Adder is the name of several snakes, most belonging to the viper family, especially the Viperinae subfamily (pitless vipers). However, there are a few exceptions: the death adder is not a viperid at all, but a member of the family Elapidae (cobras and coral snakes); and the totally harmless hognose snakes (members of the Colubridae family) are sometimes referred to as puff adders because of their threat display.