Viperinae, or viperines, are a subfamily of vipers endemic to Europe, Asia and Africa. They are distinguished by their lack of the heat-sensing pit organs that characterize their sister group, the subfamily Crotalinae. Currently, 13 genera are recognized. Most are tropical and subtropical, although one species, Vipera berus, even occurs within the Arctic Circle. Like all vipers, they are venomous.

The common names "pitless vipers", "true vipers", "Old World vipers", and "true adders" all refer to this group.

...