often allows it to escape while the venom works. Once the prey has been struck and tasted, the snake has a chemical search image that allows it to be found once released. Reproduction. Females likely mature in their third year at around 20 inches (51  cm) snout-vent length; males may mature slightly younger and smaller, although data are limited. Across the range of the species, mating has been reported in both spring and fall, with the first mating period in late summer to early fall, followed by hibernation, and the second mating period in spring shortly after the snakes emerge from hibernation. However, Smith et al. (2009) found only a single late summer (July–September) mating season in a population of eastern copperheads at the northeast extent of their range and speculated that cold spring temperatures in that area might play a role in limiting mating to late summer or early fall. During the mating season, males will often engage in male-male combat, sometimes for up to two hours. The males raise their heads and forebodies off the ground, intertwine their bodies, and attempt to push each other to the ground. Eventually one snake (usually the smaller) breaks off the encounter and leaves the area. The victor wins the opportunity to breed with the female. Males use scent trails to find females, and once a female is found, he actively courts her while she remains mostly passive. Studies indicate that females breed every other year. Only one of three Iowa adult female museum specimens was reproductive. The other two, both found in early August, did not contain enlarged follicles, embryos, or other evidence of reproduction. Eastern copperheads are ovoviviparous with females giving birth to 1 to 21 (4–8 most common) young in August or September. The single Iowa museum specimen that was reproductive was found on July 28 and contained 9 early embryos, similar to a July 27 Missouri female that contained 13 early embryos (Hurter 1911). Newborns range from 7.9 to 10 inches (20–25.4 cm) total body length. Longevity. A captive eastern copperhead survived 29 years, 10 months, and 6 days, and survival in the wild of up to 18 years has been documented.

TIMBER RATTLESNAKE Crotalus horridus Linnaeus 1758 Venomous

Timber rattlesnake from Des Moines County. Photo by Ryan D. Rasmussen.

Iowa Status. Protected in Allamakee, Appanoose, Clayton, Delaware, Des

Moines, Dubuque, Fayette, Henry, Jackson, Jones, Lee, Madison, Van Buren, and Winneshiek Counties not including an area of 50 yards (45.7 m) around houses actively occupied by humans; not protected elsewhere; species of greatest conservation need. Historical Summary. The timber rattlesnake has also been called the American

viper, bastard rattlesnake, eastern rattlesnake, velvet tail, and yellow rattlesnake. The first confirmed specimens in the state appear to be in 1879 near Keokuk in Lee County (Goodman 1948). Yarrow (1882) listed a National Museum of Natural History–Smithsonian Institution specimen from Iowa with no specific location data and an unknown date; however, the National Museum of Natural History collection does not currently list the specimen. Several county histories mention timber rattlesnakes (e.g., Anonymous 1881a, b), and Nutting (1892) listed a specimen from Iowa City in Johnson County.

308  Timber Rattlesnake, Crotalus horridus

Timber rattlesnake from Davis County. Photo by Ryan D. Rasmussen.

Description. Timber rattlesnakes are large heavy-bodied snakes with a yellow,

gray, brown, or orangish brown background color and 15 to 30 large dark jagged, almost zigzag bands with light borders crossing the back. A red to reddish orange vertebral stripe may be present. The tail is black and ends in a large tan rattle. The large head is triangle-shaped, covered with granular scales, and separated from the body by a narrow neck. Prominent heat-sensing pits are present below and in front of the eyes, and the pupils are vertically elliptical. The belly is white, cream, or yellow with some stippling. The body scales are strongly keeled and in 23 to 24 rows at midbody; the anal plate is single, as are the subcaudal scales. There are usually 13 to 15 supralabial scales and 14 to 16 infralabial scales. Juveniles are patterned like adults but with banded tails that progressively darken with age. Predominantly black individuals have been reported in the state, and an albino was found in Jones County (Arnold 1963). Ventral scales range from 154 to 179 in males and 154 to 183 in females (Ernst and Ernst 2012). Examination of sexual dimorphism in 36 Iowa adult timber rattlesnake museum specimens (12 males; 24 females) found the number of subcaudal scales (male mean 25; female mean 20) and tail length as a proportion of total body length (male 8%; female 6%) differed significantly between males and females, with males having longer tails and more subcaudal scales than females.

Crotalus horridus, Timber Rattlesnake  309

Size. Timber rattlesnakes generally range from 36 to 60 inches (91.8–152.4 cm)

total body length. The largest specimen in the Drake University Research Collection is a male from Jackson County measuring 47.8 inches (121.5 cm) total body length; the largest female is from Madison County measuring 41 inches (104.1 cm) total body length. Jeff Parmelee (personal communication, 2020) measured a 46.5-inch (118-cm) live female during his field studies in Madison County. The record total body length reported for the species is 74.5 inches (189.2 cm). Similar Species. No other Iowa snake has a yellow to orangish brown background color, dark zigzag bands across the back, and a uniformly black tail that ends in a rattle. Its size and distribution in the state separate the timber rattlesnake from Iowa’s other rattlesnakes. Bullsnakes and western foxsnakes are the harmless species most often mistaken for rattlesnakes. Bullsnakes have large plates, not granular scales, on top of the head, a very yellow background color, and distinct dorsal blotches that tend to change color from black near the head to reddish brown at midbody and back to black again near the tail. Western foxsnakes also have large plates, not granular scales, on top of the head along with a gray or light brown background color. Both species lack rattles and facial pits and are generally slenderer in build than the heavier-bodied timber rattlesnake. Distribution. Timber rattlesnakes are found in scattered populations through-

out the eastern United States from southern New Hampshire south through the Appalachian Mountains to northern Florida, west to southeast Texas and southeast Nebraska, and north along the Mississippi River corridor into southeast Minnesota and western Wisconsin. They are the most widely distributed rattlesnake in Iowa, although their range is certainly not what it once was. At present, records exist for 21 of Iowa’s 99 counties, 5 of which (24%) have only pre-1950 records. They are found in northeast Iowa down to Jones and Jackson Counties and in southeast Iowa from the Mississippi River west in the southern two tiers of counties to Monroe County. An isolated population remains in Madison County. Timber rattlesnake distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-1960

310  Timber Rattlesnake, Crotalus horridus

Newspaper accounts and county histories from the late 1800s and early 1900s suggest timber rattlesnakes were formerly distributed throughout eastern and most of southern Iowa as well as into central Iowa along major river systems, as evidenced by a 1933 account in the Rock Valley Bee that indicated that a 56-inch (142.2-cm) “black diamond variety of rattler” was killed near Clarion in Wright County. Accounts such as this, along with many others describing large rattlesnakes found in wooded areas or rattlesnake bites and deaths, support the idea of a wider range once occupied by these snakes. Although the snakes are not currently found in southwest Iowa, the History of Montgomery County, Iowa (Anonymous 1881b) states that “there are also a few of the yellow rattlesnake,” suggesting they may have occurred there at one time. Further support is provided by Fogell (2010), who reported that historically timber rattlesnakes were found as far north as Cass County, Nebraska—adjacent to Mills County, Iowa. Habitat. Crotalus horridus uses diverse habitats across its range, including timbered areas near rock outcrops, ledges, and rock slides in the Northeast; river bottoms, floodplains, and swampy areas in the South; and rocky bluffs, bluff prairies, and open oak-hickory woodlands in the Midwest. In Madison County, Parmelee and Frese (2005) found that 42 percent of the timber rattlesnakes they studied used woodland edges and shrubby habitats, 34 percent used open grasslands, and 24 percent used woodlands. They identified three types of critical habitat: hibernation and den habitat (large horizontal ledges of limestone with numerous cracks and crevices often located near creeks), transitional, rookery, and gestation habitat (open rocky areas with limited canopy cover near dens with rocks and ledges for basking and protection), and summer and foraging habitat (open woodlands, grassy areas, shrubby fencerows, and bottomland woodlands). In northeast Iowa, open dry prairies on steep bluffs adjacent to oak-hickory woodlands, oak savannas, and river bottom woodlands are used. In similar habitat in western Wisconsin, Sajdak et al. (2005, in Ernst and Ernst 2012) reported females used prairies most frequently, followed by secondary woodlands (regenerated woodlands after significant removal or disturbance of the original woodlands), marsh woodlands, and shrubby areas of sumac, dogwood, and blackberry; they were not found in agricultural habitats. Males used mature oak woodlands most frequently, followed by secondary woodlands, swamp woodlands, and less frequently agricultural habitats and sumac, dogwood, and blackberry shrubby areas. Behavior. Generally mild-tempered, timber rattlesnakes rely on camouflage to

go unnoticed, or if given the opportunity they usually retreat. If escape is not possible, they may form a loose coil, rattle, raise their head, and strike. The strike may

Crotalus horridus, Timber Rattlesnake  311

Basking timber rattlesnake in Jackson County. Photo by Matt Ricklefs.

be a false strike with the mouth closed, but then again it may not. They are primarily terrestrial but may climb trees and are good swimmers. A 1931 story in the Rock Valley Bee recounted the tale of a 50-inch (127-cm) timber rattlesnake swimming on top of the water across the Des Moines River in Van Buren County. Once the snake reached the shore, it of course was killed and turned in for a 50-cent bounty. It is generally thought that snakes are not social, coming together only for mating or hibernating. However, Clark (2004a) showed that timber rattlesnakes recognize and spend more time with their sisters even after being raised separately for over two years, suggesting there may be kin selection at work—groups of rattlesnakes made up of related individuals. The collection/observation dates of 343 Iowa timber rattlesnakes show the species has been found in Iowa from late March through early November, with the earliest record an individual found in Clayton County on March 24 and the latest 2 individuals seen in Madison County on November 8. In most years, however, the snakes are active from April through October. Information on timber rattlesnake behavior in Iowa comes primarily from the excellent field studies of Jeff Parmelee and Paul Frese (2005) in Madison County, which I have used in this section except as noted.

312  Timber Rattlesnake, Crotalus horridus

Number of Records

140

126

120 100

84

80 60

47

40 20 0

26 0

0

1

Jan

Feb

Mar

Apr

23

May

Jun

Jul

23

Aug

11 Sep

Oct

2

0

Nov

Dec

Month Collection/observation dates of 343 timber rattlesnakes in Iowa.

The snakes emerge from hibernation from April to early May, depending on the air temperature, and stay close to their den sites until air temperatures become consistently warm. By mid-June they have dispersed from the den sites to their summer feeding areas, where they establish activity ranges and remain until temperatures cool again in the fall. The serpents usually spend their time coiled motionless among leaves on the ground where they are well camouflaged; they may also lie under large rocks during cool periods and may be underground in cracks and crevices for weeks at a time. Average home range size of 7 Iowa timber rattlesnakes was 4.9 acres (2 ha), smaller than that reported for more eastern populations. Over the course of the active season, the average maximum linear distance moved from den sites in Madison County was 0.24 mile (0.38 km), and the average total distance moved in a single year was 0.68 mile (1.1 km). The snakes remain in their summer feeding areas until late September or October, when they return to their den sites. Timber rattlesnakes hibernate communally, sometimes with other species such as bullsnakes, racers, and western ratsnakes. In the past, up to 200 snakes may have congregated at suitable hibernacula, usually in crevices on south-facing rocky slopes or rock outcrops, with individual snakes showing high fidelity to their dens, some traveling long distances to reach the same den year after year. A 1919 story in the Traer Star Clipper tells of two wheelbarrow loads of rattlesnake bones and rattles being taken out of a rock outcrop near McGregor in Clayton County that was being blasted for a quarry. The author surmised the open space in the rock had been home to the snakes for many years, possibly centuries, and

Crotalus horridus, Timber Rattlesnake  313

Timber rattlesnake den site in Jackson County. Photo by Matt Ricklefs.

was well known to the early settlers of the county. Few if any large dens likely remain in Iowa, and any den site that does remain should be protected. In Madison County, hibernacula are generally located in areas of low road density, low human population, and moderate to high woodland coverage. Den sites are almost always above areas of potential flooding, where erosion-exposed bedrock creates suitable overwintering sites. Venom and Bites. Timber rattlesnake bites are among the most commonly re-

ported bites in the United States and can be life-threatening, although death is much less common than it used to be due to the availability of antivenom. The genus name Crotalus comes from the Greek krotalon meaning “a rattle”; horridus is Latin for “dreadful,” referring to the venomous nature of this snake. Adult timber rattlesnakes have fangs up to about 0.37 inch (9.3 mm) long, and young snakes are born with functional fangs able to inject venom right away (Ernst and Ernst 2012). Timber rattlesnake venom is of average toxicity for North American pit vipers and is strongly hemolytic. Symptoms of a bite include pain, swelling, blood blisters, discoloration of the skin, weakness, difficulty breathing, hemorrhaging, bleeding from the gums, weak pulse, lowered blood pressure, heart and kidney

314  Timber Rattlesnake, Crotalus horridus

failure, foaming at the mouth, paralysis, shock, and death. The estimated lethal dose for a human is 75 to 100 milligrams of venom, and the typical timber rattlesnake contains 75 to 210 milligrams of venom (Minton and Minton 1969; Russell 1983), more than enough to be fatal. Larger snakes can deliver more venom than smaller snakes. In the mid-1970s, Jim Christiansen came upon a young man in Madison County who had just been bitten by a timber rattlesnake. A fang had pierced his thumb, but there were no signs of envenomation. Jim followed up later with the lucky young man, who confirmed no ill effects. During the late 1800s and early 1900s, timber rattlesnake bites and fatalities were common throughout the current and former range of the species in Iowa. An 1866 story in the Monticello Express, for example, tells of a Civil War veteran in Jones County who was bitten on the chest while bending over to pick up grain; not believing he had actually been bitten, he continued to work until he grew blind and faint. He suffered violent convulsions for forty-eight hours, “although he took several quarts of whisky in time,” and was expected to recover. Others were not so lucky, and many died within hours of being bitten, such as a sixteen-year-old Van Buren County boy who the Keosauqua Republican reported was bitten on the foot in 1867. He started for the house immediately but fell before he got halfway and died five hours later. Bites still occur in the state, although not as frequently. Keyler (2008), researching timber rattlesnake bites between 1982 and 2002 in the upper Mississippi River valley, found that bites rarely occurred—five in Iowa— and that antivenom therapy was generally effective. He also found that more than half the bites were dry bites, and most were the result of deliberate human interaction often involving alcohol, with the typical victim being a male in his second or third decade. Threats. Natural predators, especially of young snakes, include skunks, opos-

sums, weasels, domestic dogs, foxes, hawks, owls, wild turkeys, and snakes such as western ratsnakes, kingsnakes, and eastern milksnakes. Parmelee and Frese (2005) confirmed predation on two radio-tracked timber rattlesnakes in Madison County where the predator was believed to be a ground-dwelling animal such as a coyote or a badger. They also found five timber rattlesnakes from three separate den sites exhibiting hibernation blisters, a condition where snakes show numerous blisters over the body and head and may appear sickly or skinny. Three of the five snakes were confirmed dead within one to forty-five days. Additional threats include snake fungal disease, automobiles, lawn mowers, and opportunistic killings. Often roadkills are large males, likely the result of their extended movements during the summer breeding season.

Crotalus horridus, Timber Rattlesnake  315

Nearly all encounters between timber rattlesnakes and humans end poorly for the snakes. A few are still killed in Iowa near homes or when seen on roads, although historically human persecution of timber rattlesnakes was much more intense. One of the most infamous tales is that of the Great Snake Hunt of 1848 in Madison County, where between 3,000 and 4,000 rattlesnakes had been killed by July 4 of that year, most at den sites in early spring (Mueller 1915). The following year a party visited a rocky ledge along the Des Moines River in Jasper County on a warm spring day, managed to kill over 300 rattlesnakes, and “could doubtless have much increased the pile of slain, had not the offensive odor turned their stomachs” (Anonymous 1878). A state law passed in 1909 placed a 50-cent bounty on each rattlesnake killed. The impetus for the law was the near death of a state senator from Clayton County who was bitten by a timber rattlesnake. Numerous newspaper accounts report large numbers of timber rattlesnakes killed for bounties, such as a 1912 story in the Dunlap Reporter that reported a total of 18,533 rattlesnake bounties paid in Iowa in 1911, including over 2,600 in Clayton County and 1,400 in Winneshiek County, all of which were undoubtedly timber rattlesnakes. A 1932 story in the Cedar Rapids Gazette tells of a Clayton County resident whose profession was rattlesnake hunter, but not for bounties. He found it more profitable to sell live snakes to a “snake jobber” who found buyers. The hunter claimed to have taken 300 in one day, with his record being 1,600 in a single year. More disturbing yet: he indicated he preferred to catch mothers and young because many could be caught at one time relatively easily. No population of any species can withstand long-term overexploitation, especially of females and young. Because of their late age of first reproduction, bi- or triennial reproduction, and low number of offspring, the impact of removing gravid timber rattlesnakes can have devastating effects on a population, much more so than the removal of a female gartersnake capable of producing twenty to forty young every year. Food and Feeding. These rattlesnakes hunt by thermal cues, odor, and vision and feed almost exclusively on small mammals such as mice, shrews, voles, chipmunks, squirrels, and young rabbits; snakes, lizards, and birds may also be eaten. A timber rattlesnake in Allamakee County struck and held a yellow-bellied sapsucker that was moving and calling loudly in front of it on a branch approximately 15 to 20 feet (4.5–6 m) above the ground (Sajdak and Bartz 2004). The snakes may actively forage but are primarily ambush predators that sample their environment and choose ambush sites, often along a fallen log or other natural runway, based on chemical cues from potential prey and previous experience. Radio tracking in Iowa has shown that they can remain in one location without moving for weeks at

316  Timber Rattlesnake, Crotalus horridus

a time (Jeff Parmelee, personal communication, 2020). While foraging, the snake coils its body with its head up, ready to strike at a passing rodent. When prey comes into range, the snake strikes, bites, injects venom, and most often releases it to allow it to escape while the venom works. The snake then follows the scent trail until it finds its prey. Reproduction. Females mature in approximately 4 to 13 years at around 35.4 to

37 inches (90–94 cm) total body length, while males mature in 4 to 6 years likely at a smaller size. Females typically breed every 2 to 3 years. Males begin searching for females during the second half of the summer, using scent trails to find them. Mating takes place in July and August with females being courted by one or more males. While mating is likely nearly always species-specific, Reeve Bailey (1942) found an eastern massasauga and timber rattlesnake hybrid in Lee County. Two or more males courting a single female will often engage in male-male combat for breeding privileges. After mating, the snakes separate and the female stores sperm over the winter to fertilize her eggs after ovulation in the spring. Gravid females do not move far from their hibernacula and spend time basking on rocks and ledges to regulate their body temperature, and it is possible that they do not feed or feed very little while gestating. Rookery and gestation areas generally consist of open rocky habitats near dens. Timber rattlesnakes are ovoviviparous with females giving birth to 2 to 17 young in mid-August to mid-September in Iowa. Birth dates for 11 litters of Madison County timber rattlesnakes born in Jeff Parmelee’s lab were August 19, 21, 24, 27, 29, 29, and 30 and September 11, 12, 13, and 22. The average size of the litters was 6.5 young (range 2–11) and was slightly male-biased. Newborns are 7.7 to 16.1 inches (19.5–40.9 cm) total body length. Mothers stay with the newborns for about a week, and the newborns stay at the birth site 10 to 14 days until they have shed for the first time before dispersing. Longevity. A wild-caught juvenile male survived an additional 36 years, 7 months, and 27 days.

PRAIRIE RATTLESNAKE Crotalus viridis (Rafinesque) 1818 Venomous

Prairie rattlesnake from Plymouth County. Photo by Daniel D. Fogell.

Iowa Status. Endangered; species of greatest conservation need. Historical Summary. The prairie rattlesnake has also been called the rattle-

snake of the prairies, common rattlesnake, Missouri rattlesnake, and massasauga. Somes (1911) stated the species was found in Iowa but did not reference a specimen. Guthrie (1929) reported that bounties paid showed that prairie rattlesnakes were found on the western edge of Plymouth County near the South Dakota line. The first confirmed specimens in the state were collected in 1937 in Plymouth County on hills above the Big Sioux River (San Diego Natural History Museum). Wright and Wright (1952) listed the prairie rattlesnake as “problematic” in Iowa, that is, hypothetical, accidental, introduced, puzzling, questionable, unverified, or extinct. Description. Prairie rattlesnakes are large heavy-bodied tan or yellowish brown

to slightly greenish (viridis is Latin meaning “green”) snakes with 30 to 50 irregu-

318  Prairie Rattlesnake, Crotalus viridis

lar brown dorsal blotches outlined with white that become narrower near the tail. The tail is tan with dark usually distinct cross-bands and ends in a large rattle. The large head is triangle-shaped and covered with granular scales, and there are 2 light stripes on the sides of the face, one extending from in front of the eye backward to the supralabials and the other extending from behind the eye to the corner of the mouth and then onto the neck. Prominent heat-sensing pits are present below and in front of the eyes, and the pupils are vertically elliptical. The belly is cream with indefinite markings that may somewhat align to form a double row. The body scales are strongly keeled and in 23 to 27 rows at midbody; the anal plate is single, as are the subcaudal scales. There are usually 14 to 15 supralabial scales and 15 to 16 infralabial scales. Juveniles are patterned like adults but more vividly. As the snake ages, the pattern fades and the dorsal blotches may almost disappear in adults. Ventral scales range from 164 to 189 in males and 170 to 196 in females (Ernst and Ernst 2012). Examination of sexual dimorphism in 78 Iowa adult prairie rattlesnakes (34 males; 44 females; data provided by Dan Fogell, personal communication, 2020) found the number of subcaudal scales (male mean 27; female mean 20) and tail length as a proportion of total body length (male 8%; female 6%) differed significantly between males and females, with males having longer tails and more subcaudal scales than females. Size. Prairie rattlesnakes generally range from 35 to 45 inches (89–115 cm) total

body length. The single Iowa specimen in the Drake University Research Collection is a female from Plymouth County measuring 37.8 inches (96 cm) total body length. Dan Fogell marked and released 65 individuals in Plymouth County; of these, males were slightly larger than females, averaging 35 inches (89 cm) total body length compared to an average of 32 inches (81.3 cm) for females. The largest prairie rattlesnake recorded in Iowa is a male from Plymouth County measuring 50.2 inches (127.5 cm). The record total body length reported for the species is 59.6 inches (151.4 cm). Similar Species. The ranges of Iowa’s other rattlesnakes do not overlap with that

of the prairie rattlesnake. Iowa’s harmless snakes all lack facial pits, have round not elliptical pupils, and lack a rattle at the end of their tails. While many harmless snakes mimic rattlesnakes by vibrating their tails, they generally keep them flat against the ground, whereas rattlesnakes raise them off the ground. Bullsnakes and western foxsnakes are the harmless species most often mistaken for rattlesnakes. Bullsnakes have large plates, not granular scales, on top of the head, a very yellow background color, and distinct dorsal blotches that tend to change color

Crotalus viridis, Prairie Rattlesnake  319

from black near the head to reddish brown at midbody and back to black again near the tail. Bullsnakes hiss loudly when threatened, while it is rare to hear a rattlesnake hiss. Western foxsnakes also have large plates, not granular scales, on top of the head along with a gray or light brown background color. Both species lack rattles and facial pits and are generally slenderer than the prairie rattlesnake. Distribution. Crotalus viridis is found in the Great Plains from southern Alberta

and Saskatchewan and most of Montana and southwest North Dakota south to west Texas and west through New Mexico into Arizona. A finger of the range extends east along the South Dakota–Nebraska border into very western Iowa. Iowa is at the extreme eastern edge of the species’ range and the state’s population represents an extremely small isolated fragment of the main population, which reaches its eastern extent more than 80 miles (129 km) to the west of Iowa (Fogell 2010). At present, prairie rattlesnakes are known only from one location in Plymouth County, although historic records are known from Woodbury County. Prairie rattlesnake distribution in Iowa. Blue = pre-1960 Green = both pre- and post-1960

Although no confirmed records exist from counties other than Plymouth and Woodbury, historically the prairie rattlesnake’s range likely included several additional counties in northwest Iowa. In discussing the Plymouth County population, Klauber (1938) stated, “It is evident that this is not a recent infestation; the colony is no doubt a residue of a once more widespread range, now curtailed by agricultural development, the river bluffs constituting the last undisturbed refuge of rattlers.” In support of this conclusion are numerous reports from the late 1800s and early 1900s in multiple newspapers all along Iowa’s western border of rattlesnake bites, deaths attributed to rattlesnake bites, and rattlesnakes being killed. While not all the newspaper articles may have actually been about rattlesnakes, those reporting symptoms consistent with rattlesnake bites—extreme swelling, severe pain, blackening of the skin, and death—and those reporting rattles being cut off and saved undoubtedly were about rattlesnakes.

320  Prairie Rattlesnake, Crotalus viridis

My review of historic newspaper accounts and the presumed historic ranges of Iowa’s other rattlesnakes shows it is likely that previously prairie rattlesnakes occurred from as far north as Sioux County, where multiple newspaper reports exist including a 1945 account in the Hawarden Independent of a dead 42-inch (106.7-cm) rattlesnake with “eight rattlers and a button” found at the Hawarden city dump, south to Monona County, where at least twenty newspaper reports exist. Numerous newspaper accounts of rattlesnakes also exist in Ida and Crawford Counties. An 1899 account in the Ida County Pioneer stated, “In the pioneer days of Ida County it was not an uncommon occurrence, to see, or to be bitten by rattlesnakes.” Prairie rattlesnakes may also have occurred in Harrison County, where several newspaper accounts of rattlesnakes over 3 feet (91.4 cm) in length exist, including a Dunlap Reporter story that reported the killing of a rattlesnake over 4 feet (122 cm) long with seventeen rattles. Habitat. These rattlesnakes inhabit shortgrass to mixed-grass prairies throughout much of the Great Plains. In Iowa, they are limited to the northern Loess Hills. Rock outcrops of any kind are uncommon in the Loess Hills, but not so in Woodbury and Plymouth Counties. Dan Fogell’s work showed that Iowa’s prairie rattlesnakes use a variety of habitats throughout the active season, including areas with abundant cover such as large rocks, piles of woody debris, badger and plains pocket gopher burrows, and junk piles; open grasslands dominated by native prairie species such as big and little bluestem, Indiangrass, sideoats grama, leadplant, and compass plant along with western species like soapweed and ten-petaled mentzelia; and woodland patches or woodland-grassland edges. Grasslands are used predominantly during the hottest summer months of July and August, with the snakes seeking relief from the heat by taking cover in mammal burrows or lying deep below dead standing vegetation. Behavior. Prairie rattlesnakes most often rely on camouflage to remain unde-

tected. However, when approached or otherwise startled, they are quick to rattle and announce their presence. If given the opportunity they usually retreat, all the while rattling as they dive into a burrow or take cover in vegetation. If cover is not available, they generally assume a defensive posture with their rattling tails positioned vertically and their heads raised into a tight S-shaped coil about onethird of their body length above the ground, ready for a quick strike if necessary. Information on prairie rattlesnake activity in Iowa comes primarily from the excellent field studies of Dan Fogell in Plymouth County, which I have used here except as noted. The collection/observation dates of 106 Iowa prairie rattlesnakes show the species has been found from April through October. The snakes

Crotalus viridis, Prairie Rattlesnake  321

Prairie rattlesnake from Plymouth County showing defensive posture. Photo by Daniel D. Fogell.

emerge from hibernation in early to mid-April, with the earliest Iowa record from Plymouth County on April 6. After they emerge, they stay near the den sites for a while, basking during the day and returning to their dens at night before eventually moving a short distance to areas with abundant cover in order to shed. Once the post-emergence shed is complete, they move to open grasslands where they spend the summer feeding and searching for mates. Gravid females normally remain close to their dens throughout their gestation period but will move sizable distances to find food after they have given birth. During the hottest part of the summer, July and August, the serpents may spend 30 to 50 percent of their time in mammal burrows to avoid the heat. Long-distance seasonal movements are not uncommon among prairie rattlesnakes throughout their range with distances up to 12.4 miles (20 km) from known den sites reported in some locations. Iowa’s prairie rattlesnakes do not travel nearly as far, but they still move significant distances each season. The average linear distance—the maximum distance from the den—traveled is 0.6 mile (1 km). Males travel a greater total distance throughout the year than females though the difference is small. A greater difference is seen in the average distance traveled per day, with males making longer daily movements. In September, the snakes begin moving back to their den sites and by October most have reached

322  Prairie Rattlesnake, Crotalus viridis

Number of Records

50

41

40 30 18

20

12 6

10 0

0

0

0

Jan

Feb

Mar

Apr

May

Jun

12

10

Jul

Aug

Sep

7

Oct

0

0

Nov

Dec

Month Collection/observation dates of 106 prairie rattlesnakes in Iowa.

the sites, where they again spend their days outside the dens basking and go into the dens at night as the weather cools. Over most of their range, prairie rattlesnakes can be separated into two general groups: those that use exposed rock outcrops for hibernation and those that hibernate in prairie dog burrows. Because prairie dogs are not found in the state, Iowa prairie rattlesnakes use rock outcrops to escape the cold northwest Iowa winters. Typical hibernation sites contain large rocks, which are often used for cover, and exposed limestone on a south- to southwest-facing hillside with numerous indistinct fissures that lead to deeper underground chambers. The latest Iowa record is an individual found in Plymouth County on October 13. Venom and Bites. Adults have fangs up to about 0.29 inch (7.4 mm) long, and

young snakes are born with functional fangs and are able to inject venom right from the start (Ernst and Ernst 2012). Prairie rattlesnake bites are similar to those of most rattlesnakes except that they may produce more neurotoxic effects. Symptoms include bleeding from the fang marks, instant shooting pain, dizziness, faintness, swelling and discoloration of the skin that progress outward from the bite site, vomiting, bowel movements, chills, acute thirst, headaches, sleepiness, and even death. Many bites show mild neurotoxic symptoms such as tingling in the fingers and toes, muscle twitching, high levels of muscle tension, and difficulty breathing. Larger snakes can deliver much more venom than smaller snakes, or they may not inject venom at all.

Crotalus viridis, Prairie Rattlesnake  323

Prairie rattlesnake den site in Plymouth County. Photo by Daniel D. Fogell.

Numerous bites were reported by newspapers in Plymouth, Woodbury, Ida, Monona, and Crawford Counties during the late 1800s and early 1900s, and multiple fatalities were reported in Woodbury and Monona Counties. Symptoms ranged from mild pain with complete recovery to swelling of limbs and spotting of skin, extreme pain, great discomfort, and in some cases death within minutes or days. An 1889 story in the Ida County Watch told of a three-year-old in Monona County who died within fifteen minutes of being bitten. Threats. Natural predators include skunks, badgers, coyotes, foxes, hawks, owls,

and snakes such as racers and bullsnakes. Historically, human persecution and habitat loss were major threats as northwest Iowa was being settled and prairie was being converted to cropland. Counties paid a bounty for rattlesnakes beginning in the early 1900s. Plymouth County ended rattlesnake bounties in 1978, by which time most of the surrounding counties had already stopped paying them. Today, prairie rattlesnakes are protected as an endangered species in Iowa and nearly all the land on which they occur is protected. Nevertheless, land adjacent to protected areas is still under threat of development, and conversion of adjacent agricultural fields—unsuitable habitat—to housing developments with well-maintained lawns equally as inviting to prairie rattlesnakes as a mixed-grass prairie is detrimental to the snakes. Putting rattlesnakes in close contact with

324  Prairie Rattlesnake, Crotalus viridis

humans never has positive results for the rattlesnake. The small size and isolation of Iowa’s remaining population may be the most serious threat. Small populations are at significant risk of loss of genetic diversity through inbreeding. It is unlikely that there will ever again be an exchange of genetic material between the main prairie rattlesnake population and Iowa’s population. Small populations are also at risk due to random natural events such as fire, hot or cold spells, droughts, or disease, which can reduce numbers even further. If numbers are reduced enough, they may fall below the level at which the population can survive. Food and Feeding. The prairie rattlesnake is a generalist predator that consumes a range of vertebrate prey and hunts by actively foraging or by ambushing. Prey is located either visually or by scent. When prey comes into range, the snake strikes, bites and injects venom, and most often allows it to escape while the venom works, although larger snakes may hold on. Once the prey has been struck and tasted, the snake has a chemical search image that allows it to be found when released. Newborns and small juveniles eat primarily small mammals but may also eat insects and toads, whereas large juveniles and adults have a more varied diet but still prefer mammals. The diet of Iowa’s prairie rattlesnakes has not been investigated, but in other regions prey includes deer mice, meadow and prairie voles, thirteen-lined ground squirrels, pocket gophers, cottontail rabbits, and a variety of birds such as meadowlarks and juvenile ring-necked pheasants, all of which coexist with Iowa’s prairie rattlesnakes. Reproduction. Jørgensen and Nicholson (2007, Alberta) provide a detailed discussion of the reproductive biology of prairie rattlesnakes, and the studies of Dan Fogell (personal communication, 2020) in Plymouth County provide information on prairie rattlesnake reproduction in Iowa. I have used both studies in this section except as noted. Iowa females mature in approximately 4 to 5 years at around 26 inches (66 cm) snout-vent length. Males grow faster and mature at a smaller size and an earlier age. Males begin searching for females during the second half of the summer using scent trails to find them. Mating takes place in August and September with females being courted by one or more males. If two or more males court a single female, they will often engage in male-male combat for breeding privileges. The males raise their heads and forebodies off the ground, intertwine their bodies, and attempt to push each other to the ground. No biting occurs and neither snake is harmed. The victor wins the opportunity to breed with the female. During breeding, the male moves onto the back of the female while using short jerking motions and tongue flicking in an attempt to encourage a receptive response. Copulation lasts several minutes to over an hour. Repro-

Crotalus viridis, Prairie Rattlesnake  325

Female prairie rattlesnake with newborns in Plymouth County. Photo by Daniel D. Fogell.

ductive females enter and then emerge from hibernation after having bred the previous summer or fall. Females store sperm over the winter, and ovulation occurs in the spring shortly after emergence and gestation continues through July. Gestation takes place in mammal burrows with gravid females exhibiting fidelity to their gestation burrows, leaving them only to bask and rarely traveling far from them. Multiple females may use the same burrow, likely due to a combination of habitat selection and protection, with certain burrows providing ideal gestation sites due to their protective qualities, directional aspect, and proximity to a den. Prairie rattlesnakes are ovoviviparous with females giving birth to live young in mid-August. Iowa litters generally range from 6 to 13 young, with newborns ranging from 10 to 11.3 inches (25.4–28.7 cm) total body length. Once females have given birth, they remain with their offspring for a short time before leaving the gestation site and searching for food. Longevity. A wild-caught individual survived in captivity an additional 19 years, 3 months, and 10 days.

EASTERN M ASSASAUGA Sistrurus catenatus (Rafinesque) 1818 Venomous

Light brown adult eastern massasauga from Bremer County.

Iowa Status. Endangered; species of greatest conservation need; federally listed

as threatened. Historical Summary. The eastern massasauga has also been called the swamp

rattler, sauger, prairie rattlesnake, black rattlesnake, black massasauga, dwarf prairie rattlesnake, gray rattlesnake, black snapper, and triple-spotted rattlesnake. The first confirmed specimens in the state appear to be in 1870 near Keokuk in Lee County (Goodman 1948); however, Yarrow (1882) lists a National Museum of Natural History–Smithsonian Institution specimen from Delaware County collected sometime before 1882. By the late 1800s, Osborn (1892) considered the massasauga—both eastern and prairie—to be rare in Iowa, and in the late 1920s Guthrie (1929) noted it was “probably rare or even altogether absent in most parts of the state where it once abounded before the days of drained sloughs and burning stubble, and mowers and disk harrows.”

328  Eastern Massasauga, Sistrurus catenatus

Description. Eastern massasaugas are heavy-bodied dark gray to light brown

snakes with a series of indented dark brown to black blotches down the midline of the back (catenatus is Latin meaning “chained” or “chainlike”) and 3 rows of alternating small brown or black spots on the sides of the body, the lowermost of which sometimes extends onto the belly. The tail has alternating light and dark bands and ends in a small indistinct black rattle (Sistrurus comes from the Latin sistrum meaning “rattle” and the Greek oura meaning “tail”). The belly is black with some white or cream mottling along the edges. The head is distinctly larger than the neck and has a light-bordered dark stripe extending backward from each eye, a pair of elongated dark blotches extending from the top onto the neck, and 9 large plates on top like Iowa’s nonvenomous species. Prominent heat-sensing pits are present below and in front of the eyes, and the pupils are vertically elliptical. The body scales are strongly keeled and in 25 rows at midbody; the anal plate is single, as are the subcaudal scales. There are usually 11 to 12 supralabial scales and 11 to 13 infralabial scales. Newborns are patterned like adults but the pattern is more vivid, consisting of a light gray background with dark brown or black blotches; the tails are light yellow. Examination of sexual dimorphism in 124 Iowa adult eastern massasaugas (59 males; 65 females) measured during my long-term study of the species in Bremer

Dark gray adult eastern massasauga from Bremer County.

Sistrurus catenatus, Eastern Massasauga  329

County found snout-vent length, the number of ventral scales (male mean 143; female mean 148), the number of subcaudal scales (male mean 29; female mean 24), and tail length as a proportion of total body length (male 11%; female 8%) differed significantly between males and females, with males being larger and having more subcaudal scales and longer tails than females and females having more ventral scales. Size. Sistrurus catenatus generally ranges from 18.5 to 30 inches (47–76 cm) total

body length. In Iowa, adult males average 25 inches (63.5 cm) and adult females 23 inches (58 cm) total body length. The largest specimen in the Drake University Research Collection is a male from Bremer County measuring 34 inches (86.4 cm) total body length; the largest female is also from Bremer County measuring 29.5 inches (74.9 cm) total body length. The record total body length reported for the species is 39.5 inches (100.4 cm). Similar Species. The belly of the prairie massasauga is generally light-colored with a moderate amount of dark pigmentation along the outer edges, and its range does not overlap with that of the eastern massasauga. Timber rattlesnakes grow much larger and have a yellowish background color with zigzag bands across the back, granular scales between the eyes, and a large rattle. The western foxsnake is often mistaken for a rattlesnake because it vibrates its tail when excited. In addition, its pattern and color, along with plates rather than granular scales between the eyes, make it superficially resemble the eastern massasauga. However, the western foxsnake lacks a rattle and instead has a tail that narrowly tapers to a point, lacks facial pits, has round pupils, and is longer and thinner. Both eastern milksnakes and juvenile northern watersnakes may be confused with the eastern massasauga, but both species lack facial pits and rattles and have round not elliptical pupils. Distribution. The eastern massasauga is found in scattered populations from eastern Iowa and Missouri east to western New York and southern Ontario. Eastern Iowa is at the extreme western edge of the species’ range, and Sovic et al. (2016) believe Iowa’s eastern massasaugas are unique. Using genetic evidence, they concluded that Iowa eastern massasaugas are phylogenetically distinct from all other eastern massasauga populations. They suggest this is the result of two factors: the isolation of the Iowa populations from those east of the Mississippi River approximately 34,000 years ago and hybridization between prairie massasaugas and Iowa’s eastern massasaugas approximately 11,000 years ago about the time when the last glaciers began to retreat. Currently, the ranges of the two

330  Eastern Massasauga, Sistrurus catenatus

species do not overlap in Iowa, likely the result of climatic changes since the retreat of the glaciers and the eventual arrival of European settlers who began altering the state’s landscape and eradicating rattlesnakes. Historically, eastern massasaugas probably existed throughout at least the eastern half of the state and likely much of northern Iowa wherever suitable habitats were present. Although museum specimens exist for only 9 counties in the eastern third of the state, with 3 additional counties mentioned in the literature (Ruthven 1912, Poweshiek; Gloyd 1940, Black Hawk; Platt 1973, Louisa), newspaper accounts and county histories suggest a historically wider distribution. The snakes appear to have been found in northern Iowa as far northwest as at least Kossuth County, where in 1911 the Evening Times Republican reported a fatal rattlesnake bite near Burt in Kossuth County, with the husband of the victim stating that “there are but very few of the little massasauger variety of rattlesnake” in the area. In Hancock County, a 1903 story in the Britt Tribune about the number of rattlesnakes found in Iowa that year stated, “There are few left now compared with the number 25 years ago. It was nothing for a herder to kill half a dozen a day then. They are not the genuine diamond rattlers, but the massasauger, a short dark skinned species of rattlesnake rather sluggish but fully as poisonous as the genuine rattler.” And in the History of Mitchell and Worth Counties, Iowa (Anonymous 1884) it was said, “The massasanga, which is often confused with the rattlesnake, were plenty. They were an ugly looking snake, from eighteen inches to two feet in length, clumsy and of a dirty brown color. They had three or four rattles which they used as a warning.” Although they may have been widespread in Iowa at one point, at present eastern massasaugas are found in at most only 5 of Iowa’s 99 counties. Eastern massasauga distribution in Iowa. Blue = pre-1960 Yellow = post-1960 Green = both pre- and post-196o

Sistrurus catenatus, Eastern Massasauga  331

Habitat. Eastern massasaugas are found in a variety of habitats including bogs,

fens, marshes, old fields, prairies, sedge meadows, lightly grazed pastures, and wet grasslands but tend to avoid heavily wooded areas. Over the course of more than twenty years of working with these snakes, I have found that in Iowa they are restricted to areas where open-canopy wet prairies or sedge meadows, with a stable water table within 1 to 2 feet (30.5–61 cm) of the surface during late summer, fall, and winter, are located adjacent to upland grasslands; abundant crayfish are a critical habitat component. The snakes go through a seasonal shift in habitat— using wetland areas in the spring, winter, and fall and drier upland areas during the summer. Because suitable habitats are generally limited in the few places in the state where they remain, they are often forced to use lower-quality and sometimes dangerous locations, such as levees, road ditches, and agricultural grassed waterways. Behavior. This shy docile snake rarely rattles or moves when approached; instead it relies on its near-perfect camouflage to remain unseen. When I first started studying these snakes I thought, “How hard can it be to find them? After all, they will rattle at me.” Boy, was I wrong. In over twenty years of working in the field with them, only a few rattled when I was still some distance away. They occasionally rattle when stepped on, although not always, and they often rattle when captured. But for the most part the eastern massasauga is a rattlesnake that does not use its rattle. When approached, the snakes mostly remain motionless hoping to go unnoticed. If threatened, they may take up a defensive posture, occasionally making short strikes and often twitching their heads quickly from side to side; if given the opportunity, they usually retreat into dense vegetation, sometimes rattling as they go. Information on activity comes primarily from my long-term study in Bremer County. The collection/observation dates of 320 Iowa eastern massasaugas (191 of my records; 129 museum specimens and other records) show the species is generally active from April through October. The snakes typically emerge from hibernation in early to mid-April; however, the earliest records are on March 22 after an exceptionally warm winter. Two individuals were found on that day and another 4 were found over the next three days. Spring emergence is tied to soil temperature—radio-tracking data show that in Iowa spring emergence occurs when the 6-inch (15.2-cm) soil depth temperature is above 40° F (4.4° C), and the air temperature must be above 50° F (10° C) for the snakes to be seen aboveground. After emergence, the snakes stay near their overwintering sites from a few days up to a few weeks depending on air temperature, during which time they

332  Eastern Massasauga, Sistrurus catenatus

Number of Records

100

91 73

75

67

50 26

25 0

0

0

Jan

Feb

6 Mar

32 17 6

Apr

May

Jun

Jul

Aug

Sep

Oct

0

2

Nov

Dec

Month Collection/observation dates of 320 eastern massasaugas in Iowa.

bask during the day and retreat underground at night. They are efficient thermoregulators during this early spring period, able to raise their body temperature significantly above the ambient temperature. When the days and nights have warmed enough, they begin moving away from their overwintering locations. During the summer, males and nongravid females move into upland grasslands to feed. On average, males move more frequently and make longer daily movements than either gravid or nongravid females. Males have the largest home ranges, up to 40 acres (16.2 ha) in Iowa, covering much of that area in late summer while looking for females. Among females, nongravid females have the largest home ranges, up to 20 acres (8.1 ha) in Iowa. Gravid females remain near their overwintering locations and move very little during the year in which they give birth. While they may use up to 5 acres (2 ha) throughout the year, 50 percent of their time is spent in an area less than 1 acre (0.4 ha) in size. In most years, eastern massasaugas begin moving back to their overwintering sites in mid-September and by October most have reached the locations where they will spend the winter. They spend their days aboveground basking and exploring crayfish burrows and retreat belowground at night as the weather cools. The latest Iowa records are individuals found in Bremer County on December 12 and 18. In Iowa, eastern massasaugas hibernate primarily in crayfish burrows, but small mammal burrows are sometimes used. Suitable sites may be located in open areas, under shrubs, or in willow thickets and are often near the wetland-upland boundary. In addition, sites are frequently in areas where the water table is near the surface. On numerous occasions I have observed the snakes entering crayfish

Sistrurus catenatus, Eastern Massasauga  333

Eastern massasauga from Bremer County entering a crayfish burrow.

burrows where the water table was at the surface, and once I found a female in a crayfish burrow filled with water with just her nose visible above the water. She quietly slipped underwater as I approached. Individuals show a high degree of hibernation site fidelity, often returning to within a few feet of where they hibernated the previous year. Venom and Bites. Eastern massasaugas are nice until it is time not to be nice; they should not be handled. Although they have small heads and relatively small venom glands and fangs—less than 0.25 inch (6.4 mm) long—their venom is five to ten times more toxic than that of a western diamondback rattlesnake, and a bite can be very painful and pose a serious threat (Ernst and Ernst 2011). Young are born with functional fangs and are able to inject venom from the start. Symptoms include burning, pain, skin sensitivity, discoloration and swelling spreading from the bite site, swollen and painful lymph glands, bleeding from the puncture wounds, fever, faintness, cold sweats, a metallic taste in the mouth, tremors (sometimes severe), and headaches. Larger snakes can deliver more venom than

334  Eastern Massasauga, Sistrurus catenatus

smaller snakes, or they may not inject venom at all. Although fatalities may be uncommon, human death from eastern massasauga bites has been reported (Jaffe 1957). Four confirmed eastern massasauga bites have been reported in Iowa (Dodge and Folk 1960; Christiansen and Fieselmann 1993). Although most were mild, one did produce a life-threatening condition but was not fatal. The newspaper account of the 1911 fatal bite in Kossuth County named the massasauga, and many other rattlesnake bites, including at least one death, were reported by Iowa newspapers in the 1800s and 1900s in locations where eastern massasaugas still occur today. Although the species of rattlesnake was not identified in these stories, based on the locations described it seems very likely they were eastern massasaugas. Threats. Natural predators include raccoons, weasels, foxes, hawks, and owls.

During five years of radio tracking in Bremer County, 45 percent of the snakes I tracked died, and 25 percent of these were lost to predation. In all but one instance, the predator was mammalian. Road mortality can also be a concern in places where roads pass through or adjacent to suitable habitats. Of the 78 eastern massasaugas I encountered during the first five years of my study, 10 percent were found dead on the road. Historically, human persecution was a major threat when Iowa was being settled; every rattlesnake that was found was killed. Bounties were paid for eastern massasaugas to facilitate their removal. Although bounties are no longer paid and the eastern massasauga is now protected, illegal collection still occurs in Iowa. Habitat loss—either through plowing prairies or draining wetlands or more slowly through succession of open-canopy wetlands to closed-canopy woodlands— along with fire, floods, and droughts are the greatest threats today. Climate change and snake fungal disease are both emerging dangers that seriously threaten the long-term survival of the eastern massasauga. Food and Feeding. This snake is an ambush predator whose diet varies across

its range but primarily consists of voles, mice, and shrews. When prey comes within range, the snake strikes, bites and injects venom, and most often releases it, allowing it to escape while the venom works. Young eastern massasaugas may lure prey in by waving their light yellow tails. Young-of-the-year feed primarily on other small snakes, such as juvenile gartersnakes, Dekay’s brownsnakes, and red-bellied snakes, but go through a dietary shift to small mammals as they grow. I have found young-of-the-year eastern massasaugas eating juvenile smooth greensnakes. In Wisconsin, 95 percent of all food items were warm-blooded with over 85 percent of the diet consisting of meadow voles (Keenlyne and Beer 1973). Other

Sistrurus catenatus, Eastern Massasauga  335

prey included deer mice, gartersnakes, jumping mice, red-winged blackbirds, and shrews. Prey may at times be quite large compared to the snake itself. I once captured a subadult female who regurgitated an intact and undigested meadow vole that was 55 percent of the snake’s weight. Females rarely eat while gestating but feed heavily after giving birth. I once found a female coiled in an empty mouse nest two days after she gave birth. Presumably, she had eaten the occupant of the nest. Reproduction. Iowa females mature in 3 to 4 years at around 17 to 18 inches

(43–46 cm) snout-vent length. The smallest female I have found exhibiting mating behavior was 17.4 inches (44.2 cm) snout-vent length. Examination of 10 Iowa adult female specimens in the Drake University Research Collection found the smallest mature female was 18.5 inches (47 cm) snout-vent length. Males likely mature slightly earlier and at a smaller size. Vitellogenesis in Iowa begins in late summer and fall and is completed the following spring, with follicles reaching an average of 0.9 inch (22 mm) by September and 1 inch (25 mm) by early spring. Ovulation occurs in late May or early June, as evidenced by my observations of enlarged follicles in May females and early oviductal embryos in May and June females.

Eastern massasauga male-male combat in Bremer County.

336  Eastern Massasauga, Sistrurus catenatus

Mating occurs primarily from late July through early September (rarely in spring) in Iowa with sperm stored until ovulation and fertilization the following spring. While mating is likely nearly always species-specific, Reeve Bailey (1942) found an eastern massasauga and timber rattlesnake hybrid in Lee County. Many females reproduce every other year, but I have found males together with females and newborns, indicating that males will at least court females that have recently given birth. Beginning in July, males start searching for females. At this time they become quite active, making longer and more frequent moves as they look for mates. Females may be accompanied by multiple males during a single mating season and males may engage in combat for access to females. In August 2003, I was lucky enough to observe male-male combat in Bremer County. The two males slowly raised the anterior half of their bodies into an S shape until they were nearly vertical, while keeping the posterior portions of their bodies parallel and intertwined. While in this elevated position, they pointed their snouts upward and began a lateral swaying movement; the anterior portions of their bodies occasionally made contact, and eventually one snake wrapped over the other in an attempt to gain a superior position. These pushing matches continue for approximately 2 to 3 minutes until one snake gains the superior position, at which time it rapidly pushes the other snake to the ground. The snakes reposition and the sequence begins again. A series of these small bouts may go on for over an hour until one snake retreats. No rattling or biting occurs during the encounter.

Young-of-the-year eastern massasauga from Bremer County after its first shed.

Sistrurus catenatus, Eastern Massasauga  337

Eastern massasaugas are ovoviviparous with females giving birth to 2 to 17 young in August or early September. Counts of enlarged ovarian follicles and embryos in females in the Drake University Research Collection resulted in average litter sizes of 10 (range 9–11; n = 3) and 7 (range 6–9; n = 3) young, respectively. I counted 4 litters born in the field to radio-tracked females that had 5, 6, 13, and 14 (average 9.5) young, respectively. Iowa newborns (n = 52) have total body lengths of 6.1 to 10.1 inches (15.6–25.6 cm) and snout-vent lengths of 5.5 to 9 inches (13.9– 22.8 cm) and weigh 0.2 to 0.7 ounce (6–20 g). Mothers stay with the newborns for just a day or two before leaving, and the newborns remain at the birth site 3 to 5 days before dispersing after they have shed for the first time. Longevity. A wild-caught male survived in captivity an additional 11 years, 8 months, and 14 days. Jim Christiansen had a female born in his lab at Drake University survive 10 years, 11 months, and 10 days in captivity before dying from a tumor. I recaptured a wild male 5 years after I first marked him as a juvenile, during which time he grew 10.4 inches (26.4 cm).

PRAIRIE M ASSASAUGA Sistrurus tergeminus tergeminus (Say) 1823 Venomous

Prairie massasauga from Mills County. Photo by Jeff LeClere.

Iowa Status. Endangered; species of greatest conservation need. Historical Summary. The prairie massasauga has also been called the prairie

rattlesnake, three-spotted shield rattler, pygmy rattlesnake, and triple-spotted rattlesnake. The History of Fremont County, Iowa (Anonymous 1881a) indicated the “prairie rattlesnake” was abundant; however, Osborn (1892) considered the massasauga to be rare in Iowa, and Guthrie (1929) noted it was “probably rare or even altogether absent in most parts of the state where it once abounded before the days of drained sloughs and burning stubble, and mowers and disk harrows.” The first confirmed specimens in the state appear to be two individuals found near Afton in Union County in 1940 (Iowa State Natural History Collection; University of Michigan Museum of Zoology). Two subspecies of the western massasauga, Sistrurus tergeminus, are currently recognized, only one of which, the prairie massasauga, S. t. tergeminus, has a range that includes Iowa.

340  Prairie Massasauga, Sistrurus t. tergeminus

Description. Prairie massasaugas are heavy-bodied light gray to dark brown

snakes with a series of indented dark brown to black blotches down the midline of the back and 3 rows of alternating small brown or black spots on the sides of the body (tergeminus is Latin meaning “triple” or “threefold”), the lowermost of which sometimes extend onto the belly. The tail has alternating light and dark bands and ends in a small indistinct black rattle. The belly is generally lightcolored with a moderate amount of dark pigment along the outer edges. The head is distinctly larger than the neck with a light-bordered dark stripe extending backward from the eyes, a pair of elongated dark blotches extending from the top onto the neck, and 9 large plates on top as with Iowa’s nonvenomous species. Prominent heat-sensing pits are present below and in front of the eyes, and the pupils are vertically elliptical. The body scales are strongly keeled and in 24 rows at midbody; the anal plate is single, as are the subcaudal scales. There are usually 11 to 12 supralabial scales and 11 to 13 infralabial scales. Newborns are patterned like adults but the pattern is more vivid, consisting of a light gray background with dark brown or black blotches and a light greenish or yellow tail. Ventral scales number 138 to 160 in both sexes, subcaudal scales range from 27 to 34 in males and 21 to 28 in females, and tail length as a proportion of total body length averages 11 percent in males and 9 percent in females (Ernst and Ernst Belly of a prairie massasauga from Mills County. Photo by Nick Blay.

Sistrurus t. tergeminus, Prairie Massasauga  341

2011). Only 3 prairie massasauga specimens are found in the Drake University Research Collection: a female 25 inches (63.5 cm) snout-vent length with 157 ventral scales, 27 subcaudal scales, and tail length 9 percent of total body length and 2 males 16.3 inches (41.4 cm) and 22.4 inches (57 cm) snout-vent length averaging 147 ventral scales, 28 subcaudal scales, and tail length 10 percent of total body length. Size. Prairie massasaugas generally range from 18.5 to 30 inches (47–76 cm) total

body length. The largest specimen in the Drake University collection is a female from Mills County measuring 27.4 inches (69.6 cm) total body length; the largest male is also from Mills County measuring 25 inches (63.5 cm) total body length. The record total body length reported for S. tergeminus is 34.75 inches (88.3 cm). Similar Species. The eastern massasauga has a black belly with some white or cream mottling along the edges, and its range does not overlap with that of the prairie massasauga. The western foxsnake may be mistaken for a rattlesnake due to its behavior of vibrating its tail when agitated, its pattern and coloration, and the fact that it has plates rather than granular scales between the eyes. However, it lacks a rattle and its tail narrowly tapers to a point; it lacks facial pits, has round pupils, and is longer and thinner. Both eastern milksnakes and juvenile northern watersnakes may be confused with prairie massasaugas, but both species lack facial pits, have round not elliptical pupils, and lack rattles. Distribution. Prairie massasaugas are found in scattered populations from extreme southwest Iowa and southeast Nebraska south through Kansas, western Oklahoma, and north-central Texas. Southwest Iowa is at the extreme northeast edge of the subspecies’ range; at present, the snake is known only from 1 of Iowa’s 99 counties. Historically, prairie massasaugas probably existed throughout much of southwest Iowa wherever suitable habitats were present. Museum specimens exist for only 4 counties (Fremont, Mills, Union, and Madison) with an additional county mentioned in the literature (Loomis 1948, Adams), although newspaper accounts and county histories suggest a historically wider distribution. One such example is the History of Montgomery County, Iowa (Anonymous 1881b), where a section titled “Native Reptiles, Fishes, Etc.” stated, “The most common snake is the ‘massasauger’ or prairie rattlesnake.” Based on genetic evidence, Sovic et al. (2016) concluded that approximately 11,000 years ago the ranges of the prairie and eastern massasaugas overlapped in Iowa, resulting in hybridization between the two species. At present their ranges do not overlap, probably due to climatic changes since the retreat of the glaciers as well as the arrival of European settlers who began altering Iowa’s landscape and eradicating rattlesnakes.

342  Prairie Massasauga, Sistrurus t. tergeminus Prairie massasauga distribution in Iowa. Blue = pre-1960 Green = both pre- and post-1960

Habitat. Across its range, the prairie massasauga is found in a variety of habitats including open sagebrush prairies, shortgrass and tallgrass prairies, and wet grasslands. Those populations near the northeast extent of its range, including Iowa’s only known existing population, use predominantly wet grasslands, although Reeve Bailey (1942) found a prairie massasauga in a rock outcrop in Madison County apparently hibernating with timber rattlesnakes, which suggests the snakes may have historically used a wider range of habitats in Iowa. Prairie massasaugas go through a seasonal shift in habitat. In southeast Nebraska, they use areas with saturated soils and a concentration of crayfish burrows in the spring, winter, and fall, such as lowlands and mid-slope grasslands, areas of reed canary grass and reed canary grass shrublands, shrubland-grassland edges, woodlandgrassland edges, and wetland ditches, and then shift to mainly drier open grasslands during the summer (Patten et al. 2016). In northwest Missouri, the snakes use wet prairies with crayfish burrows in the spring and move to outlying upland areas, such as old fields and deciduous woodlands, as the season progresses and then back to wet prairies in the fall (Seigel 1986). Behavior. These snakes have been described as relatively docile by some and can-

tankerous by others. Greene and Oliver (1965) stated, “In our experience, this is generally a snappy and nervous form. . . . When approaching closely, they usually coil, strike repeatedly at the collector, and rattle continuously. Two snakes collected during the day in Kansas were heard rattling before they were actually seen and vigorously resisted capture.” Like the eastern massasauga, the prairie massasauga exhibits a head-twitching behavior when excited that consists of several quick side-to-side flicks of its head. The collection/observation dates of 15 Iowa prairie massasaugas show the snake is generally active in Iowa from April through October, likely emerging from hibernation in early to mid-April. The earliest records are 2 individuals from Mills

Sistrurus t. tergeminus, Prairie Massasauga  343

Prairie massasauga from Mills County. Photo by Carter Oliver.

County found on April 20. Because no studies have been done on Iowa’s prairie massasaugas, I have based the following information on the work by Seigel (1986) in northwest Missouri and Patten and her colleagues (2016) in southeast Nebraska. The snakes become active in April and are most commonly encountered in April, May, and October. Similar to what I have seen with eastern massasaugas, Seigel (1986) acknowledged that the lower number of observations in midsummer might be due to thick vegetation that makes detection difficult. The longest movements occur during May when snakes are traveling from hibernation sites to summer habitats. Once they reach their summer areas, movements decrease until August, when they peak again as the snakes begin making their way back to their hibernation areas. They tend to be diurnal in the spring and fall and become more crepuscular or nocturnal during the heat of the summer. During the active season, their activity range may vary from 5.2 to 90.7 acres (2.1–36.7 ha); however, their core activity range—the area in which a snake spends 50 percent of its time—is from only 0.5 to 26.9 acres (0.2–10.9 ha). No significant difference is seen between male and female activity ranges, although the core activity range

344  Prairie Massasauga, Sistrurus t. tergeminus

Number of Records

5 4

4

3

3 2

2

2 1

1 0

2

0

0

0

Jan

Feb

Mar

Apr

May

Jun

1

Jul

Aug

Sep

Oct

0

0

Nov

Dec

Month

Collection/observation dates of 15 prairie massasaugas in Iowa.

of females is quite a bit less than that of males. Beginning in August, prairie massasaugas slowly begin moving toward their overwintering areas. Once they reach them, they spend their days aboveground basking and exploring crayfish burrows and their nights belowground as the weather cools. The latest Iowa record is October 21 in Union County. Prairie massasaugas hibernate singly or together primarily in crayfish or mammal burrows. However, Reeve Bailey’s (1942) find of a prairie massasauga on May 4 along with timber rattlesnakes on a wooded rocky bluff of the Middle River in Madison County suggests that the snakes had hibernated together in the rock outcrop. Two individuals were observed by Iowa Department of Natural Resources staff in the entrance to a muskrat burrow in Mills County on April 20; the snakes had likely hibernated in the burrow. Patten et al. (2016) reported several instances of multiple prairie massasaugas occupying the same crayfish burrow, sometimes along with other species such as the common gartersnake. Venom and Bites. Although they have small heads and relatively small venom glands and fangs—0.2 inch (5 mm) long—prairie massasauga venom is five to ten times more toxic than that of a western diamondback rattlesnake, and a bite can be very painful and pose serious threats (Ernst and Ernst 2011). Born with functional fangs, young snakes are able to inject venom right from the start. Symptoms include burning, pain, skin sensitivity, discoloration and swelling spreading from the bite site, swollen and painful lymph glands, bleeding from the puncture wounds, fever, faintness, cold sweats, a metallic taste in the mouth, tremors

Sistrurus t. tergeminus, Prairie Massasauga  345

Pair of prairie massasaugas from Mills County in a mammal burrow. Photo by Carter Oliver.

(sometimes severe), and headaches. Larger snakes can deliver more venom than smaller snakes, or they may not inject venom at all. Although fatalities may be uncommon, human death from prairie massasauga bites has been reported (Ernst and Ernst 2011). Although no confirmed prairie massasauga bites have been reported in Iowa, numerous newspaper accounts from the late 1800s through at least the 1960s exist of rattlesnake bites in counties where the snakes formerly occurred or currently occur. Although the species of rattlesnake was not identified in these stories, given the dates and locations, those in Mills and Union Counties were almost assuredly about the prairie massasauga. Many bites and some deaths were reported in other southwest Iowa counties as well that may also have been due to prairie massasaugas. Threats. Natural predators include raccoons, weasels, foxes, hawks, and owls.

Habitat loss, prescribed fire, floods, and drought all pose dangers along with climate change and snake fungal disease, both of which seriously threaten the long-term survival of the prairie massasauga. Human persecution was a major threat as Iowa was being settled. A story in the Malvern Leader in 1905 titled

346  Prairie Massasauga, Sistrurus t. tergeminus

“Rattlesnakes Galore” tells of a young man who found a rattlesnake in a pasture north of Hastings in Mills County while cutting thistles. He quickly killed the snake with his hoe and within an hour had killed another four. The story ends with, “They are talking now of inaugurating a big snake hunt.” In the early 1900s, counties began paying a bounty on rattlesnakes. Although bounties are no longer paid and the prairie massasauga is now protected, other threats to Iowa’s small remaining population continue. Food and Feeding. The prairie massasauga is an ambush predator whose diet consists primarily of voles, mice, and shrews, but birds, reptiles, and even carrion have been reported. When prey comes within range, the snake strikes, bites, injects venom, then most often allows it to escape while the venom works. Young prairie massasaugas may lure prey in by waving their tails. Young-of-the-year and juveniles feed on other small snakes and switch to larger mammalian prey as they grow. In Missouri, the diet was found to consist of 80 percent small mammals, including prairie voles and white-footed or deer mice, and 20 percent snakes, including Dekay’s brownsnakes and common gartersnakes (Seigel 1986), whereas in Nebraska the diet consisted of 70 percent mammals, 20 percent snakes, 5 percent lizards, and 5 percent birds (Patten et al. 2009). Reproduction. Both sexes mature in approximately 3 to 4 years at around 15.7 to

21.3 inches (40–54 cm) total body length. Mating takes place either in early spring upon emergence from hibernation or in midsummer (Fogell 2010). Patten et al. (2016) observed reproductive activity nearly immediately after emergence. Females may be accompanied by multiple males during a single mating season and males may engage in combat for access to females. Regardless of when mating occurs, sperm is stored until ovulation and fertilization occur the following spring. Some females may not reproduce every year due to reduced energy reserves. Prairie massasaugas are ovoviviparous with females giving birth to 3 to 13 young in August or early September. No Iowa-specific reproductive data are available. In Missouri, litter size ranged from 4 to 10 (average 6) young (Seigel 1986), and litter sizes of 6, 7, and 11 young were reported in Nebraska (Patten et al. 2009). Female size influences litter size, with larger females producing larger litters. Newborns average 8.5 inches (21.6 cm) total body length. Mothers stay with the newborns for a few days before leaving, and the newborns stay at their birth sites until they have shed for the first time before dispersing. Longevity. A male prairie massasauga survived in captivity 20 years and 5 days.

QUICK REFERENCE GUIDE TO SNAKES Note: This reference guide is based on Iowa specimen data.

Family

Scales

Anal Plate

Species Dekay’s brownsnake Diamond-backed watersnake Eastern hog-nosed snake Graham’s crayfish snake

Divided

Northern watersnake Plain-bellied watersnake Plains hog-nosed snake

Keeled

Red-bellied snake Western foxsnake Western ratsnake Bullsnake

Colubridae

Common gartersnake

Single

Lined snake Orange-striped ribbonsnake Plains gartersnake North American racer Prairie ring-necked snake

Divided

Smooth greensnake Western smooth earthsnake

Smooth

Western wormsnake Eastern milksnake

Single

Prairie kingsnake Speckled kingsnake Eastern copperhead Eastern massasauga

Viperidae

Keeled

Single

Prairie massasauga Prairie rattlesnake Timber rattlesnake

Dorsal Scale Rows

Subcaudal Scales (Mean) Male

Tail Length % of Total Body Length (Mean)

Female

Male

Female

Page

17

50–60 (54)

41–52 (47)

18–26 (24)

18–22 (20)

233

25–31

73–75 (74)

50–60 (55)

25–26 (25)

18–20 (20)

169

25

45–57 (51)

38–52 (42)

18–22 (20)

12–17 (14)

123

19

61–70 (65)

51–57 (55)

18–20 (19)

16–18 (17)

225

21–25

61–81 (74)

49–70 (63)

22–27 (25)

18–23 (21)

177

23–25

80

61–66 (64)

26

21–22 (21)

161

21–23

42–47 (45)

32–39 (36)

17–19 (18)

11–13 (12)

113

15

49–56 (52)

41–50 (46)

22–25 (24)

19–23 (21)

241

24

59–67 (63)

46–64 (55)

15–18 (16)

12–15 (14)

205

23–27

63–92 (80)

69–79 (73)

15–18 (17)

13–17 (16)

195

30–33

50–63 (57)

45–57 (50)

12–14 (13)

11–12 (12)

215

19

61–84 (75)

60–79 (70)

19–27 (24)

17–25 (22)

267

19

39–44 (42)

30–38 (34)

15–17 (17)

11–16 (14)

279

19

100–116 (107)

88–99 (95)

28–32 (30)

24–29 (28)

249

19–21

66–81 (74)

51–75 (64)

22–26 (24)

15–26 (21)

257

17

77–91 (86)

70–83 (76)

22–27 (25)

20–23 (22)

95

17

42–53 (49)

36–49 (43)

18–23 (20)

14–18 (16)

105

15

84–91 (88)

70–85 (76)

27–36 (33)

27–38 (29)

187

17

40–45 (42)

31–38 (34)

17–22 (20)

12–16 (15)

287

13

28–38 (34)

26–30 (28)

13–18 (16)

12–15 (13)

87

21

40–55 (49)

32–51 (44)

12–17 (14)

11–16 (13)

151

25

46–56 (52)

43–52 (47)

13–17 (15)

12–14 (13)

133

21

47

43

13

12

143

23

45–48 (47)

40–45 (43)

12–15 (13)

12–13 (13)

299

25

25–33 (29)

19–26 (24)

8–12 (11)

7–10 (8)

327

24

27–29 (28)

27

10–11 (10)

9

339

23–27

25–29 (27)

16–23 (20)

6–11 (8)

4–7 (6)

317

23–24

23–26 (25)

16–22 (20)

7–9 (8)

5–8 (6)

307

GLOSSARY

Albino:  Organism that lacks pigment in its skin and scales. Anal plate:  The last belly scale of a snake that covers the anal opening, usually larger than the other belly scales and marking the separation of the snake’s body from its tail. Anterior:  Referring to the forward or head end of an animal. Arthropods:  Invertebrate animals with jointed legs, segmented bodies, and exoskeletons such as insects, crustaceans, and spiders. Carnivorous:  Feeding on other animals, including their eggs. Cloaca, cloacal:  Referring to the common chamber into which the urinary, digestive, and reproductive tracts discharge their contents. Also called the vent or anus. Crepuscular:  Active at dusk and dawn. Diurnal:  Active by day. Dorsal:  Referring to the upper surface or back of an animal. Facial pit:  Heat-sensing organ between each eye and nostril of a pit viper that enables it to detect warm-blooded animals even in complete darkness. Femoral pores:  Large pores along the underside of the hind limbs of some lizards. Fossorial:  Burrowing, adapted to living undergound. Genus:  Principal taxonomic category that ranks above species and below family. Gravid:  Pregnant. Great Plains:  A large expanse of land, much of it grassland, east of the Rocky Mountains and west of the Missouri River that encompasses all or parts of Montana, North Dakota, South Dakota, Wyoming, Nebraska, Kansas, Colorado, Oklahoma, Texas, and New Mexico. Hemipenis:  Either of the paired copulatory organs of male snakes and lizards located at the base of the tail. Hemolytic:  Referring to the rupture or destruction of red blood cells. Herpetology, herpetologist, herpetological:  Referring to the study of amphibians and reptiles. Hibernaculum, hibernacula:  Winter quarters of a hibernating animal. Hybrid, hybridization:  The offspring of a mating between two different species. Infralabial scales:  Scales on the lower lip. Keeled scales:  Body scales with small raised ridges on the back and sides of snakes and lizards. Labial scales:  Scales bordering the mouth. Lateral:  Referring to the side of an organism. Melanistic:  Referring to an increased amount of black or nearly black pigmentation in the skin or scales. Morphology, morphological:  Referring to the study of the shapes and arrangement of plants and animals.

352  Glossary

Nasal scale:  Scale that encloses the nostril. Nocturnal:  Active at night. Oviparous:  Referring to an animal that lays eggs. Ovoviviparous:  Referring to animals that produce eggs that are retained in an amniotic sac in the oviduct of the female throughout the development of the young. The young are born completely developed. Phylogenetic:  Referring to the evolutionary development and diversification of a species or group of organisms or of a particular feature of an organism. Posterior:  Referring to the rear end of an animal. Postlabial scales:  Scales immediately behind the labial scales. Postnasal scale:  Scale behind the nostril. Prenasal scale:  Scale in front of the nostril. Rostral:  Referring to the snout or the scale covering the snout. Sexual dimorphism:  Distinct difference in size or appearance between the sexes. Smooth scales:  Body scales that lack small raised ridges on the back and sides of snakes and lizards. Snout-vent length:  Measurement taken from the tip of the snout to the most posterior opening of the cloaca. Species:  The basic unit of classification and a taxonomic rank of an organism, a group of organisms that can reproduce with one another in nature and produce fertile offspring. Subcaudal scales:  Series of scales along the ventral surface of the tail of snakes and lizards. Subspecies:  Taxonomic group that is a division of a species, designates a population of a particular region genetically distinguishable from other populations of the same species and capable of interbreeding with them where its range overlaps theirs. Substrate:  The surface on which an animal lives, such as soil and rock. Supralabial scales:  Scales on the upper lip. Tail length:  Measurement taken from the posterior edge of the anal plate to the tip of the tail, not including the rattle in rattlesnakes. Thermoregulation, thermoregulator:  Referring to the maintenance or regulation of body temperature. Total body length:  Measurement taken from the tip of the snout to the tip of the tail, not including the rattle in rattlesnakes. Type specimen:  The specimen designated as the name-bearing “type” by the original author of the species to which the scientific name of that organism is formally attached. Vent:  The external orifice of the cloaca. Ventral:  Referring to the underside or belly of an animal. Vitellogenesis, vitellogenic:  Referring to the process of yolk formation via nutrients deposited in the immature egg. Viviparous:  Referring to an animal that gives birth to live young that have developed inside the body of the parent.

REFERENCES

Adams, A., J. Garrison, S. McDaniel, E. Bueche, and H. Howell. 2020. Don’t tread on me: An examination of the anti-predatory behavior of eastern copperheads (Agkistrodon contortrix). Acta Herpetologica 15:31–37. Aldridge, R. D., and D. E. Metter. 1973. The reproductive cycle of the western worm snake, Carphophis vermis, in Missouri. Copeia 1973:472–477. Anderson, P. 1965. The Reptiles of Missouri. University of Missouri Press, Columbia. Anonymous. 1878. History of Jasper County, Iowa. Western Historical Company, Chicago. Anonymous. 1881a. History of Fremont County, Iowa. Iowa Historical Company, Des Moines. Anonymous. 1881b. History of Montgomery County, Iowa. Iowa Historical Company, Des Moines. Anonymous. 1884. History of Mitchell and Worth Counties, Iowa. Union Publishing Company, Springfield. Arndt, R. G. 1980. A hibernating eastern hognose snake, Heterodon platyrhinos. Herpetological Review 11:30–32. Arnold, B. 1963. Albino timber rattlesnake, Crotalus horridus. Turtox News 41:208. Attum, O., Y. M. Lee, J. H. Roe, and B. A. Kingsbury. 2007. Upland-wetland linkages: Relationship of upland and wetland characteristics with watersnake abundance. Journal of Zoology 271:134–139. Bailey, R. M. 1939. Carphophis amoena vermis and Lampropeltis calligaster in Iowa. Copeia 1939:218–220. Bailey, R. M. 1940. The northern copperhead in Iowa. Iowa State College Journal of Science 15:1–2. Bailey, R. M. 1942. An intergeneric hybrid rattlesnake. American Naturalist 76:376–385. Bailey, R. M. 1943. Four species new to the Iowa herpetofauna, with notes on their natural histories. Proceedings of the Iowa Academy of Science 50:347–352. Bailey, R. M. 1948. Winter mortality in the snake Storeria dekayi. Copeia 1948:215. Bailey, R. M. 1949. Temperature toleration of gartersnakes in hibernation. Ecology 30:238–242. Baker, R. G., C. A. Chumbley, P. M. Witinok, and H. K. Kim. 1990. Holocene vegetational changes in eastern Iowa. Journal of the Iowa Academy of Science 97:167–177. Baldwin, F. M. 1928. Oxygen consumption at 20° in certain snakes Pituophis sayi and Lampropeltis getulus holbrooki with some notes on size and seasonal difference. Proceedings of the Iowa Academy of Science 35:313–318. Ballinger, R. E., J. D. Lynch, and G. R. Smith. 2010. Amphibians and Reptiles of Nebraska. Rusty Lizard Press, Oro Valley, and University of Nebraska Press, Lincoln. Ballinger, R. E., J. W. Nietfeldt, and J. J. Krupa. 1979. An experimental analysis of the

354  References

role of the tail in attaining high running speed in Cnemidophorus sexlineatus (Reptilia: Squamata: Lacertilia). Herpetologica 35:114–116. Beebe, W. 1906. The Bird: Its Form and Function. Henry Holt, New York. Beltz, E. 2007. Scientific and common names of the reptiles and amphibians of North America explained. Ebeltz.net/herps/etymain.html. Berberich, J. J., C. H. Dodge, and G. E. Folk, Jr. 1971. Overlapping of ranges of eastern and western hognose snakes in southeastern Iowa. Proceedings of the Iowa Academy of Science 78:25–26. Bernstein, N. P. 1998. Iowa’s declining flora and fauna: A review of changes since 1980 and an outlook for the future. Journal of the Iowa Academy of Science 105:133–140. Best, L. B. 1974. Blue racers prey on field sparrow nest. Auk 91:168–169. Best, L. B. 1977. Bull snake preys on rough-winged swallow nest. Condor 79:509–510. Betz, T. W. 1963. The gross ovarian morphology of the diamond-backed water snake, Natrix rhombifera, during the reproductive cycle. Copeia 1963:692–697. Bishop, R. A. 1981. Iowa’s wetlands. Proceedings of the Iowa Academy of Science 88:11–16. Bishop, R. A., J. Joens, and J. Zohrer. 1998. Iowa’s wetlands, present and future with a focus on prairie potholes. Journal of the Iowa Academy of Science 105:89–93. Black, J. H. 1985. The lined snake as food for the great horned owl. Bulletin of the Oklahoma Ornithological Society 18:14–15. Blanchard, F. N. 1921. A revision of the king snakes: Genus Lampropeltis. Nos. 114–117. U.S. Government Printing Office. Blanchard, F. N. 1923. The amphibians and reptiles of Dickinson County, Iowa. University of Iowa Studies in Natural History 10:19–26. Blanchard, F. N. 1924. The forms of Carphophis. Papers of the Michigan Academy of Science, Arts, and Letters 4:527–530. Blanchard, F. N. 1925. A key to the snakes of the United States, Canada, and lower California. Papers of the Michigan Academy of Science, Arts, and Letters 4:1–65. Blanchard, F. N. 1937. Data on the natural history of the red-bellied snake, Storeria occipitomaculata (Storer), in northern Michigan. Copeia 1937:151–162. Blanchard, F. N. 1942. The ringneck snakes, genus Diadophis. Bulletin of the Chicago Academy of Science 7:1–144. Blaney, R. M. 1977. Systematics of the common kingsnake, Lampropeltis getulus (Linnaeus). Tulane Studies in Zoology and Botany 19:47–104. Blem, C. R., and L. B. Blem. 1985. Notes on Virginia (Reptilia: Colubridae) in Virginia. Brimleyana 11:87–95. Bragg, A. N. 1960. Is Heterodon venomous? Herpetologica 16:121–123. Brazeau, D. J., and S. J. Hecnar. 2018. Summer movements of the common five-lined skink (Plestiodon fasciatus) in the northern portion of its range. Herpetological Conservation and Biology 13:743–752. Breckenridge, W. J. 1943. The life history of the black-banded skink Eumeces septentri­ onalis septentrionalis (Baird). American Midland Naturalist 29:591–606.

References  355

Breckenridge, W. J. 1944. Reptiles and Amphibians of Minnesota. University of Minnesota Press, Minneapolis. Breckenridge, W. J. 1958. Reptiles and Amphibians of Minnesota. 2d ed. University of Minnesota Press, Minneapolis. Brischoux, F., L. Pizzatto, and R. Shine. 2010. Insights into the adaptive significance of vertical pupil shape in snakes. Journal of Evolutionary Biology 23:1878–1885. Brodie, E. D., III, and P. K. Ducey. 1989. Allocation of reproductive investment in the redbelly snake Storeria occipitomaculata. American Midland Naturalist 122:51–58. Brown, E. E. 1979. Stray food records from New York and Michigan snakes. American Midland Naturalist 102:200–203. Buchanan, S. W., B. C. Timm, R. P. Cook, and R. Couse. 2012. Heterodon platirhinos (eastern hog-nosed snake): Hibernacula site fidelity. Herpetological Review 43:493–494. Buchanan, S. W., B. C. Timm, R. P. Cook, R. Couse, and L. C. Hazard. 2017. Spatial ecology and habitat selection of eastern hognose snakes. Journal of Wildlife Management 81:509–520. Burghardt, G. M. 1968. Chemical preference studies on newborn snakes of three sympatric species of Natrix. Copeia 1968:732–737. Burt, C. E. 1928. Insect food of Kansas lizards with notes on their feeding habits. Journal of the Entomological Society 1:50–68. Burt, C. E. 1931. A study of the teiid lizards of the genus Cnemidophorus with special reference to their phylogenetic relationships. No. 154. U.S. Government Printing Office. Burt, C. E. 1935. Further records of the ecology and distribution of amphibians and reptiles of the Middle West. American Midland Naturalist 16:311–336. Burt, C. E., and M. D. Burt. 1929. Field notes and locality records on a collection of amphibians and reptiles chiefly from the western half of the United States II: Reptiles. Journal of the Washington Academy of Science 19:448–460. Burt, C. E., and W. L. Hoyle. 1934. Additional records of the reptiles of the central prairie region of the United States. Transactions of the Kansas Academy of Science 37:193–216. Busby, W. H., and G. R. Pisani. 2014. Ecological studies of the smooth earth snake (Virginia valeriae) and redbelly snake (Storeria occipitomaculata) in eastern Kansas. Open-file Report No. 179. Kansas Biological Survey, Lawrence. Byrd, W., E. Hanebrink, and W. Meshaka. 1988. Food, feeding behavior, sex ratios, and measurements of three species of water snakes (Nerodia spp.) collected from northeastern Arkansas. Bulletin of the Chicago Herpetological Society 23:55–57. Cagle, F. R. 1942. Herpetological fauna of Jackson and Union Counties, Illinois. American Midland Naturalist 28:164–200. Call, R. E. 1891. On a new serpent from Iowa. American Journal of Science 41:297– 299.

356  References

Campbell, K. R., and T. S. Campbell. 2001. The accumulation and effects of environmental contaminants on snakes: A review. Environmental Monitoring and Assessment 70:253–301. Carlander, K. D., and R. B. Moorman. 1950a. Those elusive colonies of lizards. Iowa Conservationist 9:57, 62. Carlander, K. D., and R. B. Moorman. 1950b. Ugly acting snakes. Iowa Conservationist 9:81, 86. Carlander, K. D., and R. B. Moorman. 1950c. Iowa’s big snakes. Iowa Conservationist 9:89, 94. Carlander, K. D., and R. B. Moorman. 1951. How big are Iowa’s snakes? Iowa Conservationist 10:105, 111. Carpenter, C. C. 1982. The bullsnake as an excavator. Journal of Herpetology 16:394–401. Carpenter, C. C. 1985. Lampropeltis calligaster calligaster (prairie kingsnake): Reproduction. Herpetological Review 16:81. Carpenter, C. C., and J. C. Gillingham. 1977. A combat ritual between two male speckled kingsnakes (Lampropeltis getulus holbrooki: Colubridae, Serpentes) with indications of dominance. Southwestern Naturalist 22:517–524. Cavanaugh, C. J. 1994. Crotalus horridus (timber rattlesnake): Longevity. Herpetological Review 25:70. Christiansen, J. L. 1961. A survey of reptiles and amphibians of Buena Vista County, Iowa. Proceedings of the Iowa Academy of Science 68:625–634. Christiansen, J. L. 1973. The distribution and variation of the western earth snake, Virginia valeriae elegans (Kennicott) in Iowa. Proceedings of the Iowa Academy of Science 80:167–170. Christiansen, J. L. 1981. Population trends among Iowa’s amphibians and reptiles. Proceedings of the Iowa Academy of Science 88:24–27. Christiansen, J. L. 1983. Temporal separation of sympatric hognose snake species (Heterodon) in Iowa. Abstracts of papers, 95th Session, Iowa Academy of Science, Luther College, Decorah, Iowa, April 22–23, 1983. Proceedings of the Iowa Academy of Science 90:20. Christiansen, J. L. 1998. Perspectives on Iowa’s declining amphibians and reptiles. Journal of the Iowa Academy of Science 105:109–114. Christiansen, J. L., and R. M. Bailey. 1986. The snakes of Iowa. Special Publication of the Iowa Conservation Commission, Des Moines. Christiansen, J. L., and R. M. Bailey. 1988. The lizards and turtles of Iowa. Iowa Department of Natural Resources Nongame Technical Series 3:1–19. Christiansen, J. L., and R. M. Bailey. 1990. The snakes of Iowa (revised). Iowa Department of Natural Resources Nongame Technical Series 1:1–16. Christiansen, J. L., and R. M. Bailey. 1997. The lizards and turtles of Iowa (revised). Iowa Department of Natural Resources Nongame Technical Series 3:1–20. Christiansen, J. L., and R. R. Burken. 1978. The endangered and uncommon amphibians and reptiles of Iowa. Iowa Science Teachers Journal 15:1–86.

References  357

Christiansen, J. L., and J. Fieselmann. 1993. Massasauga rattlesnake bites in Iowa. Iowa Medicine: Journal of the Iowa Medical Society 83:187–191. Christiansen, J. L., J. M. Gryzbowski, and E. R. Jacobson. 2008. Sistrurus catenatus catenatus (eastern massasauga): Leiomyoma. Herpetological Review 39:358–359. Christiansen, J. L., and J. B. LeClere. 2002. Nerodia erythrogaster neglecta in Iowa with comments on ontogenesis of color and pattern. Herpetological Review 33:152–154. Christiansen, J. L., and C. M. Mabry. 1985. The amphibians and reptiles of Iowa’s Loess Hills. Proceedings of the Iowa Academy of Science 92:159–163. Christiansen, J. L., and J. R. Parmelee. 2003. A key to the eggs and nests of Iowa turtles. Journal of the Iowa Academy of Science 110:44–50. Christiansen, J. L., and T. VanDeWalle. 2000. Effectiveness of three trap types in drift fence surveys. Herpetological Review 31:158–160. Clark, D. R., Jr. 1967. Experiments into selection of soil type, soil moisture level and temperature by five species of small snakes. Transactions of the Kansas Academy of Science 70:490–496. Clark, D. R., Jr. 1970. Ecological study of the worm snake Carphophis vermis (Ken­ nicott). University of Kansas Public Museum of Natural History 19:85–194. Clark, D. R., Jr. 1974. The western ribbon snake (Thamnophis proximus): Ecology of a Texas population. Herpetologica 30:372–379. Clark, R. W. 2004a. Kin recognition in rattlesnakes. Proceedings of the Royal Society of London Series B Biology Letters 271: S243–S245. Clark, R. W. 2004b. Feeding experience modifies the assessment of ambush sites by the timber rattlesnake, a sit-and-wait predator. Ethology 110:471–483. Clark, R. W. 2004c. Timber rattlesnakes (Crotalus horridus) use chemical cues to select ambush sites. Journal of Chemical Ecology 30:607–617. Clarke, R. F. 1958. An ecological study of reptiles and amphibians in Osage County, Kansas. Emporia State Reservation Study 7:1–52. Cochran, P. A. 1994. A longevity record for the eastern hognose snake (Heterodon platirhinos). Bulletin of the Chicago Herpetological Society 29:117–118. Collins, J. T. 1993. Amphibians and Reptiles in Kansas. 3d ed. Museum of Natural History, University of Kansas, Lawrence. Conant, R. 1940. A new subspecies of the fox snake, Elaphe vulpina Baird and Girard. Herpetologica 2:1–14. Conant, R. 1951. The Reptiles of Ohio. 2d ed. Notre Dame University Press, Notre Dame. Conant, R. 1958. A Field Guide to Reptiles and Amphibians. Houghton Mifflin, Boston. Cope, E. D. 1900. The crocodilians, lizards, and snakes of North America. Annual Report, U.S. National Museum 1898, 153–1294. Cox, C. L., E. S. Farrar, and J. D. Hey. 2005a. Opheodrys vernalis (smooth greensnake) USA: Iowa. Herpetological Review 36:339. Cox, C. L., E. S. Farrar, and J. D. Hey. 2005b. Regina grahami (Graham’s crayfish snake) USA: Iowa. Herpetological Review 36:340.

358  References

Cox, C. L., E. S. Farrar, J. D. Hey, and M. C. Morrill. 2009. Cover object usage among an assemblage of Iowa snakes. Herpetological Conservation and Biology 4:80–84. Cox, C. L., and M. C. Morrill. 2019. Herpetofaunal assemblage and natural history of a wetland and prairie complex of the northern Great Plains. Southwestern Naturalist 64:89–97. Criddle, S. 1937. Snakes from an ant hill. Copeia 1937:142. Crother, B. I., J. Boundy, F. T. Burbrink, and S. Ruane. 2017. Squamata (in part): Snakes. In B. I. Crother, ed., Scientific and Standard English Names of Amphibians and Reptiles of North America North of Mexico, with Comments Regarding Confidence in Our Understanding. Society for the Study of Amphibians and Reptiles Herpetological Circular 43:59–80. Crother, B. I., M. E. White, J. M. Savage, M. E. Eckstut, M. R. Graham, and D. W. Gardner. 2011. A reevaluation of the status of the fox snakes Pantherophis gloydi Conant and P. vulpinus Baird and Girard (Lepidosauria). International Scholarly Research Network Zoology (436049) 2011:1–15. Cunningham, G. R. 2006. Post-fire reptile survey of the Baylor Tract in Fremont County, Iowa. Unpublished report to the Iowa Chapter of the Nature Conservancy. Cunnington, G. M., and J. E. Cebek. 2005. Mating and nesting behavior of the eastern hognose snake (Heterodon platirhinos) in the northern portion of its range. American Midland Naturalist 154:474–478. Curry, B. B., and R. G. Baker. 2000. Paleohydrology, vegetation, and climate since the late Illinois Episode (~130 ka) in south-central Illinois. Palaeogeography, Palaeoclimatology, Palaeoecology 155:59–81. Czaplicki, J. A., and R. H. Porter. 1974. Visual cues mediating the selection of goldfish (Carassius auratus) by two species of Natrix. Journal of Herpetology 8:129–134. Davis, D. D. 1946. Observations on the burrowing behavior of the hog-nosed snake. Copeia 1946:75–78. Diener, R. A. 1957. An ecological study of the plain-bellied water snake. Herpetologica 13:203–211. Dinsmore, J. J. 1984. A country so full of game: The story of wildlife in Iowa. University of Iowa Press, Iowa City. Dodge, C. H. 1963. The western hog-nosed snake (Heterodon nasicus nasicus Baird and Girard) in southeastern Iowa. Proceedings of the Iowa Academy of Science 70:516–517. Dodge, C. H., and G. E. Folk, Jr. 1960. A case of rattlesnake poisoning in Iowa with a description of early symptoms. Proceedings of the Iowa Academy of Science 67:622–624. Dolan, C., V. Polton, J. Lamer, J. Tucker, and J. Parmelee. 2011. Lampropeltis triangu­ lum (eastern milk snake). Herpetological Review 42:394. Drda, W. J. 1968. A study of snakes wintering in a small cave. Journal of Herpetology 1:64–70. Dunbar, G. L. 1979. Effects of early feeding experience on chemical preference of the

References  359

northern water snake, Natrix s. sipedon (Reptilia, Serpentes, Colubridae). Journal of Herpetology 13:165–169. Dundee, H. A. 1996. Some reallocations of type localities of reptiles and amphibians described from the Major Stephen H. Long Expedition to the Rocky Mountains, with comments on some of the statements made in the account written by Edwin James. Tulane Studies in Zoology and Botany 30:75–89. Durso, A. M., and S. J. Mullin. 2017. Ontogenetic shifts in the diet of plains hog-nosed snakes (Heterodon nasicus) revealed by stable isotope analysis. Zoology 120: 83–91. Durso, A. M., D. A. Warner, T. S. Mitchell, and A. M. Reedy. 2011. Heterodon nasicus (western hog-nosed snake): Diet. Herpetological Review 42:439–440. Dyrkacz, S. 1977. The natural history of the eastern milk snake (Reptilia, Serpentes, Colubridae) in a disturbed environment. Journal of Herpetology 11:155–159. Edgren, R. A. 1955. The natural history of the hog-nosed snakes, genus Heterodon: A review. Herpetologica 11:105–117. Ernst, C. H., and E. M. Ernst. 2003. Snakes of the United States and Canada. Smithsonian Institution, Washington, D.C. Ernst, C. H., and E. M. Ernst. 2011. Venomous Reptiles of the United States, Canada, and Northern Mexico. Vol. 1: Heloderma, Micruroides, Micrurus, Pelamis, Agkistro­ don, Sistrurus. Johns Hopkins University Press, Baltimore. Ernst, C. H., and E. M. Ernst. 2012. Venomous Reptiles of the United States, Canada, and Northern Mexico. Vol. 2: Crotalus. Johns Hopkins University Press, Baltimore. Ernst, S. G. 1962. Notes on the life history of the eastern ringneck snake. Turtox News 40:266–267. Ernst, S. G. 1963. Pieces of the puzzle. National Parks Magazine 37:20–21. Evans, L. T. 1959. A motion picture study of maternal behavior of the lizard, Eumeces obsoletus Baird and Girard. Copeia 1959:103–110. Evans, P. D., and H. K. Gloyd. 1948. The subspecies of the massasauga, Sistrurus cate­ natus, in Missouri. Bulletin of the Chicago Academy of Science 8:225–232. Fitch, H. S. 1954. Life history and ecology of the five-lined skink, Eumeces fasciatus. University of Kansas Publications of the Museum of Natural History 8:1–156. Fitch, H. S. 1955. Habits and adaptations of the Great Plains skink (Eumeces obsoletus). Ecological Monographs 25:59–83. Fitch, H. S. 1956a. A ten-year-old skink? Herpetologica 12:328. Fitch, H. S. 1956b. Temperature responses in free-living amphibians and reptiles in northeastern Kansas. University of Kansas Publications of the Museum of Natural History 8:417–476. Fitch, H. S. 1958. Natural history of the six-lined racerunner (Cnemidophorus sexlinea­ tus). University of Kansas Publications of the Museum of Natural History 11:11–62. Fitch, H. S. 1960. Autecology of the copperhead. University of Kansas Publications of the Museum of Natural History 13:85–288. Fitch, H. S. 1963a. Natural history of the racer, Coluber constrictor. University of Kansas Publications of the Museum of Natural History 15:351–468.

360  References

Fitch, H. S. 1963b. Natural history of the black rat snake (Elaphe o. obsoleta) in Kansas. Copeia 1963:649–658. Fitch, H. S. 1967. Ecological studies of lizards on the University of Kansas Natural History Reservation. In Lizard Ecology: A Symposium, 13–15 June 1965, ed. W. W. Milstead, 30–44. University of Missouri at Kansas City, Kansas City. Fitch, H. S. 1970. Reproductive cycles in lizards and snakes. University of Kansas Museum of Natural History Miscellaneous Publication 52:1–247. Fitch, H. S. 1975. A demographic study of the ringneck snake (Diadophis punctatus) in Kansas. University of Kansas Museum of Natural History Miscellaneous Publication 62:1–53. Fitch, H. S. 1978. A field study of the prairie kingsnake (Lampropeltis calligaster). Transactions of the Kansas Academy of Science 81:353–363. Fitch, H. S. 1982. Resources of a snake community in prairie-woodland habitat of northeastern Kansas. In Herpetological Communities, ed. N. J. Scott, Jr., 93–97. U.S. Fish and Wildlife Service, Washington, D.C. Fitch, H. S. 1985. Variation in clutch and litter size in New World reptiles. University of Kansas Publications of the Museum of Natural History 76:1–76. Fitch, H. S. 1989. A field study of the slender glass lizard, Ophisaurus attenuatus, in northeastern Kansas. University of Kansas Museum of Natural History Occasional Papers 125:1–50. Fitch, H. S. 1999. A Kansas Snake Community: Composition and Changes over 50 Years. Krieger Publishing Company, Malabar. Fitch, H. S. 2006. Ecological succession on a natural area in northeastern Kansas from 1948 to 2006. Herpetological Conservation and Biology 1:1–5. Fitch, H. S., and R. R. Fleet. 1970. Natural history of the milk snake (Lampropeltis tri­ angulum) in northeastern Kansas. Herpetologica 26:387–396. Fogell, D. D. 2010. A Field Guide to the Amphibians and Reptiles of Nebraska. University of Nebraska Press, Lincoln. Fogell, D. D., T. J. Leonard, and J. D. Fawcett. 2002. Crotalus horridus horridus (timber rattlesnake): Climbing. Herpetological Review 33:212. Force, E. R. 1931. Habits and birth of young of the lined snake, Tropidoclonion lineatum (Hallowell). Copeia 1931:51–53. Ford, N. B., and P. M. Hampton. 2009. Ontogenetic and sexual differences in diet in an actively foraging snake, Thamnophis proximus. Canadian Journal of Zoology 87:254–261. Forstner, M. R. J., and J. R. Dixon. 2010. Heterodon platirhinos (eastern hog-nosed snake): Oviposition. Herpetological Review 41:364–365. Fox, J. J. 1986. Ecology and management of the bullsnake, Pituophis melanoleucus sayi, in the Nebraska Sandhills: Final report. Crescent Lake National Wildlife Refuge, Nebraska. Fox, W. 1956. Seminal receptacles of snakes. Anatomical Record 124:519–539.

References  361

Fremling, C. R. 1960. Ecological history of the upper Mississippi River. Cal Fremling Papers 37. https://openriver.winona.edu/calfremlingpapers/37. Frese, P. W. 2000. The natural history of the northern prairie skink in a heavily disturbed landscape. Missouri Herpetological Association Newsletter 13:5. Frese, P. W. 2003. Eumeces septentrionalis (northern prairie skink): Nesting behavior. Herpetological Review 34:143. Garman, H. 1892. A synopsis of the reptiles and amphibians of Illinois. Bulletin of the Illinois State Laboratory of Natural History 3:215–385. Gehlbach, F. R. 1970. Death-feigning and erratic behavior in leptotyphlopid, colubrid, and elapid snakes. Herpetologica 26:24–34. Gibbons, J. W., and M. E. Dorcas. 2004. North American Watersnakes: A Natural History. University of Oklahoma Press, Norman. Gibbons, J. W., D. E. Scott, T. J. Ryan, K. A. Buhlmann, T. D. Tuberville, B. S. Metts, J. L. Greene, T. Mills, Y. Leiden, S. Poppy, and C. T. Winne. 2000. The global decline of reptiles, déjà vu amphibians: Reptile species are declining on a global scale. Six significant threats to reptile populations are habitat loss and degradation, introduced invasive species, environmental pollution, disease, unsustainable use, and global climate change. BioScience 50:653–666. Giles, L. W. 1940. Food habits of the raccoon in eastern Iowa. Journal of Wildlife Management 4:375–382. Gillingham, J. C. 1974. Reproductive behavior of the western foxsnake, Elaphe v. vul­ pina (Baird and Girard). Herpetologica 30:309–313. Gloyd, H. K. 1940. The rattlesnakes, genera Sistrurus and Crotalus. Chicago Academy of Sciences Special Publication 4. Gloyd, H. K., and R. Conant. 1990. Snakes of the Agkistrodon complex. Society for the Study of Amphibians and Reptiles Contributions to Herpetology 6:1–614. Godley, J. S., R. W. McDiarmid, and N. H. Rojas. 1984. Estimating prey size and number in crayfish-eating snakes, genus Regina. Herpetologica 40:82–88. Goodman, J. D. 1948. A report on the reptiles collected by J. M. Shaffer from the Keokuk area, 1863–1895. Proceedings of the Iowa Academy of Science 55:365–366. Goodyear, S. E., and J. A. Feinberg. 2006. Heterodon platyrhinos (eastern hognose snake): Envenomation and prey survival. Herpetological Review 37:352–353. Gratz, R. K. 1978. Ventilation and gas exchange in the diamondback water snake, Natrix rhombifera. Journal of Comparative Physiology 127:299–305. Gray, B. 2002. Thamnophis sirtalis sirtalis (eastern garter snake): Diet. Herpetological Review 33:142–143. Gray, B. S. 2014. The relative importance of slugs and earthworms in the diet of Dekay’s brownsnake, Storeria dekayi, from northwestern Pennsylvania. Bulletin of the Chicago Herpetological Society 48:157–165. Greene, H. W., and G. V. Oliver. 1965. Notes on the natural history of the western massasauga. Herpetologica 21:225–228.

362  References

Gregory, P. T. 2009. Northern lights and seasonal sex: The reproductive ecology of cool-climate snakes. Herpetologica 65:1–13. Grisnik, M., J. E. Leys, D. Bryan, R. H. Hardman, D. L. Miller, V. A. Cobb, C. Ogle, C. Simpson, J. R. Campbell, and R. D. Applegate. 2018. Host and geographic range of snake fungal disease in Tennessee, USA. Herpetological Review 49:682–690. Grobman, A. B. 1941. A contribution to the knowledge of variation in Opheodrys verna­ lis (Harlan), with the description of a new subspecies. Miscellaneous Publications of the Museum of Zoology, University of Michigan 50:1–38. Grogan, W. L., Jr. 1974. Effects of accidental envenomation from the saliva of the eastern hognose snake, Heterodon platyrhinos. Herpetologica 30:248–249. Guthrie, J. E. 1926. The snakes of Iowa. Iowa State College of Agriculture and Mechanical Arts Bulletin 239:147–192. Guthrie, J. E. 1929. Snake notes. Proceedings of the Iowa Academy of Science 36:349–359. Guthrie, J. E. 1930a. A color-mutation in Graham’s watersnake. Journal of Heredity 21:237–240. Guthrie, J. E. 1930b. Color dimorphism in Graham’s watersnake, Natrix grahamii (Baird and Girard). Copeia 1930:39. Guthrie, J. E. 1930c. Freak color inheritance in Graham’s watersnake. Proceedings of the Iowa Academy of Science 37:375–377. Guthrie, J. E. 1932. Snakes versus birds; birds versus snakes. Wilson Bulletin 44:88–101. Hall, R. J. 1969. Ecological observations on Graham’s watersnake (Regina grahami Baird and Girard). American Midland Naturalist 81:156–163. Hall, R. J. 1971. Ecology of a population of the Great Plains skink (Eumeces obsoletus). University of Kansas Science Bulletin 49:357–387. Hall, R. J. 1972. Food habits of the Great Plains skink (Eumeces obsoletus). American Midland Naturalist 87:258–263. Hampton, P. M. 2008. Prey items of the western ribbon snake, Thamnophis proximus. Southwestern Naturalist 53:115–118. Harding, J. H., and K. Rockafield. 2012. Nerodia sipedon (northern watersnake): Captive longevity. Herpetological Review 43:265. Harrison, M. B. 1933. The significance of knobbed anal keels in the garter snake, Thamnophis sirtalis sirtalis (Linnaeus). Copeia 1933:1–3. Hay, O. P. 1892. The Batrachians and Reptiles of the State of Indiana. Wm. B. Burford, Indianapolis. Hayes, W. K., and F. E. Hayes. 1985. Human envenomation from the bite of the eastern garter snake, Thamnophis s. sirtalis (Serpentes: Colubridae). Toxicon 23:719–721. Hebrard, J. J., and H. R. Mushinsky. 1978. Habitat use by five sympatric water snakes in a Louisiana swamp. Herpetologica 34:306–311. Hecnar, S. J., R. Freitag, and D. R. Hecnar. 2002. Eumeces fasciatus (five-lined skink): Diet. Herpetological Review 33:307–308.

References  363

Hecnar, S. J., and D. R. Hecnar. 2019. Clutch size in Plestiodon fasciatus near its northern range boundary and variation across the species range. Herpetological Review 50:712–717. Hecnar, S. J., and R. T. M’Closkey. 1998. Effects of human disturbance on the fivelined skink, Eumeces fasciatus, abundance and distribution. Biological Conservation 85:213–222. Henderson, R. W., M. H. Binder, R. A. Sajdak, and J. A. Buday. 1980. Aggregating behavior and exploitation of subterranean habitat by gravid eastern milksnakes (Lampropeltis t. triangulum). Milwaukee Public Museum Contributions in Biology and Geology 32:1–9. Hileman, E. T., R. B. King, J. M. Adamski, T. G. Anton, R. L. Bailey, S. J. Baker, N. D. Bieser, T. A. Bell Jr., K. M. Bissell, D. R. Bradke, H. Campa III, G. S. Casper, K. Cedar, M. D. Cross, B. A. DeGregorio, M. J. Dreslik, L. J. Faust, D. S. Harvey, R. W. Hay, B. C. Jellen, B. D. Johnson, G. Johnson, B. D. Kiel, B. A. Kingsbury, M. J. Kowalski, Y. Lee, A. M. Lentini, J. C. Marshall, D. Mauger, J. A. Moore, R. A. Paloski, C. A. Phillips, P. D. Pratt, T. Preney, K. A. Prior, A. Promaine, M. Redmer, H. K. Reinert, J. D. Rouse, K. T. Shoemaker, S. Sutton, T. J. VanDeWalle, P. J. Weatherhead, D. Wynn, and A. Yagi. 2017. Climatic and geographic predictors of life history variation in eastern massasauga (Sistrurus catenatus): A range-wide synthesis. PLOS One 12(2):p.e0172011. Hollander, P. J., and M. C. Barnhart. 1976. Opheodrys vernalis blanchardi (western smooth green snake). Herpetological Review 7:124. Holtzman, D. A. 2001. Thamnophis sirtalis sirtalis (eastern garter snake): Courtship behavior. Herpetological Review 32:110. Holycross, A. T., T. G. Anton, M. E. Douglas, and D. R. Frost. 2008. The type localities of Sistrurus catenatus and Crotalus viridis (Serpentes: Viperidae), with the unraveling of a most unfortunate tangle of names. Copeia 2008:421–424. Hopkins, W. A., and C. T. Winne. 2006. Influence of body size on swimming performance of four species of neonatal natricine snakes acutely exposed to a cholinesterase-inhibiting pesticide. Environmental Toxicology and Chemistry: An International Journal 25:1208–1213. Howes, B. J., B. Lindsay, and S. C. Lougheed. 2006. Range-wide phylogeography of a temperate lizard, the five-lined skink (Eumeces fasciatus). Molecular Phylogenetics and Evolution 40:183–194. Howes, B. J., and S. C. Lougheed. 2004. The importance of cover rock in northern populations of the five-lined skink (Eumeces fasciatus). Herpetologica 60:287–294. Hoyt, J. S. Y. 1941. High speed attained by Cnemidophorus sexlineatus. Copeia 1941:80–180. Hubbs, B. 2009. Common Kingsnakes: A Natural History of Lampropeltis getula. Tricolor Books, Tempe. Hurter, J. 1911. Herpetology of Missouri. St. Louis Academy of Science Transactions 20:59–274.

364  References

Iowa Department of Natural Resources. 2015. Securing a Future for Fish and Wildlife: A Conservation Legacy for Iowans. Iowa Department of Natural Resources, Des Moines. Isbell, L. A. 2009. The Fruit, the Tree, and the Serpent: Why We See So Well. Harvard University Press, Cambridge. Iverson, J. B. 1990. Nesting and parental care in the mud turtle, Kinosternon flavescens. Canadian Journal of Zoology 68:230–233. Iverson, J. B. 2019. Female reproduction in western hognose snakes (Heterodon na­ sicus) in the Nebraska Sandhills, USA. Herpetological Conservation and Biology 14:627–640. Iverson, J. B., C. A. Young, T. S. Akre, and C. M. Griffiths. 2012. Reproduction by female bullsnakes (Pituophis catenifer sayi) in the Nebraska Sandhills. Southwestern Naturalist 57:58–73. Jaffe, F. A. 1957. A fatal case of snake bite. Canadian Medical Association Journal 76:641–643. James, E. 1823. Account of an expedition from Pittsburgh to the Rocky Mountains, performed in the years 1819, 1820. Vol. 1. Longman, Hurst, Rees, Ovme, and Brown, London. Johnson, S. R., and M. Stark. 2017. Snake sightings, Marion County, Iowa, 2010–2016. Bulletin of the Chicago Herpetological Society 52:49–50. Johnson, T. R. 2000. The Amphibians and Reptiles of Missouri. 2d ed. Missouri Department of Conservation, Jefferson City. Jones, P. C., R. B. King, R. L. Bailey, N. D. Bieser, K. Bissell, H. Campa III, T. Crabill, M. D. Cross, B. A. DeGregorio, M. J. Dreslik, F. E. Durbian, D. S. Harvey, S. E. Hecht, G. C. Jellen, G. Johnson, B. A. Kingsbury, M. J. Kowalski, J. Lee, J. V. Manning, J. A. Moore, J. Oakes, C. A. Phillips, K. A. Prior, J. M. Refsnider, J. D. Rouse, J. R. Sage, R. A. Seigel, D. B. Shepard, C. S. Smith, T. J. VanDeWalle, P. J. Weatherhead, and A. Yagi. 2012. Range-wide analysis of eastern massasauga survivorship. Journal of Wildlife Management 76:1–11. Jørgensen, D., C. C. Gates, and D. P. Whiteside. 2008. Movements, migrations, and mechanisms: A review of radiotelemetry studies of prairie (Crotalus v. viridis) and western (Crotalus oreganus) rattlesnakes. In The Biology of Rattlesnakes, ed. W. K. Hayes, K. R. Beaman, M. D. Cardwell, and S. P. Bush, 303–316. Loma Linda University Press, Loma Linda. Jørgensen, D., and J. Nicholson. 2007. Reproductive biology of female prairie rattlesnakes (Crotalus viridis) in Alberta. Alberta Sustainable Resource Development, Fish and Wildlife Division, Alberta Species at Risk Report No. 103, Edmonton. Jungst, S. E., D. R. Farrar, and M. Brandrup. 1998. Iowa’s changing forest resources. Journal of the Iowa Academy of Science 105:61–66. Kahle, D., and H. Wickham. 2013. ggmap: Spatial visualization with ggplot2. R Journal 5:144–161. Kapfer, J. M., J. R. Coggins, and R. Hay. 2008. Spatial ecology and habitat selection of

References  365

bullsnakes (Pituophis catenifer sayi) at the northern periphery of their geographic range. Copeia 2008:815–826. Keegan, H. L. 1944. An albino fox snake from Iowa. Copeia 1944:59. Keenlyne, K. D., and J. R. Beer. 1973. Food habits of Sistrurus catenatus catenatus. Journal of Herpetology 7:382–384. Keller, W. L., and E. J. Heske. 2000. Habitat use by three species of snakes at the Middle Fork Fish and Wildlife Area, Illinois. Journal of Herpetology 34:558–564. Keogh, J. S., and F. P. DeSerto. 1994. Temperature dependent defensive behavior in three species of North American colubrid snakes. Journal of Herpetology 28:258–261. Kerr, P. J. 2018. Middle to early-late Wisconsinan glaciation in north central Iowa: Timing, distribution, and implications for reconstructions of the Laurentide Ice Sheet during MIS3. Master’s thesis, University of Iowa. Kerr, P. J., S. A. Tassier-Surine, and C. J. Korht. 2019. Trends in Eolian features on the Iowan Erosion Surface, Geological Society of America Abstracts with Programs. Geological Society of America, Manhattan, 10.1130/abs/2019SC-326991. Keyler, D. E. 2008. Timber rattlesnake (Crotalus horridus) envenomations in the upper Mississippi River valley. In The Biology of Rattlesnakes, ed. W. K. Hayes, K. R. Beaman, M. D. Cardwell, and S. P. Bush, 569–580. Loma Linda University Press, Loma Linda. Kingsbury, B. A., and C. J. Coppola. 2000. Hibernacula of the copperbelly water snake (Nerodia erythrogaster neglecta) in southern Indiana and Kentucky. Journal of Herpetology 34:294–298. Klauber, L. M. 1938. Notes from a herpetological diary, I. Copeia 4:191–197. Klauber, L. M. 1956. Rattlesnakes, Their Habits, Life Histories, and Influence on Mankind. Vols. 1 and 2. University of California Press, Berkeley. Klimstra, W. D. 1950. Notes on some amphibians and reptiles from Davis County, Iowa. Iowa State College Journal of Science 24:429–431. Klimstra, W. D. 1958. Some observations on snake activities and populations. Ecology 39:232–239. Klimstra, W. D. 1959a. Foods of the racer, Coluber constrictor, in southern Illinois. Copeia 1959:210–214. Klimstra, W. D. 1959b. Food habits of the yellow-bellied king snake in southern Illinois. Herpetologica 15:1–5. Knoot, T. G., and L. B. Best. 2011. A multiscale approach to understanding snake use of conservation buffer strips in an agricultural landscape. Herpetological Conservation and Biology 6:191–201. Kofron, C. P., and J. R. Dixon. 1980. Observations on aquatic colubrid snakes in Texas. Southwestern Naturalist 25:107–109. Krause Danielsen, A. 2012. Using landowner knowledge and field captures to determine habitat use by the northern prairie skink (Plestiodon septentrionalis) on exurban residential land in southwestern Manitoba. Ph.D. dissertation, University of Manitoba.

366  References

Krohmer, R. W. 1989. Body temperature relationships in the lined snake, Tropidoclo­ nion lineatum. Comparative Biochemistry and Physiology 92A:541–543. Krohmer, R. W., and R. D. Aldridge. 1985a. Male reproductive cycle of the lined snake, Tropidoclonion lineatum. Herpetologica 41:33–38. Krohmer, R. W., and R. D. Aldridge. 1985b. Female reproductive cycle of the lined snake. Herpetologica 41:39–44. Kroll, J. C. 1976. Feeding adaptations of hognose snakes. Southwestern Naturalist 20:537–557. Lang, J. W. 1969. Hibernation and movements of Storeria occipitomaculata in northern Minnesota. Journal of Herpetology 3:196–197. Langford, G. J., and J. Janovy Jr. 2011. Heterodon nasicus (western hog-nosed snake): Diet and arboreal foraging behavior. Herpetological Review 42:291. Lannoo, M. J. 1996. Okoboji Wetlands: A Lesson in Natural History. University of Iowa Press, Iowa City. Laposha, N. A., J. S. Parmerlee Jr., R. Powell, and D. D. Smith. 1985. Nerodia erythro­ gaster transversa (blotched water snake): Reproduction. Herpetological Review 16:81. LeClere, J. B. 2013. A Field Guide to the Amphibians and Reptiles of Iowa. ECO Herpetological Publishing, Rodeo. LeClere, J. B., E. P. Hoaglund, J. Scharosch, C. E. Smith, and T. Gamble. 2012. Two naturally occurring intergenetic hybrid snakes (Pituophis catenifer sayi × Pan­ therophis vulpinus; Lampropeltini, Squamata) from the midwestern United States. Journal of Herpetology 46:257–262. Lillywhite, H. B. 1985. Trailing movements and sexual behavior in Coluber constrictor. Journal of Herpetology 19:306–308. LoBue, V., and J. S. DeLoache. 2008. Detecting the snake in the grass: Attention to fearrelevant stimuli by adults and young children. Psychological Science 19:284–289. Loomis, R. B. 1948. Notes on the herpetology of Adams County, Iowa. Herpetologica 4:121–122. Lundgren, S. A., K. Geluso, and C. W. Schoenebeck. 2012. Terrestrial and semi-aquatic vertebrates in diets of largemouth bass in central Nebraska. Prairie Naturalist 44:105–108. Lynch, J. D. 1966. Communal egg laying in the pilot blacksnake, Elaphe obsoleta obso­ leta. Herpetologica 22:305. Makowsky, R., J. C. Marshall Jr., J. McVay, P. T. Chippindale, and L. J. Rissler. 2010. Phylogeographic analysis and environmental niche modeling of the plain-bellied watersnake (Nerodia erythrogaster) reveals low levels of genetic and ecological differentiation. Molecular Phylogenetics and Evolution 55:985–995. Markezich, A. 1962. Ophiophagy in western fox snakes, Elaphe v. vulpina. Bulletin of the Philadelphia Herpetological Society 10:5. Markezich, A. L. 2010. Thamnophis sirtalis (common garter snake): Scavenging. Herpetological Review 41:99–100.

References  367

Mason, J. A. 2015. Up in the refrigerator: Geomorphic response to periglacial environments in the upper Mississippi River basin, USA. Geomorphology 248:363–381, 10.1016/j.geomorph.2015.08.004. McCallister, C. T. 1985. Nerodia rhombifera (Hallowell), diamondback water snake. Catalogue of American Amphibians and Reptiles 376:1–4. McCallum, M. L., S. E. Trauth, and R. G. Neal. 2006. Tail-coiling in ringneck snakes: Flash display or decoy? Herpetological Natural History 10:91–94. McCranie, J. R. 1990. Nerodia erythrogaster (Forster), plainbelly water snake. Catalogue of American Amphibians and Reptiles 500:1–8. McKinistry, D. M. 1978. Evidence of toxic saliva in some colubrid snakes of the United States. Toxicon 16:523–534. McKnight, D. T., J. R. Harmon, J. L. McKnight, and D. B. Ligon. 2014. Notes on the diets of seven sympatric snakes in the genera Agkistrodon, Nerodia, Sistrurus, and Thamnophis. Herpetology Notes 7:171–177. Meshaka, W. E., Jr., and A. Klippel. 2011. Seasonal activity, reproduction, and growth of the northern redbelly snake, Storeria occipitomaculata occipitomaculata (Storer, 1839), from Pennsylvania. Journal of Kansas Herpetology 37:16–20. Meshaka, W. E., S. E. Trauth, and C. Files. 1988. Elaphe obsoleta obsoleta (black rat snake): Antipredatory behavior. Herpetological Review 19:84. Minton, S. A. 1972. Amphibians and reptiles of Indiana. Indiana Academy of Science Monographs 3:1–346. Minton, S. A., and M. R. Minton. 1969. Venomous Reptiles. Charles Scribner’s Sons, New York. Mitchell, J. C., and R. A. Beck. 1992. Free-ranging domestic cat predation on native vertebrates in rural and urban Virginia. Virginia Journal of Science 43:197–207. Moehn, L. D. 1967. A combat dance between two prairie kingsnakes. Copeia 1967:480–481. Moorman, R. B., and K. D. Carlander. 1950a. Iowa’s striped snakes. Iowa Conservationist 9:65, 68. Moorman, R. B., and K. D. Carlander. 1950b. Our timid small snakes. Iowa Conservationist 9:73, 79. Moorman, R. B., and K. D. Carlander. 1951. Iowa’s poisonous snakes. Iowa Conservationist 10:97, 103–104. Moriarty, J. J., and M. Linck. 1998. Reintroduction of bullsnakes into a recreated prairie. In Minnesota’s Amphibians and Reptiles: Their Conservation and Status: Proceedings of a Symposium, ed J. J. Moriarty and D. Jones, 43–52. Serpent’s Tale, Lanesboro. Morris, M. A. 1985. Envenomation from the bite of Heterodon nasicus (Serpentes: Colubridae). Herpetologica 41:361–363. Mosauer, W. 1932. On the locomotion of snakes. Science 76:583–585. Mueller, H. A. 1915. History of Madison County, Iowa, and Its People. Vol. 1. S. J. Clarke Publishing Company, Chicago.

368  References

Mushinsky, H. R., and J. J. Hebrard. 1977. Food partitioning by five species of water snakes in Louisiana. Herpetologica 33:162–166. Mushinsky, H. R., J. J. Hebrard, and D. S. Vodopich. 1982. Ontogeny of water snake foraging ecology. Ecology 63:1624–1629. Mushinsky, H. R., J. J. Hebrard, and M. G. Walley. 1980. The role of temperature on the behavioral and ecological associations of sympatric water snakes. Copeia 1980:744–754. Mushinsky, H. R., and D. E. Miller. 1993. Predation on water snakes: Ontogenetic and interspecific considerations. Copeia 1993:660–665. Mutel, C. F. 1989. Fragile Giants: A Natural History of the Loess Hills. University of Iowa Press, Iowa City. Mutel, C. F. 2008. The Emerald Horizon: The History of Nature in Iowa. University of Iowa Press, Iowa City. Nelson, W. F. 1963. Natural history of the northern prairie skink, Eumeces septentriona­ lis septentrionalis (Baird). Ph.D. dissertation. University of Minnesota. Nutting, C. C. 1892. Report of Committee on State Fauna. Proceedings of the Iowa Academy of Science 1:39–42. Oldfield, B., and J. J. Moriarty. 1994. Amphibians and Reptiles Native to Minnesota. University of Minnesota Press, Minneapolis. Olson, D. H., and D. Saenz. 2013. Climate Change and Reptiles. U.S. Department of Agriculture, Forest Service, Climate Change Resource Center, https://www.fs.usda .gov/ccrc/topics/reptiles-and-climate-change. Ortenburger, A. I. 1928. The Whipsnakes and Racers, Genera Masticophis and Coluber. University of Michigan Studies, Memoirs of the University of Michigan Museums. Osborn, H. 1892. A partial catalogue of the animals of Iowa, represented in the collections of the Department of Zoology and Entomology of the Iowa Agricultural College (1891), Ames. 1–39. Over, W. H. 1943. Amphibians and reptiles of South Dakota. South Dakota Geology and Natural History Survey Bulletin 12:1–34. Parmelee, J. R., and P. Frese. 2005. The ecology and conservation of the timber rattlesnake (Crotalus horridus) in the agricultural landscape of central Iowa. In Timber Rattlesnake (Crotalus horridus) Biology and Conservation in the Upper Mississippi River Valley, ed. D. E. Keyler and P. A. Cochran, 15–16. St. Mary’s University, Winona. Patten, T. J., J. D. Fawcett, and D. D. Fogell. 2009. Natural history of the western massasauga (Sistrurus catenatus tergeminus) in Nebraska. Journal of Kansas Herpetology 30:13–20. Patten, T. J., D. D. Fogell, and J. D. Fawcett. 2016. Spatial ecology and habitat use of the western massasauga (Sistrurus tergeminus) in Nebraska. Journal of North American Herpetology 2016:31–38. Paulissen, M. A. 1987. Diet of adult and juvenile six-lined racerunners, Cnemidophorus sexlineatus (Sauria: Teiidae). Southwestern Naturalist 32:395–397.

References  369

Penning, D. A., and B. R. Moon. 2017. The king of snakes: Performance and morphology of intraguild predators (Lampropeltis) and their prey (Pantherophis). Journal of Experimental Biology 220:1154–1161. Pisani, G. R. 2009a. Use of an active ant nest as a hibernaculum by small snake species. Transactions of the Kansas Academy of Science 112:113–118. Pisani, G. R. 2009b. Virginia valeriae and Storeria dekayi in a northeast Kansas grassland community: Ecology and conservation implications. Journal of Kansas Herpetology 32:20–36. Pitt, W. 2001. Density of prairie skinks (Eumeces septentrionalis) in old-field habitats. American Midland Naturalist 146:86–93. Platt, D. R. 1969. Natural history of the hognose snakes, Heterodon platyrhinos and Heterodon nasicus. University of Kansas Publications of the Museum of Natural History 18:253–420. Platt, W. J. 1973. Comparison of vertebrate communities of Coralville Reservoir and Cone Marsh, Iowa. Proceedings of the Iowa Academy of Science 80:117–128. Platt, W. J. 1975. The vertebrate fauna of Cayler Prairie Preserve, Dickinson County, Iowa. Proceedings of the Iowa Academy of Science 82:106–108. Pleyte, T. A. 1976. A study of a population of the slender glass lizard in Waushara Co., Wisconsin. Field Station Bulletin 9:16–19. Plummer, M. V. 2002. Observations on hibernaculae and overwintering ecology of hognose snakes (Heterodon platyrhinos). Herpetological Review 33:89–90. Plummer, M. V. 2010. Habitat use and movements of kingsnakes (Lampropeltis getula holbrooki) in a partially abandoned and reforested agricultural landscape. Herpetological Conservation and Biology 5:214–222. Plummer, M. V., and N. E. Mills. 2000. Spatial ecology and survivorship of resident and translocated hognose snakes (Heterodon platyrhinos). Journal of Herpetology 34:565–575. Plummer, M. V., and N. E. Mills. 2006. Heterodon platirhinos (eastern hognose snake): Road crossing behavior. Herpetological Review 37:352. Porchuk, B. D., and R. J. Brooks. 1995. Coluber constrictor (blue racer), Elaphe vulpina (eastern fox snake), and Chelydra serpentina (snapping turtle): Reproduction. Herpetological Review 26:148. Powell, R., R. Conant, and J. T. Collins. 2016. Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America. 4th ed. Houghton Mifflin Harcourt Publishing Company, New York. Prior, J. C. 1991. Landforms of Iowa. University of Iowa Press, Iowa City. Prior, J. C., J. L. Boekhoff, M. R. Howes, R. D. Libra, and P. E. VanDorpe. 2003. Iowa’s groundwater basics. Iowa Geological Education Series 6. Punzo, F., J. Laveglia, D. Lohr, and P. A. Dahm. 1979. Organochlorine insecticide residues in amphibians and reptiles from Iowa and lizards from the southwestern United States. Bulletin of Environmental Contamination and Toxicology 21:842–848.

370  References

Pyron, R. A., and F. T. Burbrink. 2009. Lineage diversification in a widespread species: Roles for niche divergence and conservation in the common kingsnake, Lampropel­ tis getula. Molecular Ecology 18:3443–3457. Pyron, R. A., F. W. Hsieh, A. R. Lemmon, E. M. Lemmon, and C. R. Hendry. 2016. Integrating phylogenomic and morphological data to assess candidate speciesdelimitation models in brown and red-bellied snakes (Storeria). Zoological Journal of the Linnean Society 177:937–949. Ramsey, L. W. 1946. Captive specimens of Tropidoclonion lineatum. Herpetologica 3:112. Ramsey, L. W. 1947. Feeding behavior of Tropidoclonion lineatum. Herpetologica 4:15–18. Ray, J. W., R. B. King, M. R. Duvall, J. W. Robinson, C. P. Jaeger, M. J. Dreslik, B. J. Swanson, and D. Mulkerin. 2013. Genetic analysis and captive breeding program design for the eastern massasauga Sistrurus catenatus catenatus. Journal of Fish and Wildlife Management 4:104–113. Reed, B. F. 1913. History of Kossuth County, Iowa. Vol. 1. S. J. Clarke Publishing Company, Chicago. Richardson, M. L., P. J. Weatherhead, and J. D. Brawn. 2006. Habitat use and activity of prairie kingsnakes (Lampropeltis calligaster calligaster) in Illinois. Journal of Herpetology 40:423–428. Robson, L. E., and G. Blouin-Demers. 2013. Eastern hognose snakes (Heterodon plati­ rhinos) avoid crossing paved roads, but not unpaved roads. Copeia 2013:507–511. Roe, J. H., B. A. Kingsbury, and N. R Herbert. 2003. Wetland and upland use patterns in semi-aquatic snakes: Implications for wetland conservation. Wetlands 23:1003–1014. Rossi, J. V., and R. Rossi. 2003. Snakes of the United States and Canada: Natural History and Care in Captivity. Krieger Publishing Company, Malabar. Rossman, D. A., N. B. Ford, and R. A. Seigel. 1996. The Garter Snakes: Evolution and Ecology. University of Oklahoma Press, Norman. Rossman, D. A., and P. A. Myer. 1990. Behavioral and morphological adaptations for snail extraction in the North American brown snakes (genus Storeria). Journal of Herpetology 24:434–438. Ruane, S., R. W. Bryson Jr., R. A. Pyron, and F. T. Burbrink. 2014. Coalescent species delimitation in milksnakes (genus Lampropeltis) and impacts on phylogenetic comparative analyses. Systematic Biology 63:231–250. Russell, F. E. 1983. Snake Venom Poisoning. Scholium International, Great Neck. Ruthven, A. G. 1908a. The faunal affinities of the prairie region of central North America. American Naturalist 42:388–393. Ruthven, A. G. 1908b. The variations and genetic relationships of the garter-snakes. U.S. National Museum Bulletin 61:1–201. Ruthven, A. G. 1910. Contributions to the herpetology of Iowa. Proceedings of the Iowa Academy of Science 17:198–209.

References  371

Ruthven, A. G. 1912. Contributions to the herpetology of Iowa, II. Proceedings of the Iowa Academy of Science 19:207. Ruthven, A. G. 1919. Contributions to the herpetology of Iowa, III. Occasional Papers of the Museum of Zoology, University of Michigan 66:1–3. Sagan, C. 1977. The Dragons of Eden: Speculations on the Evolution of Human Intelligence. Ballantine Books, New York. Sajdak, R. A., and A. W. Bartz. 2004. Crotalus horridus (timber rattlesnake): Arboreality, diet. Herpetological Review 35:60–61. Sajdak, R. A., and S. L. Sajdak. 1999. Thamnophis sirtalis sirtalis (eastern garter snake): Carrion feeding. Herpetological Review 30:229. Saxe, L. H., and E. M. Schmidt. 1953. Trimitus parvus Grasse (Protozoa, Mastigophora) from a garter snake, Thamnophis radix. Proceedings of the Iowa Academy of Science 60:754–758. Schmidt, K. P., and D. D. Davis. 1941. Field Book of Snakes of the United States and Canada. G. P. Putnam’s Sons, New York. Scott, T. G. 1938. Wildlife mortality on Iowa highways. American Midland Naturalist 20:527–539. Scott, T. G., and R. B. Sheldahl. 1937. Black-banded skink in Iowa. Copeia 1937:192. Secor, S. M. 1987. Courtship and mating behavior of the speckled kingsnake, Lampro­ peltis getulus holbrooki. Herpetologica 43:15–28. Seibert, H. C., and C. W. Hagen. 1947. Studies on a population of snakes in Illinois. Copeia 1947:6–22. Seigel, R. A. 1986. Ecology and conservation of an endangered rattlesnake, Sistrurus catenatus, in Missouri. Biological Conservation 35:146–160. Seigel, R. A. 1992. Ecology of a specialized predator: Regina grahami in Missouri. Journal of Herpetology 26:32–37. Seigel, R. A., and N. B. Ford. 1987. Reproductive ecology. In Snakes: Ecology and Evolutionary Biology, ed. R. A. Seigel, J. T. Collins, and S. S. Novak, 210–252. McGraw-Hill, New York. Shine, R. 1983. Reptilian reproductive modes: The oviparity-viviparity continuum. Herpetologica 39:1–8. Shine, R., M. Lemaster, M. Wall, T. Langkilde, and R. Mason. 2004. Why did the snake cross the road? Effects of roads on movement and location of mates by garter snakes (Thamnophis sirtalis parietalis). Ecology and Society 9:9. Smith, C. F., G. W. Schuett, R. L. Earley, and K. Schwenk. 2009. The spatial and reproductive ecology of the copperhead (Agkistrodon contortrix) at the northeastern extreme of its range. Herpetological Monographs 23:45–73. Smith, C. F., G. W. Schuett, R. S. Reiserer, C. E. Dana, M. L. Collyer, and M. A. Davis. 2019. Drought-induced suppression of female fecundity in a capital breeder. Scientific Reports 9:1–13. Smith, H. M. 1946. Handbook of Lizards. Cornell University Press, Ithaca.

372  References

Smith, P. W. 1961. The amphibians and reptiles of Illinois. Illinois Natural History Survey Bulletin 28:1–298. Smith, P. W., and H. M. Smith. 1962. The systematic and biogeographic status of two Illinois snakes. Occasional Papers of the C. C. Adams Center for Ecological Studies 5:1–10. Smith, P. W., and H. M. Smith. 1963. The systematic status of the lined snake of Iowa. Proceedings of the Biological Society of Washington 76:297–304. Snider, A. T., and J. K. Bowler. 1992. Longevity of reptiles and amphibians in North American collections. 2d ed. Society for the Study of Amphibians and Reptiles Herpetological Circular 21:1–40. Somes, M. P. 1911. Notes on some Iowa reptiles. Proceedings of the Iowa Academy of Science 18:149–154. Somma, L. A. 1987. Reproduction of the prairie skink, Eumeces septentrionalis, in Nebraska. Great Basin Naturalist 47:373–374. Somma, L. A. 1989. Influence of substrate water content on neonate size in the prairie skink, Eumeces septentrionalis. Great Basin Naturalist 49:198–200. Somma, L. A. 1990. Observations on the nesting ecology of the prairie skink (Eu­ meces septentrionalis) in Nebraska. Bulletin of the Chicago Herpetological Society 25:77–80. Somma, L. A., and J. D. Fawcett. 1989. Brooding behaviour of the prairie skink, Eu­ meces septentrionalis, and its relationship to the hydric environment of the nest. Zoological Journal of the Linnean Society 95:245–256. Sovic, M. G., A. C. Fries, and H. L. Gibbs. 2016. Origin of a cryptic lineage in a threatened reptile through isolation and historical hybridization. Heredity 117:58–366. Spaur, R. C., and H. M. Smith. 1971. Adrenal enlargement in the hognosed snake Het­ erodon platyrhinos. Journal of Herpetology 5:197–199. Stanford, K. M., and R. B. King. 2004. Growth, survival, and reproduction in a northern Illinois population of the plains gartersnake, Thamnophis radix. Copeia 2004:465–478. Steen, D. A., C. J. McClure, W. B. Sutton, D. C. Rudolph, J. B. Pierce, J. R. Lee, L. L. Smith, B. B. Gregory, D. L. Baxley, D. J. Stevenson, and C. Guyer. 2014. Copperheads are common when kingsnakes are not: Relationships between the abundances of a predator and one of their prey. Herpetologica 70:69–76. Stejneger, L. 1891. Notes on some North American snakes. Proceedings of the United States National Museum 14:501–505. Stephenson, M., R. Ruden, L. Schulte Moore, R. Klaver, and J. Adelman. 2020. Snake fungal disease in Iowa. Paper presented at the Iowa Chapter of the Wildlife Society Winter Workshop, February 11, 2020. Stoner, D. 1936. Wildlife casualties on the highways. Wilson Bulletin 48:276–283. Stull, O. G. 1940. Variations and relationships in the snakes of the genus Pituophis. U.S. National Museum Bulletin 175:1–225. Taylor, E. H. 1935. A taxonomic study of the cosmopolitan scincoid lizards of the genus

References  373

Eumeces with an account of the distribution and relationships of the species. Kansas University Science Bulletin 23:1–643. Taylor, E. W. 1892. The Ophidia of Nebraska. Annual Report to the Nebraska State Board of Agriculture (1891–1892):310–357. Thomson, G. W., and H. G. Hertel. 1981. The forest resources of Iowa in 1980. Proceedings of the Iowa Academy of Science 88:2–6. Tiebout, H. M., III, and J. R. Cary. 1987. Dynamic spatial ecology of the water snake, Nerodia sipedon. Copeia 1987:1–18. Tinkle, D. W. 1957. Ecology, maturation and reproduction of Thamnophis sauritus prox­ imus. Ecology 38:69–77. Transeau, E. N. 1935. The prairie peninsula. Ecology 16:423–437. Trauth, S. E. 1984. Seasonal incidence and reproduction in the western slender glass lizard, Ophisaurus attenuatus (Reptilia, Anguidae), in Arkansas. Southwestern Naturalist 29:271–275. Trauth, S. E., R. L. Cox Jr., W. E. Meshaka, B. P. Butterfield, and A. Holt. 1994. Female reproductive traits in selected Arkansas snakes. Proceedings of the Arkansas Academy of Science 48:196–209. Trauth, S. E., H. W. Robison, and M. V. Plummer. 2004. The Amphibians and Reptiles of Arkansas. University of Arkansas Press, Fayetteville. Tryon, B. W., and G. Carl. 1980. Reproduction in the mole kingsnake, Lampropeltis calligaster rhombomaculata (Serpentes, Colubridae). Transactions of the Kansas Academy of Science 83:66–73. Tucker, J. K. 2000. Illinois snakes: Young-of-the-year morphology and food habits. Herpetological Review 31:106–107. Vandermast, D. B. 1999. Elaphe obsoleta (black rat snake): Antipredator behavior. Herpetological Review 30:169. Van Devender, T. R. 1990. Pleistocene forests and copperheads in the eastern United States, and the historical biogeography of New World Agkistrodon. In Snakes of the Agkistrodon Complex: A Monographic Review, ed. H. K. Gloyd and R. Conant, 6. Society for the Study of Amphibians and Reptiles, New York. VanDeWalle, T. J. 2005. Sistrurus catenatus catenatus (eastern massasauga): Male-male combat. Herpetological Review 36:196–197. VanDeWalle, T. J. 2010. Snakes and Lizards in Your Pocket: A Guide to Reptiles of the Upper Midwest. University of Iowa Press, Iowa City. VanDeWalle, T. J., and S. J. Carlson. 2009. Geographic distribution: Storeria occipito­ maculata occipitomaculata. Herpetological Review 40:117. VanDeWalle, T. J., and W. L. VanDeWalle. 2008. Sistrurus catenatus catenatus (eastern massasauga): Diet. Herpetological Review 39:358. Vanek, J. P., and D. K. Wasko. 2017. Spatial ecology of the eastern hog-nosed snake (Heterodon platirhinos) at the northeastern limit of its range. Herpetological Conservation and Biology 12:109–118. Van Le, Q., L. A. Isbell, J. Matsumoto, M. Nguyen, E. Hori, R. S. Maior, C. Tomaz,

374  References

A. H. Tran, T. Ono, and H. Nishijo. 2013. Pulvinar neurons reveal neurobiological evidence of past selection for rapid detection of snakes. Proceedings of the National Academy of Science, early edition: 10.1073/pnas.1312648110. Virgin, E. E., and R. B. King. 2019. What does the snake eat? Breadth, overlap, and non-native prey in the diet of three sympatric natricine snakes. Herpetological Conservation and Biology 14:132–142. Vogt, R. C. 1981. Natural History of Amphibians and Reptiles of Wisconsin. Milwaukee Public Museum, Milwaukee. Wacha, R. S., and J. L. Christiansen. 1974. Systematics of the eimerian parasites from North American snakes of the family Colubridae, and their prevalence in colubrids from Iowa. Journal of Protozoology 21:483–489. Weatherhead, P. J., and M. B. Charland. 1985. Habitat selection in an Ontario population of the snake, Elaphe obsoleta. Journal of Herpetology 19:12–19. Weaver, W. G., Jr. 1965. The cranial anatomy of the hog-nosed snakes (Heterodon). Bulletin of the Florida State Museum 9:275–304. Weinstein, S. A., C. F. Dewitt, and L. A. Smith. 1992. Variability of venom-neutralizing properties of serum from snakes of the colubrid genus Lampropeltis. Journal of Herpetology 26:452–461. Wendelken, P. W. 1978. On prey-specific hunting behavior in the western ribbon snake, Thamnophis proximus (Reptilia, Serpentes, Colubridae). Journal of Herpetology 12:577–578. Werler, J. E., and J. R. Dixon. 2000. Texas Snakes: Identification, Distribution, and Natural History. University of Texas Press, Austin. Wilgers, D. J., and E. A. Horne. 2006. Effects of different burn regimes on tallgrass prairie herpetofaunal species diversity and community composition in the Flint Hills, Kansas. Journal of Herpetology 40:73–84. Williams, K. L. 1978. Systematics and Natural History of the American Milk Snake, Lampropeltis triangulum. 2d ed. Milwaukee Public Museum, Milwaukee. Wilsey, C., B. Bateman, L. Taylor, J. X. Wu, G. LeBaron, R. Shepherd, C. Koseff, S. Friedman, and R. Stone. 2019. Survival by Degrees: 389 Bird Species on the Brink. National Audubon Society, New York. Wright, A. H., and A. A. Wright. 1952. List of the snakes of the United States and Canada by states and provinces. American Midland Naturalist 48:574–603. Wright, A. H., and A. A. Wright. 1957. Handbook of Snakes of the United States and Canada. Cornell University Press, Ithaca. Yarrow, H. C. 1882. Check-list of North American Reptilia and Batrachia, with catalogue of specimens in the United States National Museum. U.S. National Museum Bulletin 24:1–249. Zim, H. M., and H. S. Smith. 1953. Reptiles and Amphibians: A Guide to Familiar American Species. Golden Press, New York.

LIFE LISTS

You can use this alphabetical list of all the species and subspecies in this book to keep life lists of Iowa lizards and snakes. Check those species you see and identify, record the dates you see them, and make other notes about them. In this way, the book can become a personal lifetime natural history diary of each new sighting. LIZARDS

☐  Common Five-Lined Skink ☐  Great Plains Skink ☐  Northern Prairie Skink ☐  Prairie Racerunner ☐  Western Slender Glass Lizard SNAKES

☐  Blue Racer ☐ Bullsnake ☐  Chicago Gartersnake ☐  Dekay’s Brownsnake ☐  Diamond-Backed Watersnake ☐  Eastern Copperhead ☐  Eastern Gartersnake ☐  Eastern Hog-Nosed Snake ☐  Eastern Massasauga ☐  Eastern Milksnake ☐  Eastern Yellow-Bellied Racer ☐  Graham’s Crayfish Snake ☐  Lined Snake ☐  Northern Watersnake

376  Life Lists

☐  Orange-Striped Ribbonsnake ☐  Plain-Bellied Watersnake ☐  Plains Gartersnake ☐  Plains Hog-Nosed Snake ☐  Prairie Kingsnake ☐  Prairie Massasauga ☐  Prairie Rattlesnake ☐  Prairie Ring-Necked Snake ☐  Red-Bellied Snake ☐  Red-Sided Gartersnake ☐  Smooth Greensnake ☐  Speckled Kingsnake ☐  Timber Rattlesnake ☐  Western Foxsnake ☐  Western Ratsnake ☐  Western Smooth Earthsnake ☐  Western Wormsnake

INDEX OF SCIENTIFIC AND COMMON NA MES

Boldface numbers indicate detailed discussion. Agkistrodon contortrix, 299–305 Aspidoscelis sexlineata viridis, 71–79 blue racer, 95–104, 189, 197 brownsnake, Dekay’s, 108, 233–40, 243, 270, 289 bullsnake, 125, 135, 198, 206, 208, 215–23, 309, 318–19 Carphophis vermis, 87–93 Chicago gartersnake, 227, 267–77, 281 Coluber constrictor, 95–104 Coluber constrictor flaviventris, 95–104 Coluber constrictor foxii, 95–104 common five-lined skink, 45–52, 62, 73 common gartersnake, 84, 227, 251, 259, 267–77, 281 copperhead, eastern, 153, 299–305 crayfish snake, Graham’s, 163, 225–32, 270, 281 Crotalus horridus, 307–16 Crotalus viridis, 317–25 Dekay’s brownsnake, 108, 233–40, 243, 270, 289 Diadophis punctatus arnyi, 105–12 diamond-backed watersnake, 163, 169– 75, 179, 197–98, 227, 300 earthsnake, western smooth, 89, 108, 189, 235, 243, 287–94 eastern copperhead, 153, 299–305 eastern gartersnake, 227, 267–77, 281 eastern hog-nosed snake, 115, 123–31, 300

eastern massasauga, 125, 208, 296, 327–37, 341 eastern milksnake, 135, 145, 151–59, 300, 329, 341 eastern yellow-bellied racer, 95–104, 189, 197 foxsnake, western, 135, 153, 198, 205–13, 217, 300, 309, 318–19, 329, 341 gartersnake, Chicago, 227, 267–77, 281 gartersnake, common, 84, 227, 251, 259, 267–77, 281 gartersnake, eastern, 227, 267–77, 281 gartersnake, plains, 227, 251, 257–65, 270, 281 gartersnake, red-sided, 227, 267–77, 281 glass lizard, western slender, 35–41 gophersnake, 216 Graham’s crayfish snake, 163, 225–32, 270, 281 Great Plains skink, 47, 53–59, 62–63 greensnake, smooth, 98, 187–94 Heterodon nasicus, 113–21 Heterodon platirhinos, 123–31 hog-nosed snake, eastern, 115, 123–31, 300 hog-nosed snake, plains, 113–21, 124–25 kingsnake, prairie, 133–41, 145, 153, 206, 217 kingsnake, speckled, 143–50

378  Index of Scientific and Common Names

Lampropeltis calligaster, 133–41 Lampropeltis holbrooki, 143–50 Lampropeltis triangulum, 151–59 lined snake, 259, 270, 279–86 massasauga, eastern, 125, 208, 296, 327–37, 341 massasauga, prairie, 125, 208, 329, 339–46 milksnake, eastern, 135, 145, 151–59, 300, 329, 341 Nerodia erythrogaster, 161–68 Nerodia rhombifer, 169–75 Nerodia sipedon sipedon, 177–85 North American racer, 95–104, 163, 189, 197 northern prairie skink, 47, 55, 61–68, 73 northern watersnake, 153, 163, 171, 177–85, 197–98, 208, 227, 300, 329, 341 Opheodrys vernalis, 187–94 Ophisaurus attenuatus, 35–41 orange-striped ribbonsnake, 227, 249–56, 259, 270, 281 Pantherophis obsoletus, 195–203 Pantherophis ramspotti, 205–13 Pituophis catenifer sayi, 215–23 plain-bellied watersnake, 98, 161–68, 179, 197–98, 227, 300 plains gartersnake, 227, 251, 257–65, 270, 281 plains hog-nosed snake, 113–21, 124–25 Plestiodon fasciatus, 45–52 Plestiodon obsoletus, 53–59 Plestiodon septentrionalis, 61–68 prairie kingsnake, 133–41, 145, 153, 206, 217 prairie massasauga, 125, 208, 329, 339–46 prairie racerunner, 47, 63, 71–79 prairie rattlesnake, 317–25

prairie ring-necked snake, 89, 105–12, 243–44 prairie skink, northern, 47, 55, 61–68, 73 racer, blue, 95–104, 189, 197 racer, eastern yellow-bellied, 95–104, 189, 197 racer, North American, 95–104, 163, 189, 197 racerunner, prairie, 47, 63, 71–79 ratsnake, western, 98, 145, 153, 195–203, 208 rattlesnake, prairie, 317–25 rattlesnake, timber, 307–16, 329 red-bellied snake, 89, 108, 235, 241–48, 270 red-sided gartersnake, 227, 267–77, 281 Regina grahamii, 225–32 ribbonsnake, orange-striped, 227, 249– 56, 259, 270, 281 ring-necked snake, prairie, 89, 105–12, 243–44 Sistrurus catenatus, 327–37 Sistrurus tergeminus tergeminus, 339–46 skink, common five-lined, 45–52, 62, 73 skink, Great Plains, 47, 53–59, 62–63 skink, northern prairie, 47, 55, 61–68, 73 slender glass lizard, western, 35–41 smooth earthsnake, western, 89, 108, 189, 235, 243, 287–94 smooth greensnake, 98, 187–94 speckled kingsnake, 143–50 Storeria dekayi, 233–40 Storeria occipitomaculata, 241–48 Thamnophis proximus proximus, 249–56 Thamnophis radix, 257–65 Thamnophis sirtalis, 267–77 Thamnophis sirtalis parietalis, 267–77 Thamnophis sirtalis semifasciatus, 267–77

Index of Scientific and Common Names   379

Thamnophis sirtalis sirtalis, 267–77 timber rattlesnake, 307–16, 329 Tropidoclonion lineatum, 279–86 Virginia valeriae elegans, 287–94 watersnake, diamond-backed, 163, 169– 75, 179, 197–98, 227, 300 watersnake, northern, 153, 163, 171, 177– 85, 197–98, 208, 227, 300, 329, 341 watersnake, plain-bellied, 98, 161–68, 179, 197–98, 227, 300

western foxsnake, 135, 153, 198, 205–13, 217, 300, 309, 318–19, 329, 341 western ratsnake, 98, 145, 153, 195–203, 208 western slender glass lizard, 35–41 western smooth earthsnake, 89, 108, 189, 235, 243, 287–94 western wormsnake, 87–93, 108, 244, 289 wormsnake, western, 87–93, 108, 244, 289 yellow-bellied racer, eastern, 95–104, 189, 197

SELECTED BUR OAK BOOKS AND BUR OAK GUIDES

A Country So Full of Game: The Story of Wildlife in Iowa by James J. Dinsmore The Emerald Horizon: The History of Nature in Iowa by Cornelia F. Mutel Fish in Your Pocket: A Guide to Fish of the Upper Midwest by Terry VanDeWalle Fragile Giants: A Natural History of the Loess Hills by Cornelia F. Mutel Frogs and Toads in Your Pocket: A Guide to Amphibians of the Upper Midwest by Terry VanDeWalle

Of Men and Marshes by Paul L. Errington Of Wilderness and Wolves by Paul L. Errington Out Home by John Madson Salamanders in Your Pocket: A Guide to Caudates of the Upper Midwest by Terry VanDeWalle Snakes and Lizards in Your Pocket: A Guide to Reptiles of the Upper Midwest by Terry VanDeWalle Stories from under the Sky by John Madson

Green, Fair, and Prosperous: Paths to a Sustainable Iowa by Charles E. Connerly

A Sugar Creek Chronicle: Observing Climate Change from a Midwestern Woodland by Cornelia F. Mutel

An Illustrated Guide to Iowa Prairie Plants by Paul Christiansen and Mark Müller

The Tallgrass Prairie Reader edited by John T. Price

Iowa’s Remarkable Soils: The Story of Our Most Vital Resource and How We Can Save It by Kathleen Woida

Turtles in Your Pocket: A Guide to Freshwater and Terrestrial Turtles of the Upper Midwest by Terry VanDeWalle

Landforms of Iowa by Jean C. Prior

Up on the River: People and Wildlife of the Upper Mississippi by John Madson

Where the Sky Began: Land of the Tallgrass Prairie by John Madson Wildflowers and Other Plants of Iowa Wetlands by Sylvan Runkel and Dean Roosa

Wildflowers of Iowa Woodlands by Sylvan Runkel and Alvin Bull Wildflowers of the Tallgrass Prairie by Sylvan T. Runkel and Dean M. Roosa