Rattlesnake

Rattlesnake

Rattlesnake
Crotalus cerastes
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Viperidae
Subfamily:	Crotalinae
Genera
Crotalus Linnaeus, 1758 Sistrurus Garman, 1883

There are 32 known species of rattlesnake, with between 65-70 subspecies, all native to the Americas, ranging from southern Alberta and southern British Columbia in Canada to Central Argentina.
Rattlesnakes are predators that live in a wide array of habitats, hunting small animals such as birds and rodents. They kill their prey with a venomous bite, rather than by constricting. All rattlesnakes possess a set of fangs with which they inject large quantities of hemotoxic venom. The venom travels through the bloodstream, destroying tissue and causing swelling, internal bleeding, and intense pain. Some species, such as the Mojave Rattlesnake, additionally possess a neurotoxic component in their venom that causes paralysis and other nervous symptoms.
Habitat:
Rattlesnakes are native to the Americas, living in diverse habitats from Southwestern Canada to Central Argentina. The large majority of species live in the American Southwest and Mexico. Four species may be found east of the Mississippi river, and two in South America. In the United States, the state with the most forms of rattlesnakes is Arizona, with seventeen species and subspecies.

Predators:

Newborn rattlesnakes are heavily preyed upon by a variety of species including ravens, crows, roadrunners, raccoons, opossums, skunks, coyotes and weasels, whipsnakes, kingsnakes, and racers. Neonates of the smaller Crotaline species are frequently killed and eaten by small predatory birds such as jays, kingfishers, and shrikes. Some species of ants in the genus Formica are known to prey upon neonates, and it is very likely that Solenopsis invicta (fire ants) do as well. On occasion, hungry adult rattlesnakes will cannibalize neonates. The small proportion (often as few as 20%) of rattlesnakes that make it to their second year are heavily preyed upon by a variety of larger predators including coyotes, eagles, hawks, owls, feral pigs, badgers, indigo snakes, and kingsnakes.

Sensory organs:

Like all pit vipers, rattlesnakes have two organs that can sense radiation: their eyes, and a set of heat-sensing "pits" on their face that enable them to locate prey and strike towards it, based on the prey's thermal radiation signature. These pits have a relatively short effective range of approximately 1 ft, but nevertheless give the rattlesnake a distinctive advantage in hunting for warm-blooded creatures at night.