• Steam rises off of the colorful Mammoth Hot Springs Terraces. Photo courtesy Jacob W. Frank


    National Park ID,MT,WY


wandering garter snake
Wandering garter snake (Thamnophis elegans vagrans) is the most common reptile in the park, but small size and limited habitat make it a rare sighting.
NPS/Jeff Arnold

Yellowstone is home for a very small variety of reptiles. Glacial activity and current cool and dry conditions are likely responsible for their relatively low numbers in Yellowstone. Population numbers for reptile species are currently unknown.

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.

Reptiles in Yellowstone

  • prairie rattlesnake
  • bull snake
  • valley garter snake
  • wandering garter snake
  • rubber boa
  • sagebrush lizard.

Did You Know?