Snake bites are not common in the United States, where they are very rarely fatal. Not all species of snake are venomous. Knowing which snake has bitten a person will help with treatment.
The injuries that snake bites can cause range from mild to severe, but the chance of dying from one in the U.S. is virtually zero. People can usually survive venomous snake bites if they seek immediate medical attention.
All snake bites require medical attention, even if the snake is nonvenomous. Proper wound care can help prevent infection and limit how severe the injury becomes.
It is vital never to assume that a snake is nonvenomous without first consulting an expert. The misclassification of snake species could be fatal.
In this article, we discuss snake bite symptoms and explain how to identify venomous and nonvenomous snakes in the U.S. We also cover treatment and first aid for snake bites.
- About 7,000–8,000 people get venomous snake bites in the U.S. each year, but only five of them die as a result.
- All venomous snakes in North America are either pit vipers or coral snakes. The vast majority of venomous bites are from pit vipers, and 50 percent of these are from rattlesnakes.
- Snakes will not bite humans unless they feel threatened, so leaving them alone is the best strategy for preventing a bite.
- Dead snakes can still bite, so avoid handling any snake in the wild.
Usually, people know right away if a snake has bitten them. However, these animals can strike quickly and disappear before people have time to react.
Most snake bites can cause pain and swelling around the bite. Those that are venomous may also cause fever, a headache, convulsions, and numbness. However, these symptoms can also occur due to intense fear following the bite.
Bites can cause an allergic reaction in some people, which may include anaphylaxis.
All venomous snakes can deliver dry bites, which are bites that do not inject venom. They do this because they have limited venom stores, so they save venom where possible. According to estimates, 20–25 percent of pit viper bites and 50 percent of coral snake bites are dry bites.
Below, we discuss the symptoms of venomous and nonvenomous snake bites in more detail.
Symptoms of venomous snake bites
Venomous snakes have two fangs that deliver venom when they bite. A venomous snake bite will usually leave two clear puncture marks. In contrast, a nonvenomous bite tends to leave two rows of teeth marks.
It can be difficult to tell the difference between puncture wounds from venomous and nonvenomous snakes. People should seek medical attention for all snake bites.
The typical symptoms of a venomous snake bite include:
- two puncture wounds
- swelling and pain around the bite area
- redness and bruising around the bite area
- numbness of the face, especially in the mouth
- elevated heart rate
- difficulty breathing
- blurred vision
- excessive sweating
Symptoms of nonvenomous snake bites
Nonvenomous snakes do not produce toxins. Unlike venomous snakes, they do not have fangs. Instead, they have rows of teeth.
Some symptoms of nonvenomous snake bites include:
- pain near the bite area
- swelling and redness near the bite area
- itching near the bite area
Without treatment, nonvenomous bites can lead to skin infections and necrosis, or tissue death, so it is essential to look after the wound. Bites can also cause allergic reactions in some people.
Although most snakes in the U.S. are not venomous, several types of snake are. People should treat all snake bites as though the snake were venomous and seek immediate medical attention.
There are two primary groups of venomous snake in the U.S.:
- pit vipers (Crotalinae), which include rattlesnakes, copperheads, and cottonmouths
- coral snakes (Elapidae)
Within the groups, venomous snakes often have similar features, such as a triangular head (pit vipers), bright colors (coral snakes), or a rattle (rattlesnakes).
People can identify pit vipers by looking for a small depression, or pit, sitting between the eye and nostril on both sides of the head. This pit contains a heat-sensing organ that many nonvenomous snakes do not have.
The following sections describe how to identify venomous snakes in the U.S.
It is easy to identify rattlesnakes by the segmented rattle on the end of their tails. Rattlesnakes use their rattles to scare off predators.
There are many different species of rattlesnake in the U.S., and they vary in size and appearance. However, they all have relatively heavy bodies and diamond-shaped heads.
Species of rattlesnake that live in North America include:
- timber rattlesnakes
- prairie rattlesnakes
- North American massasauga
- pygmy rattlesnakes
Rattlesnakes live in a diverse range of habitats, including prairies, deserts, and forests, and they prefer warmer climates. People may see rattlesnakes sunbathing on rocks or burrowed in the shade of bushes.
Cottonmouth or water moccasin
Cottonmouth snakes, or water moccasins, get their name from the white, cotton-like appearance of the inside of their mouths.
They are around 50–55 inches long and either dark brown or black. Sometimes, these snakes have very faint crossbands on their bodies. Young cottonmouth snakes have very distinctive orange and yellow crossband patterns.
Cottonmouth snakes are mainly present in southeastern states, such as Florida, Alabama, and Mississippi. They spend most of their lives in or around water. These snakes do not scare easily, and they can attack underwater.
Although these snakes are more aggressive than other species, they only strike when they feel threatened and will flee if they have the chance.
Their venom is incredibly toxic because it breaks down blood cells and prevents blood from clotting. Bites from a cottonmouth can cause:
- extreme pain
- tissue damage
Coral snakes belong to the Elapidae family. They have alternating black, yellow, and red bands along their bodies.
People often confuse the coral snake with the nonvenomous king snake, but their patterns consist of different arrangements of colored bands. The coral snake has red bands with yellow rings surrounding them, while the king snake has black rings surrounding red bands.
Coral snakes typically live in southern states, such as Texas and the Carolinas. They prefer wooded and marshy habitats.
Coral snakes have neurotoxic venom, which affects nerve tissue and disrupts the communication pathways between the brain and other parts of the body.
Copperhead snakes are fairly large, heavy-bodied snakes, which range in length from around 24 to 40 inches. They have triangular heads and vertical pupils. Their bodies are tan or brown with darker hourglass-shaped bands along them.
Copperhead snakes mainly live in central and eastern states, but they are absent from most of Florida and south-central Georgia.
These snakes prefer forested areas and often make their home in rocky areas. Some live in marshy areas near rivers. Copperhead snakes are not aggressive.
People should get medical attention for all snake bites. On receiving a bite, a person can use first aid to improve their condition.
If someone gets a snake bite, they should take the following steps while awaiting medical attention:
- remain calm
- call 911 immediately
- gently wash the area with soap and water if possible
- remove tight clothing or jewelry because the area around the bite is likely to swell
- keep the bite area below the heart if possible
- do not attempt to catch or kill the snake
If a doctor suspects that someone has received a bite from a venomous snake, they will give them antivenom medication. It helps if the person knows which species of snake bit them, as different snake bites require different types of antivenom.
There are many misconceptions about first aid for snake bites. The following list describes what to avoid doing after a snake bite:
- do not cut into the bite wound
- do not wrap a cloth above the wound to restrict blood flow
- do not apply ice to the wound
- do not suck the venom from the wound
- do not use a suction device to remove venom
- do not give a person medication unless a healthcare professional gives this instruction
People who receive bites from venomous snakes should call 911 and move to the nearest medical facility immediately. A healthcare professional will perform a physical examination and use diagnostic tests to determine the best course of treatment.
Where possible, a doctor will give the person a specific antivenom. The antivenom will depend on the type of snake responsible for the bite.
If the bite comes from a nonvenomous snake, a person should still seek medical attention to receive proper wound care and prevent infection.
In most cases, snake bites are preventable. Snakes are not aggressive toward humans unless they feel threatened, and they will attempt to flee before biting a human.
People can usually avoid snake bites by doing the following:
- avoiding handling snakes in the wild
- staying away from places where there may be snakes, such as areas with tall grass, shrubs, or piles of rocks
- wearing boots, thick pants, and gloves at all times when working outdoors
- giving a snake room to get away if one appears
- avoiding trying to kill or capture a snake
Snake bites are rarely fatal as long as people receive proper medical attention. Most snake bites cause localized pain and swelling. The symptoms of snake bites vary depending on the species of snake and whether or not their bite contained venom.
Very few snakes are aggressive, and most snakes will avoid humans. Snakes only attack in self-defense, so people should not attempt to interact with these animals in the wild. If someone comes into contact with a snake, they should back away slowly, giving the snake enough space to retreat.
People should never assume that a snake is nonvenomous as the misidentification of snake species can be fatal. If someone does get a snake bite, they should remain calm and call 911 immediately. Even nonvenomous snake bites require proper wound care to prevent infection.