Wednesday, March 18, 2009

Venomous snakes - poisonous snakes


An average of five people are killed due to venomous (poisonous) snake bites a year in the USA (Gold et al., 2002)1. Approximately 8000 venomous snakebites are reported per year in the USA and the total number of bites per year in the USA is estimated to 45000 bites (ibid).

Statistics show that only about 18 percent of snake bites in the USA are from venomous species. However, it should be mentioned that other survey's reports fewer bites a year (Litovitz et al., 1997)2.

Medical symptoms from venomous bites vary a lot. Besides wound discharge some of the symptoms associated with these types of bites are the same as in severe cases of flu.

In Australia 18 snake bites had a deadly outcome (see later) over a 10-year period, according to an article by Sutherland (1992)3. The author does however state, that probably not all lethal cases has been reported.

Only 4 species poses a hazard to humans in the US and none of these snakes are among the most venomous in the world.

In South America and Central Americas a bites from venomous species is a worse medical problem than in the US. In Costa Rica the annual number of hospital admissions because of snake bites is 22.4 per 100000 inhabitants (Rojas et al., 1997)4, which is quite a large number compared to USA standards.

When compared to how many are killed by lightning a year, which in a period from 1959 to 1994 was 0.42 people per million USA citizens a year (Curran et al., 1994)5, injuries caused by snakes seems a minor problem.

This does not make snakes and especially the venomous ones less interesting. This webpage is dedicated to venomous snakes, their habitat, ecology, life-cycle, how to avoid bites, species descriptions and much more.

Poisonous Snakes - a technical misunderstanding

The correct term to use is venomous. Normally venom is harmless if ingested but if the venom is injected into some tissue it is toxic and the tissue around the site of injection and other parts of the body will suffer one way or another.

Below is a overview of some of the species presented here.


Rattlesnakes with the Latin Name Crotalus sp. comes in different varieties and there are numerous sub species, color variations etc. One thing that they do however have in common is jointed rattles on their tail.

In the section about rattlesnakes you'll find detailed descriptions of the most common rattlesnakes in USA. A bite from a rattlesnake can be deadly.


The cottonmouth snake is also known as the water moccasin. The name cottonmouth comes from the fact that its mouth looks like cotton when it opens it mouth. This snake has been considered aggressive but studies have shown that this is not the case. Cottonmouths reach a length of approximately 30-48 inches. The Cottonmouth Snake is one of the most common snakes in Florida. Other Florida Snakes includes the 3 other not very deadly US snakes also described on this website.

Coral Snakes

Coral snakes are easy to recognize from their alternating black, red and yellow bands. They are usually shorter than 40 inches. Their preferred place of staying is beneath debris or flatwood or anywhere that offers some kind of protection.

Black Mamba Snakes

Black mamba snakes are some of the most venomous snakes in the world. It is also one of the largest, in fact the longest venomous snake in the world.


A Copperhead Snake is even shorter than both the coral- and the cottonmouth snake. It's the most often encountered snake in Eastern parts of the United States like Alabama, Missouri and Arkansas, but of course also all other states. Copperheads are responsible for most venomous snake bites in the USA. Bites are however the last line of defence for this and many other poisonous/venomous snakes.

Sea Snakes

Sea snakes are close related to Cobras. True sea snakes, as some herpetologist call them, only lives in water. They have adapted to a live in water and have small flattened heads that minimizes water resistance when they swim. Their favorite food is fish.

Cobra Snakes

This is perhaps the most dangerous (but not the most poisonous snake) snake in the world when it comes to person damages. Under conditions of high prey availability they can reach a length of 6 feet. Prey is completely paralysed by its venom making resistance impossible.

Snakes in general

Snakes serve an important role as a predator in the ecosystem and snakes are signs of a healthy ecosystem . It helps in maintaining populations of rodents and other prey at a constantly acceptable level. Just think of farmers and the problems they got with rodents. Snakes are actually responsible for keeping crop yields at an acceptable level and preventing spreading of diseases by preventing rats from propagating, just to take an example.

Avoiding snake bites

There are some simple rules to follow that will minimize the risk of snakebite. If you follow these simple five rules the risk of having poison injected into your body will decrease dramatically.

  • Don't try to handle a snake if you don't have any formal training in doing so.

  • Stay away from tall grass - remain on hiking paths.

  • Avoid rock climbing or be very cautious climbing in rocks.

Symptoms of a venomous bite

You should probably know when a snake has injected its venom into your tissue. Here is however, a list of common symptoms often encountered from a poisonous snake bite.

Each individual will experience symptoms somehow differently. The following symptoms are the most often reported

  • Discharge of blood from the wound

  • Marks in the skin and swelling at the site of the snake bite

  • Severe pain around the bite site

  • Diarrhea

  • Convulsion of varying severity

  • Blurred vision, weakness, dizziness and fainting

Antivenin can be administered at any hospital.

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