Cottonmouth Snake Care Sheet

Scientific Facts

Common Name: Cottonmouth Snake, Water Moccasin
Scientific Name: Agkistrodon Piscivorus
Life Span: 15 to 20 years
Mass: 3 to 4 pounds
Length: 50 to 120 centimeters
Clutch Size: 10 to 15
Habitat: Swamps, Marshes, Pond Edges
Country of Origin: Southeastern USA

Physical Description

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Cottonmouth snakes are relatively large snakes, reaching up to 120 centimeters in length. They are known to feature big jowls, typically due to their venom glands, as well as their “cat-eye” pupils. These snakes also feature some dark stripes in each nostril, along with some pale snouts which come in pretty helpful when it comes to determining features.

Cottonmouth snakes have large and triangular heads which are quite distinct from their thinner necks. This is unlike other kinds of snakes which usually do not have a distinctive neck. Their muscular, thick bodies are stout in comparison for their length. They are also covered in ridged, or keeled scales. Their color typically varies from black to olive, dark brown, yellow or branded brown. Their bellies are noticeably paler compared to their backs.

Young cottonmouth snakes are different in appearance than the adults. The juveniles usually have bands along with their bodies and are lighter brown in color. The patterns, despite being striking, fade as they age. The young snakes undulate their tail tip back and forth slowly in order to lure prey within distance.

Cottonmouth snakes are typically confused with other nonvenomous snakes, resulting in the death of harmless snakes. For one, it looks similar to the Northern Water-Snake. The appearance is similar, though the crossbands on the snake back do not widen at the ends. Just like all other pit vipers, cottonmouth snakes feature heat-sensing facial pits that are located between their nostrils and eyes. Nonvenomous snakes do not have these pits.

Cottonmouth Snakes Subspecies

In general, there are three cottonmouth subspecies, including the following:

Eastern Cottonmouth

They are considered as the nominative subspecies, which means that they are the default version. They live along the east coast, ranging from South Virginia to Georgia.

Western Cottonmouth

The Western cottonmouth subspecies have a wider range of geographically compared to other subspecies. They can be found in the far north, as well as Indiana in the East. They can also be found in the South, and in the West.

Florida Cottonmouth

This subspecies is unique in Florida, as well as the south of Georgia.

Baby Cottonmouth Snakes

Baby cottonmouth snakes usually reach ten inches in length. The venom produced by cottonmouth snakes usually develop at a young age, and they can also be very dangerous. Even if you encounter a baby snake, it is wise to treat it as an adult snake, staying at a safe distance because the venom produces the same effects in both young and adult cottonmouth snakes.


Cottonmouth snakes have generally described as long ones, as a mature adult is typically two to four feet in length. Male snakes are usually larger than the female ones, which is not really common among snakes. The size may also vary from the mentioned three subspecies. The western cottonmouths are the smallest, while the Florida cottonmouths are the largest ones. The longest cottonmouth snake ever recorded reached 74 inches or more than six feet.

In terms of size, cottonmouth snakes are not really long, compared to other snakes. In fact, they only range between two to four feet in length, on the average. Still, there are still some specimens which may reach up to six feet in length in the wild. This is because these snakes do not stop growing. In fact, they usually grow to their average length in just three or four years, continuing to grow longer and longer as time passes by. This means that if you see one that is bigger than the usual, it is usually much older as well.

Patterns and Colors

The colors of cottonmouth snakes may vary. When they are still young, the snakes usually have a lighter skin composed of tans, yellows, olives, and brown shades, with some bold patterns. The belly of a cottonmouth is usually paler than the rest.

As they age through adulthood, the colors start to fade to darker overall tones. Usually, an adult snake will be either brownish-black or completely black with faded bands. The underbelly also goes through a similar change to either a yellowish hue or darker brown.

Life Span

The lifespan of cottonmouth snakes in the wild reaches about 15 to 20 years. The oldest cottonmouth recorded in captivity reached 24.5 years.


In general, cottonmouth snakes are found rarely far from a water source, like the edge of a lake, slow-moving stream, swamp or pond. Throughout their life, these snakes are usually present in bald cypress swamps or open flat wood pine forests.


A terrarium with a 50 to 75-gallon capacity is enough for a single, or a pair of Cottonmouth snakes. A sufficiently large water receptacle for your snakes should also be present for the snakes to use in soaking and drinking. The water should always be kept clean and fresh.


The substrate to be placed inside the cage need to be dry, and may also use folded newspapers, aspen shavings, several paper towels, or cypress shavings. Visual barriers and a hide box should also be installed inside the cage.

Lighting and Temperature

Daytime light should be provided. The room temperature inside the cage should be at 76 to 83 degrees Fahrenheit. This is the temperature suitable for the terrarium. At nighttime, a temperature of about 70 degrees is enough. A hot spot at daytime of about 92 to 95 degrees needs to be given using a basking lamp.

If you are planning to keep your cottonmouth as a pet, they may be kept active and warm all winter, and they usually continue to eat during these months. On the other hand, if you plan to breed these snakes, they usually need a 90 day dormancy period.

Diet and Eating Habits

Cottonmouth snakes may become aggressive. They usually stand their ground. The venom of cottonmouths is stronger, and they also tend to be bigger, which makes them quite dangerous. According to the results from tests that are designed to measure the behaviors of free-ranging cottonmouths and their encounters with humans, 50% of the test subjects attempted to escape, and 78% used some defensive tactics and threat displays.

It should be noted, however, that it will only be when cottonmouth snakes were picked up using a mechanical hand are they most likely to bite. When faced with a threat, or is startled, a cottonmouth snake usually stands on its ground, opening its mouth in order to warn their predators to stay away. This act is viewed several times as aggressive, though, when left alone, they usually just slip away.

Cottonmouths also love swimming with most of their bodies floating beyond the surface. This is what distinguishes them from other water snakes, as these snakes tend to swim below the surface of the water, with their heads protruding at times.

They also have a wide variety of prey in their favorites list. Their diet includes small mammals, fish, birds, lizards, baby alligators, small turtles, as well as other snakes. Typically, a victim is quickly envenomed with a bite and released immediately. If the prey does not immediately succumb, the predator tracks the prey by scent.

Just like all other pit vipers, cottonmouths have pits on the edges of the nose, sensing the body heat of warm-blooded animals with infrared light. As such, the hunting ability of cottonmouths is not impaired even at night. The term “cottonmouth” comes from the tendency of these snakes to open their mouth widely, showing off white tissue, similar to cotton, inside as a gesture of warning.

Cottonmouth snakes are generally known as ambush predators. Cannibalism has been reported in this group, with the juveniles feeding on invertebrates. They also use their bright tails to attract prey, such as amphibians.

Omni carnivorous Nature

Cottonmouth snakes are Omni carnivorous in nature. This means that they can eat almost anything, except plants and leaves. Just like all other snakes, they eat birds and mammals, and smaller amphibians, such as toads and frogs.

On top of that, they also eat a lot of fish, and smaller turtles present in the water. They love hunting for fish in shallow waters, especially those that are close to the bank. Cottonmouths find it difficult to hunt and swim at the same time, which is why they will try to corner a fish near the bank or against a log for the kill.

Their diet, however, does not stop there. They also feed on insects such as snails, cicadas, caterpillars, and snugs. They even eat on other snakes, including other cottonmouths.

Sleeping and Brumation

Most snakes, Cottonmouths included bromate during the winter. The process of brumation is similar to hibernation, where snakes enter a period of almost no activity. During this period, they will stop eating, stop moving around, and will not be mating. It is like they are simply taking the winter off.

During brumation, cottonmouths usually hide in dens such as logs, under rocks and hollow trees. They can also sleep anywhere they feel safe. By nature, cottonmouth snakes tend to sleep deeper compared to the snakes in the South because of their need to conserve more energy.

Another interesting thing about cottonmouth snakes during brumation is that they do not bromate alone. Some snakes sleep over the winter in dens, typically sharing the place with other venomous snakes. It seems like they all agree that it is for their good if they gather together to gather a little more warmth. This is also good because snakes lose their appetite during this season, which means that they usually do not get into fights with each other.

Once the snakes are finished bromating in the spring, they will come out and start mating and eating again. This, however, is a behavior that is unique to cottonmouths from the North. The ones from the south do not bromate very long. This is because it is still warm enough at that time that they can move around safely without getting too cold.

When it is very cold, they will lose too much heat in their bodies and die. Aside from that, they will also not be able to digest their food when it is too cold. In warmer locations, however, such as in Florida, cottonmouth snakes can stay active during winter.

Development and Reproduction

Cottonmouth Snakes are referred to as ovoviviparous, which means that they develop in eggs that are protected inside the body of their mother until the moment that they hatch, or just about to hatch. This kind of reproduction is also common among other forms of aquatic life.

Nourishment comes from the egg yolk, rather than the mother. However, the body of the mother provides a gas exchange. Afterwards, the eggs hatch inside their mother, and around 15 litter are birthed alive. Female cottonmouth snakes usually give birth every other year.

The breeding typically happens during the warmer months. On the other hand, most of the births happen after a gestation period of three months. The differences in the physiology of the snakes may result with the actual gestation period to differ from season to season. Cottonmouth snakes are also not known to provide parental care after giving birth, though there have been reported cases of mothers showing defensive behavior towards her litter.

Cottonmouth snakes can also reproduce without breeding.  This is an interesting story. If a snake cannot find a suitable mate, they create young without even breeding. This is a process referred to as “facultative parthenogenesis”.

This process is complicated, as it involves the split of chromosomes, and combining them again differently. Using this genetic material, an egg will grow in the way it usually would. The difference, though, is that only the genetic material is involved, instead of the genetic material that comes from both father and mother.

This is interesting and rare because only a few animals can reproduce their young like this. Still, it is best that offspring are produced as a result of regular breeding, as they are to thrive more likely.

Heat Sensors

Cottonmouth snakes are also called as pit vipers. This means that they are among a group of snakes which use heat-sensing pits located on their faces. These pits are small and are located right on their nose, just between the nostrils.

These heat sensors are very effective in detecting infrared radiation, especially heat, from even a yard away. This is also effective when locating, and attacking prey. These pit organs feature a thin membrane which detects the warmth of infrared radiation.

Possible Danger to Humans

The venom of cottonmouth snakes is potent. In fact, they are among the most venomous snakes in the United States. These snakes usually use their venom in order to trap their prey and immobilize it. Venom from cottonmouths is mainly composed of hemotoxins which break down blood cells.

Their venom is composed of toxic enzymes which offer an adverse impact on the body. There are also different types of venom produced. Some of the venoms attack the nervous system primarily. When this happens, the brain will stop communicating with the body, stopping anybody bitten from being able to breathe.

Other venoms also destroy the body tissues, while others stop the blood from clotting. This also results in several other adverse effects. When this happens, blood is prevented from clotting or coagulating. This results in something very serious, even fatal. The good news is that fatalities are rare among humans. In fact, they will only bite if they are constantly provoked. This means that if you encounter a cottonmouth in the wild, it is recommended to leave them alone.

With their prey, however, it is deadly. As the venom incapacitates their prey, preventing them from escaping. Then the snakes eat it while dying, or when dead. The effects of the bite of cottonmouth snakes include hemorrhaging of the circulatory system where the venom has spread. A bite from a cottonmouth snake may result to either a temporary or a permanent muscle or tissue damage, loss of an extremity, depending on the bite’s location, extreme pain surrounds the area or internal bleeding. If you are bitten by a cottonmouth snake, it is recommended to seek immediate medical attention. Antivenin for their bites is available.

The bites of cottonmouths are very painful. Similar to a viper, a cottonmouth’s bite is one of the most painful among snake bites. The bites usually start a strong and powerful burning sensation. This is a result of the tissues breaking down.

The venom of cottonmouths works in a way that it starts to dissolve tissue right after the bite. This will help them quickly digest their food. Humans may be too big for them to eat, but humans that are bitten by cottonmouth snakes will certainly feel the pain on the skin as the cells start to break down.

Peaceful Snakes

Contrary to the violent nature of other snakes, cottonmouth snakes are afraid of conflict and fighting. Instead of biting or musking, cottonmouths would try to escape first. If they see someone approaching them, they will try to run away as fast as they can. They even escape and jump into the water if they see it.

They usually hang out on branches or logs right next to the edge of the water so that they can easily dive in for a faster escape. They are aware that they can move faster in the water than on land, which is why they would rather stay safe.

Cottonmouth snakes usually attack, only when they are stressed or threatened. If you own a snake, you will notice that they tend to attack when they are stressed, maybe because they are hungry, or they just want to be left alone as they try to digest something inside them. They may also attack if their owners handle them too frequently, which is one of the primary stressors among captive snakes.

Unique Keeled Scales

If you think that all snakes have similar kinds of scales, it may be time to think again. Cottonmouth scales have a unique kind of scale, the keeled scale. This is where every scale features a ridge that runs from top to bottom. Aside from making them stand out and look different from other snakes, keeled snakes also help cottonmouths to grip the surfaces better. The principle is similar to the reason why we also have fingerprints.

The ridges of our fingerprints allow us to hold on to things even though they are slippery and wet. In the same way, the ridges on the scales of cottonmouth snakes help them to grip tree branches and rocks even better.

Myths about Cottonmouth Snakes

There are some stories about cottonmouth snakes. One of the most popular ones is the story wherein somebody was out skiing in the water and fell into the water after losing control. Suddenly that person felt falling into a big ball of barbed wire. Of course, it is not really barbed wire, but a mass of cottonmouths, moving, and a group of 50 to 100. As the person was pulled back to the boat, the person was covered all over with bites.

There are several variations of this story, one of which includes a group of young boys going swimming. Suddenly, one shouted “the last one is a rotten egg!”, jumping right into the water, finding himself falling into that same huge ball of cottonmouths.

It is such a relief, however, that none of these stories is true. For one, cottonmouth snakes do not nest together in water, whether shallow or deep. They are described as solitary snakes, not really social, which means that they are not usually together in bigger groups.

Conservation and Threats

The cottonmouth snake is classified as a Least Concern (LC) species under the IUCN Red List. This is because of the wide distribution of snake and presumed huge population. In 2007, it was assessed that the population trend among cottonmouth snakes was stable.

However, drainage of the wetland habitat for development, as well as the persecution in these species has also taken its toll on the population of these snakes. Despite this threat, cottonmouth snakes stay as a common species in several areas. In Indiana, however, cottonmouth snakes are listed as endangered species.

Availability – Where to Get One?

There are certain snake sellers where you can purchase cottonmouth snakes for pets. It should be noted, however, that this variety is rare since not many want to keep it as pets due to their bite.

Fun Facts About Cottonmouth Snakes

Here are some interesting facts about cottonmouth snakes:

  • Cottonmouth snakes have dozens of nicknames. This is because they are really common in the US. Aside from being called by their scientific name, they are also referred to as pit vipers, water pilots, river rattlers, mangrove rattlers, pond rattlers, and swamp rattlers. This is because they rattle their tails when they are treated.
  • Their scientific name actually means fish eater. Agkistrodon Piscivorus is descriptive, just like other scientific names. This is because it has been noticed by scientists that cottonmouth snakes love to eat fish.
  • They have a wide variety of color. Snakes with dark colors vary between black and dark brown. On the other side, the lighter colors also vary between brown, olive and yellow, while their tummies are a lighter brown, or even white.
  • Cottonmouth snakes lose color as they age. Their color gets darker through time. As time passes by, their top turns into ruddy black, while their bellies become whiter. This is common among longer snakes, as they are the older ones. They also tend to lose their green and yellow tail tip. Older snakes may lose so much color that it completely disappears.
  • Cottonmouth snakes also have predators of their own. This is true even though they are considered venomous snakes. In fact, they are preyed on by several other animals, including bird preys such as horned owls, falcons, hawks, and eagles. Other predators are also present in the same habitat they are in, such as birds like cranes and herons, as well as alligators. They are also being preyed by other snakes, even other cottonmouth snakes.
  • Even though they are also related to vipers, with venom like vipers, cottonmouth snakes are the only aquatic viper species. This means that they are very unique.
  • Interestingly, cottonmouths are somewhat monogamous. During the breeding season, cottonmouths usually pair up, staying in that pair during the breeding season. The male even has to fight other males who try to mate with a specific female. After the breeding season is finished, however, the pair will separate. They will then select a different partner for the next breeding season.
  • Even the young cottonmouth’s snake bite. This is a fact. The moment a young snake is born, they are ready for everything. This means that they start producing venom early on. Even though their fangs may not be as big as they are young, but the effect of the venom is still powerful and strong.
  • Good news – cottonmouth snakes do not really just bite for nothing. In order for them to produce venom, they need to use a lot of energy. This energy is earned by hunting. It is highly possible that a snake has run out of venom, either because all has been spent already, or because they have been milked. For this reason, biting among cottonmouths is a last resort.
  • Milking is a method of collecting venom from snakes without unnecessary killing them. This is done by draining out the venom from the venom glands. Snakes who go through this process do not produce venom upon biting.
  • If a cottonmouth does not bite, it is likely to simply “musk” at you. This is similar to what skunks produce, which smells horrible. This musk is sprayed by cottonmouths, and you get covered in it, scaring you away.
  • Cottonmouth Snakes have keeled snakes. This means that they are different from that of other snakes. A keeled scale is one wherein each scale has a ridge that runs from top to bottom, such as from the end that is closest to the head, to the other end that is closest to the tail.
  • Cottonmouth snakes are better swimmers compared with other snakes. This is because they spend a lot of time in the water, training them to become excellent swimmers. They are amazingly buoyant, which means that they can keep their entire body at water level, including their head, middle, tail and the rest. This is very important because they cannot breathe underwater.

FAQ Section

How can you initially tell if a snake is a cottonmouth snake?

The head of a cottonmouth snake is usually arrow-shaped, and almost triangular in top view. One thing to note, however, is that some non-venomous snakes tend to flatten their heads when approached by danger. This is done as a way to appear larger than their real size. This means that the head shape is a difficult way to identify cottonmouth snakes.

What is the difference between a water moccasin and a cottonmouth?

Cottonmouths and water moccasins are one and the same. They are characterized by their triangular, big heads with a dark line through the eye, elliptical pupils and big jowls because of their venom glands.

Are cottonmouth snakes aggressive?

Cottonmouths are known to be aggressive. However, in contrast, they are actually peace-loving, and rarely bite humans. When a snake feels threated, it usually coils its body, opening its mouth really wide in order to expose the white color of the inner part of their mouth.

How long can cottonmouth snakes get?

Adult cottonmouths usually go over 80 centimeters in length. Males, however, grow larger compared to the females. They usually have a heavy body with a long tail. In certain occasions, some snakes exceed 180 centimeters in length, particularly those in the Eastern part of the country.

Why do water moccasins stink?

Most varieties of snakes have scent glands that are used in deterring predators and communicating with other snakes. Water moccasins, like other snakes in their genus, have a unique stinky musk that smells bad.

Can a cottonmouth kill you?

Some people believe that cottonmouths are very deadly. On the contrary, they are not really deadly. The maximum amount of venom produced by a cottonmouth is enough to kill a person.

How dangerous are cottonmouth snakes?

The bite of a cottonmouth snake is more harmful and dangerous to humans that the bite of a copperhead. However, the bite rarely results in death. The cottonmouth snake, however, is more aggressive, though biting is not really common unless the cottonmouth is actually touched.

How long does it take for a cottonmouth bite kill you?

Fatality may happen up to several days after the bite. It could also be as fast as two hours. The average death among pit viper bites happens in two days. If the bite is focused on the vein, artery, lymphatics or a nerve, death may happen in just 30 seconds to 10 minutes.

How do you treat a cottonmouth snake bite?

When bitten by a cottonmouth snake, it is best to get away from the area where the snake is present. Remove any jewelry or clothing from the area surrounding the bite before any swelling starts to occur. Stay as calm as possible, and make sure to position yourself so that the area of the bite is below heart level.

What type of venom does a water moccasin have?

Water moccasins are actually pit vipers, similar to rattlesnakes. This only means that their venom is hemotoxic, which may lead to problems of the red blood cells and the tissues of the body.

Can a water moccasin bite you in the water?

Yes. In fact, they can open their mouths wide and bite when provoked underwater. Even though they prefer to lounge on tree limbs or logs at water’s edge, they usually swim underwater to capture food.

How do you kill a water moccasin?

While it would be too brutal to kill them if they are not doing anything, the best way to get rid of them is by leaving them alone. A trap can also be used to catch them.

How do cottonmouth snakes smell like?

In woodland ponds, in particular, cottonmouths are present in almost every few years. At times, they can be detected because of their musky smell in the air.

Why do cottonmouths swim well?

Cottonmouth snakes are amazingly buoyant. This means that they can keep their entire body at water level, including their head, middle part, and tail. This is very important because they cannot breathe underwater.

Are cottonmouth snakes confrontational creatures?

Cottonmouth snakes are usually afraid of conflict. As such, they usually try to escape and run away when they see somebody coming towards them.

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