Tuesday, July 17, 2007

Coral Snakes


Well, we had snake education 101 tonight. Turns out Nolan's plan was to "step on" a snake and kill it himself! NICEEEEEEEEEEEEEEEE. Nathan's plan was to yell: "Mommy! Daddy! There is a big snake in the yard!" We got out all our stuffed snake toys and demonstrated snake attacks ( I may be up tonight consoling nightmared children) but I think I drove home the point. So here is info for anyone who is curious:


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 to 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.

Photo of a coral snake in the park , showing typically reclusive behavior of hiding under rotting wood. Note the red and black bands separated by yellow. This one was well over 30 inches long, but slightly less than an inch across.

[edit] 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 not aggressive creatures 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. No deaths related to coral snake bites have been reported in the United States since coral snake antivenin became available. Before that time, the estimated case fatality rate was 10%. 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 antivenom for coral snake species found in Mexico. A third type of antivenom is manufactured in Brazil to treat bites from some coral snake species found there. Unfortunately, no one antivenom is effective against all coral snake envenomations, and due to the relative rarity of bites from coral snakes and high cost of the antivenom, few hospitals stock it.

[edit] 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.

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