Garter Snake - biology.

Garter Snake - biology. Garter Snake, common name for a group of harmless snakes, among the most common snakes in the United States. About 15 species are found in the United States; garter snakes are also common in Canada and Mexico. They can be found in developed areas in parks, vacant lots, or backyards. Garter snakes have ridged, or keeled, scales and are named for the garterlike pattern of some species: Three pale stripes run the length of the darker body, one on either side and one along the back. A large garter snake may attain a length of about 1 m (about 3 ft) and a diameter of about 2.5 cm (about 1 in). When in danger, the snakes often hide their heads and secrete a foul-smelling fluid from glands at the base of the tail. They bear their young alive, usually 6 to 25 in a litter. The most common prey of garter snakes are coldblooded animals such as earthworms, frogs, toads, salamanders, and fish. The best-known garter snakes in the United States are the common garter snake and the ribbon snakes. The common garter snake occurs in a variety of habitats, including woods, rocky regions, swamps, and along streams. Varieties that live near water may dive into it when alarmed. A western variety of garter snake has a brickred tinge to its sides, and a common eastern variety is spotted but stripeless. The ribbon snakes differ from other garter snakes in that they are more slender, less than 1.2 cm (less than 0.5 in) in diameter; they are always found near water; and they average no more than 13 young in a litter. Scientific classification: Garter snakes belong to the family Colubridae. The common garter snake is classified as Thamnophis sirtalis and the ribbon snakes as Thamnophis proximus and Thamnophis sauritus. Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.