Garter Snakes

Common name: Garter Snakes

Scientific names: Thamnophis sirtalis sirtalis (Common Garter Snake) and Thamnophis elegans elegans (Western Terrestrial Garter Snake)
Phylum: Chordata
Class: Reptilia
Order: Squamata

Family: Colubridae

Habitat: vernal pool grasslands and many other habitats, often near water

Size: 0.46 to 1.3 meters

Description: The Common (or Valley) Garter Snake is easily identifiable by a black body, yellow stripes down the back, and red blotches on the sides. The Western Terrestrial Garter Snake has a black or dark gray back with a dull yellow stripe down the middle. The dark background color has tiny white spots, which can be hard to see.

Fun facts: When handled or otherwise disturbed, Garter Snakes usually release a stinky-smelling musk.

Life cycle: During the winter, Garter Snakes hibernate under rocks and rotting logs, and in rodent burrows. They select mates in the spring after they come out of hibernation. In July, seven to thirty young are born live.

Ecology: Garter Snakes feed on many different animals, including fish, frogs, toads, salamanders, insects, and earthworms. They are excellent swimmers and are usually found close to some source of water. They are eaten by a variety of mammals, birds and other snakes.

Conservation: Some people kill snakes because they are afraid that the snakes might hurt them. They do not realize that the snakes are even more afraid of humans than we are of them! Garter Snakes, like many snakes, play an important role in controlling populations of rodents. Rodents are a group of mammals that includes mice, pocket gophers, voles, ground squirrels and other species.

Investigate: Garter Snakes are one of the most common snakes at Mather Field. With luck (and quiet movement) you may see one slithering through the grass as you approach. If you inspect the ground you will see how much habitat is created for snakes by the burrowing rodents in the vernal pools and grasslands. The burrows of the California Vole and Botta’s Pocket Gopher are everywhere and they are great places for snakes to seek protection from sun, cold, predators and you! Many of their prey hide in those same underground shelters.