a black tailed rattlesnake, crotalus molossus

america animal black brown carnivore carnivorous close coiled coils crotalinae crotalus dangerous diamondback dog faced green head lethal life mexico molossus mountain natural nature pit poisonous predator rattle rattler rattlers rattles rattlesnake rattlesnakes reptile scales scary serpent snake snakes southwest southwestern states tail tailed united usa venom venomous viper viperidae vipers wild wildlife world yellow