Rattlesnakes, like other members of the Squamata order, contain a circulatory system that is powered by a three-chambered heart composed of two atria and one ventricle.

The common kingsnake (Lampropeltis getula) is not only immune to the venom of rattlesnakes and other vipers, but has the astonishing ability to overpower and eat rattlers and other snakes that are much larger than they are.

Arizona is home to 13 species of rattler, more than any other state. Texas comes in second with 10 species.

The rattlesnake eye lacks a fovea, making it impossible for them to see sharply defined images. Instead, they mostly rely on the perception of movement.

Although the bald eagle won out, the timber rattlesnake (Crotalus horridus) was under serious consideration as America's national symbol and appeared on many early flags.

Rattlesnakes rarely bite unless provoked, and the bites are seldom fatal if treated promptly. Nevertheless, it has been estimated that 7,000 to 8,000 people per year are bitten by venomous snake in the United States, and about five of those people die. Most fatal bites are attributed to the eastern diamondback rattlesnake and the western diamondback rattlesnake.