HerpIndiana

Eastern Gartersnake (Thamnophis sirtalis)

Adult from Boone County

Description

A medium-sized brownish to olive-colored snake with a distinct dorsolateral stripe. The underbelly can be light yellow or blue-green in coloration. Adult Gartersnakes rarely grow to much over 3ft in length. Usually 7 upper labials, 10 lower labials, and 19 midbody scale rows. The anal plate is undivided and dorsal scales are heavily keeled. Juveniles are similar to a adults, but tend to be darker with a less distinct pattern. (Minton 2001, 251-252).

Distribution

Eastern Gatersnakes are common throughout Indiana (Minton 2001, 252).

Activity

Gartersnakes are generally active from sometime in March to October (Minton 2001, 253-254).

Taxonomy

The Common Gartersnake (Thamnophis sirtalis sirtalis) occurs throughout most of Indiana. The Chicago Gartersnake (Thamnophis sirtalis semifasciatus) is restricted to the northwestern portion of the state. The Eastern Gartersnake belongs to the genus Thamnophis and is in the family Natricidae which is represented in Indiana by 13 different species.

Natural History

Gartersnakes are generalists and are found in almost all habitat types. They are most prevalent in open, marshy areas or riparion environs. This species tolerates habitat alteration well and is a common snake in suburban yards and vacant city lots. They have a very varied diet, but take earthworms, toads, frogs, and salamanders with more frequency. Fish, Insects, small mammals, and small reptiles are also occasionally eaten. Birds, small mammals, other snakes, fish and domestic pets will prey on this species. Mating usually occurs shortly after emergence from hibernation. Females bare live young, usually some time in late summer (Minton 2001, 252-256).