The official Arizona state reptile is the ridge-nosed rattlesnake. This small snake grows no longer than 24 inches and lives only in the south central part of Arizona. It is dark brown to reddish-brown with many thin white stripes across its body. This rattlesnake gets its name from a unique ridge of raised scales on its nose. 

The Arizona ridge-nosed rattlesnake was the last species of rattlesnake to be discovered in the United States.