Viperidae

Illustration of Crotalus spp. (Rattlesnake) venomous pitvipers found only in the Americas from southern Canada to northern Argentina. The name is derived from the Greek word krotalon, which means "rattle" or "castanet", and refers to the rattle on the end of the tail that make this group so distinctive

Illustration of Crotalus viridis cereberus (Arizona Black Rattlesnake)