Foreword
This is the eighth of the manual series of the Illinois Natural History Survey. The first was titled Fieldbook of Illinois Wild Flowers and was published in 1936. Subsequent manuals have dealt with shrubs, land snails, mammals, mussels, and, most recently, the northeastern longhorned beetles.
This field guide on the amphibians and reptiles of Illinois is written for those who are not necessarily experts on these groups, but who wish to have an easy-to-use guide in the field. Identifications can be made through use of the keys or through excellent photographs of each species.
One of the goals of this book is to help the reader learn about all 102 species of amphibians and reptiles that live within the boundaries of Illinois. Basic information is presented on their biology and life history, as well as a brief discussion of the species that are listed as threatened or endangered under the state’s Endangered Species Protection Act. There is a discussion of declining amphibian populations, particularly the cricket frog, and the effects that highways are having on a number of our amphibians and reptiles. This fits nicely with the section "Geologic and Climatic History of Illinois," which discusses how climatic changes previously had an important impact on species distribution and abundance, but now these changes in species distribution are primarily due to the activities of man. There are also sections on the collecting and keeping of amphibians and reptiles, and on ways to improve their habitats.
It is a particular credit to the authors that in addition to all their other duties they were able to put the time and effort in to develop this excellent manual. Tom Rice did an outstanding job of editing and layout for this publication. Many other staff participated in collections and identifications, and as with most of these endeavors a variety of personnel and resources were needed to bring it to successful fruition.
It is hoped that this Manual will be useful to a wide variety of audiences and that it will further and enhance an appreciation of the amphibians and reptiles found in Illinois. These species are important indicators of the state of our natural habitats in Illinois, and their declines are telling us much about habitat loss and environmental alterations in the state.
David L. Thomas
Chief
The idea of an amphibian and reptile guide written for a general audience originated with the Illinois Endangered Species Protection Board. Partial funding for this book was provided by the Bureau of Design and Environment, Illinois Department of Transportation. We would like to thank Lauren Brown of Illinois State University, Gary Casper of the Milwaukee Public Museum, and Tom Johnson of the Missouri Department of Conservation for reviewing the manuscript; the curators and managers of collections for providing data on specimens in their care; and our family and friends for encouragement and support. We would also like to thank Tom Rice for editing and layout, and Charlie Warwick for guiding the product through printing. Figures 3, 5, 6a-b, 7a-b, 10a-b, 11, 14, 15, 16, 19a-b, 20, 21a-b, 22a-b, 24a-b, 25a-b, 26a-b, 27a-b, and 31 were drawn by Mark Sabaj; 2, 9, 23 (bottom), 28a-b, 30a-b, and 32a-b by Alice Prickett; 4, 13a-b, 17b, 23 (top), and 29 by Joseph Leveque; 12a,b,c,d by Thomas Johnson (reprinted with permission of the Missouri Conservation Commission); 18a,b by Jeanne Serb; 8a,b by Ron Brandon; and 17a by Chris Phillips. Range maps were produced by Tom Kompare. Special thanks to the photographers who graciously donated their images, without which this guide would not have been possible. Of particular note to users of this web version of the field guide is the homepage of Mike Redmer, who donated more than 90% of the photos in the guide. Click here to see more of Mike's images on his homepage.
Amphibians and reptiles probably evoke more unwarranted fear and loathing than any other group of organisms. This may be the result of the mistaken notions that all are wet and slimy and that many are dangerous to humans. So much mythology has developed around amphibians and reptiles, especially snakes, that it is not easy to separate fact from fancy. A first step in the right direction is to recognize that herpetologists study two different groups of animals, the class Amphibia and the class Reptilia, members of which differ greatly in structure, physiology, behavior, and ecology. While it is true that many amphibians are wet and slimy to the touch, reptiles, unless they are in water, are dry. It is also true that amphibians usually are cool to the touch, but reptiles, through their basking behavior and heat-managing adaptations, maintain body temperature as high as our own, sometimes higher, when they are active. While 4 of the 38 species of snakes (11%) in Illinois are venomous, only the copperhead is relatively widespread; however, it is found only in the southern half of the state, and is secretive, shy, and not prone to bite. The other three have limited distributions and specific habitat requirements that you can learn, or learn to avoid, as you like. Indeed, one of the goals of this book is to help you learn more about all 102 species of amphibians and reptiles that live within the boundaries of Illinois.
Food and Feeding
Most amphibians and reptiles are predators of a wide variety of other kinds of animals, even of each other. Some are omnivorous (eat animals and plants), and some are herbivorous (eat only plants).
Salamanders, both larvae and adults, are generalized predators, eating about any other animal they can capture and swallow, including fish, insects, crayfish, and snails. Salamander larvae begin life eating tiny, almost microscopic, animals known as plankton. As they grow, they eat larger and larger prey. Aquatic salamanders capture prey by lunging and simultaneously opening the mouth and expanding the throat to draw in a rush of water. Because this method does not work in air, terrestrial salamanders simply grasp worms, insects, slugs, snails, and so forth with their jaws or use their protrusible, sticky tongues to pull prey into their mouths.
Most frog and toad tadpoles scrape algae and bacteria from substrate and filter them from water, or scavenge decaying organic matter. Adults are mostly insectivorous, capturing a variety of insects with their protrusible, sticky tongues.
Among reptiles, snakes and most lizards are strictly predatory, but most turtles are omnivorous. Diet may change with age. For example, juvenile red-eared sliders feed mainly on invertebrates, while adults are largely herbivorous.
Foraging is simple for most turtles. Aquatic individuals swim or walk slowly along the bottom and grasp or bite food with their sharp but toothless jaws. Like salamanders, they can create suction by expanding the throat to draw in detached food. Food too large to be swallowed whole is held in the jaws and torn apart with claws of the front feet. The long-necked snapping turtles and softshell turtles may stalk or lie in ambush for prey, then capture them in a rapid biting and sucking strike. The unique alligator snapping turtle has a wormlike lure on its tongue that entices fish within range of its sharp jaws.
Lizards are chiefly bite-and-grasp predators that simply overpower a variety of invertebrates. Most small snakes, as well as garter snakes, racer, and water snakes, simply capture prey with their jaws and swallow them. Snakes that feed largely on mammals and birds use constriction or venom to subdue prey. The constricting bullsnake, rat snakes, and kingsnakes grasp a small mammal or bird in their jaws, coil around it, and squeeze until it is subdued by suffocation or circulatory failure. The venomous pit vipers (copperhead, cottonmouth, and rattlesnakes) inject venom in a rapid strike, then track their stricken prey through their keen sense of smell made possible by the tongue and vomeronasal organ in the roof of the mouth. The fast-acting venom, produced by modified salivary glands, is injected through a pair of long, hollow fangs that can be folded against the roof of the mouth.
Reproduction
Though most frogs and salamanders reproduce during spring, that’s where the similarities end. Frog breeding is a clamorous, raucous affair whereas breeding salamanders are secretive and quiet. Male frogs attract females to breeding sites by species-specific vocalizations. Where many individuals of several frog species call simultaneously, the result can be deafening. Males usually arrive at the breeding site before females. When a male is approached by a gravid female, he climbs on her back and holds on with his forearms around her body (a behavior called amplexus). Sometime thereafter, the female releases eggs into the water and the male fertilizes them by expelling sperm on top of them.
Rather than vocalizing, male salamanders entice females to engage in a ritual courtship behavior through an exchange of chemical cues, or pheromones, produced by specialized glands and released into the water or onto the body. During courtship, the male, except the hellbender, deposits spermatophores (small gelatinous pyramids capped with spermatozoa) and leads the female over them. With her cloaca, she removes spermatozoa, which are stored in a special sac-like structure. The eggs are then fertilized inside the female’s body. Rather than producing spermatophores, male hellbenders simply spread spermatozoa (milt) over eggs left in a gravel depression by one or more females.
In the biphasic life history of most amphibians in Illinois, eggs laid in water develop into aquatic larvae that grow and transform into juveniles that resemble adults in body form. In the hellbender, mudpuppy, and lesser siren salamanders, larvae mature without transforming and never leave the water. Woodland salamanders (genus Plethodon) bypass the larval stage altogether. They lay eggs on land and embryonic development is modified so that hatchlings resemble adults in body form. The external gills, conspicuous on salamander larvae, are concealed in tadpoles beneath an operculum on each side of the head.
Most Illinois reptiles court and mate in spring or autumn. Fertilization is internal with sperm transferred by one of the paired copulatory organs (hemipenes) in lizards and snakes, or by a penis in turtles. All turtles, lizards, and many snakes in Illinois lay eggs. May and June are peak months for egg laying, and many species lay 2&endash;3 times during the nesting season. While eggs of most Illinois turtles are elliptical with flexible leathery shells, eggs of snapping turtles and softshell turtles are spherical and those of mud, musk, and softshell turtles have hard, brittle shells. Female turtles use their hind feet to excavate a nest hole in mud or sand, and carefully cover it after laying eggs. Lizards and snakes conceal eggs under rocks, in or under logs, in organic debris, or in burrows. Female broadhead and five-lined skinks stay with their eggs throughout incubation in a rare display of reptilian parental care. Kirtland’s snake, water snakes, Graham’s crayfish snake, queen snake, brown snake, redbelly snake, garter snakes, ribbon snakes, lined snake, smooth earth snake, and pit vipers are all live bearers.
Geologic and Climatic History of Illinois
During the last 20,000 years, the Midwest has experienced glaciation and approximately six major climatic phases that greatly influenced current landforms, soils, stream patterns, and vegetation. This in turn influenced the distributions of amphibians and reptiles. For practical purposes, the modern history of amphibian and reptile distributions in Illinois began when the most recent ice sheet, the Laurentide of the Wisconsin glacial period, began to recede from the Midwest. At that time, approximately 15,000&endash;18,000 years before the present (BP), the northern two-thirds of the region that became Illinois was covered with a thick sheet of ice. Much of the remainder was tundra or boreal spruce-fir forest and probably was devoid of reptiles and amphibians. Approximately 10,000 years BP, the climate warmed further and, over the next several thousand years, birches and pines replaced boreal forest. Little is known about the composition of the herpetofauna during this time. The period from approximately 10,000 to 8,000 years BP was characterized by slightly higher temperatures and higher humidity. Vegetation changed from pines to mesic hardwoods such as oak, elm, maple, and beech. During this period, southern species like the mole salamander, bird-voiced treefrog, cottonmouth, and mud snake occurred farther north than they do currently.
The climate from approximately 8,000 to 6,000 years BP was characterized by higher temperature but low humidity. A combination of oak-hickory forest and tallgrass prairie replaced mesic hardwood forests as the dominant vegetation in much of the state. Species that adapted to the xeric Great Plains and southwestern parts of the continent extended their ranges into Illinois as the Prairie Peninsula expanded into what is now Illinois. Some of these species, such as the yellow mud turtle and western hognose snake, still occur in the state although their ranges have been reduced greatly.
About 4,000 years BP, the climate changed to its current moderate temperature and humidity, with subsequent decrease in area of prairie as mesic forest once again expanded and oak-hickory forest whittled into the prairie from all sides. The seesaw battle between forest and prairie continued for the next few thousand years, controlled by smaller-scale climatic fluctuations and by fires caused by lightning or set by indigenous peoples. The Natural Divisions of Illinois map (Fig. 1) reflects the distributional responses of amphibians and reptiles to the climatic and geologic histories of the state.
The most recent chapter shaping distributions of amphibians and reptiles, especially in prairie habitats, began as Native Americans were replaced by European settlers who had little interest in maintaining prairie plants through periodic burning, but instead controlled wildfires and broke the prairie sod for agriculture. These settlers drained the extensive prairie marshes and brought them under cultivation. Thus, an entire ecosystem was nearly eliminated, as were some amphibians and reptiles adapted to it. During the past 100 years, urban development, road construction, forest fragmentation, siltation and chemical pollution of streams, containment of major rivers within levees, and drainage of wetlands have further altered and fragmented ranges of amphibians and reptiles.
Endangered and Threatened Species
In 1972, the Illinois legislature passed the Illinois Endangered Species Protection Act to control exploitation of animals and plants and prevent their continued loss. The act has been revised several times. Under provisions of the act, permits are required to possess, take, transport, sell, offer for sale, give, or otherwise dispose of individuals of any species protected by either the Illinois or the federal endangered species act. By definition, a State Endangered Species is any species that is in danger of extinction as a breeding species in Illinois. A State Threatened Species is any breeding species that is likely to become a state endangered species within the foreseeable future in Illinois. Decisions to list are made by the Illinois Endangered Species Protection Board (appointed by the governor) with advice from Endangered Species Technical Advisory committees composed of experts from around the state. Seven amphibians and fifteen reptiles currently are state-listed. They are listed here as they appear in the Checklist of Endangered and Threatened Animals and Plants of Illinois, produced by the Illinois Endangered Species Protection Board.
|
Common Name |
Species |
Status |
|
Silvery salamander |
Ambystoma platineum |
Endangered |
|
Hellbender |
Cryptobranchus alleganiensis |
Endangered |
|
Dusky salamander |
Desmognathus fuscus |
Endangered |
|
Jefferson salamander |
Ambystoma jeffersonianum |
Threatened |
|
Four-toed salamander |
Hemidactylium scutatum |
Threatened |
|
Bird-voiced treefrog |
Hyla avivoca |
Threatened |
|
Illinois chorus frog |
Pseudacris streckeri |
Threatened |
|
Alligator snapping turtle |
Macroclemys temminckii |
Endangered |
|
Spotted turtle |
Clemmys guttata |
Endangered |
|
River cooter |
Pseudemys concinna |
Endangered |
|
Illinois mud turtle |
Kinosternon flavescens |
Endangered |
|
Blanding's turtle |
Emydoidea blandingii |
Threatened |
|
Coachwhip |
Masticophis flagellum |
Endangered |
|
Broad-banded water snake |
Nerodia fasciata |
Endangered |
|
Eastern massasauga |
Sistrurus catenatus |
Endangered |
|
Eastern ribbon snake |
Thamnophis sauritus |
Endangered |
|
Kirtland’s snake |
Clonophis kirtlandii |
Threatened |
|
Great Plains rat snake |
Elaphe guttata emoryi |
Threatened |
|
Western hognose snake |
Heterodon nasicus |
Threatened |
|
Mississippi green water snake |
Nerodia cyclopion |
Threatened |
|
Flathead snake |
Tantilla gracilis |
Threatened |
|
Timber rattlesnake |
Crotalus horridus |
Threatened |
Collecting, Keeping, and Permits
Keeping and caring for captive amphibians and reptiles can be an emotionally satisfying and educationally enriching hobby, and recently their popularity as pets has been growing tremendously. Quite naturally, concerns about protecting landowners and depleting natural populations have led to some legal restrictions. For example, the state considers venomous reptiles and "life-threatening" reptiles (crocodilians and large constricting snakes) to be dangerous. It is illegal to keep them, and licensed pet stores may not sell any boa or python over six feet long. Because of concerns about infections of salmonella, it is illegal to sell within the United States any turtle with a carapace length under four inches. Many cities have ordinances that ban as pets venomous lizards and snakes as well as large nonvenomous lizards and snakes. You should consult the Illinois Department of Natural Resources and municipal Animal Control Officers for details.
Illinois State law prohibits the use of any wild-caught amphibian or reptile, or any of their parts, eggs, or offspring, for commercial purposes. For personal enjoyment, a person may collect nonlisted Illinois species but none may be sold or traded. They may be captured by any device that is not designed to cause death or serious injury. If released, individuals must be returned to the place where they were captured. Check with the Illinois Department of Natural Resources, Office of Law Enforcement, for details on the capture limits and season. Offspring produced in captivity are exempt from the possession limit for 90 days, but they may not be sold, bought, or traded.
With a valid fishing license one may take turtles (by hand, hook and line, or dip net) and bullfrogs (by hand, hook and line, dip net, gig, pitchfork, spear, or bow and arrow) within designated daily catch and possession limits.
It is illegal to collect within Shawnee National Forest, National Wildlife Refuges, nature preserves, county forest preserves, and all Department of Natural Resources owned or managed areas (state parks, fish and wildlife areas, natural areas, conservation areas, etc.) without appropriate permits. Permission must also be secured from all private landowners.
Because of their limited or historically greatly reduced populations in Illinois, state endangered and threatened species (see list, pp. 7&endash;8), even those not collected in the state, may not be possessed, harbored, cared for, sold, offered for sale, handled, harassed, harmed, or imported without a permit from the Illinois Department of Natural Resources.
Presently, no Illinois amphibian or reptile is listed as federally threatened or endangered but, through a memorandum of understanding between the Illinois Department of Natural Resources and the U.S. Fish and Wildlife Service, the copperbelly water snake is protected as though it were listed.
Habitat Improvement for Amphibians and Reptiles
Human activities have profoundly affected the distribution and abundance of amphibians and reptiles in Illinois. As the state’s natural landscape has been transformed over the past 150 years, natural habitats have been modified and converted to meet human needs, being fragmented by railroads, highways, deforestation, prairie agriculture, and drainage of great expanses of marsh and floodplain swamps. Although the state still has large areas of surface water, it is largely in man-made lakes constructed at the expense of stream habitat. All of these impoundments, and most smaller farm ponds, are stocked with fish that prey on amphibians and reptiles and, in some cases, eliminate them. Channel-ization of other streams has eliminated large areas of floodplain and slough habitats. Faced with such widespread habitat loss, which shows no signs of slowing, amphibians and reptiles can benefit greatly from even modest forms of habitat improvement.
Making habitats more suitable for amphibians and reptiles often is simple if you concentrate on the ecological requirements of particular species: food, shelter, basking sites (for reptiles), egg-deposition sites, larval habitat (for most amphibians), and hibernating sites. Two simple modifications that will benefit most amphibians and many reptiles are (1) excavate small seasonal pools that may dry up in late summer or fish-free permanent ponds in or near woods or fallow fields, and (2) allow emergent and shoreline vegetation to develop naturally. In addition to providing egg-laying sites and habitat for the aquatic larval stages of amphibians, ponds will increase populations of many of the invertebrates fed upon by amphibians, many of which, in turn, are eaten by reptiles. Over the years, many seasonal pools, water-filled tire ruts, and poorly drained lands have been drained, developed, or poisoned for mosquito control. Unfortunately, many species of amphibians and reptiles cannot survive without these aquatic habitats. Managing a pond for amphibians and reptiles is largely a matter of letting nature take its course, and keeping fish and livestock away from it. Logs, rocks, and brush piles along the shores will provide shelter and basking sites.
Reptiles must have access to suitable basking places so they can regulate their body temperature. Good basking places not only allow exposure to direct sunlight but also provide crevices into which individuals can retreat once heated or when threatened by a predator. Brush and rock piles along edges of woodlands, fields, ditches, and streams can meet these needs and encourage populations of prey organisms (invertebrates and small rodents) as well. The key to managing a woodland for amphibians and reptiles is habitat diversity. Dead standing and fallen trees, logs, bark, and small brush piles offer shelter, dens, and places where lizard and snake eggs may be laid as well as increase the availability of food organisms.
Tremendous numbers of amphibians and reptiles perish annually because of a deadly, relatively new predator for which they have no adaptive defense, one that kills but does not eat&emdash;the motor vehicle. Heavy-bodied animals like turtles and large snakes are easily recognized by passing motorists, but lizards, small snakes, frogs, and salamanders flattened into the pavement usually are not. In some places, especially during warm summer rains and during the autumn, the carnage is much greater than most would imagine. During five autumn days in 1991, 150 brown snakes, most of them killed by vehicles, were found on 1.3 miles of secondary hard-surfaced road. Illinois is crisscrossed by gravel roads and hard-surfaced highways. It is estimated that there are over 138,000 miles of roads in Illinois, and it is difficult in much of the state to stray more than a short distance from a road. Amphibians and reptiles cross roads when moving among overwintering sites, summer feeding grounds, nesting sites, or bodies of water where eggs and tadpoles develop. Besides forming barriers to movement among these habitat components, highways warmed by the sun can be fatally seductive to snakes using them to raise their body temperatures after a cool night, or to a frog drawn to insects attracted by automobile or street lights. Closing all highways to protect amphibians and reptiles from this new source of mortality is not practical, but there is no justification for running over them on purpose. At least one gravel road in Shawnee National Forest is closed biannually so amphibians and reptiles can migrate safely between their rocky overwintering sites and summer habitat, and at least one project is attempting to get a state-threatened snake to migrate in tunnels under a road rather than over it. Roads are not entirely harmful to amphibians and reptiles. Many of them are raised above a coarse rocky base that provides underground cavities for shelter and overwintering for some species, and water-filled ditches alongside are excellent summer habitat for many species.
Declining Amphibian Populations
Over the last few years there has been increased concern about worldwide declines and even extinctions of frog and toad species. Habitat destruction and degradation are clearly responsible in most cases but alarming declines have occurred in relatively pristine environments such as the rainforests of eastern Australia and the cloud forests of Costa Rica. Closer to Illinois, biologists in the upper Midwest have been noticing the disappearance of our smallest frog, the cricket frog (Acris crepitans). Until the early 1980s, cricket frogs were among the most common anurans in Illinois, and they could be found in almost every county. Today, only a handful of populations are known from the northern one-third of Illinois. The puzzling part of this observation is that cricket frogs do not appear to be declining in the southern two-thirds of the state. Among the causes that have been suggested for this mysterious observation are buildup of toxic substances (pesticides, heavy metals) in the frogs’ breeding ponds, habitat fragmentation, increased parasite levels, and increased levels of ultraviolet radiation.
The Declining Amphibian Population Task Force (DAPTF) is a global network of biologists and conservationists concerned with the issue of declining amphibian populations. The DAPTF has two primary objectives: (1) to determine the geography and extent of declines and disappearances of amphibians, and (2) to determine the causes of amphibian declines and disappearances. The DAPTF operates through a network of working groups, over 80 of which represent different regions of the world, that collect geographical data on amphibian declines and their causes. Other issue-based working groups are concerned with specific topics, including disease and pathology, monitoring techniques, chemical contaminants, and climatic and atmospheric change. The United States Central Division Working Group includes the states of Iowa, Missouri, Illinois, Indiana, and Ohio.
This guide is intended to aid biologists, naturalists, teachers, land managers, law enforcement officials, and students in the identification of amphibians and reptiles found in Illinois. It is meant to be used in the field, so the characters stressed in the keys and species accounts can be viewed with the unaided eye or, at most, a small hand lens. Occasionally, technical terms are used to describe anatomical features; these terms are defined in the Glossary.
The species are grouped according to systematic relationships: salamanders, frogs, turtles, lizards, and snakes. This means that similar-looking species are usually, but not always, grouped together. The book is set up so that identification can be achieved either by using the traditional dichotomous keys on pages 20&endash;54 or by using the color photographs and "key characters" section included in each species account. The dichotomous keys are the most effective way to identify an animal, but some readers unfamiliar with keys may find the photographs a more user-friendly starting point. Only a handful of the 102 species covered by this guide are distributed statewide; therefore, many species may be eliminated from consideration because they do not occur in the geographic region you are studying.
Explanation of Species Accounts
Each species account has three components: text, photograph, and range map.
Text
Each account lists the common and scientific names of the species. The taxonomic arrangement and names used in this guide follow the expanded third edition of A Field Guide to the Reptiles and Amphibians of Eastern and Central North America (Conant & Collins 1998). Exceptions to this are: Rana sphenocephala is recognized by the International Commission on Zoological Nomenclature as the appropriate name for the southern leopard frog instead of Rana utricularia; Fowler’s toad is treated as a full species, Bufo fowleri; the upland chorus frog is treated as a full species, Pseudacris feriarum; the Mississippi map turtle, Graptemys kohnii, is not recognized as a distinct species; the Ouachita map turtle, Graptemys ouachitensis, is treated as a species distinct from G. pseudogeographica; and the western worm snake is treated as a subspecies, Carphophis amoenus vermis. Each species account contains the following text components: key characters, similar species, subspecies, description, habitat, natural history, and status.
Key characters. This section lists the most useful and prominent features for identification of each species.
Similar species. Many species of amphibians and reptiles are similar in appearance. This section lists one or more species that often are confused with the focal species.
Subspecies. The subspecies designation is used to describe geographic variation in a species. Subspecies are geographically separated throughout most of the species range, but may mix in a narrow zone where they meet. This is known as a zone of intergradation and the individuals in this zone are referred to as intergrades. If subspecies have been described for a species, those known to occur in Illinois are listed in this section.
Description. A more thorough list of characters than those appearing in the Key Characters section is given. Average or maximum size is also given.
Habitat. Amphibian and reptile species display a wide range of habitat preferences. A few are found throughout the state, but most are restricted to a smaller area by such factors as climate, dominant vegetation, and prey items. This section describes the specific habitat attributes for each species.
Natural History. This section lists the activity period, diet, predators, reproductive data, and any unique behaviors for each species.
Status. This section gives information on distribution and abundance in Illinois. If a species has state or federal listing status (endangered or threatened), that is indicated.
Photographs
In most cases, the photographs used in this guide are of Illinois specimens. Exceptions were made for species that are difficult to obtain in Illinois because of rarity. In these cases, specimens from other states were used. The photos are not to scale, so the reader should refer to the text section of the species account for information on size. Inset photos have been provided for some species to show details of diagnostic characters and illustrate differences between adults and juveniles or subspecies. Most of the photographs in this guide were taken by Michael Redmer (MR), free-lance photographer and biologist. Other photos were taken by Scott Ballard (SB), a District Heritage Biologist with the Illinois Department of Natural Resources in Marion; Eric Routman (ER), Assistant Professor in the Department of Biological Sciences at San Francisco State University; R. Wayne Van Devender (RWV), Professor of Biology at Appalachian State University in Boone, North Carolina; and the authors (RAB, EOM, & CAP). Credits are given in the legend of each photo.
Range Maps
The maps show the counties for which a vouchered specimen, photo, or sight record of the focal species exists. The information used to prepare the maps was taken from lists of cataloged specimens or photographs provided by the following collections: Academy of Natural Sciences, Philadelphia; American Museum of Natural History, New York; Auburn University Museum, Auburn, AL; Bobby Witcher Memorial Collection, University of Missouri, Columbia; Burpee Museum of Natural History, Rockford, IL; California Academy of Sciences, San Francisco; Carnegie Museum of Natural History, Pittsburgh; Chicago Academy of Science; Field Museum of Natural History, Chicago; Florida Museum of Natural History, University of Florida, Gainesville; Harlan D. Walley Collection, De Kalb, IL; Illinois Natural History Survey, Champaign; Illinois State Museum, Springfield; Louisiana State University Museum of Natural Science, Baton Rouge; Milwaukee Public Museum; Museum of Comparative Zoology, Harvard University, Cambridge, MA; Museum of Vertebrate Zoology, University of California, Berkeley; National Museum of Natural History, Smithsonian Institution, Washington, DC; Natural History Museum of Los Angeles County; Nebraska State Museum, University of Nebraska, Lincoln; Principia College, Elsah, IL; Minton Herpetological Collection, Indianapolis; Southern Illinois University at Carbondale; Southern Illinois University at Edwardsville; Texas Cooperative Wildlife Collection, Texas A&M University, College Station; Tulane University Museum of Natural History, New Orleans; University of Illinois Museum of Natural History, Champaign; University of Kansas, Museum of Natural History, Lawrence; University of Michigan Museum of Zoology, Ann Arbor; and University of Wisconsin-Stevens Point. Only a fraction of the nearly 28,000 Illinois specimens listed by these collections has been examined by the authors, so these records must be considered tentative. Sight records were taken from the literature, reliable biologists and naturalists, and the Illinois Department of Natural Resources Natural Heritage Database (NHD).
In the range maps, hatching indicates a record is based on data prior to the arbitrary cutoff of 1980; solid indicates post-1980. However, if more than one category of record exists for a species-county combination, the order of precedence is vouchered, photo, then sight-- regardless of the date of the records. This means that a pre-1980 vouchered record takes precedence over a post-1980 photo or sight record. This is potentially misleading because readers may conclude that species have declined in counties where there are no post-1980 records. In some cases declines surely have occurred, but in others the absence of post-1980 records reflects the lack of recent field work in the area or the fact that the species is so common that no one bothered to collect more recent specimens. This problem is not restricted to range maps with a temporal aspect. Keep in mind that all range maps based on data culled from natural history collections or literature records can misrepresent species distributions because it is unlikely that all areas of a given region have been visited with equal frequency. We know, for example, that collection efforts are often greater around large cities, universities, or outstanding natural features. Therefore, it is best to view these maps as rough guides to known locations and avoid inferences about exact distribution or temporal changes in distribution. These maps can also be used to guide future collection efforts to those areas and species currently underrepresented in collections and the literature.
Range maps for several species require additional explanation because of taxonomic confusion. For example, until the 1970s the plains and southern leopard frogs were not recognized as species distinct from the northern leopard frog. Therefore, many cataloged specimens and much of the early literature on the northern leopard frog may actually refer to one or a combination of these species; thus, the range maps of the leopard frogs show only those records that have been explicitly assigned to one of the three species. In most cases the authors or other reliable authorities have examined the specimens. The second problematic group consists of the western and upland chorus frogs, which were considered a single species until recently. Our maps use an arbitrary geographical cutoff to distinguish among these species’ records. In reality the two species’ ranges overlap in southern Illinois. The third problematic group is the gray treefrog complex. Individuals of these two species are distinguishable only by chromosome number, cell size, or mating call. Our range map makes no attempt to distinguish between the two. The final group consists of the false and Ouachita map turtles, which were recognized as distinct species in the 1990s. Our range maps show only those records that have been explicitly assigned to each of the species. Again, the authors or reliable authorities have examined the specimens. Much work remains concerning the distribution of these four groups.
Adpressed limbs - front leg extended backward and the back leg forward in an attempt to overlap the limbs (Fig. 5)
Amplexus - embrace used by amphibians during mating; initiated by the male.
Anal plate - scale(s) that covers the vent (Fig. 27)
Balancer - slender projection on each side of the head of recently hatched salamander larvae
Biphasic - having two distinct parts
Bridge - bony connection between the upper and lower shells of a turtle (Fig. 15)
Carapace - upper shell of a turtle (Fig. 13a)
Cirrus (pl. cirri) - downward projection of the upper lip, below the nostril
Cloaca - internal chamber at the base of the tail that receives the digestive, urinary, and reproductive tracts
Costal grooves - vertical grooves on the side of the body each corresponding to the location of a rib (Fig. 2)
Dorsal - upper surface or back
Dorsolateral fold - ridge or fold of skin along the side of the back of frogs (Fig. 9)
Eft - terrestrial stage in newt’s life cycle between metamorphosis and first return to breeding pond as aquatic adult
Femoral - referring to the thigh region
Fossorial - living mainly underground, burrowing
Gill filament - smallest (secondary) branch of the external gill (Fig. 3)
Gill ramus (pl. rami) - stouter, central (primary) branch of the external gill; the filaments project from the rami (Fig. 3).
Gill slit - the slit or hole through which water passes from the throat to the exterior (Fig. 3)
Gravid - full of eggs
Groin - where the thigh attaches to the body on the belly
Gular fold - a fold of skin across the throat (Fig. 3)
Hedonic - pertaining to stimulation during courtship
Hemipenis - one of the paired, protrusible, copulatory organs of male lizards and snakes
Intergradation - interbreeding among members of two or more subspecies along a zone of contact
Keratinized - covered with a hard, horny substance (keratin) similar to fingernails
Larva (pl. larvae) - the immature form; in amphibians, aquatic with fins and gills
Maxillary - pertaining to the upper jaw
Mental - on the underside of the chin
Metamorphosis - the change or transformation from larva to juvenile
Nasolabial groove - slit or furrow from the nostril opening to the upper lip (Fig. 4)
Operculum - flap of skin covering the gill slit
Oviduct - tube that carries eggs to the cloaca
Parotoid gland -&endash; poison-producing gland on the top of a toad’s head, usually behind the eye
Plastron - bottom part of a turtle’s shell (Fig. 13b)
Polyploid - having more than the usual two sets of chromosomes
Riparian - found along rivers and streams
Scute - large scale, especially in turtles (Fig. 16)
Snout-vent length - distance between the tip of the snout and the posterior end of the vent
Spermatophore - structure produced by most male salamanders that includes a gelatinous stalk with a packet of sperm on top
Tibial - referring to the lower leg or tibia (Fig. 9)
Tympanum - rounded, external eardrum on the side of the head (Fig. 9)
Tympanic fold - fold of skin around the eardrum
Vent - external opening of the cloaca
Ventral - underside or belly
Vernal &endash; pertaining to the spring season
Vomeronasal organ - organ located in the roof of the mouth of a snake and used for smelling or tasting particles picked up from the air by the tongue
Yolk sac - small external sac of nutrients carried by hatchlings
ORDER CAUDATA &emdash; SALAMANDERS
Twenty species of salamanders, representing six families, occur in Illinois. They are secretive, being most active at night, and may be the least observed of the state's amphibians and reptiles. Although resembling lizards in body form (head, trunk, tail, usually four legs), salamanders live in water or in cool, high-humidity environments in or near the ground where they feed on a variety of other small animals. Salamander skin is thin, scaleless, and covered with a layer of moisture secreted by glands.
The hellbender (family Cryptobranchidae), mudpuppy (family Proteidae), and lesser siren (family Sirenidae) spend their entire lives in lakes, ponds, permanent streams, or swamps where they sometimes are encountered by fishermen. The eastern newt (family Salamandridae) is peculiar in having three life stages: adults that live and breed in lakes and ponds, aquatic larvae, and a terrestrial juvenile stage called the eft. The eight species of mole salamanders (family Ambystomatidae) live in and under rotting logs and in burrows in the forest floor, emerging, usually at night, during heavy rain and during the annual breeding season. Adults sometimes are observed crossing highways as they migrate to breeding ponds on rainy spring or autumn nights. They court and deposit eggs in ponds and temporary pools where their larvae can be found feeding and growing during spring and early summer. The remaining eight terrestrial or streamside species, the lungless salamanders (family Plethodontidae), seldom are active on the surface of the ground except at night, usually following rain. Because they respire through their skin and dry out easily, these animals live mostly under moist leaves, logs, and rocks, or in burrows in the ground. Some lungless salamanders are more common around caves, springs, or spring-fed streams (cave, four-toed, longtail); some along banks of small, rocky streams (dusky, southern two-lined); and others in forest floor litter (redback, zigzag, slimy).
Most adult salamanders are relatively easy to identify by distinctive coloration or pigment distribution, number of legs and toes, presence or absence of a nasolabial groove, presence and number of costal grooves, and body proportions. However, larvae and juveniles can be difficult to identify immediately after metamorphosis. Sometimes larvae are best identified by allowing them to transform and develop adult coloration.
Four salamanders have very limited distributions within Illinois: the silvery salamander is a biologically peculiar all-female species known from only one natural population; the dusky salamander occurs in only two counties; the four-toed salamander is a relic from an earlier climatic era; and the hellbender was, until recently, considered extirpated from the state. Many populations of other species have been eliminated, reduced, or fragmented through loss of habitat: draining of wetlands, channelizing of streams, reduction of temporary ponds and sloughs, and clearing of forests.
In the species accounts that follow, size is given in "cm TL," which is the straight line length from the tip of the nose to the end of the tail, given in centimeters. The maximum size listed in the "Description" section for each species is the greatest TL recorded for specimens in Illinois unless otherwise stated.
ORDER ANURA &emdash; FROGS & TOADS
Twenty-one species of frogs and toads representing five families occur in Illinois. Although usually secretive, these species may be the most conspicuous of the amphibians and reptiles in the state during the breeding season because of the loud vocalizations of the males. Also, frogs and toads have a unique body form. While salamanders may be confused with lizards, frogs and toads are unmistakable because of their short bodies, large heads, and enlarged hind legs. Like salamanders, most frogs and toads live in water or in cool, high-humidity environments in or near the ground. Also like salamanders, they lack scales and have a thin, respiratory skin covered with a layer of moisture secreted by glands. Because of their thicker skins, Illinois' two species of toad (family Bufonidae) can withstand slightly drier conditions than frogs. The treefrogs (family Hylidae) are distinctive in having adhesive disks (toe pads) at the ends of their toes (toe pads of some species are large, of others quite small). The true frogs (family Ranidae) probably are the most familiar members of the order Anura, and include the common leopard frogs and the bullfrog, which is the largest species in Illinois. Two families are represented in Illinois by only one species each. The eastern spadefoot (family Pelobatidae) and eastern narrowmouth (Microhylidae) often are called toads, but lack the extensive warts and cranial crests of true toads (family Bufonidae).
Most adult frogs and toads can be identified by presence or absence of toe pads, dorsolateral folds on the back, parotoid glands on the head, and the amount of webbing between toes. Tadpoles, however, present a challenge and are best identified by allowing them to transform and develop juvenile coloration.
The Illinois chorus frog has a limited distribution within the state and is restricted to sandy soils. Cricket frog populations appear to be declining in the northern third of the state. Many populations of other species have been eliminated, reduced, or fragmented through loss of habitat: draining of wetlands, channelization of streams, reduction of temporary ponds and sloughs, and clearing of forests (see "Declining Amphibian Populations," p. 12).
In species accounts, size is given as "cm SVL," the straight line length from the tip of the nose to the anal opening, in centimeters. Maximum size is the greatest recorded for a specimen from Illinois unless stated otherwise.
ORDER TESTUDINES &emdash; TURTLES
Turtles are among the most distinctive reptiles. Salamanders can be confused with lizards, and legless lizards can be confused with snakes, but the unique shell identifies a turtle beyond doubt. Turtles dwell in forests, prairies, marshes, swamps, ponds, lakes, streams, and rivers. Because of their penchant for basking, many species are conspicuous on sunny days as they line almost every log and sand bank within the habitat. In the spring, turtles are also regularly encountered crossing highways as they search for new habitats, mates, or nesting sites. All species of turtle in Illinois bury their eggs in the soil. Seventeen species representing four families inhabit the state. The majority (11 species) are pond and box turtles (family Emydidae) while the mud turtles (family Kinosternidae) have three species, and the snapping turtles (family Chelydridae) and softshell turtles (family Trionychidae) contain two species each.
Fortunately, most adult turtles can be identified by their shell alone because newly captured animals typically retract their soft parts (i.e., head, neck, legs, and tail) within the shell making viewing difficult. Useful shell characteristics include a covering of scutes (large horny scales) or leathery skin, a hinged or solid plastron, and the number of plastral and marginal scutes. Should examination of the soft parts be necessary, a stubborn turtle can sometimes be coaxed into extending its head and neck by submergence in water or by picking it up by the rear edge of the shell so that the head hangs downward.
A number of turtles are of conservation concern. The yellow mud turtle, river cooter, alligator snapping turtle, and spotted turtle are state listed as endangered and Blanding's turtle as threatened. Furthermore, many of the other species are declining. A variety of causes may be cited but most are closely tied to human activity. Most problems either result directly from purposeful exploitation by humans or indirectly from habitat alteration. Direct causes include exploitation for food (usually snappers and softshells) and for the pet trade. Untold numbers are killed by automobiles as they attempt to cross highways. Many are drowned in fishing nets set below the surface or are killed when they are caught on fishermen's hooks. Others are killed by irresponsible riflemen who inexplicably require living organisms for target practice. Indirect causes include draining of wetlands, pollution and siltation of aquatic habitats, and straightening of streams and rivers.
In the species accounts that follow, size is given in "cm CL," which is the straight line length of the carapace (upper shell) given in centimeters. The maximum size listed in the "Key Characters" section for each species is the greatest CL recorded for specimens in Illinois unless otherwise stated.
ORDER SQUAMATA, SUBORDER SAURIA &emdash;LIZARDS
Lizards are most often confused with salamanders because of similarities in overall body plan (usually four limbs and a long tail). The exceptional glass lizard (Ophisaurus attenuatus) is a limbless burrowing species. In contrast to the smooth-skinned, moist salamanders, however, all lizards are covered with dry scales. All of the lizards in Illinois except one are small to medium-sized and, therefore, are inconspicuous. There are only six native species of lizard in Illinois representing four families: the fence lizard (family Phrynosomatidae), three skinks (family Scincidae), the six-lined racerunner (family Teiidae), and the legless slender glass lizard (family Anguidae). A seventh species, the collared lizard, has been introduced into a small portion of Johnson County. Lizards are most abundant in the southern third of the state in forests, glades, and rocky bluffs.
Distinguishing between two of the three skinks can be difficult and relies on detailed counts of very small head scales; the third is rather distinctive. No lizard is listed as endangered or threatened in Illinois.
In the species accounts, size is given in "cm TL," which is the straight line length in centimeters from the tip of the nose to the end of the tail. Maximum size is the greatest TL recorded in Illinois, unless otherwise stated.
ORDER SQUAMATA, SUBORDER SERPENTES &emdash; SNAKES
Snakes can be confused only with legless lizards; however, snakes lack eyelids and ear openings. In Illinois there are 38 snake species representing two families. The majority (34 species) are in one family, the Colubridae, and the remaining 4 species are the venomous vipers (family Viperidae). Snakes can be found in every natural habitat in Illinois, and are often encountered basking in sunny areas or crossing highways as they move to and from den sites in the spring and fall.
Useful characteristics for identifying snakes include whether each scale has a ridge down the middle (keeled) or not (smooth) and whether the scale over the anal opening is single or divided. All snakes in Illinois have small overlapping scales on the back and sides and wide, rectangular plates on the belly. Coloration and pattern on the belly often contrast with the back and sides.
A number of snakes in Illinois are of conservation concern, notably the venomous species. Many are killed out of fear and ignorance, but the majority are killed inadvertently by automobiles on highways. Other snakes that are of conservation concern include species whose ranges barely include Illinois: the western hognose, a relic from an earlier climatic era, and Kirtland's snake, a species restricted to undisturbed wet prairie.
In the species accounts that follow, size is given in "cm TL," which is the straight line length from the tip of the nose to the end of the tail, given in centimeters. The maximum size listed in the "Key Characters" section for each species is the greatest TL recorded for Illinois specimens unless otherwise stated.
Species of Questionable Occurrence in Illinois
Tremblay's Salamander Ambystoma tremblayi
This unisexual member of the A. jeffersonianum complex was accidentally introduced to a pond in Cook County in the late 1970s. Recent surveysindicate that this all-female species has colonized neighboring ponds.
Three Toed Box Turtle Terrapene carolina triungus
This subspecies of the common box turtle is not considered native to Illinois. Over the last several years, four individuals have been captured along the Mississippi River in western Illinois. Because the three-toed box turtle is an inhabitant of adjacent Missouri, these individuals may have crossed the river by swimming or during flood events. It is also possible that they were introduced into Illinois by humans.
Scarlet snake Cemophora coccinea
The only Illinois specimen of this species, SIUC-R 1048, was collected by F.R. Cagle at Wolf Lake Swamp in Union County, It was originally catalogued as Lampropeltis triangulum syspila, but later identified as Cemophora coccinea by Phil Smith, noted herpetologist at the Illinois Natural History Survey. Repeated searching of Wolf Lake and the slopes of adjacent Pine Hills Recreation Area, thought to be more suitable habitat, has not yielded any additional specimens. Phil Smith accepted the record as valid, based mainly on similar isolated records for this species in Indiana and Missouri.
Additional Reading
Ballard, S.R. 1996. Don’t let these snakes rattle you!! Illinois Audubon, Spring 1996 (256):4-7.
Ballard, S.R. 1994. Threatened and endangered Illinois herpetofauna. The Illinois Steward 3(3):23-26.
Brandon, R.A., and S.R. Ballard. 1996. Are frogs, toads and salamanders declining in Illinois? Illinois Audubon, Winter 1996-97 (259):4-9.
Conant, R., and J.T. Collins. 1991. A field guide to reptiles and amphibians of eastern and central North America [Peterson field guide series]. 3d ed. Houghton Mifflin Co., Boston & New York. xx + 450 pp.
Dreslik, M.J, E.O. Moll, C.A. Phillips, and T.P. Wilson. 1997. The endangered and threatened turtles of Illinois. Illinois Audubon, Winter 1997-98 (263):10-15.
Garman, H. 1892. A synopsis of the reptiles and amphibians of Illinois. Illinois Laboratory of Natural History Bulletin 3(13):215-388.
Johnson, T.R. 1987. The amphibians and reptiles of Missouri. Missouri Department of Conservation, Jefferson City. 368 pp.
Lueth, F.X. 1941. Manual of Illinois snakes. Illinois Department of Conservation, Springfield. 48 pp.
Minton, S.A. 1972. Amphibians and reptiles of Indiana. Indiana Academy of Science Monograph No. 3:1-346.
Moll, E.O. 1997. Illinois' yellow mud turtle. The Illinois Steward 6(1):16-19.