Coral snake

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Coral Snakes
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Elapidae
Genus: Leptomicrurus
Micrurus
Micruroides

Species

Over 65, see article.

The coral snakes are a large group of elapid snakes that can be divided into two distinct groups, New World coral snakes and Old World coral snakes. There are three genera among New World coral snakes that consist of over 65 recognized species. Taxonomic classification is ongoing, so literature may vary depending on the source.

Description

Coral snakes are most notable for their red, yellow, and black colored banding. Several nonvenemous species have similar coloration, however, including the Scarlet Kingsnake and the Milk Snake. In some regions, the order of the bands distinguishes between the non-venomous mimics and the venomous coral snakes, inspiring the rhyme — Red touching yellow kills a fellow; Red touching black is a friend of Jack. The rhyme also goes as Red on yellow, kill a fellow; Red on black, friend to Jack. In actuality, this only applies to Micrurus fulvius and Micrurus tener, found in the south and eastern United States. Coral snakes found in other parts of the world can have distinctly different patterns, and can even have red bands touching black bands, have only red and black banding, or have no banding at all.

Most species of coral snake are small in size. North American species average around 24" in length, but specimens of up to 35" or slightly larger are not unheard of. South American species can get much larger. They are thin bodied snakes, with a head the same width as the body, small eyes, and a rounded snout. Aquatic species have flattened tails, to act as a fin, aiding in swimming.

Behavior

Coral snakes vary widely in their behavior, but most are very secretive, fossorial snakes which spend the vast majority of their time buried in the ground or in leaf litter of a rainforest floor, only coming to the surface during rains or during breeding season. Some species, like Micrurus surinamensis are almost entirely aquatic and spend most of their lives in slow moving bodies of water that have dense vegetation.

Like all elapid snakes, coral snakes use a pair of small fangs, which are fixed in the front of their top jaw, to deliver their venom. Due to the time it takes for the venom take effect, coral snakes have a tendency to hold on to a victim when biting, unlike vipers which have retractable fangs and tend to prefer to strike and let go immediately. Coral snakes are not aggressive or prone to biting however, and account for less than a single percent of the number of snake bites each year in the United States. Most coral snake bites occur because of accidental handling of the snake while engaged in an activity like gardening.

Venom

Due to the small size of coral snakes, along with their having much smaller fangs than pit vipers, bites are frequently ineffective and have some difficulty penetrating shoes or even thick clothing. This along with the fact that coral snakes are quite shy and reclusive makes bites quite rare. However, coral snakes are highly venomous, being the only relative of the cobra found in the New World. Despite their relatively small size, their venom is a powerful neurotoxin, quite capable of killing an adult human. Any bite from a coral snake should be considered life threatening and immediate treatment should be sought. Often there is very little reaction around the bite area, as opposed to the pain and swelling usually associated with a viper bite, and systemic effects can delay manifestation for 8-24 hours. This potential delay in symptoms makes treating coral snake bites particularly tricky, and often results in preventative treatment whether one is displaying symptoms or not. Once the neurotoxin takes effect, it causes the neurotransmitters between the brain and muscles to malfunction. Initially symptoms are slurred speech, double vision, difficulty swallowing, but can quickly progress to muscular paralysis, and even respiratory or cardiac failure if not treated.[1]

Wyeth manufactures a North American coral snake antivenom, also Instituto Bioclon manufactures an antivenin for coral snake species found in Mexico. A third type of antivenin is manufactured in Brazil to treat bites from some coral snake species found there. Unfortunately, no one antivenin is effective against all coral snake envenomations, and due to the relative rarity of bites from coral snakes and high cost of the antivenin, few hospitals stock it.

Diet

Most species of coral snakes are ophiophagous, feeding primarily on other, smaller species of snakes, but they will often also consume lizards, and infrequently, small rodents. Aquatic species are known to be specialists in feeding on freshwater eels, but sometimes will also consume knifefish. Coral snake venom is much stronger than is generally considered necessary to subdue their typical prey items.

Taxonomy

Genus Leptomicrurus:

Genus Micruroides:

Genus Micrurus:

File:Micrurus tener.jpg
Texas Coral Snake, Micrurus tener

External links