Pit viper

The pit vipers are actually a sub-family of the viperids. Known scientifically as he crotalines, consisting of about 150 species and making up the largest of the viper sub-families. (some taxonomist have argued in favour of separating he pit vipers into their own family the crotalids). They are distinguished from the true vipers by the presence of heat-sensitive pits on either side of the face. The familiar rattle snakes are pit vipers, as are the North American copperheads and all of the Latin American vipers. With the exception of the coral snakes, which are the only venomous snakes found in North America. Pit vipers are also common in southern Asia. They are not found in Africa (Flank, 1998).