- Cool, dry conditions limit Yellowstone's reptile to six species.
- Population numbers for these species are not known.
- Reptiles: prairie rattlesnake, bull snake, valley garter snake, wandering garter snake, rubber boa, sagebrush lizard.
Yellowstone is home for a small variety of reptiles. Glacial activity and current cool and dry conditions are likely responsible for their relatively low numbers in Yellowstone.
In 1991 park staff began cooperating with researchers from Idaho State University to sample additional park habitats for reptiles and amphibians. This led to establishment of long-term monitoring sites in the park. The relatively undisturbed nature of the park and the baseline data may prove useful in testing hypotheses concerning the apparent declines of several species of toads and frogs in the western United States. Reptile and amphibian population declines may be caused by such factors as drought, pollution, disease, predation, habitat loss and fragmentation, introduced fish and other non-native species.
Although no Yellowstone reptile or amphibian species are currently listed as threatened or endangered, several–including the boreal toad–are thought to be declining in the West. Surveys and monitoring are underway to try to determine if amphibian populations are declining in Yellowstone National Park.