Crotalus viridis (Common names: prairie rattlesnake, Great Plains rattlesnake,) is a venomous pit viper species native to the western United States, southwestern Canada, and northern Mexico. Currently, two subspecies are recognized, including the prairie rattlesnake (Crotalus viridis viridis), the nominate subspecies, and the Hopi rattlesnake (Crotalus viridis nuntius). Source: Wikipedia (en)