Prairie Research Institute

Illinois Natural History Survey

In Illinois, 25 reptile and 15 amphibian species are listed as Species in Greatest Conservation Need. Unfortunately, this means that more than 25 percent of our herpetofauna require conservation action. INHS herpetologists survey at-risk species of amphibians and reptiles as part of long-term projects with the Illinois Tollway in the Chicagoland area and the Illinois Department of Transportation to ensure that transportation infrastructure initiatives will have minimal adverse effects on these species. In addition, INHS herpetologists work closely with numerous non-profit and governmental land management and conservation agencies to recover imperiled species.

Collaboration, both internal to and outside of the organization, is key to the amphibian and reptile research conducted at INHS. For example, INHS scientists collaborate with those from the National Great Rivers Research and Education Center on several projects, ranging from assessments of bottomland forest amphibian and reptile communities to the demographic processes of treefrogs and pond breeding salamanders. Collaboration is also evident among INHS scientists and the county-level forest preserve districts throughout Illinois.


Survey methods to study amphibians and reptiles vary by species, habitat, and even by season. For example, pond-breeding amphibians are best surveyed during the breeding season when they congregate at wetlands. During this time, some frogs can be identified by their unique breeding calls. Other sampling methods include minnow traps, dip nets, or by hand. Stream and seep/marsh-dwelling salamanders are surveyed by visual encounters, transect surveys, or time-constrained searches, where researchers visually search an area, distance, or a time period, examining all possible hiding spots to find the species.

Herpetologists conduct field surveys to determine potential adverse impacts of transportation initiatives on species and their habitats and provide suggestions to minimize these impacts. They are also active in mitigation and restoration projects to offset any negative impacts that may occur.

Environmental DNA

Another way to study amphibians and reptiles is through environmental DNA (eDNA). Snakes, lizards, salamanders, and other species constantly shed saliva, scales, and other material, leaving detectable traces of their DNA in the environment. Conservation biologists harness the power of this eDNA to determine whether species are present in a given ecosystem. Scientists collect samples from the environment rather than the organism (water from streams and fecal matter, for example), isolate and sequence DNA from the samples, and compare the resulting DNA sequences to that of the species they’re trying to detect.

Read more about INHS environmental DNA research.


In the Phillips Herpetology Lab researchers study diseases that impact the health and future wellbeing of amphibian and reptile species in Illinois and beyond. Current research includes assessing the prevalence and impact of various diseases, including chytridiomycosis, a disease of North American amphibians caused by a chytrid fungus; ophidiomycosis, an emerging infectious disease of snakes caused by the fungus Ophidiomyces ophiodiicola; and various infectious diseases of eastern box turtles (ranavirus, herpesvirus, and mycoplasma).

Read more about INHS infectious disease research.

Long-term demography

The Population and Community Ecology Lab’s major research focus is the demography and life history of amphibians and reptiles to aid conservation action. Most work has focused on the eastern massasauga (Sistrurus catenatus) and several turtle species. Work on the eastern massasauga began in 1999, and the demographic data collected have been used for recovery planning and for the federal listing process. Other long-term studies focus on the Blanding’s turtle (Emydoidea blandingii), eastern box turtle (Terrapene carolina), ornate box turtle (Terrapene ornata), and spotted turtle (Clemmys gutatta) at various sentinel sites across Illinois.

INHS scientists have joined with the Forest Preserve District of Will County to study Illinois’ remaining spotted turtle populations to create a 30-year data set. Additionally, similar work and collaboration have been done with the Illinois Department of Natural Resources to augment a 30-year monitoring data set for the ornate box turtle. Because turtles tend to be long-lived, we must understand how long-term processes affect their populations to recover them.

Recovery action

Much of the amphibian and reptile research conducted at the INHS is geared toward recovery and conservation applications. Such work includes assessments of head-starting efforts, population projections, and guiding management-related activities.

Alligator snapping turtle

In collaboration with the Illinois Department of Natural Resources, INHS scientists have been releasing head-started alligator snapping turtles in southern Illinois since 2014 for recovery. The work has shown recovery in Illinois may be impossible due to high mortality levels from predators, illegal fishing with traps, and habitat degradation.

Spotted turtle

Monitoring of spotted turtle populations revealed the two existing Illinois populations are likely to decline in the future, with numbers bottoming out in 10 to 15 years for the more vulnerable one. The predicted declines resulted in recommended conservation strategies, such as predator control and habitat restoration.

Ornate box turtle

When considering ornate box turtles, although prescribed burns are necessary to maintain habitat, they could have an adverse effect if timed inappropriately. INHS herpetologists gathered data about dates of turtle emergence from brumation to better inform decisions about the timing of prescribed burns in the turtles’ range.

Vernal and semi-permanent wetlands

Semi-permanent and seasonal wetlands provide essential habitat for amphibians. In Illinois, however, about 90 percent of these historical wetlands have been lost, causing concern about local amphibian species extirpation and widespread decreases in populations. INHS scientists sample wetlands in Illinois to assess the abundance of adults during the breeding season and determine how climate and environmental factors affect amphibians’ pond use and productivity. Additionally, they examine source-sink dynamics and recruitment from both natural and created wetlands. Researchers also study plant diversity and water chemistry in wetlands to understand the conditions that may affect amphibian recruitment.

Scientists study various bottomland forests and swamp habitats in southern Illinois to provide land managers with information on the quality of habitats and the distribution and abundance of amphibians and reptiles living there.

Amphibian and Reptile Collection

INHS houses two herpetology collections, the INHS Amphibian and Reptile Collection (INHS) and the University of Illinois Museum of Natural History Amphibian and Reptile Collection (UIMNH), for which INHS took over curation and management in 1997. The two collections were not merged, but no new specimens are being added to the UIMNH collection. Information about the UIMNH collection, including a searchable database of holdings and an updated Catalogue of Primary Types, can be found at the University of Illinois Museum of Natural History webpage.

The INHS Amphibian and Reptile Collection contains approximately 30,000 cataloged specimens, representing 55 families and over 550 species (51 percent Amphibia, 49 percent Reptilia). The Illinois emphasis (75%) is from Phil W. Smith’s 1935 to 1949 collections for his 1961 comprehensive study “The Amphibians and Reptiles of Illinois.” In addition to the Illinois material, the INHS collection also houses specimens from 45 other U.S. states, Canada, the Caribbean, Mexico, South America, Asia, Africa, and Europe. Most notable among these are specimens collected by Phil W. Smith from California (1943–1952) and Mexico (1957–1965); specimens of S.A. Minton from Pakistan, Mexico, and Texas; and specimens from Thailand collected by R.W. Larimore (1963). The Illinois Natural History Survey Amphibian and Reptile Collection database is available online.

INHS also maintains a tissue collection that contains high-quality tissues from a portion of their vouchered specimens, primarily those collected after 1998.

Read more about all INHS biological collections.


An updated second edition of the Field Guide to Amphibians and Reptiles is available for order from the University of Illinois Press. This manual offers up-to-date information on the state’s 102 species of frogs and toads, salamanders, turtles, lizards, and snakes. Detailed descriptions by authors Christopher A. Phillips, John A. Crawford, and Andrew R. Kuhns include habitats, distinguishing features, behaviors, and other facts, while revised range maps and full-color photographs help users recognize animals in the field. In addition, an identification key and easy-to-navigate page layouts guide readers through extensive background material on each species’ population, diet, predators, reproduction, and conservation status.

Other online resources include keys to identify Illinois’ frog, toad, salamander, turtle, snake, and lizard species and Illinois distribution by county and species.