The names “cottonmouth” and “water moccasin” frequently lead to questions about whether they refer to the same snake. This common confusion arises from the snake’s reputation and regional designations. Understanding the correct terminology and characteristics of this species can clarify these distinctions.
Unraveling the Mystery: Are They the Same?
Cottonmouths and water moccasins are indeed the same snake, representing a single species known scientifically as Agkistrodon piscivorus. “Cottonmouth” is a widely used common name derived from its defensive display, where the snake opens its mouth to reveal a striking white interior. “Water moccasin” is another prevalent common name for this semi-aquatic venomous snake.
Key Identification Features
Cottonmouths are heavy-bodied snakes, ranging from 2 to 4 feet in length, with some individuals reaching up to 6 feet. Their heads are broad and triangular, distinct from their narrower necks. A deep facial pit, which senses heat, is present between each eye and nostril, characteristic of pit vipers. Their pupils are vertically elliptical, resembling a cat’s eye.
The coloration of a cottonmouth varies, from olive or brown to almost black, often displaying broad crossbands that may become obscure with age. Juveniles exhibit more distinct patterns and possess a bright yellow or greenish tail tip, used to lure prey. When threatened, a cottonmouth will coil its body, vibrate its tail, and gape its mouth widely, exposing the pale, cotton-white lining.
Where They Live and What They Do
Cottonmouths are found throughout the southeastern United States, with a range extending from Florida and southern Virginia west to central Texas and Oklahoma. They are the most aquatic venomous snakes in North America, preferring habitats such as swamps, marshes, ponds, lakes, and slow-moving streams. They are often seen basking on logs or branches at the water’s edge.
Their varied diet makes them opportunistic feeders. Cottonmouths consume fish, amphibians, small mammals, birds, and even other snakes. They are ambush predators, lying in wait for prey to come within striking distance. While primarily active at night, they can also be observed during daylight hours, particularly in spring and fall.
Common Look-Alikes and Distinctions
Many non-venomous water snakes, such as Northern Water Snakes, are frequently mistaken for cottonmouths. One key difference is pupil shape: cottonmouths have vertically elliptical pupils, while water snakes have round pupils. When viewed from above, a cottonmouth’s eyes cannot be seen due to an overhanging brow ridge, unlike the visible eyes of water snakes. Cottonmouths swim with most of their body on the surface, while water snakes swim with their bodies submerged.
Copperheads are another venomous snake species sometimes confused with cottonmouths, especially juveniles. While both are pit vipers, copperheads have lighter, coppery-colored crossbands that resemble an hourglass or “Hershey kiss” shape, and are more terrestrial. Cottonmouth patterns are more jagged or pixelated and can become uniformly dark with age. Copperheads have solid-colored heads, whereas cottonmouths often have a dark stripe through the eye.
Safety When Encountering a Cottonmouth
Encountering a cottonmouth requires caution, as they are venomous snakes. Observe them from a safe distance and never attempt to handle them. Recommendations for avoiding bites include watching where you step, especially near water, and refraining from disturbing any snake you encounter.
Cottonmouth venom is primarily hemotoxic, meaning it affects blood and tissues, causing pain, swelling, and potential tissue damage. If a bite occurs, seek immediate medical attention by calling emergency services. Remaining calm, removing any jewelry or tight clothing from the bitten area, and keeping the affected limb still and at heart level can help. Avoid traditional remedies like applying a tourniquet, cutting the wound, or attempting to suck out venom, as these can cause more harm. Bites are defensive and occur when the snake feels threatened.