Derivation of the scientific name:
Thamnophis, Greek thamnos, bush; ophio, snake.
One of the most common snakes found throughout North America.
Common Garter Snakes can be distinguished from Western Terristrial Garter Snakes because they usually have 7 upper labial scales (the scales that border the mouth opening), while the Western Terristrial Garter Snakes usually have 8 upper labial scales. The 6th and 7th upper labial scales are not enlarged in Common Garter Snakes as they are with Terrestrial Garter Snakes.
Common Garter Snakes have dorsal scales that are keeled and their pupils are round.