Common Gartersnake Thamnophis sirtalis

Subadult from Lake County

Identification

Gartersnakes and ribbonsnakes are Indiana's only distinctively striped snakes and this is the most common and widespread species of the group. They vary in color from gray-green to dark brown and, in rare cases, entirely black (melanistic). Most Common Gartersnakes have a light brown to white dorsal stripe extending from just behind the head to the tail and lateral stripes that nearly merge with the light brown-tan underbelly. Though some large female Common Gartersnakes may exceed four feet (1.2 m) in length, most adults are under three feet (1 m).

Plains Gartersnakes occur in the northwestern corner of the state and have an orange dorsal stripe and black spots between the lateral stripes and the underbelly. Butler's Gartersnakes are smaller and seldom seen in Indiana. They have a relatively smaller head and an indistinct neck. Both Eastern Ribbonsnakes and Western Ribbonsnakes are slender, elongate snakes with much longer tails that are more often found around aquatic habitats. While Common Gartersnakes have lateral stripes on scale rows two/three (counted up from the belly scales), all other Indiana Thamnophis have lateral stripes on scale rows three/four. DeKay's Brownsnakes are superficially similar to young Common Gartersnakes, but lack distinct stripes.

Ecology and Conservation

Common Gartersnakes are true generalists; they are found in nearly every habitat and eat a wide variety of vertebrate and invertebrate prey. Like other natricine snakes, Common Gartersnakes give live birth in the summer.

These are common, widespread snakes and are not of conservation concern.

Distribution

Common Gartersnakes occur throughout Indiana and may be found in nearly any habitat, including urban and suburban lots, parks, yards, and gardens. These snakes are most abundant in grassy, open habitat with ample moisture; such as wet meadows and stream margins.

Taxonomy

Several subspecies of the Common Gartersnake (Thamnophis sirtalis) are recognized. Indiana is home to the Eastern Gartersnake (T. s. sirtalis) throughout most of the state and the Chicago Gartersnake (T. s. semifasciatus) in the northwestern part of the state. 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 Common Gartersnake (Thamnophis sirtalis)
Photographs