Scientific Name: Thamnophis sirtalis tetraenia
The San Francisco Garter Snake is a colorful garter snake, averaging 2-3 ft. in length. It can be recognized by its mid-dorsal stripe of greenish-yellow bordered by a black and a red stripe on each side which may be broken or divided. The belly is greenish-blue, and the top of the head is red. All known populations of this species occur in San Mateo County, CA. It mates in early March, and lives on a diet consisting primarily of frogs, toads, immature newts, fishes and occasional small mammals.
Habitat: Near freshwater marshes, ponds, and slow-moving streams; upland areas near pond/marsh habitat are important in fall and winter. Marshes provide important feeding and breeding habitat; often basks on floating algae or rush mats or on grassy hillsides near drainages and ponds; seeks cover in bankside vegetation such as cattails, bulrushes, and spikerushes, and in rodent burrows.
Threats: Urbanization has destroyed most prime habitat, leaving highly fragmented populations.