The vast majority of snakes live on land. Many people are surprised that some species of snakes live in water. But should you be worried about being bitten by a snake in the water?
All snakes can swim and bite underwater. There are venomous water snakes, such as the cottonmouth (a semi-aquatic pit viper), that will bite you underwater if it considers you a threat. Dangerous water snakes can be found in the ocean, streams, rivers, and lakes.
The only aquatic snakes you have to watch out for in the U.S. are the cottonmouth and coral snakes, which are relatively easy to recognize. The problem is that it’s not always easy to see snakes when they are submerged in water, or due to their natural camouflage.
Do Snakes Bite in Water?
Some snakes are adapted perfectly to live in oceans, streams, rivers, and lakes. But even of those that aren’t, many—like the rattlesnake—know how to swim and bite underwater anyway.
The first part of this guide starts by looking at snakes that are adapted to aquatic environments, including sea snakes and water snakes.
What Are Sea Snakes?
Sea snakes are a subfamily of the Elapid family of snakes. Coral snakes are an example of this family that lives in the U.S., although these aren’t true sea snakes in the same subfamily.
Snakes, such as the black-banded sea krait, spend almost their entire lives in water. Most of them can’t even move on land. They’ve adapted to life in the ocean by:
- Developing a tail that’s a little like a paddle
- Making their bodies narrower so that they can swim more efficiently, almost like an eel
- Losing their ventral scales, i.e., the unique scales on the underside of a snake’s body
These ventral scales are necessary for snakes to move on land. The fact that most species of sea snake have gotten rid of them—so that their bodies can be narrower and sleeker, better for moving in water—means that they can’t move on land at all.
There are 69 known species of sea snake, making them the most varied subfamily/group of reptiles in the ocean. The longest sea snakes are ten feet long.
Sea snakes aren’t the only snakes that enjoy an aquatic environment. There are quite a few other species that live mostly in water, if not in the sea, i.e., in rivers and lakes.
The Nerodia genus of colubrids is also referred to as ‘water snakes,’ and contains nine species. All of these nine species live in North America in slow-moving streams, ponds or lakes. These species are non-venomous snakes that bite in the water.
Besides, all snakes can swim, and many more spend much of their time in or near water. Another example is the water moccasin or cottonmouth snake. These snakes are semiaquatic and eat fish.
They’re also exceptionally venomous, and can easily kill somebody if they can’t find antivenom. Their bites also result in pain, tissue death, and may necessitate amputation.
Can Sea Snakes Bite Underwater?
Can snakes attack underwater? Sea snakes have to be able to bite underwater, or they wouldn’t be able to eat. Fortunately, because humans are so large compared to them, they’re more afraid of us than we are of them. They’ll typically try and get away from you rather than taking you on.
Even aside from snakes that live in water, more well-known species can swim and bite too. Rattlesnakes can swim and bite underwater.
Of course, this is rare. Other types of water snake that bite includes cottonmouth snakes (water moccasins), garter snakes, and coral snakes.
How Long Can a Snake Stay Underwater?
Sea snakes have become adept at staying underwater, which makes sense since they spend their lives out at sea. But sea snakes don’t have gills. This means that they aren’t fully aquatic like fish or eels. They have to surface regularly to breathe.
However, a sea snake can stay underwater for an hour without breathing. This allows them to hunt or hide for extended periods of time.
Water snakes and other snakes that can swim can’t last that long without breathing. Even corn snakes can stay underwater for up to fifteen minutes when they’re soaking or bathing.
Do Snakes Drown If They Bite Underwater?
Since they don’t have gills, sea snakes and other water snakes have to surface regularly, or they might drown. However, they won’t drown just because they bite underwater.
Think of the last time you went swimming. You can open your mouth without immediately drowning. That’s because your body knows not to open your windpipe. And if your mouth fills with water, all you have to do is breathe out a little, and it’ll clear out.
The only exception might be if they bite but then don’t let go. Many snakes do this so that they can inject more venom into the wound they’ve created.
This is how they can attack animals much bigger than themselves. They’ll bite and stay stuck to you, for minutes at a time.
However, a snake is unlikely to do this to you when you’re underwater. They’re far more likely to bite once, and then swim away. Either that or avoid you altogether.
Are Sea Snakes Venomous?
Sea snakes are among the most venomous snakes in the world. Not only that, but many species of sea snake are exceptionally aggressive.
They can try to attack you unprovoked, thinking that you’re a threat or a predator. Fortunately, sea snakes don’t always envenomate their victims.
This means that while they might bite you, they only rarely inject you with their venom. The scary thing is that their bites are usually painless. You might not even notice that you’ve been bitten.
After half an hour, you might notice a headache, thirst, and sweating. You may also vomit. Over the next few hours, you may also become achy and stiff.
Your jaw especially might become rigid and stiff (lockjaw). If a medical expert doesn’t see you, you will eventually have difficulty swallowing and breathing, which is why these snakebites can be fatal.
Can a water moccasin bite kill a human? You bet they can, and so can coral snakes. Fortunately, neither of these snakes will go out of their way to attack you. They’ll most likely leave you alone. That’s why there’s only been one coral snake death in the last forty years.
Where Can You Find Sea Snakes?
Sea snakes are found across the world. True sea snakes are from the Pacific Ocean, where it’s a little warmer than the Atlantic. So you won’t find them on either the east or the west coast.
The only place you’ll find them in the U.S. is in Hawaii. There, you can find just one species, the yellow-bellied sea snake. However, if you wanted to find water snakes, they’re all across the U.S.
Cottonmouth snakes, which you really shouldn’t be looking for, are mostly in the southwest and range from Texas to Virginia.
If you wanted to go out in search of true sea snakes, you would have to head to the other side of the world. They live in the Pacific. You can find them in the Indian Ocean too, from the east coast of Africa to India and across to Indonesia.
They’re also common in the waters around Japan, all the way south to Australia, and further out east in the Pacific island chains.
How to Recognize Venomous Aquatic Snakes
In America, there are two main venomous water snakes that you have to watch out for. These are the cottonmouth (water moccasin) and coral snakes.
There are several species of the coral snake, but they share the same identifying marks. They’re red, yellow/white and black. Many non-venomous snakes share similar but different markings. However, it’s easy to tell the difference if you know how.
How to Identify a Coral Snake
A coral snake’s markings are in bands along their body. You can tell whether you’re looking at a coral snake because the black bands will be next to the yellow bands. You can remember this in two ways.
- Yellow, red, stop
- Red next to yellow, kills a fellow. Red next to black, friend of Jack
The problem is that there’s another snake, called the scarlet king snake, which shares the same markings. The only difference is that in the scarlet king snake, the red bands touch the black bands, not the yellow bands. These snakes are harmless.
How to Identify a Cottonmouth Snake
You also have to watch out for cottonmouth snakes. These snakes don’t have pretty banded markings like coral snakes, but you can still identify them.
They get to about three feet long, and they’re big and bulky snakes. If you have any experience with snakes, you’ll immediately notice that they’re fatter than usual. Their tails are short and thick, too.
Regarding color, they’re a basic tan or brown color with dark bands. Their pattern and color are a little reminiscent of a boa constrictor, in that they have saddles all along their back.
They’re highly unlikely to approach you, and will instead try to escape. They often literally hang out on branches and rocks over a source of water like a lake or slow-moving stream.
To get away from you, they’ll try to slip into the water unnoticed. If you go up to one and threaten it, cottonmouths will shake their tail almost like a rattlesnake or colubrid.
What to Do If You See a Snake Underwater
If you ever encounter a snake in the wild, there are simple rules that you can follow:
- Never panic. The vast majority of snakes that you’ll encounter in any circumstance are non-venomous. And even if you do meet a venomous snake on your travels, they’re unlikely to attack you. They’re more afraid of you than you are of them. If you do panic, waving your arms around and making sharp movements, the snake will interpret this as threatening.
- Let the snake escape. If you see a snake a few feet away or in the distance, stop still to gauge the snake’s reaction. Nine times out of ten, they’ll try to get away, either by slipping into some bushes or going in the opposite direction. A snake underwater will swim away.
- Move away straight away. If you step on, touch or hit the snake by accident, move away immediately. A shocked snake is a defensive snake, and a defensive snake can strike.
If you’re out in nature, leave the snake be. If you’re somewhere that somebody else is likely to encounter the snake, then call pest control or somebody else who can help get rid of the snake.
If you’re on a scuba dive, tell your instructor what you saw. These are common-sense tips. When you see a snake, think, and always play it safe by wearing the appropriate snake-safe clothing/footwear.