Prairie Rattlesnake (Crotalus viridis)

As its name implies, the prairie rattlesnake is found on the grasslands of North America. Rattlers may live 18-25 years. This snake's most obvious and well known feature is the rattle, consisting of loose-fitting rings of dried keratinized skin at the end of the snake's tail. When the rattler vibrates its tail, the separate pieces knock together, creating the rattling sound, which can be heard for several yards. It can vary the speed of its rattle and the sound, depending on the degree of annoyance it is experiencing. The snake adds a new ring each time it sheds, and since rattlers shed from 3 to 5 times a year, even a young snake may have a very long string of rattles.

Rattlesnakes prey on rodents, lizards, birds, and their eggs. They are able to identify and kill their prey in total darkness. The rattler's heat sensors can detect the prey's body heat from a considerable distance. When the snake strikes, its head and fangs are precisely guided by additional heat sensors on its upper mandible. The rattlesnake's fangs are usually folded back against the roof of its mouth, but when the jaws open to strike, special muscles bring the fangs into position, and venom is pumped into the prey by glands in the snake's head. Rattler's jaws fit together loosely--attached by a ligament almost like a rubber band--so the snake's mouth can open very wide. This is useful both for striking and for swallowing animals whole, since snakes are unable to chew their food. Beware--a rattlesnake's fangs and head muscles are capable of injecting venom even after the snake is dead!

Rattlesnakes give birth to live young. The males are territorial--they don't like to find other males in their hunting area. When two males meet, they neck-wrestle to determine who will stay. Prairie rattlers are often found in prairie dog burrows which they use to escape extreme heat or cold and to hunt other animals using the burrows for shelter. Rattlers gather in these underground burrows to sleep through the winter. During this period of hibernation, their body processes slow down so much, they don't need to eat.