Cottonmouths, known scientifically as Agkistrodon piscivorus, are a venomous pit viper that lives in the southern and eastern parts of the United States. They’re one of the first snakes that many of us encounter in the wild. But just because they’re often encountered, that doesn’t mean that there are many fun and interesting water moccasin facts for us to discover.
The inside of a cottonmouth’s mouth is a cotton-like white. When they’re threatened, they’ll ‘gape,’ which is where they sit with their mouth open, staring at you. That’s when you see the color of their mouth and gums. Aside from ‘cottonmouth’, they’re also known as ‘water moccasins’. It’s less clear exactly why the water moccasin is named after a kind of shoe. There are explanations, though:
- Some Native Americans may have made shoes from their skin.
- Native Americans may have made shoes in a pattern that’s similar to their skin.
- It might be because they can move around quietly, like somebody wearing moccasins.
There’s so much more to learn about these fascinating snakes. Did you know that they can produce baby snakes without mating? Or that they’ll eat almost anything, from fish and tiny turtles to squirrels and other snakes—including other cottonmouths? Or that they have tiny sensors on their nose that can find prey using heat vision?
Cool Cottonmouth Snake Facts
We’ve found all the most fun facts about cottonmouth snakes, so let’s take a close look at this information:
Agkistrodon Piscivorus Means ‘Fish Eater’
Their scientific name, Agkistrodon piscivorus, is descriptive. Scientists noticed that they love to eat fish, so they gave it the name ‘piscivorus.’
This comes from the Latin ‘piscis,’ which means fish, and ‘voro,’ which means eat greedily. So, if you know some Latin, you are able to figure out that this snake loves to eat fish.
The first part of their scientific name (Agkistrodon) refers to a genus (big group) of snakes called pit vipers, which are found in North and Central America.
You’ll also see these Latin terms in the star sign Pisces, or in the words carnivorous or omnivorous.
Since they’re so common across the U.S., cottonmouths have many common names. You might have heard them called:
- Agkistrodon piscivorus, their scientific name
- Pit viper, which is their family of snakes
- Water pilots
- Mangrove rattlers, river rattlers, swamp rattlers or pond rattlers (they rattle their tails when threatened)
- Black snakes, black water vipers or black moccasins (when they get old, they lose their coloration and can become pure black)
- Trap-jaws or snap jaws (because when you touch them on the nose, they’ll snap their jaws shut)
Cottonmouth may seem like a peculiar name for such a venomous snake because their bite is anything but soft like cotton. The name has absolutely nothing to do with their bite, though.
The inside of a cottonmouth’s mouth is a cotton-like white. When they’re threatened, they’ll ‘gape,’ which is where they sit with their mouth open, staring at you. That’s when you’ll see the color of their mouth and gums.
Subspecies are different kinds of snake that are very similar but differ in minor ways, such as their pattern and location.
|Eastern cottonmouth:||This is the ‘nominative’ subspecies. That’s why their scientific name is Agkistrodon piscivorus piscivorus. The eastern cottonmouth lives across the east coast, from Virginia south to Georgia.|
|Florida cottonmouth:||They live in Florida and the very south of Georgia. The scientific name is Agkistrodon piscivorus conanti.|
|Western cottonmouth:||These have a wider geographic range than the other subspecies. You can find them as far north and east as Indiana, and as far south and west as Texas. The scientific name is Agkistrodon leucostoma.|
In Alabama, Georgia, and Mississippi there’s an area where these subspecies are mixed. They’ll share the characteristics of all 3 snakes.
Young cottonmouth snakes have a yellow or green tail tip. They use it to lure in prey, like frogs and lizards. This is called ‘caudal luring,’ where ‘caudal’ means related to the tail.
They’ll wiggle their tail around in front of a frog or a lizard. Because their tail looks a little like a tasty worm, the frog will hop closer in order to try to catch it. The cottonmouth will keep going, reeling them in, until the frog or lizard is close enough for them to strike.
Lose Color With Age
As a water moccasin grows older, their coloration becomes darker. Eventually, their top becomes a ruddy black, and their underside becomes whiter. You’ll see this in longer water moccasins, around 4 feet long, because these are the older specimens.
They’ll also lose their yellow/green tail tip. The older snakes can lose so much of their coloration that it disappears completely.
Water moccasins are venomous, but many lookalike snakes aren’t. There are lots of snakes across the U.S. that have similar markings to cottonmouths that aren’t venomous at all, including:
- Eastern green water snakes
- Brown water snakes
- Red-bellied water snakes
- Banded water snakes
- Northern water snakes
The unnecessary killing of non-venomous snakes is illegal under state law in many states, including Tennessee, Georgia, and Texas.
Babies Without Breeding
If they can’t find a suitable mate, water moccasins will create young without breeding. This is called ‘facultative parthenogenesis.’
It’s a complicated process that involves splitting the chromosomes and recombining them differently. With this genetic material, the egg will grow just as it usually would.
The only difference is that there’s only the mother’s genetic material involved, rather than genetic material from both a mother and father.
Believe it or not, but several different kinds of animal can create young this way. Plenty of other snakes do—in fact, the Bimini blind snake exclusively reproduces this way. However, it’s best for the offspring if they’re the result of regular breeding, as they’re more likely to thrive.
Ovoviviparous means giving birth to live young, but their young develop inside them, inside eggs. Oviparous snakes lay eggs, whereas viviparous snakes incubate young as mammals do.
The female cottonmouth will fertilize her eggs. They’ll then sit inside her reproductive tract as the snakes develop inside their eggs.
She won’t lay them at any point. This gives them an advantage because nothing can predate upon them, such as mongooses.
When it’s time for them to hatch, they’ll hatch inside the mother. The tiny snakes will then make their way out of her cloaca, and slither off to live lives of their own.
Snakes don’t look after their young once they’ve hatched. They usually just lay their eggs and leave, so cottonmouths are an exception.
Brumate with Other Snakes
Most snakes brumate over the winter. Brumation is similar to hibernation, where the snake enters a period of low activity. They’ll stop eating, moving around, and mating during this time.
They’ll hide in dens like under rocks, in logs and hollow trees, anywhere that they’ll be safe. According to Comparative Biochemistry and Physiology, cottonmouths in northern states have to sleep deeper than those in the south because they need to conserve more energy.
But when water moccasins brumate, they don’t brumate for alone. Some water moccasins sleep for the winter in dens, which they share with other venomous snakes.
It’s like they all agree to come together to conserve a little more warmth. This is helped by the fact that snakes lose their appetite over the winter, so they don’t get the urge to fight each other as much.
Monogamous During Breeding Season
Very few animals are truly monogamous. That’s because it’s beneficial for an animal to try and have as many offspring as possible. That’s easier if you have multiple partners across your lifetime, rather than just the one. Cottonmouths, though, are ‘almost’ monogamous.
When it comes to breeding season (the beginning of spring), cottonmouths will pair up. They’ll then stay in that pair throughout the breeding season, the males fighting off any other males that want to mate with that particular female. They’re hoping that they can protect their female, who they want to have their babies so that they can carry on their genetic line.
Once the breeding season is over, the pair will ‘split up.’ When it comes to the breeding season next year, both snakes will pick a different partner.
Use Heat Sensors
Water moccasins are a ‘pit viper.’ That means that they’re one of a group of snakes that have heat-sensing pits on their faces. These small pits sit right on their nose, between their nostrils.
These sensors help them detect infrared radiation, essentially heat, from about a yard away. Of course, this is for finding and striking out at prey.
According to the journal Nature vipers, pythons and boas share these heat-sensing pits. These ‘pit organs’ contain a thin membrane that picks up on the warmth of infrared radiation.
This membrane sits inside a tiny, hollow bone chamber that allows it to detect even very small changes in warmth
Venom Is Hemotoxic
Cottonmouth venom is ‘hemotoxic.’ According to Toxicon, cottonmouth venom is made up of many enzymes including phospholipase A2, Asp49, and Lys49. This means that the venom attacks and destroys red blood cells, which has all sorts of effects. It stops the blood from coagulating (clotting).
You’ll experience both external and internal bleeding, which is uncontrollable. So, you’ll bleed from your eyes, ears, and nose. It’s the internal bleeding that’s the worst, though.
Unless you receive prompt medical attention, you’ll experience permanent muscle damage. It might even result in needing your arm or leg amputated.
The cottonmouth has a very painful bite. Their bites create a strong burning sensation, which is because your tissue is breaking down. Cottonmouth venom is designed so that it starts dissolving tissue immediately after you’re bitten. This helps them digest more quickly after they eat you.
While you’re far too big for such a small snake to eat, you’ll still feel the excruciating pain of your skin and cells breaking down.
Afraid of Conflict
Rather than bite or musk, water moccasins would much rather try and escape. If they see somebody coming towards them, they’ll try and get away by entering the water.
Water moccasins hang out on logs or branches next to the water’s edge so that they can dive in for a quick getaway. They know that they can move quicker in the water than they can on land.
Water moccasins will eat almost anything—well, anything apart from leaves and plants. Like all snakes, they eat mammals and birds, as well as small amphibians (frogs and toads).
But aside from that, they eat a lot of fish, as well as small turtles that they find in the water. They’ll hunt for fish in shallow waters. They find it more difficult to swim and bite at the same time, so they’ll try and corner a fish up against a log or the bank before going in for the kill.
But their diet doesn’t stop there. They’ll eat insects like cicadas, snails, slugs, and caterpillars. All sorts of studies on cottonmouths have looked into what they eat, and the list is almost endless. They’ll even eat other snakes, including other cottonmouths.
Since they spend so much time in the water, water moccasins have become accomplished swimmers. Most snakes, including sea snakes, swim while entirely underwater. Non-aquatic snakes will do the same, but with their head poking out of the top of the water.
However, water moccasins are able to keep their whole body at water level. That’s important because they can’t breathe underwater, and this stops them from having to come up for air all the time while they swim.