viper - venomous Old World snakes characterized by hollow venom-conducting fangs in the upper jaw

Crotalidae, family Crotalidae - New World vipers: pit vipers

Agkistrodon contortrix, copperhead - common coppery brown pit viper of upland eastern United States

Agkistrodon piscivorus, cottonmouth, cottonmouth moccasin, water moccasin - venomous semiaquatic snake of swamps in southern United States

rattler, rattlesnake - pit viper with horny segments at the end of the tail that rattle when shaken

Bothrops atrops, fer-de-lance - large extremely venomous pit viper of Central America and South America