Garter Snake (San Francisco) / Thamnophis sirtalis tetrataenia

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Like other garter snakes it has a red tongue which is thought to act as lure to fish and other prey

This subspecies of the common garter snake is found on the San Francisco peninsula where it inhabits the scattered wetland areas.

Its favourite habitat is the dense aquatic vegetation at the edges of ponds, marshes and wetlands. They rarely stray from near the water where they will retreat if threatened by danger. If the ponds dry up during the hot summer months the snakes will aestivate (enter a dormant state) in rodents’ borrows.

Like all snakes the San Francisco garter snake is carnivorous, feeding on frogs, newts, salamanders, fish, and worms. The prey is not constricted but is grabbed and swallowed whole in one motion.

Garter snakes mate in the spring and are ovoviviparous producing eggs which hatch in the within the females body. The young which average 16 in number are born alive. They feed on small worms, tadpoles and frogs.

Threatened in the wild by habitat loss, and collection for the pet trade, the San Francisco garter snake is protected by the US authorities.