Aquatic Garter Snake (California Garter Snakes)

Aquatic Garter Snake

Thamnophis atratus

Summary ⁵

Thamnophis atratus or the Aquatic Garter Snake is a species of colubrid snake residing exclusively along the coast of Oregon and California. Two subspecies are currently recognized. One variety of the snake has a blue-gray background color with a faint olive colored dorsal stripe and white dots along its sides. Another morph has a yellow dorsal stripe with black spots along its sides. The second variation is the more classic garter snake look however, due to...

Identification ⁵

Never has any red pigmentation (make sure to check the ventral scales), throat is usually lemon yellow, internasal scales are acute.

Habitat ⁵

Comments: Habitats include rocky fast-flowing streams, sluggish streams with soft bottoms, ponds, small lakes, and the adjacent riparian zone, in areas surrounded by woodlands, woodland-grass ecotones, or chaparral (Nussbaum et al. 1983, Rossman et al. 1996, Ernst and Ernst 2003, Stebbins 2003). This snake basks on boulders and vegetation along banks and in mid-stream; it seeks cover under water under rocks or among exposed tree roots. In most areas this snake is closely tied to water, but individuals sometimes travel on land away from water.

Trophic strategy ⁵

Comments: Forages in water; eats fishes (including sculpins and trout up to 2.4 cm in length), tadpoles (though not especially effective as a predator of bullfrog larvae; Kupferberg, 1994, Herpetol. Rev. 25:95-97), frogs (e.g., RANA BOYLII), salamanders, and salamander (e.g., DICAMPTODON) larvae (Nussbaum et al. 1983, Brown et al. 1995).

Range description ⁵

This species is endemic to the west of the United States. Its range includes southwestern Oregon and western California north of Point Concepcion, at elevations from sea level to around 1,920 m (Nussbaum et al. 1983, Brown et al. 1995, Rossman et al. 1996, Stebbins 2003).

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Range Map

iNat Map

Region	Bay Area, Northern CA

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