Adder (snake)

To many, the terms adder and "viper" are interchangeable, referring to any member of the Viperidae family. Although adder was more universally popular in the past, in the literature today it is still often used in combined names that refer to species belonging to the subfamily Viperinae (pitless vipers), especially those found in Europe and Africa. Only one species is still regularly referred to simply as "adder":Vipera berus, a.k.a. the common European adder.
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