Cottonmouth

Agkistrodon piscivorus

Last updated: May 11, 2022
Verified by: AZ Animals Staff
Image Credit jo Crebbin/Shutterstock.com

The cottonmouth (also known as a water moccasin) is a highly venomous pit viper that spends most of its life near water.

Cottonmouth Scientific Classification

Kingdom
Animalia
Phylum
Chordata
Class
Reptilia
Order
Squamata
Family
Viperidae
Genus
Agkistrodon
Scientific Name
Agkistrodon piscivorus

Read our Complete Guide to Classification of Animals.

Cottonmouth Conservation Status

Cottonmouth Locations

Cottonmouth Locations

Cottonmouth Facts

Prey
Fish, rodents, shrews, frogs, reptiles, birds, insects, and eggs
Fun Fact
The cottonmouth (also known as a water moccasin) is a highly venomous pit viper that spends most of its life near water.
Litter Size
Up to 16 live young
Diet
Carnivore
Common Name
Cottonmouth

Cottonmouth Physical Characteristics

Color
  • Brown
  • Black
  • Olive
Skin Type
Scales
Lifespan
15-20 years
Length
2-6 feet

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The cottonmouth (also known as a water moccasin) is a highly venomous pit viper that spends most of its life near the water.

Cottonmouths are considered to be one of the few semi-aquatics snakes in the world. They can sometimes be seen swimming in both freshwater and saltwater areas. There are generally two species: the northern cottonmouth and the Florida cottonmouth. This article will cover some interesting facts about the identification, habitat, diet, lifespan, and size of both species.

What’s the difference between a cottonmouth vs. a water moccasin?

There is no difference. They are simply two different names for the exact same species.

5 Cottonmouth Amazing Facts

  • The cottonmouth goes by many different names, including the water moccasin, swamp moccasin, rusty moccasin, and black moccasin. A moccasin is essentially a type of shoe or slipper made from leather.
  • The cottonmouth can choose to mate at any time throughout the entire year, but its reproductive season usually takes place in April and May. In order to attract a mate, the male cottonmouth will perform a combat dance in which he slithers back and forth and waves his tail. Males will also fight each other for access to females. Cottonmouths are thought to be monogamous.
  • Females will give birth to an average of five to nine live young at a time (16 is usually the maximum number) after a gestation period of five months. However, because of predators, only two or three young will usually make it to adulthood. It takes about three years for female to reach full sexual maturity (the sexual maturity of the male is unknown). If they survive, then they have a typical lifespan of 20 to 25 years.
  • The predators of juvenile or baby cottonmouths include eagles, egrets, raccoons, longnose gars, largemouth bass, and snapping turtles. Adult cottonmouths, by contrast, have very few predators.
  • Female cottonmouths are capable of both sexual and asexual reproduction. This means they can produce young in the absence of males (although at the cost of genetic diversity).

Where to Find Cottonmouths

Cottonmouths can be found all year-round in many aquatic locations, including cypress swamps, river floodplains, lakes, bays, and wetlands, throughout the southeastern United States. Their range extends all the way up to southern Illinois and west to Texas; there is also a bit of overlap in Florida between the northern cottonmouth and the Florida cottonmouth. They like to spend their days basking near logs, rocks, and branches close to the location of the water’s edge. The size of the snake’s territory depends on its physical size and sex (males tend to have larger home ranges).

Cottonmouth Scientific Name

The scientific name of the northern cottonmouth is Agkistrodon piscivorus, whereas the Florida cottonmouth is called Agkistrodon conanti. The genus name Agkistrodon essentially means hook tooth (or a tooth like a fishhook) in reference to the shape of the fangs. The species name piscivorus essentially means fish devourer or fish eater, whereas conanti is named in honor of noted herpetologist Roger Conant.

The northern vs. Florida cottonmouth distinction only came about in 2015. Before then, there used to be three subspecies recognized: the eastern, western, and Florida cottonmouths. However, based on DNA analysis, it was determined to make the Florida cottonmouth its own species and eliminate the eastern/western distinction entirely. That leaves us with two species, the Florida and northern cottonmouths, and no subspecies. Both of these species are closely related to copperheads and the cantils in the same genus of Agkistrodon.



Cottonmouth Population & Conservation Status

According to the IUCN Red List, the snake is a species of least concern. While we don’t have enough facts about population numbers to make a proper estimate, this species does appear to be fairly common throughout most of its natural range. However, the loss of wetlands habitats throughout the southern United States does pose a danger to certain cottonmouth populations.

How to Identify Cottonmouths: Appearance and Description

The adult can reach anywhere between 2 feet and 6 feet long with the largest cottonmouth ever recorded measuring 74 inches in length. Males are typically longer and heavier, with more scales on the tail than their female counterparts. This should make the identification of the sexes easier. The snake is characterized by a large, spade-shaped head, bright white mouths, and alternating bands of light and dark patterns. Black, brown, and olive are the most common colors; they help the snake blend in against the surrounding environment. Juveniles and babies are also fairly distinctive from adults. They have even stronger contrasting bands of colors; the tip of the tail is sometimes yellow or greenish as well.

How to identify the snake:

  • Large spade-shaped head
  • Long, thick, muscular body measuring up to 6 feet in size
  • Black, brown, and olive colors alternating in light and dark bands
  • Bright white mouths

Cottonmouth Pictures

Side view of a Cottonmouth snake, ready to strike. The snake has a large spade-shaped head.
Side view of a Cottonmouth snake, ready to strike. The snake has a large spade-shaped head.

KF2017/Shutterstock.com

Cottonmouth swimming in water. The snake has a long, thick, muscular body measuring up to 6 feet in size.
Cottonmouth swimming in water. The snake has a long, thick, muscular body measuring up to 6 feet in size.

Seth LaGrange/Shutterstock.com

The cottonmouth is characterized by a large, spade-shaped head, bright white mouths, and alternating bands of light and dark patterns.
The cottonmouth is characterized by a large, spade-shaped head, bright white mouths, and alternating bands of light and dark patterns.

iStock.com/Saddako

Cottonmouth: How Dangerous Are They?

These snakes have highly potent venom that destroys the tissue and causes significant swelling and pain. It is generally more dangerous than the copperhead venom but less so than the rattlesnake. The venom will sometimes leave behind permanent scars and very rarely necessitates an amputation, but it is almost never fatal even in the absence of treatment. Nevertheless, you should still seek medical attention immediately after a bite. The antivenom is highly effective at minimizing the effects of the toxin.

Cottonmouth Behavior and Humans

Cottonmouths are widespread throughout the south, and encounters with them are fairly common. Although quite dangerous in theory, cottonmouths tend not to bite humans very often in practice. They would rather run away and flee. Before striking, the snake will give a warning signal by shakings its tail, opening its mouth, and raising its head above the ground. They also have the ability to release a pungent, foul-smelling musk to deter potential threats. Even if one did happen to bite you, however, they deliberately release less venom in a defensive bite than an offensive one against their prey.

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Cottonmouth FAQs (Frequently Asked Questions) 

What snakes are cottonmouths mistaken for?

Cottonmouths are mistaken for many snakes, but a primary one is the northern water snake. Both snakes are aquatic and have similar coloration. However, the key difference between northern water snakes and cottonmouths is that cottonmouths are venomous while northern water snakes are not.

Cottonmouths are also sometimes confused for other water snakes like the yellow-bellied watersnake or the Florida banded watersnake. Once again, yellow-bellied watersnakes are not venomous while cottonmouths are.

What is the difference between cottonmouths and kingsnakes?

When separating kingsnakes vs. cottonmouths, the most important difference is that kingsnakes are nonvenomous while cottonmouths are venomous. In fact, kingsnakes are constrictors that often hunt venomous snakes!

How do cottonmouths compare to coachwhips?

Coachwhips are more slender and faster than cottonmouths. The primary difference to be aware of between coachwhips and cottonmouths is that coachwhips are nonvenomous while cottonmouths are venomous.

Are cottonmouths venomous?

Yes, the cottonmouth venom is quite dangerous. While they do tend to hold back against people by injecting only a partial dose, the venom can still do serious damage, especially if left untreated. People often make a mistake in terminology by calling this snake poisonous. In fact, a venomous animal creates and then injects its own toxins, whereas poisonous animals are toxic to eat. Therefore, very few snakes are truly poisonous.

How do cottonmouths hunt?

Cottonmouths have multiple ways to find and identify prey. They often make use of their developed hearing and vision. They can also sense smells by flicking the tongue into the air and then pressing the scent molecules against a sensory organ on the roof of the mouth (they smell with the nose too, but it’s not as effective). Once they’ve made a proper identification, the cottonmouths will bite the prey and release the venom into its body. The prey will be held in the coils until it is dead. The cottonmouth has the ability to detach its jawbone to swallow the prey whole.

Are cottonmouths aggressive?

These reptiles can be quite aggressive if they are cornered or provoked in some manner. For this reason, they should not be approached in the wild. However, most of these snakes would rather run away and flee than stand their ground and strike.

Where do cottonmouths live?

These reptiles live near sources of water, including wetland habitats, lakes, rivers, and bays. Northern cottonmouths are found in various locations throughout the southeastern United States. The range of the Florida cottonmouth, as the name suggests, is mostly restricted to that state.

What do cottonmouths eat?

The diet largely consists of fish, rodents, and other small mammals. They will also sometimes consume birds, frogs, turtles, eggs, insects, and other snakes. Baby cottonmouths are basically born ready to hunt and feed on smaller animals.

Why is it called cottonmouth?

They are called cottonmouths because of the bright white coloration inside of the mouths, which they show off when threatened. Water moccasin is another accepted name.

What's the difference between a cottonmouth and a rattlesnake?

The main differences between a cottonmouth and a rattlesnake are their preferred habitats and physical appearances. Cottonmouths have white mouths, and rattlesnakes have rattles on the ends of their tails.

What are the differences between brown water snakes and cottonmouths?

The differences between brown water snakes and cottonmouths are their appearance, preferred habitat, behavior, diet, and relative danger.

How do cottonmouths compare to timber rattlesnakes?

Both cottonmouths and timber rattlesnakes have territory that overlaps, but they prefer different habitats. While cottonmouth snakes enjoy aquatic areas, timber rattlesnakes are normally found in forested areas. The bite of the timber rattlesnake is generally considered more serious, although bites from both snakes demand medical attention.

What's the difference between a black racer and a cottonmouth?

When comparing a black racer vs. a cottonmouth snake, while they both can share similar habitats throughout the southeast of America, the two snakes look very different. Most importantly, black racers are non-venomous while cottonmouths have venom.

Can cottonmouths breed with copperheads?

Because the two species are in the same genus (Agkistrodon), interbreeding is possible.

Is a cottonmouth more venomous than a coral snake?

No. A coral snake is more venomous than a cottonmouth snake.

Sources
  1. University of Georgia, Available here: https://srelherp.uga.edu/snakes/agkpis.htm
  2. Animal Diversity Web, Available here: https://animaldiversity.org/accounts/Agkistrodon_piscivorus/

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