U.S. Coral Snakes

Texas Coral Snake (Micrurus tener)

Many reptiles and amphibians are beautifully colored, particularly the poisonous ones. When I was growing up, I had a set of field guides of the creatures of North America.  Of all the land animals of North America, the animals which I thought were most beautifully colored were the coral snakes. Coral snakes constitute four genera of snakes within the family of elapid snakes (cobras, mambas, sea snakes, kraits, and other poisonous snakes from warm climates).  Many coral snakes live in South America and the old world (where some coral snake species are evolving into sea snakes), but I’m going to stick to writing about the gorgeous red, yellow, and black coral snakes of North America.  These snakes are brightly colored to warn potential predators that they are extremely venomous.  This strategy has failed somewhat when it comes to intimidating humans, who have a collective fascination with pretty colors.

Eastern Coral Snake (Micrurus fulvius)

There are three coral snakes which live in the United States.  The eastern coral snake (Micrurus fulvius) ranges from North Carolina to Texas (including Florida and the Gulf Coast swamps). The Texas coral Snake (Micrurus tener) ranges from northeast Mexico up through Texas, Louisiana, and Arkansas.  The Arizona coral snake (Micruroides euryxanthus) lives in the Sonoran desert through Southern New Mexico, Arizona, and Sinaloa.  All species of coral snakes in the United States can be identified by the fact that their red bands touch the yellow bands (which is in marked opposition to mimics like king snakes and milk snakes).  Coral snakes from Central/South America and from Asia do not always follow this rule: the black bands can sometimes touch the red bands, or the bands can be colors other than red, yellow, and black–or there might be no bands at all!

Arizona Coral Snake (Micruroides euryxanthus)
Photographer: Wayne Van Devender

Coral Snakes are fossorial predators which spend most of their life just beneath the leaf litter or loose topsoil where they hunt lizards, frogs, insects, and smaller snakes.  Baby snakes are 18 centimeters (7 inches long) when they hatch from their eggs. Adult snakes can grow to 0.6 meters (2 feet) in length. Coral snakes can live up to seven years in captivity.

Coral Snakes are extremely poisonous, but they are also shy and retiring. Instead of hanging around biting, they would prefer to escape as quickly as possible.  This makes sense from the snake’s perspective, since their fangs are very tiny and they have to chew directly on their prey in order to inject a fatal dose.  Since they have tiny mouths, it is not necessarily easy for them to score a direct bite on humans.  Additionally their venom acts slowly—at first there is only a mild tingling associated with the bite. Lethargy, disorientation, and nausea set in hours later.  In extreme cases, coral snake bites can cause respiratory arrest.  Fatal bites are extremely rare: most sources state that nobody has been killed by a coral snake in the US since antivenin was released in 1967 (although I also found allusions to a 2009 case where a man laughed off a bite only to die hours later).

A coral snake’s little teeth.

Coral Snake antivenin was solely manufactured by one US drug company, Wyeth Pharmaceuticals (now a wholly owned subsidy of Pfizer Inc.). In 2003 Wyeth ceased manufacturing coral snake antivenin since too few people were bitten to make the product profitable.  There is still a small supply left on hand (although the expiration date has been extended twice), but Pfizer does not seem to have any intention of pursuing a microscopic niche market when it has more profitable businesses to pursue.  Foreign pharmaceutical companies continue to produce coral snake antivenin, but they do not sell it in the United States because of prohibitive licensing and regulatory costs (hooray! the United States health care system is unsolving problems which were figured out 40 years ago!).

Actually Wyeth just doesn’t want to save this guy.*

*Don’t be this guy.