Sierra Garter Snake
Thamnophis couchii
An aquatic garter snake restricted to Sierra Nevada foothill streams and rivers of California.
- Venomous?
- Mildly venomous
- Adult length
- 0.5-1.0 m (1.6-3.3 ft)
- Range
- Sierra Nevada foothills and Central Valley drainages of California
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Overview
The Sierra garter snake is a highly aquatic species endemic to California, associated with clear, rocky rivers and streams draining the Sierra Nevada foothills.
It is closely related to and sometimes confused with other members of the aquatic garter snake group, from which it is separated primarily by range and subtle scale characteristics.
How to identify it
- Dark gray to brown background color
- Reduced or faint striping, sometimes appearing largely patternless
- Keeled scales
- Slender, streamlined body
- Round pupils
- Distinguished from related species mainly by its restricted Sierra Nevada foothill range
Habitat & range
Restricted to rocky, flowing rivers and streams in the Sierra Nevada foothills and adjacent Central Valley drainages of California, rarely straying far from water.
Behavior, diet & reproduction
Strongly aquatic, foraging in and along streams for fish and amphibian larvae. Basks on rocks and vegetation near water and dives in readily when disturbed. Gives birth to live young in summer.
Frequently asked questions
Where is the Sierra garter snake found?
It is restricted to foothill streams and rivers draining the Sierra Nevada in California.
Is it venomous?
It has mild venom for prey but is not a threat to humans.
How does it differ from other aquatic garter snakes?
It is separated mainly by its limited range in the Sierra Nevada foothills rather than obvious pattern differences.
What does it eat?
It primarily hunts fish and amphibian larvae in flowing water.
Sierra Garter Snake guides
In-depth guides for identifying and understanding Sierra Garter Snake.
