A viper is a type of venomous snake that belongs to the family Viperidae. They are known for having long, hinged fangs that can deliver a powerful bite and inject venom into their prey or predators. Some species of vipers are also referred to as pit vipers because they have heat-sensitive pits between their eyes and nostrils which help them detect the presence of warm-blooded animals. Viperidae is one of the four families within the suborder Serpentes, along with Boidae (boas), Colubridae (colubrids) and Elapidae (coral snakes).