Pituophis catenifer is a species of nonvenomous 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, but can be easily distinguished from a rattlesnake by the lack of a tail rattle, no black-and-white banding on its tail, and the shape of its head, which is narrower than a rattlesnake's. Additionally, rattlesnakes 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.