A subspecies of North American garter snake, "Thamnophis sirtalis pickeringii", is named in his honor. The common garter snake, "Thamnophis sirtalis", is the state reptile of Massachusetts. The common garter snake ("Thamnophis sirtalis") is a snake indigenous to North America. The common garter snake, "(Thamnophis sirtalis)" is a snake indigenous to North America. Unlike "Thamnophis sirtalis", there are no black spots between stripes in "T. brachystoma". The valley garter snake "(Thamnophis sirtalis fitchi)" is a subspecies of the common garter snake. The valley garter snake, "(Thamnophis sirtalis fitchi)" is a subspecies of the common garter snake. "Thamnophis sirtalis infernalis" occurs throughout California and is found primarily in coastal dunes and marshes. Another indirect form of sexual coercion occurs in red-sided garter snakes, "Thamnophis sirtalis parietalis".