Rattlesnake, also called rattler, any of 30 species of venomous snakes characterized by a horny rattle at the tip of the tail, which is shaken vigorously to warn off intruders. Rattlesnakes are members of a larger family of poisonous snakes called pit vipers. Pit vipers have heat-sensitive pits on the sides of their heads that help them detect warm-blooded prey. The largest Rattlesnake is the eastern diamondback, which can grow to just under 2.5 m (8 ft) and weigh 9 kg (20 lbs). Rattlesnakes have a pair of long, hollow fangs that lie folded back against the roof of their mouth. These fangs are connected to the venom glands by small tubes, or ducts. Rattlesnakes produce venom that may contain two types of poisons. One poison impairs the functioning of the victim’s heart and lungs, and the other causes the victim’s tissues to begin to disintegrate. When a Rattlesnake strikes, it swings its fangs downward so that they are in position for biting. Venom travels from glands on either side of the head to the fangs and into the victim. After striking, the Rattlesnake recoils from the prey and waits for it to be immobilized by the venom. Contrary to popular belief, humans are rarely bitten by Rattlesnakes—in the United States, Rattlesnakes cause fewer than 12 deaths each year.
The Rattlesnake’s nasty bite can be crippling to opponents, especially when this creature is combined with large animals. In addition, the Rattlesnake’s natural camouflage allows it to blend into its surroundings and hide from most enemy units.