Snakes are found almost everywhere in the world. Most people are not fond of them and are especially afraid of venomous snakes. Although usually not as large or powerful as their constrictor cousins, venomous snakes are certainly more deadly to humans. Venomous snakes are roughly divided into four families: elapids, viperids, colubrids and hydrophiidae. Within these families are classified the most dangerous snakes in the world.
Elapids comprise perhaps the deadliest of the venomous snakes. These snakes are classified by their smaller, fixed fangs. In this group are cobras, mambas, kraits, taipans and a host of others. The North American coral snake is also an elapid, although few bites have been recorded from this snake. Elapids often have a neurotoxic venom, which means it acts on the nervous system. People usually die from paralysis of the lungs and heart. Elapids, like most snakes, usually shun human contact, but are territorial and bite if cornered.
The viperid family is probably the most familiar one to U.S. residents, in the form of pit vipers. A pit viper has indentations on its head that sense heat, assisting it in hunting. U.S. pit vipers include copperheads, rattlesnakes and water moccasins - also known as cottonmouths. One famous South American pit viper is the bushmaster, and the fer-de-lance is found widely in Central America.
“True” vipers lack the “pit” of the New World vipers, but they all share the large, hollow, retractable fangs. The Russell’s viper, saw-scaled viper, temple viper and death adder are all examples of the true viper, as are the spectacularly colored Gaboon and rhinoceros vipers. Vipers of all kinds tend to be heavy-bodied snakes with triangular-shaped heads. Although the composition of their venom can vary, it is often hemotoxic, cardiotoxic or cytotoxic, meaning it acts on the blood, heart or skin, respectively.
Colubrids are the third family of venomous snakes. Most colubrids are only mildly venomous snakes, with their rear-mounted, grooved fangs. Such snakes as the mangrove and vine snakes are rarely dangerous to humans, but there are always exceptions to the rule, and the exceptions in this case are the African twig snake and the boomslang. Bites from these snakes are not common, but they are a medical emergency.
Not all colubrids are venomous snakes, however. Most are not, in fact. Racers, the hognose snake and king snakes are all colubrids, but none are venomous snakes. A bite from one of these snakes may require medical treatment, however, since their teeth can puncture the skin whether venom is released or not, and a lot of undesirable bacteria reside in their mouths.
Sea snakes are the fourth family of venomous snakes, the hydrophiidae. Although they are extremely venomous, bites are rare. Sea snakes are usually docile creatures, and rarely bite unless abused. This is a good thing, because their venom is highly neurotoxic.
Antivenin exists for the bites of almost all venomous snakes, but treatment differs. The compression bandage treatment is favored for elapid bites. Their venom is primarily neurotoxic, so a tight compression bandage is indicated to keep the venom from reaching the body before antivenin can be administered. Viper bites tend to break down skin, so a compression bandage is contraindicated for these snakebites, although for serious envenomations, the compression therapy is gaining popularity, under the theory that it is better to have tissue breakdown locally than to allow the venom throughout the rest of the body. The best field treatment in absence of a snakebite kit is to remove any jewelry or tight clothing immediately and to get the victim to a hospital.
Venomous snakes do not generally bite in defense. Their first instinct is to run. Also, a surprisingly high number of snakebites are “dry” bites — that is, the snake does not inject venom into the bite. This is thought to be because a snake does not have an unlimited supply of venom, and instinct tells it that an envenomed bite for defense is venom wasted for a potential meal. Venom is their hunting weapon, not a defensive one. However, every bite from a venomous snake should be treated as a medical emergency, until time and medical attention determine whether or not the bite was dry.
Most bites from venomous snakes in the U.S. come from people trying to capture or otherwise molest the snake. Accidental bites from venomous snakes come most frequently from hikers stepping on a camouflaged snake, or construction workers running across one at a site and stepping on it or touching it in some way.
The best way to avoid a snakebite of any kind while outdoors is to make a good bit of noise. Stomp around and wear boots for protection. Snakes can feel the vibration and will usually hide on their own when they sense a human’s presence.
Be aware of logs, crevices and piles of leaves that could conceal a snake, and use extreme caution when approaching these. If you see a snake, freeze. Allow it to move away undisturbed. Treat every snake as venomous, and your chances of being bitten decrease tremendously.
Around the house, clear out woodpiles, junk piles and so on. Snakes like quiet, undisturbed places, so keeping the yard free of debris and good nesting sites will usually keep the snake population at a minimum.