Venomous Snakes in North America Guide

Venomous snakes in north america

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Snakes have something of a bad rep largely because a lot of them are venomous. Most snakes only bite when they are frightened or feel threatened, but unfortunately, humans can surprise a snake without knowing, scaring it and causing it to bite.

According to statistics, there are around 8000 venomous snake bites in the US every year. Fortunately, only about 1 in 50 million bites are fatal. But the symptoms can be very unpleasant. Knowing what you’re dealing with can go a long way in preventing an attack.

How Do Venomous Snakes Produce Their Venom?

Snakes have venom glands located in the back of the throat where the salivary glands would be located. These venom glands evolved from salivary glands. It is here that venom is created and what’s fascinating is that where saliva is made from certain proteins, snake venom is merely a variation on this but with toxic enzymes.

When it comes to injecting venom, snakes use their hollow fangs which perform in a very similar manner to a hypodermic needle. Some snakes have very large fangs which rest back inside the mouth and will flip down when the snake needs to use them. As the snake bites down, the muscles in its head are forced down onto the venom glands which in turn, squeeze out the liquid, through the hollow fangs.

Why Do Snakes Create Venom?

Why do snakes create venom?
Eastern Diamondback Rattlesnake (Crotalus adamanteus) With Prey

It seems pretty scary to think about snake venom, especially when you realize what it can do to your body. But it was never intended to harm humans, it’s just that we get caught in the crossfire sometimes.

Primarily, snake venom is used as a way of immobilizing the snake’s prey. When they hunt, they are able to stop their prey in its tracks so they don’t have to fight it. What’s interesting is that not all snake venom will affect all other animals. Some snakes have venom that specifically targets their main prey, while the same venom may be useless on another animal.

But venom is also used as a protective thing, and snakes will bite predators, injecting venom, which allows them to get away.

Types of Snake Venom

Types of snake venom

Not all snakes are equipped in the same way, and this means that there are several different types of snake venom. Each of these venom types behaves in a different way and will have various effects on the victim.


Hemotoxins affect your circulatory system and once it enters, it will start destroying your red blood cells. As a result of this, your body loses the ability to clot the blood which then means severe internal bleeding.

These toxins are not as fast-acting as others but can be fatal if you do not receive treatment. As a result of the damaged red blood cells which begin to build up, patients may experience kidney failure and if the veins become blocked, it can also cause the heart to fail.


Your central nervous system relies on the transfer of neurotransmitters and receptors which send signals around the body. When you are injected with snake venom containing neurotoxins, these interfere with these transmitters and receptors meaning that even the basic functions of your body, like breathing, are affected.

If your nervous system becomes overloaded with neurotoxins, this can cause convulsions or muscle twitches. When left untreated, it is not uncommon for this type of venom to kill you. However, seeking fast medical assistance can lead to survival, and the after-effects are very few other than some scarring at the bite site.


Fortunately, cytotoxins are not quite as lethal as other types of snake venom but that’s not to say that they can’t do some serious damage. The main way in which it does this is by killing off tissues within the body, including your vital organs.

This type of venom is used by snakes to start digesting their prey before eating which explains why it breaks down tissues. It’s extremely fast-acting and you will notice things like skin blistering, the blackness of the skin, and pain. In severe cases, amputation may be required to prevent the venom from further spreading around the body. However, other than this, the survival rate is quite good.


Myotoxins are responsible for causing muscular and skeletal damage by breaking down the tissues. They cause your muscle cells to stop working properly, preventing them from being able to contract which eventually can lead to the death of these cells.

The most worrying part of this is that the toxins can affect the heart muscle and when this stops working properly, you will experience cardiac arrest.

How Dangerous are Bites from Venomous Snakes?

How dangerous are bites from venomous snakes
Eastern Diamondback Rattlesnake (Crotalus adamanteus), the Largest and Most Venomous Snake in the US

The idea of being bitten by a snake is terrifying, even for people who aren’t generally afraid of snakes. But how dangerous is it really and are you likely to die?

The truth is that a snake bite is more dangerous the longer you leave it to seek help. If you are bitten by a snake, unless you can be 100% certain that it is not venomous, you should get medical assistance as soon as possible and it should be treated as an emergency.

Experts claim that First Aid could do more harm than good when bitten by a snake so it’s best not to do things like use ice packs or tourniquets. The only thing that you could do to improve the situation before getting to a hospital would be to use a venom extractor but this should be done within the first five minutes of being bitten.

The good news is that it is thought that only 1 in 50 million snakebites will result in death. However, there are around 130,000 snakebite fatalities around the world each year. Snake venom can be more dangerous if you already have health problems or are vulnerable in any way.

Fortunately, there are lots of effective treatments for snake bites and you will normally need to stay in hospital for at least 24 hours for observation before being sent home. If you do continue to experience symptoms, you should return to hospital immediately.

Venomous Snakes in the United States

The USA is home to around 30 species of venomous snakes. Most of these are within the rattlesnake family. Let us introduce you to some of the most common venomous snakes in North America.

1. Coral Snake (Micrurus fulvius)

Coral (Micrurus fulvius) venomous snake

Coral snakes only account for around 1% of US snake bites every year. However, they are incredibly venomous and while slow to bite, should still be avoided.


Coral snakes are usually found in the southern United States, such as Texas and the Carolinas. They prefer forested areas and can often be found buried among leaf litter or even under the ground. But it also frequents arid and desert regions.


The coral snake has a very obvious appearance with alternating bands of red and black separated by yellow rings. They’re not huge snakes and don’t typically grow to more than a meter in length. Be mindful that these snakes do look a little like the king snake, which isn’t venomous.


Coral snake venom is a neurotoxin that will affect your nervous system. This results in symptoms such as difficulty breathing and if the dose of venom is large enough and left untreated, it could result in death in as little as two hours.

2. Copperhead/Highland Moccasin (Agkistrodon contortrix)

Copperhead/Highland Moccasin (Agkistrodon contortrix) are large snakes that have hemotoxic venom
Peter Paplanus / Flickr / CC BY 2.0

Copperheads are not especially aggressive but they are rather large snakes that have hemotoxic venom which can cause some nasty symptoms.


You’ll find the copperhead snake in the eastern and central states. However, they are not found in Florida or Georgia. They enjoy habitats with plenty of rocky areas to build a home as well as marshland and forests.


Copperhead snakes can get quite big, with the largest being up to 40 inches in length. Their pupils are vertical and they have triangular-shaped heads with very specific markings on the body. These are shaped like hourglasses and are a darker brown color than the rest of the snake which can range from tan to brown.


The copperhead snake won’t bite unless it’s really threatened and will usually hide from humans. However, when they do bite, the venom is relatively weak so doesn’t usually result in any serious complications or death.

Being a hemotoxin, the copperhead venom can cause problems with blood clotting along with symptoms like pain, nausea, muscle swelling, and stomach cramping.

3. Cottonmouth/Water Moccasin (Agkistrodon piscivorus)

Cottonmouth/Water Moccasin (Agkistrodon piscivorus) are a a semi-aquatic species

The cottonmouth is a rather aggressive snake species but only when it feels threatened. If bitten, you could end up with permanent damage.


The cottonmouth, also called the water moccasin, is found in the southern parts of the United States. This is a semi-aquatic species so you will find it where there are bodies of water such as slow-flowing rivers, lakes, and swamps.


The cottonmouth is a brown-colored snake or sometimes black with faint markings on the body. Younger cottonmouths may have yellow or orange crossbands which fade as they reach adulthood when they could get up to 55 inches long.


This is another snake with hemotoxic venom and when bitten, you may experience symptoms like tissue breakdown, hemorrhaging, severe pain, and internal bleeding. Most cottonmouth bites are not fatal when treatment is quickly sought but there may be permanent tissue damage and scarring at the bite site.

4. Western Diamondback Rattlesnake (Crotalus atrox)

Western Diamondback Rattlesnake (Crotalus atrox) also called the called the Texas Diamondback

You’ll sometimes hear the western diamondback being called the Texas Diamondback, owing to its location. Its venom isn’t hugely toxic but since it delivers it in large doses, this makes it more dangerous.


This species of snake is common in desert areas and grasslands in the southern United States. You will also find them in some northern parts of Mexico.


As the name suggests, the western diamondback has a diamond-like pattern down its back. There are two dark lines running back from the eyes on a triangular-shaped head. These snakes are quite heavy-bodied and thick and can grow up to six feet.


Western diamondback venom contains three different types of toxins including myotoxins, hemotoxins, and cytotoxins. This means that the symptoms can be varied but may include things like swelling, blisters and skin damage, internal bleeding, and vomiting. While human fatalities are low, as many as 20% of bite victims will die.

5. Eastern Diamondback Rattlesnake (Crotalus adamanteus)

Eastern Diamondback Rattlesnake (Crotalus adamanteus) the largest venomous snake in the US

An interesting fact about the eastern diamondback is that it is the largest venomous snake in the US, with the biggest measuring up to 7.8 ft! It almost became the national animal of the US instead of the bald eagle.


The eastern diamondback likes coastal regions and will spend its days in forests, woodlands, and swamps. It is common in Florida, Louisiana, and the Carolinas as well as on islands off the coast of Florida and in the Gulf of Mexico.


These snakes are exceptionally long and can weigh up to 30lbs. They have a similar diamond pattern to their western cousins and have brown to grey coloration.


This is another snake with hemotoxins in its venom and it is pretty potent. When bitten you may experience things like muscle spasms, pain, bleeding, and vomiting. Unfortunately, this snake does regularly cause death with 25% of victims becoming a fatality.

6. Timber Rattlesnake (Crotalus horridus)

Timber Rattlesnake (Crotalus horridus) are commonly found across eastern parts of the United States

The timber rattlesnake is one of several species of rattlesnake found in North America. They live in a variety of habitats and while their venom does cause some unpleasant symptoms, it’s rarely fatal.


Timber rattlesnakes are commonly found across eastern parts of the United States. They will inhabit a variety of terrains but generally prefer rocky areas and woodlands.


The timber rattlesnake can grow up to five feet, depending on its diet and available food sources. They have grey coloration with a slight pinkish tinge and brown to black markings. There is an obvious stripe down the back but the color of this will vary between individuals.


Much like many of the other snakes on this list, the timber rattlesnake has hemotoxic venom which can cause symptoms like swellings, blood clots, chest pain, and vomiting. The good news is that these snakes rarely kill humans with their venom but you should still seek medical attention if bitten.

7. Prairie Rattlesnake (Crotalus viridis)

Prairie Rattlesnake (Crotalus viridis) contains neurotoxins which means it affects the nervous system
Patrick Alexander / Flickr / CC0 1.0

Out of all of the venomous snakes in the US, the prairie rattlesnake is probably the one you’d want to be bitten by, given a choice. It is responsible for the least amount of deaths.


The prairie rattlesnake is quite widespread and can be found in some parts of Canada, down through the western states, and as far as Mexico. As you might guess, their primary habitat is prairies but they’re also found in wooded mountainous areas.


The prairie rattlesnake has a large triangular-shaped head and can grow to around five feet, typically. They vary in color but tend to have a white to cream underbelly and brown to grey coloration on the back with olive, brown, or even black markings.


The venom of the prairie rattlesnake contains neurotoxins which means it affects the nervous system. This could result in things like difficulty breathing, confusion, chest pain, shock, but very rarely do these snakes kill humans.

8. Mojave Rattlesnake (Crotalus scutulatus)

Mojave Rattlesnake (Crotalus scutulatus) has a neurotoxic venom

There is a lot of speculation that the Mojave rattlesnake is among one of the most aggressive towards humans, although there’s no evidence to back up this claim. That said, their bite is incredibly venomous so it’s best to steer clear.


The Mojave rattlesnake lives in desert areas around the southern United States and into Mexico. It likes to hide around long desert grasses and cacti.


You can identify  the Mojave rattlesnake by looking at its coloration which can be anywhere between brown and green. In fact, a lot of individuals are more green and so have earned the name ‘Mojave green,’ The rattle is usually more white in color and the snake will typically be no longer than around three feet.


The Mojave rattlesnake has a neurotoxic venom that affects the central nervous system. The bite doesn’t usually result in death although a number of cases have been recorded. The problem is that the venom of these snakes is slow to act and so you may not experience symptoms for up to 24 hours. Moreover, the bite site doesn’t tend to bleed heavily so it’s easy to be blase about it.

9. Sidewinder Rattlesnake (Crotalus cerastes)

Sidewinder Rattlesnake (Crotalus cerastes) can be found in all of the four major desert regions of the United States

The sidewinder is not the largest snake, but it does have a potent bite and a very distinct appearance. If you see one, admire it from afar.


The sidewinder rattlesnake can be found in all of the four major desert regions of the United States. Most commonly, you’ll find it in the southwestern states as well as in Mexico. They prefer very sandy habitats.


One of the easiest ways to identify a sidewinder is to look for the horn-like structures above the eyes. They have a triangular-shaped head and a dorsal pattern with colors that range between sandy, brown, and black.


Like many other rattlesnakes, the sidewinder, aptly named because of the way it moves, has hemotoxic venom. This interacts with the blood causing problems with clotting due to a breakdown of red blood cells. While you may experience symptoms, the sidewinder venom is not as strong as some of its relatives and is unlikely to kill you.

10. Southern Pacific Rattlesnake (Crotalus helleri)

Southern Pacific Rattlesnake (Crotalus helleri) is also called the black diamond rattlesnake

The southern Pacific rattlesnake is sometimes called the black diamond rattlesnake. But however you refer to it, be careful as the venom is among the most toxic among US snakes.


You will find the southern Pacific rattlesnake mostly in southwestern parts of the United States as well as in Mexico. But there are reports of it being spotted as far north as western Canada. They can be found on coastal dunes, rocky areas, mountains, and grasslands as they have a rather versatile natural habitat.


The color of the southern Pacific rattlesnake can vary from yellow to brown to grey. But in any case, you will notice dorsal markings that are typically very dark in color. As the snakes get older, the color around the head can become completely dark. They’re thick-set snakes whose length can reach up to four feet.


The venom of the southern Pacific rattlesnake contains two types of toxins; myotoxins and hemotoxins so it affects the body in two different ways. As a result of this, a bite is more likely to be fatal due to problems with both the muscles and the blood.

However, there is some good news and that is that the southern Pacific rattlesnake’s venom can be used to treat bites from North American pit vipers.

11. Massasauga Rattlesnake (Sistrurus catenatus)

Massasauga Rattlesnake (Sistrurus catenatus) also known as the black rattlesnake

The massasauga rattlesnake is sometimes simply referred to as the black rattlesnake. It’s a smaller species and fortunately, is not responsible for many fatalities at all.


The massasauga rattlesnake is typically found in northern parts of the United States and up into Canada. It’s very common in places like the Missouri valley and Colorado. Typical habitats include grasslands and marshes.


This species of snake is quite small and doesn’t usually grow any more than about two feet. Their bodies are quite thick and their head is heart-shaped with a white stripe across it. The underside of the snake is marbled while the back has a clear blotchy pattern in browns, greys, whites, and blacks.


The massasauga rattlesnake possesses a cytotoxic venom and this will affect the tissues in the body, breaking them down and ultimately destroying them. Moreover, the venom will prevent your blood from clotting and so can cause internal bleeding. However, in humans, there have only ever been two recorded deaths as a result of a bite from this snake.

12. Tiger Rattlesnake (Crotalus tigris)

Tiger Rattlesnake (Crotalus tigris) he second most dangerous venomous snake in the US

The tiger rattlesnake is known to be the second most dangerous venomous snake in the US, and yet it’s also one of the smallest.


You will find the tiger rattlesnake in the southern parts of the United States and through into Mexico. They have a range of habitats such as scrublands and grasslands but generally prefer rocky areas and foothills.


The tiger rattlesnake is one of the more colorful venomous snakes in the US and can vary between lavenders, pinks, and other colors for its cross patterns. They are a very small species, rarely exceeding two feet in length and their head is spade-shaped.


The venom of the tiger rattlesnake contains two types of toxins; myotoxins and neurotoxins. This can cause pain and swelling but since the snake is so small, it’s usually difficult for it to deliver enough venom to kill a human. That said, children or adults with allergies to the venom may be more at risk.

How to Prevent Getting Bitten by a Venomous Snake?

How to prevent getting bitten by a venomous snake?

Nobody wants to get bitten by a snake but it’s inevitable that you’ll come across one sooner or later if you enter into its habitat. Snakes won’t usually attack humans without good reason and will typically try to flee before you even notice them. But here are some quick tips on how to avoid getting bitten.

  • Don’t approach snakes in the wild and never attempt to handle them.
  • When walking in the wild, be aware of the snakes’ natural habitats and try to avoid these; things like long grass and rocky areas could be particularly dangerous.
  • Try to avoid being outdoors during the night and in warmer weather as this is when snakes will be more active. If you are working in an area where there are snakes, be sure to protect yourself by wearing strong boots, leather gloves, and long trousers.
  • If you encounter a snake, take a step back to let it know you’re not a threat, this will give it a chance to move away.

How to Identify Venomous Snakes in the US

How to identify venomous snakes in the US
Cottonmouth/Water Moccasin (Agkistrodon piscivorus)

It’s essential to be able to tell venomous snakes apart from those that are harmless. In the USA, there are two different types of venomous snakes. These are pit vipers and coral snakes. There are a few ways to reliably tell whether a snake is venomous. However, if you are in any doubt, we would suggest taking extra care.

You might think that looking at the coloring of the snake would be an easy way to tell if it was venomous. However, there are lots of venomous and non-venomous snakes that look alike. For example, the coral snake has incredibly similar markings to the king snake, which is not at all venomous.

A better way to tell a venomous snake is to look at the head. This is one of the key characteristics of venomous snakes and will usually be pointed, spade-shaped or triangular. Whereas a non-venomous snake’s head would be more rounded.

While looking at the head, see if you can get a clear view of the eyes. A distinguishing feature of a poisonous snake is the vertical pupils which are not present in non-venomous snakes. They may also have eyeballs that are yellowish-green in color.

What Are the Symptoms of a Bite from a Venomous Snake?

What are the symptoms of a bite from a venomous snake
Sidewinder Rattlesnake (Crotalus cerastes)

Snake bite symptoms will vary depending on the species and type of venom, but generally speaking, these are some of the most common.

  • Bite marks which may be painful, swollen or bleeding
  • Radiating pain around the site of the bite
  • Tissue damage
  • Abnormal blood clotting
  • Raised heart rate
  • Low blood pressure
  • Kidney failure
  • Sweating or excess saliva
  • Numbness
  • Muscle weakness or spasming
  • Difficulty Breathing
  • Swollen tongue (in the case of an allergic reaction to the venom)
  • Vomiting
  • Headaches

What to Do If You Get Bitten by a Venomous Snake?

What to do if you get bitten by a venomous snake
Coiled Prairie Rattlesnake (Crotalus viridis)


If you are ever bitten by a snake, unless you can be 100% certain that it is not venomous, you should immediately seek medical attention.

Before help arrives, you should take off any jewelry or other items that might cut the skin should swelling occur.

Try to remain as calm as possible and get yourself into the recovery position. Doing this will reduce how quickly the venom spreads around your body. If you get worked up, it will only make things worse. Also, make sure that you keep the bite site below heart level as this will slow the spread of the venom.

You can cover the bite with a compression bandage but do not apply any ice to the area as this is known to make things worse. While some people used to believe that a tourniquet would help, this has now proven to be ineffective and should be avoided. Similarly, you should not attempt to cut into the wound in an attempt to release venom.

While the last thing you probably feel like doing after having received a snake bite is to have a drink, it is worth noting that alcohol should be avoided. It’s also wise to avoid caffeinated drinks.

Even if you have no current symptoms, it is important to get help immediately. Some snake venom takes longer to act but the sooner you get treatment, the better your prognosis will be.

What Are the Common Uses of Snake Venom?

Common uses of snake venom
Milking a Cobra for Venom Extraction

Snake venom is designed to immobilize prey and protect the snake so it’s pretty lethal. But it’s not all bad and venom is actually used in antivenoms as a antidote for snake bites and in medicines for very positive things. Amazingly, scientists can extract certain components from venom and put them to good use.

For example, the venom of the jararaca snake, from Brazil, is often used to treat conditions like hypertension and heart failure. This works because of the component in the venom that usually stops blood vessels from dilating and allows them to widen therefore lowering blood pressure.

The saw-scaled viper’s venom has been developed into a medication that is used to treat blood clots. While there are only a few snake species whose venom is used in medicine, it proves that there can be some good done with it.

Frequently Asked Questions

Skull of a venomous snake
Snake Skull

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