Rattlesnakes are a group of venomous snakes, genera Crotalus and Sistrurus. They belong to the subfamily of venomous snakes known commonly as pit vipers. Overview There're approximately thirty species of rattlesnake, with numerous subspecies. They receive their name for the rattle located at the end of their tails. The rattle's used as a warning device when threatened. The scientific name Crotalus derives from the Greek, κρόταλον, meaning "castanet". The… (More on Rattlesnake)