Photo by Chris Brown

Scientific name: Thamnophis sirtalis infernalis

Common name: California Red-Sided Garter Snake

Size: 15-30 in (38-77 cm)

Distinguishing characters: A slender species; dark olive to nearly black ground color with red blotches; head olive; yellow mid-dorsal and lateral stripes well defined; yellow-green or blue venter; eyes well defined; dorsal scales keeled; red tongue.

Juveniles: Similar to adults.

Dimorphism: Female has extremely constricted tail immediately posterior to vent.

Similar species: Thamnophis hammondii: Lacks mid-dorsal stripe; no red markings on sides. Thamnophis elegans: Has mid-dorsal stripe and solid dark sides; lacks red blotches; only occurs in the San Bernardino Mountains.

Additional notes: A rare snake within study area, but apparently associated with extensive riparian systems. Excretes foul smelling musk when handled.

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fieldguide/thsi.htm
Last update: 05 March 2003