Garter snakes are slender to moderately built snakes that usually have three yellowish or greenish stripes running the length of their bodies. They average 23 to 30 inches long and have ridged scales. Their heads are wider than their bodies and are usually solid-colored. Many species have two-colored tongues.
There are 30 species of garter snakes, which belong to the genus Thamnophis in the family Colubridae. They live from coast to coast throughout the continental United States and range as far north as southern Canada. There are also isolated populations in northern Mexico. Garter snakes inhabit a wide variety of habitats including woodlands, meadows, marshes and hillsides, but prefer to be near water, especially in arid areas.
Garter snakes eat small invertebrates, fish, amphibians and other snakes. In turn, they serve as food for various birds of prey, snapping turtles, raccoons, large fish and many other predators. Their primary defense is stealth, aided by their natural camouflage, which makes them hard to see in the grassy environments they prefer. If captured, garter snakes release foul-smelling musk and may bite. Some garter snakes have a mildly neurotoxic venom; their bites are harmless to most human beings, although rare allergic reactions can occur.