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Medical Author:

Jerry R. Balentine, DO, FACEP

Jerry R. Balentine, DO, FACEP

Dr. Balentine received his undergraduate degree from McDaniel College in Westminster, Maryland. He attended medical school at the Philadelphia College of Osteopathic Medicine graduating in1983. He completed his internship at St. Joseph's Hospital in Philadelphia and his Emergency Medicine residency at Lincoln Medical and Mental Health Center in the Bronx, where he served as chief resident.

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Medical Editor:

Charles Patrick Davis, MD, PhD

Charles Patrick Davis, MD, PhD

Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

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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.

Pictures of 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). Photograph by Joe McDonald.

Black mamba (Dendraspis polylepis), an extremely fast, large, and dangerous African elapid. Photograph by Joe McDonald.

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." Photograph by Joe McDonald.

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. Photograph by Joe McDonald.

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.

Western diamondback rattlesnake (Crotalus atrox), an American pit viper, with rattle vibrating. This is one of the most dangerous snakes of North America. Photograph by Joe McDonald.

Timber rattlesnake (Crotalus horridus), American pit viper, caught yawning after a big meal. Photograph by Joe McDonald.

Cottonmouth or water moccasin (Agkistrodon piscivorous), American pit viper usually found in or near water. Photograph by Joe McDonald.

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. Photograph by Joe McDonald.

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.