Garter Snake, a harmless snake found in the United States, southern Canada, and Mexico. Garter snakes are from two to four feet (60 to 120 cm) long. They are usually brownish or greenish, with three light stripes running the full length of their slender bodies. Some species are checkered between the stripes. Garter snakes are found in damp places, often in parks and gardens. They feed chiefly on field mice, insects, worms, toads, and frogs. When caught, some garter snakes throw off a strong odor from their glands. The young are born alive, often 20 or more to a litter.

Garter snakes belong to the genus Thamnophis of the family Colubridae.