Sierra Garter Snake

Thamnophis couchii

The Sierra garter snake, Thamnophis couchii, is a semi-aquatic garter snake of California's Sierra Nevada and nearby mountain drainages. It is usually seen close to rocky streams, spring runs, lakes or wet meadows, where it basks at the edge and slips into the water when alarmed. Color varies by locality, but many are olive, brown or dark gray with muted side stripes, checkering and strongly keeled scales. Like other garter snakes, it gives birth to live young and takes small aquatic prey such as fish, tadpoles, frogs and invertebrates.

This is not a routine pet-shop snake, and collecting wild garter snakes is often restricted. Specialist or rehabilitation housing needs clean cool water, a dry basking area, dense cover and secure lids, with minimal handling to reduce stress. In the field, stewardship centers on healthy stream margins, clean runoff and connected wetland habitat. Surveys may also track the effects of drought, water diversion, nonnative trout and amphibian declines, since these snakes are closely tied to aquatic food webs.