.Identification:
Common garter snakes can be identified by their 3 lengthwise stripes on the body (these stripes are mostly yellow, but can also be brown, green or black). The ground color is usually dark brown but may be black, green, or olive. Adults can reach 18-54 inches.
Niche:
The garter snake is a consumer because it eats and doesn't produce anything. The garter eats worms, slugs, larval amphibians, some insects, small fish, nestling birds, and small mammals. The garter snake spends most of its time baking in the sun. This snake is found across North America.
http://en.wikipedia.org/wiki/Common_Garter_Snake