Pituophis catenifer

Common names: Pacific gopher snake, coast gopher snake, western gopher snake (more here).

Pituophis catenifer is a species of non-venomous colubrid snake endemic to North America. Nine subspecies are currently recognized, including the nominotypical subspecies, P. c. catenifer, described here. This snake is often mistaken for the prairie rattlesnake (Crotalus viridus), but can be easily distinguished from a rattlesnake by the lack of a tail rattle, no black-and-white banding on its tail, and by the shape of its head, which is narrower than a rattlesnake's. Additionally, rattlesnakes (and indeed most vipers) possess a large venom gland located behind each eye, giving their heads a much rounder, more angular shape, as opposed to the more cylindrical, slender head shape of a gopher snake or other colubrid.