Plains Gartersnake Thamnophis radix

Adult from Lake County

Identification

At first glance, this snake is similar to its eastern counterpart, but this species's vibrant colors and restricted range sets it apart. Plains Gartersnakes are dark brown to black snakes with a yellow to orange dorsal stripe and lighter lateral stripes. Though adult females may grow to over three feet (1 m) in length, most adults are around two feet (60 cm) long.

Subadult from Lake County

Common Gartersnakes occur alongside Plains Gartersnakes in northwestern Indiana but tend to have a less vibrant dorsal stripe (never orange) and are often lighter in color. Upon close examination the lateral stripes are also positioned lower on Common Gartersnakes (scale rows two/three) than on Plains Gartersnakes (scale rows three/four). Eastern Ribbonsnakes and Western Ribbonsnakes are overall very similar, but tend to be notably slimmer with a longer tail.

Ecology and Conservation

Plains Gartersnakes are found in open moist grassy areas usually around marshes, peat bogs, or lake borders. In general, these snakes are not found in well drained, sandy areas. However, they can be found around vacant urban lots. Their diet is similar to that of the Common Gartersnake and consists of earthworms, insects, and small amphibians and their larvae.

The Plains Gartersnake is a State Endangered species in Ohio.

Remnant prairie in Lake County

Distribution

Plains Gartersnakes are a species of the Great Plains and, in Indiana, are only found in the northwestern corner of the state. The distribution of the Plains Gartersnake extends from western Indiana to northwest New Mexico, and north to southern Alberta. Isolated populations exist in Ohio and a continuous region of Illinois and Indiana.

Taxonomy

There are no recognized subspecies of the Plains Gartersnake (Thamnophis radix). These snakes are members of the family Colubridae, which is represented by a total of 28 species in Indiana.

Literature Cited

Conant, R. and J. T . Collins. 1998. Reptiles and Amphibians of Eastern and Central North America. Third Edition, Expanded. Houghton Mifflin, New York, NY.

Minton, S. A. Jr. 2001. Amphibians and Reptiles of Indiana. Indiana Academy of Science, Indianapolis, IN.

Distribution Map
Distribution map of Plains Gartersnake (Thamnophis radix)
Photographs