Mary Allen
Virtually anywhere in the southeastern United States — as far north as Indiana and as far west as Texas — the snake swimming to your boat is likely to be a more venomous water moccasin (Agkistrodon piscivorus) than a harmless water snake. Water moccasins are pit vipers, meaning they have large, heavy bodies and triangular heads. At least one other snake simulates these traits, but you need more information to make a positive identification. Luckily, water moccasins have idiosyncratic markings and swimming habits, so while panicking finding one is doable, it’s not easy.
Cottonmouths can hunt prey in water or on land. They eat fish, small mammals, birds, amphibians, and reptiles — including other snakes and even smaller water moccasins, according to the University of Michigan’s Animal Diversity Web (opens in new tab) (ADW).
Water moccasin appearance
A water moccasin may first appear uniformly dark brown or black, but if you look closely you can often distinguish tan and yellowish bands surrounding its heavily scaled body. If the snake is young enough, these markings can be bright. While not diamond-shaped, the bands are somewhat reminiscent of the markings on a rattlesnake, which makes sense because the rattlesnake is a relative.
Like all pit vipers, the water moccasin has a neck much narrower than its triangular head and powerful body. You probably won’t want to get close enough to notice this, but a water moccasin has vertical pupils shaped like slits, rather than the rounded pupils of most harmless water snakes. It also has a single row of scales on its tail, unlike non-venomous snakes, which have two rows next to each other.
Cottonmouths are water moccasins
The water moccasin is also known as the cottonmouth, and the reason comes from the defensive posture the snake adopts when threatened. She wraps up her body, raises her head and opens her mouth as wide as possible. The color of the skin in the snake’s mouth is as white as cotton – hence the name cottonmouth. When you see this behavior, it’s time to back off, gently but quickly, because the snake is ready to strike.
Water Moccasins Love Water
You won’t see water moccasins far from the water. They prefer ponds, lakes and streams with plenty of food for them to catch. Cottonmouths eat fish, amphibians, birds, mammals, baby alligators, and smaller cottonmouths.
A swimming cottonmouth is easily distinguished from a common water snake. It keeps most of its body above the water, almost as if it’s swimming. Water snakes, on the other hand, keep most of their bodies submerged; only the head is visible.
When not swimming, water moccasins like to soak up the sun on rocks and logs near the water. They don’t climb trees, so you don’t have to worry about getting a drop on your head, but if you’re walking along a stream or lake – even in winter – it’s a good idea to check the far side of a log before stepping over it.
Beware of imitations
The banded water snake (Nerodia fasciata) mimics traits of the water moccasin to enjoy the benefits of a venom delivery system without actually possessing one of them. He flattens his head and body when threatened to display the water moccasin’s fat body and triangular head more than passably. However, it is not a perfect impression. It is belied by the water snake’s overly slender torso, extra-long, narrow tail, and markings that do not turn black towards the tail like the markings on a water moccasin.
Even when not tried, the banded water snake looks similar to a water moccasin, but the most telltale difference between them is the heat-sensing pit, which gives pit vipers their name. It is located on the forehead above and between the nostrils of the water moccasin. The banded water snake has no such pit.
Where are most water moccasins found?
Water moccasins are found in the eastern US from the Great Dismal Swamp in southeast Virginia, south through the Florida peninsula and west to Arkansas, eastern and southern Oklahoma, and western and southern Georgia (excluding Lake Lanier and Lake Allatoona).
What kills cottonmouth?
Kingsnakes have a natural resistance to pit viper venom and regularly kill and eat cottonmouths, rattlesnakes, and copperheads.
How far can a water moccasin strike?
Full-grown cottonmouths can approach six feet in length but many are smaller, usually three- to-four feet. The snake characteristically holds its head at an angle of 45 degrees and can detect movement for a distance of at least fifty feet.
How long do you have after a water moccasin bite?
Patients presenting after a cottonmouth bite should undergo observation for eight hours post-envenomation. If there are no physical or hematologic signs within eight hours, then the patient can be discharged home.
How do you repel water moccasins?
Can a water moccasin bite you underwater?
Besides sea-snakes, there are two common snakes that can live in or near water – the cottonmouth (water moccasin) and the water snake. Not only can snakes bite underwater, but water moccasins join a list of more than 20 species of venomous snakes in the United States making them even more of a threat.
Are water moccasins aggressive?
Water moccasins are not aggressive, even though most people say so. The best way to avoid them is to try your best to keep out of their way. Once you accidentally step on them, they may lash out and bite as a self-defense instinct.