Most Venomous (Poisonous) Snakes to Humans
Two major families of snakes account for most venomous snakes dangerous to humans.
1. The elapid family includes:
- the cobras (Naja and other genera) of Asia and Africa;
- the mambas (Dendroaspis) of Africa; the kraits (Bungarus) of Asia;
- the coral snakes (Micrurus) of the Americas; and the Australian elapids, which include the coastal taipan (Oxyuranus scutellatus),
- tiger snakes (Notechis), king brown snake (Pseudechis australis), and
- death adders (Acanthophis).
- Highly venomous sea snakes are closely related to the Australian elapids.
Snakes from the elapid family
King cobra (Ophiophagus hannah), a dangerous Asian elapid and longest of the venomous snakes at around 4 m (13 ft).
Black mamba (Dendraspis polylepis), an extremely fast, large, and dangerous African elapid.
Coral snake (Micrurus fulvius), a shy American elapid that accounts for only about 1% of venomous snakebites in the United States. Recognize it by this catch phrase: "Red on yellow, kill a fellow."
Milk snake (Lampropeltis triangulum), a harmless mimic of the coral snake. "Red on black, venom lack," although this old saying becomes unreliable south of the United States.
2. The viper family includes:
- the rattlesnakes (Crotalus) (Western diamondback rattlesnake and timber rattlesnake), moccasins (Agkistrodon), and lance-headed vipers (Bothrops) of the Americas;
- the saw-scaled vipers (Echis) of Asia and Africa;
- the Russell's viper (Daboia russellii) of Asia; and
- the puff adder (Bitis arietans) and Gaboon viper (Bitis gabonica) of Africa.
Snakes from the viper family
Western diamondback rattlesnake (Crotalus atrox), an American pit viper, with rattle vibrating. This is one of the most dangerous snakes of North America.
Timber rattlesnake (Crotalus horridus), American pit viper, caught yawning after a big meal.
Cottonmouth or water moccasin (Agkistrodon piscivorous), American pit viper usually found in or near water.
Northern copperhead (Agkistrodon contortrix), an American pit viper. Bites by this species tend to be less severe than rattlesnake or water moccasin bites but still require urgent medical attention.
Most species of the most widely distributed and diverse snake family, the Colubrids, lack venom that is dangerous to humans. Some species, however, including the boomslang (Dispholidus typus), twig snakes (Thelotornis), the Japanese garter snake (Rhabdophis tigrinus), and brown tree snake (Boiga irregularis), can be dangerous. Other members of this family, including American garter snakes, kingsnakes, rat snakes, and racers, are harmless to humans.