Viperidae
Viperidae is the family name for all of the vipers. Beneath this classification are the four subfamilies of vipers, three of which are found in Asia. The only subfamily not found in Asia is causinae, or more commonly known as night adders, which are native to subSaharan Africa. Vipers all have venom and inject it through hollow fangs. The venom kills and it begins the digestive process for the hunter.
Azemiopinae
This subfamily has only one species in it, fea's viper. Fea's viper is native to Burma, Tibet and China, where it resides even during the harsh winters by brumating. Brumation is a snake's period of rest similar to hibernation. Fea's viper is black with an orange head and orange bands down the snake. The snake is rare but not listed on any endangered species lists.
Crotalinae
The next subfamily, which is much more populous, is crotalinae, or more commonly known as pit vipers. They are named for the pit in their face that they use to sense heat, using an organ just below the surface of the skin. Asian genera of this subfamily are: the Malayan pitviper, hundred-pace pit viper, gloydius, hump-nosed pit vipers, mountain pit vipers, Asian lanceheads and temple vipers.
Viperinae
The last subfamily of vipers are the true or pitless vipers, viperinae. These vipers are just as dangerous as the pit vipers and are still venomous but characterized by the lack of that heat-sensing organ. The Asian members of this subfamily are: Russel's viper, saw-scaled vipers, McMahon's viper, Palearctic and large Palearctic vipers, and the false-horned viper.