Common Garter Snake

(Thamnophis sirtalis)

Identification tips: The Common Garter Snake is a medium sized snake (up to 100 cm long) that appears very long and slender when young, but eventually becomes thick with age. This is a dark bodied snake with three stripes lining the body (which is a characteristic of all Midwestern garter snakes). The stripes can either be yellow, green, tan, or shades of color between. The stripe that runs down the middle of the snake is often lighter than the other two stripes. Some of these snakes have solid dark skin between the side stripe and the back stripe, while others have square patches of red or yellow on their sides. The belly of the Common Garter snake is either cream, gray, or green in color, often in a solid pattern. The upper lip of the Common Garter Snake is light colored with dark vertical bars.

Natural history: The Common Garter Snake is the most widespread snake in North America. This is one of the most commonly encountered snakes, for it is active during the day and lives on the edges of forest or prairie habitats wherever water is present. The Common Garter Snake is quick to hide in vegetation near water or to flee to the water when approached by predators or people. The Common Garter Snake can be found near the water around the wetland area on the west end of the lake, among the arrowleaf and cattail plants across the road on the north side of the lake where the metal culvert drains into a small pool, and near parts of Walnut Creek where the water moves slowly and the vegetation is thick.

There is one other species of garter snake that lives around Lake Eureka that can be confused with the Common Garter Snake. The Plains Garter Snake (Thamnophis radix) also has three light stripes on a dark body, and is similar in size to the Common Garter Snake. The Plains Garter Snake has dark black blotches along its side, and its stripes tend to be lighter than the stripes of the Common Garter Snake. The Plains Garter Snake also has a pair of tiny light spots on top of its head that are not present on Common Garter Snakes.

The Common Garter Snake is one of the most cold-tolerant snakes in Illinois. This snake can emerge in early March after a series of warm days and back in the sun. This snake has a diet that is suited for habitat near water because it eats amphibians (small salamanders and frogs), worms, small fish, slugs, and small rodents. Female Common Garter Snakes give birth to live young, and when they are born they are very thin and range between 12 and 23 cm long. When captured by predators or people, Common Garter Snakes bite ferociously and release a terrible smelling musk. Their bite, although it does pinch a little, is harmless, and Common Garter Snakes will not bite if they are left alone. Common Garter Snakes are often eaten by birds of prey and predatory mammals. People often incorrectly call these snakes "Garden" or "Gardener" Snakes, which may make since if they are seen in a garden; however, the proper name "Garter" refers to their slender striped body that resembles a garter belt

For additional information, please visit the Illinois Natural History Survey site for Common Garter Snakes

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