Which venomous snake is named for the rattle at the end of its tail?

The rattlesnake is the venomous snake named for the rattle at the end of its tail. The rattle produces a loud buzzing sound when the snake rapidly vibrates its tail, warning predators and other animals to keep away.

Rattlesnakes are pit vipers in the genera Crotalus and Sistrurus. Their tail rattle is made of interlocking segments of keratin, the same structural material found in human fingernails. Each time the snake sheds its skin, a new segment may be added, although old rattles can break, so segment count cannot reliably reveal a snake's age.

There are dozens of rattlesnake species, all native to the Americas, with habitats ranging from southern Canada to Argentina. Their venomous bite is used to subdue prey such as rodents and birds. A common misconception is that a rattlesnake always rattles before striking; it may remain silent, especially when surprised or when the rattle is damaged.