Venomous Snakes of North America

Snakes can be found in every part of the world. The majority of snakes are harmless and beneficial creatures that eat insects and mice. Then there are the others-the venomous kinds.

Snakes catch prey in one of three ways, the first is to sneak up on some food and grab the unsuspecting critter in its mouth. This is how the friendly Garter snake in your garden catches bugs or frogs. Snakes don’t chew their food; they can only swallow it whole which leads us to the second type of snake, the constrictor.


Constrictors such as the Boa or Black Rat Snake sneak up on their meal then very quickly wrap themselves around the critter and squeeze it so hard that all the bones and solid parts of the meal are crushed allowing the snake to easily swallow it. Some constrictors will wrap themselves around their prey tight enough to suffocate it, enabling them to then swallow it whole. Constrictors tend to be larger snakes and are capable of crushing and eating animals the size of rabbits, ducks, rats, and even bigger creatures-like pigs and deer!

The longest snakes in the world are the Reticulated Python which can grow to nearly 30’ long and 350lbs, and the largest is the Anaconda which can grow to over 20’ long and weigh more than 500lbs.

The third type of snake is the venomous kind. Strictly speaking a “poisonous” animal is something that is touched or ingested that kills you (such as a poisonous toad, lizard or plant). Snakes are venomous; they inject powerful venom into you through fangs in their mouth when they bite. The venom which is either a neurotoxin or hemotoxin very quickly kills the prey enabling the snake to swallow it which can take a considerable amount of time. Neurotoxins are venom that attacks the brain and central nervous system causing paralysis which is usually fatal to humans within a few hours.

Hemotoxins are venom that breaks down red blood cells and then organs as it spreads out from the bite and injection site causing the surrounding tissue, then the victim, to die in a few hours. This tissue generally cannot be re-grown in humans. Both types of venom cause extreme pain to whoever gets bitten.

The good news regarding venomous snakes is that of the roughly 8000 bites reported in the United States every year, only about 10 people actually die. Snakes take time to regenerate the venom that they inject so for most it is a last resort to bite. Roughly 50% of bites do not contain any venom at all and are mearly warning shots. All snake bites do contain bacteria that can cause severe infections, so the safest course of action is to seek medical help immediately after being bitten.

Fortunately, there are only 4 types of venomous snakes in North America; these are the Pit Vipers (Rattlesnakes), Coral Snakes, Copperheads, and the Water Moccasin or Cottonmouth.

The Pit Vipers which includes the Rattlesnake family has over 20 different species in it. These include the Eastern Rattlesnake, Western Rattlesnake, Timber Rattlesnake, Mohave Rattlesnake, Sidewinder, and Massauga Rattlesnake. Most Rattlesnakes inject a hemotoxin venom and can be found anywhere from British Columbia, Alberta and Saskatchewan in Canada to most parts of the central to southern United States, including California, the Carolinas, New Mexico, Arizona, Texas, and Mexico.

Rattlesnakes can grow to 8’ in length and weigh 10 lbs. They have a diamond shaped head and dark diamond shapes on a grayish body colour. All members of the Pit Viper family have dark pits above their nostrils and under the eyes which sense heat to find prey.

venomous snakes

The Western Diamondback Rattlesnake accounts for most of the snake bites each year. The rattlesnake will usually make a rattling sound by shaking its tail before it bites.

Rattlesnakes are known for their distinctive rattle sound that they make when agitated. It takes a fair bit of agitation to get a rattler to bite, but when they do you have only a few hours before permanent organ and tissue damage sets in. Always listen for the rattle sound when outside. Snakes inhabit many different locations including deserts, woods, water, brush, fields, under houses and in logs so you never know exactly where you will stumble across one.

It is important to remember that some rattlers such as the Massauga Rattlesnake which can be found in Ontario and other parts of Canada don’t always rattle when threatened so be careful.

recognizing venomous snakes

The Eastern Coral snake is more deadly than rattlesnakes, but less aggressive. The coloured bands are used to identify this cobra relative from other non-venomous snakes.

Coral Snakes have three species in their family. The Western Coral Snake, Eastern Coral Snake, and Yellow Belly Sea Snake are in this family which is related to the Cobra. They are all mostly found everywhere in the southern United States and are equally dangerous, possibly more so than a Pit Viper as they do not make a sound before attacking.

Coral Snakes have smaller fangs than Rattlers so it is not always evident that they have bitten and injected you. Coral snakes inject neurotoxin venom when they bite and the venom is stronger than other snakes found in North America but generally Coral Snakes are not aggressive and only bite as a last resort when threatened by people or dogs. Coral snakes can be recognized by the red, yellow, black banding colours and grow to over 3’ in length. Exercise caution as non venomous snakes can closely resemble Coral snakes.

North American snakes

Copperhead snakes are relatives of the Water Moccasin and are found in the Central to South Eastern United States. Copperheads are aggressive and tend not to flee in an attack.

The final types of venomous snakes to be found in North America are the Copperhead and Water Moccasin which is also known as the Cottonmouth. Copperheads are frequently found by accident as they use their camouflage colours to blend in with their environment very well. Copperheads will freeze in place when startled rather than run away. The Copperhead will often bite, then not flee rather they rely on their camouflage to avoid detection.

Copperheads are found mostly in the woodlands of the Central to Southeastern United States and are easily agitated. Their venom is weaker than other types of snakes but still dangerous to humans. Adult Copperheads are able to control the amount of venom that is injected based on the size of the animal they are attacking. Like the Rattlesnake, the larger the snake the more control it has over how much is injected. A small Copperhead is in some ways more dangerous as it cannot control how much venom it is injecting when it bites. A full grown Copperhead is 36” long and has a light tan colour with pale tan crossbands which can be darker towards the middle of the snake.

venomous snakes of north america

The Water Moccasin or Cottonmouth are also found in the Central to South Eastern United States. They are more deadly than Copperheads and will give a warning by opening their mouths before biting.

The Water Moccasin or Cottonmouth is a cousin to the Copperhead. The Water Moccasin is found in lakes, streams, creeks, ditches and other wetlands or areas mostly in the Central to South Eastern United States, but can be found throughout the country. The Water Moccasin is longer and larger than a Copperhead and has more powerful venom. Both snakes’ venom is a hemotoxin. The Cottonmouth is also an aggressive snake and will open its mouth as a warning before it bites. The interior often resembles cotton giving the Water Moccasin the nick name “Cottonmouth”. Water Moccasins will often grow to over 32” in length and can even surpass 70” in length. Their colours vary and change with age from brown to almost black.

There are many different and beautiful snakes in the world. Many live in far away exotic places, but some are right in you back yard. Familiarize yourself with how snakes in your area look and where they can be found. Never attempt to catch or pick up a live snake as they are wild animals and this is where the majority of bites come from. When it comes to preventing snake bites the vast number of places and situations where they can be found means the responsibility is yours to properly learn how to identify, protect yourself and seek help in the unlikely event of an attack.


Copyright 2016 Mike Wilson

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