The timber rattlesnake, Crotalus horridus, is the last apex predator in the northeastern United States, having outlasted lynx, mountain lions, and wolves.

The timber rattlesnake — Crotalus horridus — is a large, venomous pit viper with a range that covers much of the Eastern United States.

This rattlesnake was of the species Crotalus tergeminus, first described by Say, which is very common on the Missouri.