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San Francisco Garter Snake Thamnophis sirtalis infernalis (Thamnophis sirtalis tetrataenia)


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Family: Colubridae, Colubrid Snakes view all from this family

Description 18-51" (46-131 cm). One of North America's most beautiful snakes. Yellowish-green stripe down back; black-bordered red stripe on each side. Top of head red. Belly greenish-blue. Usually 7 upper lip scales. Scales keeled, in 19 rows. Anal plate single.

Endangered Status The San Francisco Garter Snake, a subspecies of the Common Garter Snake, is on the U.S. Endangered Species List. It is classified as endangered in California. This subspecies has suffered as its habitat, in San Mateo County, has been consumed by urban growth. The residential and industrial development of the Bay Area and the attendant degradation of water quality have limited this snake's habitat severely. Collectors, coveting it for its rarity and beauty, have further depleted the small populations.

Breeding Live-bearing. Mates mostly in spring, occasionally in fall. 12-24 young born July to August. Young are 5-9" (13-23 cm) long; mature in 2 years.

Habitat Near water: wet meadows, marshes, irrigation and drainage ditches.

Range San Mateo County, California.

Discussion Usually active in morning and afternoon; most often seen in moist vegetation seaching for frogs, toads, salamanders, and earthworms. Will slip into water if disturbed. Hibernates in burrow.