In South America, most snakes consume a crocodile.
The largest concentration of them is found in the southwestern United States and in northern Mexico. Arizona is home to 13 species of rattlesnakes, more than any other state. The most distinctive feature shared by these species is the rattlesnake.
Residents of the southwestern United States have likely heard the characteristic buzz of these vipers. Its namesake rattle is a very effective warning signal telling predators to stay away. 
“Rattles are segments of keratin that fit loosely inside one another at the end of the snake’s tail,” explained Sara Viernum, a Madison, Wisconsin, herpetologist.
