Vipers and Pitvipers: Viperidae

According to the World Conservation Union (IUCN), seven species are Critically Endangered; four species are Endangered; seven species are Vulnerable, and one species is listed as Data Deficient. The Critically Endangered species face an extremely high risk of extinction in the wild, while the Endangered species face a very high risk, and the Vulnerable face a high risk. Scientists have too little information on those noted as Data Deficient to make a judgment about the threat of extinction. The U.S. Fish and Wildlife Service lists one U.S. and one foreign species as Threatened or likely to become endangered in the foreseeable future, and one foreign species as Endangered or in danger of extinction throughout all or a significant portion of its range. Overall, the loss of habitat and outright killing of the snakes by humans are the greatest risks the snakes face.