Are water moccasins good for anything?

Quick Overview

Water moccasins, also known as cottonmouths, are venomous pit vipers found in the southeastern United States. They are generally considered a nuisance and danger to humans. However, like most animals, they play an important role in their natural ecosystems.

What are water moccasins?

The water moccasin (Agkistrodon piscivorus) is a venomous pit viper species found in the southeastern United States. They are often called cottonmouths due to the white lining of their mouth which they display when threatened. Other common names include black moccasin, water viper, and stub-tailed viper.

Water moccasins are semi-aquatic, usually found near calm, shallow waters such as swamps, marshes, canals, lakes, and rivers. They are endemic to the southeastern United States from southern Virginia to Florida and west to central Texas and Oklahoma.

Adult water moccasins typically reach lengths of 2-4 feet. They have a dark, thick bodied appearance with a broad, triangular head. Their coloration varies from black, brown, olive green to reddish. Juvenile cottonmouths have vibrant patterns of crossbands that fade as they mature.

Like other pit vipers, water moccasins have heat-sensing loreal pits between their eyes and nostrils used to detect prey. They also have keeled scales and vertically elliptical pupils common among venomous snakes.

Water moccasins produce potent cytotoxin venom that attacks tissues and blood vessels. Their venom is used to immobilize and kill prey quickly. And while cottonmouths will often flee from threats, they may stand their ground and strike if cornered. Their bites, while very rarely fatal to humans, require immediate medical treatment.

Water moccasin habitat

Water moccasins reside in the wetlands and waterways of the southeastern United States, ranging across the following states:

  • Virginia
  • North Carolina
  • South Carolina
  • Georgia
  • Florida
  • Alabama
  • Mississippi
  • Louisiana
  • Arkansas
  • Oklahoma
  • Texas

Within these states, cottonmouths frequent swamps, marshes, rivers, lakes, and ditches containing slow-moving, shallow water with abundant vegetation and prey. They are often found resting in trees, under brush, or other cover along the water’s edge.

Water moccasins thrive in warm environments and require semi-aquatic habitats to survive. Their prey includes fish, frogs, smaller snakes, rodents, and other small mammals that dwell near water.

During the winter, water moccasins brumate, sheltering communally in dens or hollows. In the spring they emerge to mate before dispersing to hunt and spend summer around water sources.

Water moccasin diet

Water moccasins are carnivorous ambush predators that feed on a variety of prey, including:

  • Fish – Top choice prey, including perch, catfish, bass, etc.
  • Amphibians – Frogs, toads, and salamanders.
  • Reptiles – Snakes, smaller turtles, lizards.
  • Small mammals – Rodents, rabbits, moles, etc.
  • Birds – Chicks, eggs, small waterfowl.
  • Invertebrates – Large insects, crayfish, etc.

They are not picky eaters and prey opportunistically on most small animals near the water’s edge. Fish make up 50-60% of their diet when available.

Water moccasins utilize ambush tactics, waiting motionless for prolonged periods until potential prey comes along. They then strike quickly, injecting their venom and swallowing prey alive. Their flexible jaws allow them to consume fairly large prey relative to their body size.

These snakes are well adapted for an aquatic hunting lifestyle. Their thick, muscular bodies propel them through the water. The heat-sensing pits between their eyes and nose help detect warm-blooded prey in water.

Cottonmouths play an important role as apex predators in their aquatic ecosystems, helping regulate populations of various fish, amphibians, and small mammals that form their prey base.

Water moccasin behavior

Water moccasins exhibit some unique behaviors and adaptations suited for a semi-aquatic lifestyle:

  • Swimming ability – They are strong swimmers and can remain submerged for up to 30 minutes.
  • Muscular bodies – Thick, powerful bodies allow them to move adeptly on land and water.
  • Heat sensing pits – Specialized pits detect thermal signatures of prey.
  • Open-mouthed threat – When threatened they often gape their mouth showing white interior.
  • Defensive attitude – More prone than many snakes to stand ground when confronted.
  • Communal winter dens – Gather in groups in hollows and caves for warmth in winter months.
  • Birthing live young – Give birth to live young (viviparous reproduction) with litters of 6-20 offspring.

In terms of disposition, water moccasins tend to have a surly reputation. Due to their habit of standing their ground, many bites occur from people unintentionally getting too close.

They do not generally chase or lunge at threats unless severely provoked. Given room and opportunity to flee, cottonmouths will usually retreat from humans and larger animals. But they are quick to defend themselves with a bite if cornered.

Water moccasin self-defense

When threatened, water moccasins rely on several defensive adaptations and behaviors:

  • Intimidating open-mouthed threat displays
  • Musk and feces excretion to deter threats
  • Camouflaged coloration to hide
  • Biting as a last resort
  • Thick body armor resistant to injury
  • Potent cytotoxic venom to quickly dispatch predators

The most distinctive defensive behavior is gaping their mouth wide open to show the striking white oral lining, often accompanied by deep hissing. This serves to startle and intimidate predators.

If further provoked, cottonmouths will coil their body and strike with fangs bared. Their venom can cause severe tissue damage, though rarely kills a healthy human.

Overall water moccasins prefer escape to confrontation. But their defensive posture gives them a much fiercer reputation compared to many other snake species.

Water moccasin bites

Water moccasin fangs can inject large quantities of potent venom when biting defensively. Here are key facts about cottonmouth bites:

  • Cause severe pain, swelling, tissue destruction at the bite site.
  • Damage blood vessels, resulting in internal bleeding in severe cases.
  • Can lead to temporary or permanent muscle damage.
  • Without treatment bites can be disabling or disfiguring but are rarely fatal.
  • Seek medical aid immediately if bitten.
  • Antivenom available to counteract venom effects.
  • Often are “dry bites” with no venom injected.

Bites occur most frequently from accidental encounters when waders or swimmers splash near camouflaged cottonmouths. Provoking cottonmouths intentionally is extremely hazardous.

While cottonmouth venom can have devastating local effects and needs urgent treatment, fatalities are uncommon assuming proper medical care. Pain management, antivenom, and prevention infection are key elements of treating severe bites.

Water moccasin predators

Young water moccasins fall prey to a variety of predators, including:

  • Larger snakes – King snakes, rat snakes, etc.
  • Alligators
  • Turtles
  • Birds of prey – Hawks, herons, crows
  • Raccoons
  • Opossums
  • Wild boar
  • Large fish
  • Other carnivores

Adult cottonmouths larger than 2 feet have fewer predators, but may still occasionally be killed by owls, alligators, larger snakes, or other predators capable of overcoming their venomous bite.

However, water moccasins are apex predators in their swamp and marsh habitats. They help control populations of prey and smaller competing snake species.

Their fearsome reputation protects them against many potential predators. Very few animals are willing risk a defensive bite when confronting a cottonmouth.

Significance of water moccasins to ecosystems

Water moccasins play an important ecological role in their native habitats by:

  • Preying on abundant small animals like frogs, fish, and rodents.
  • Regulating populations of prey species.
  • Competition and predation on smaller snakes.
  • Prey for larger predators they do not dominate.
  • Dispersing seeds and nutrients from prey.
  • Indicator species of habitat health.

As major aquatic predators, water moccasins help structure the overall food chain. Both their prey populations and predator numbers are kept in balance, promoting biodiversity. Declines in cottonmouth numbers can reflect problems in an ecosystem.

Through predation and scavenging of dead cottonmouths, nutrients are cycled through food webs. And the movement of snakes distributes plant seeds that get carried on their scales.

Water moccasins are an integral part of southeastern US wetlands despite their fearsome reputation.

Differences between water moccasins and other water snakes

Water moccasins are often confused with harmless, nonvenomous snakes sharing the same aquatic habitats. Here are some key differences:

Water moccasin Water snake
Elliptical pupils Round pupils
Single row of scales on underside of tail Double row of scales on tail
Thick, triangular head Slim head
Heat pits between eyes and nostrils No heat pits
Prominent fangs Small teeth, no fangs
Thick bodied Thinner body
Give live birth Lay eggs

When confronted water moccasins open their mouth in threat, while harmless water snakes will flee. So key differences in appearance and behavior help distinguish these often confused snakes.

How dangerous are water moccasins?

Water moccasin bites should always be taken very seriously given the risk of tissue damage, but some key facts:

  • They are shy and typically flee humans if given the chance.
  • Bites often occur from stepping on them or getting too close rather than intentional attacks.
  • Most bites are “dry” without venom injected.
  • They do not chase people and rarely strike unless severely threatened at very close range.
  • Antivenom prevents severe complications and deaths.
  • Average of only 5 human deaths per year from cottonmouth bites.

So while water moccasin bites are medically dangerous, the snakes themselves are not aggressive toward humans. Most bites only happen when accidentally stepped on or handled.

Still, it is wise to give water moccasins plenty of space and not disturb or provoke them intentionally, as they can deliver a fast, painful, and damaging bite in self-defense.

Are water moccasins protected?

Water moccasins are classified as a moderately threatened species. Their legal status includes:

  • Not currently endangered or protected overall, but declining in some areas.
  • Classified as a Protected Nongame Species in Georgia.
  • Considered a Priority Species of Greatest Conservation Need in Mississippi.
  • Harvest is illegal in Kentucky and Tennessee.

While not directly protected on a federal level, wanton killing of water moccasins is often discouraged. Their ecological importance and lack of aggression toward humans unless provoked makes them a valuable wildlife species, despite potential dangers from bites.

If residing on private property, property owners may decide to remove them. But professional snake removal is recommended, as they can be hazardous to handle.


In summary, water moccasins are venomous, often feared snakes that pose modest risks to humans if left undisturbed. But they fill an important ecological role as predators in wetland environments across the southeastern United States. This includes regulating prey populations and providing food for other predators. Intentionally provoking or harming cottonmouths should be avoided both for safety and environmental reasons. But with responsible precautions, water moccasins can coexist with humans.

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