Pituophis catenifer is a species of nonvenomous colubrid snake endemic to North America. Six subspecies are currently recognized, including the nominotypical subspecies, Pituophis catenifer catenifer, described here. This snake is often mistaken for a diamondback rattlesnake but can be easily distinguished from a rattlesnake by the lack of black and white banding on its tail, and by the shape of its head which is narrower than a rattlesnake's.