The western pygmy rattlesnake is a highly venomous viper native to arid deserts of North America. It has a short, stout body with a stubby tail fitted with keratin rattles to warn threats. Its brown mottled scales help it blend into sand and rocks. It ambushes small rodents and carries hemotoxic venom, making its bite dangerous. Normally shy, it shakes its rattle first to scare off intruders instead of attacking people. Habitat loss reduces its wild population, so it is protected under local wildlife laws.