Common Garter Snake

The Common Garter Snake (Thamnophis sirtalis) is common to North America. T.s. parietalis has also been introduced to northern Holland in Sweden, where it thrives. The habitat of these snakes can range from forests, fields and prairies to streams, wetlands, meadows, marshes and ponds, but they’re more often found near water being semi-aquatic animals. Habitats range from sea level to mountain locations. Their diet consists of amphibians, insects, fish, small birds, and rodents. Predators to the common garter snake are: large fish, bull frogs, snapping turtles, milk snakes, hawks, and foxes. Most garter snakes have a pattern of yellow stripes on a brown background and their average length is about 3 – 4.5 ft (1 – 1.5 m). Like any other snake, garter snakes use their tongue to smell.

Water contamination, urban expansion, and residential and industrial development are all threats to the garter snake’s species. The San Francisco Garter Snake (T.s. tetrataenia), which is extremely scarce and occurs only in the vicinity of ponds and reservoirs in San Mateo County, California, has been listed as an endangered species by the U.S. Fish and Wildlife Service since 1967.

Garter snakes can make excellent pets as they are small, easily kept in terrariums and feed readily on goldfish and other commercially available live foods. It is advisable not to give a steady diet of earthworms or night crawlers as these lack sufficient vitamins for the snake’s health. Although they are usually found near water, the pet habitat must be dry with only a water bowl to avoid serious skin diseases. This is true of all snake species, including water snakes.

Life history

The Common Garter Snake is a diurnal snake. During the summer it is most active in the morning and late afternoon and in cooler seasons or climates, it restricts its activity to the warm afternoons.

In southern, warm areas, the Common Garter Snake is active year-round; otherwise, it hibernates in common dens, sometimes in great numbers. On warm winter afternoons, some Common Garter Snakes have been observed to emerge from their hibernacula to bask in the sun.

Garter snakes generally mate in March or April, after hibernation. The species is viviparous; females give birth to a litter of 12-40 live young anytime from July through October.


The saliva of a garter snake may be toxic to amphibians and other small animals. For humans, a bite is not dangerous, but may produce a swelling or a burning rash. Most garter snakes also secrete a foul-smelling fluid from postanal glands when handled or harmed. Like any predator they are highly unpredictable.