Species of the Month

California Red-sided Garter Snake (Thamnophis sirtalis infernalis)

California Red-sided Garter Snakes are commonly found on Humboldt Bay National Wildlife Refuge. Gartersnakes have toxins in their saliva which are deadly to their prey, but their bite is not considered dangerous to humans. Garternsnakes will release cloacal contents and musk when handled and may strike.

Adult gartersnakes are anywhere from 18 to 55 inches in length, but the average adult size is under 36 inches. Garternsnakes are primarily active during daylight and are good swimmers, often escaping into the water when threatened. A good place to look for gartersnakes on the refuge is near the Richard J. Guadagno Memorial plaque or hiding in the cover of the native plant garden on sunny days.

Gartersnakes eat a wide variety of prey, including amphibians and their larvae, fish, birds, bird eggs, small mammals, reptiles, earthworms, slugs and leeches. Mating occurs in the spring (and possibly the fall) and young are born live from spring to fall.

California Red-sided Gartersnakes range from Humboldt County south, along the coast ranges (excluding much of the San Francisco peninsula) and east of the San Francisco Bay to just below Monterey Bay where T.S. fitchi drops out in Santa Barbara County south along the coast to San Diego County. Gartersnakes utilize a wide variety of habitats- forests, mixed woodlands, grassland, chaparral, farmlands, often near ponds, marshes, or streams.

Watchable Wildlife Brochure (344K pdf)