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Is there a snake that looks like a water moccasin?

The water moccasin, also known as the cottonmouth, is a venomous pit viper found in the southeastern United States. With its distinctive pattern and coloring, the cottonmouth is easily recognizable and can often be identified at a distance.

However, there are a few other snakes that bear a resemblance to the cottonmouth and are often mistaken for this dangerous viper. In this article, we’ll take a closer look at some of the most common water moccasin look-alikes and discuss ways to tell them apart.

The Northern Water Snake

Perhaps the snake most often confused with the cottonmouth is the northern water snake. This nonvenomous colubrid inhabits many of the same regions as the cottonmouth and has similar behavioral tendencies. It’s found primarily around bodies of water like lakes, rivers, and streams.

When threatened, the northern water snake will often flatten its head and body to appear more intimidating. This defensive posture resembles the aggressive nature of the cottonmouth, leading many observers to misidentify the harmless northern water snake.

Here are some ways to distinguish between the northern water snake and the cottonmouth:

Northern Water Snake Cottonmouth
– Round pupils – Vertical, cat-like pupils
– Divided anal plate – Single anal plate
– Dark crossbands on lighter body – Dark body with lighter crossbands

When observed up close, the northern water snake can be identified by its round pupils, divided anal plate, and dark crossbands on a lighter colored body. The cottonmouth has vertical pupils, a single anal plate, and a uniformly dark body with lighter crossbands.

The Banded Water Snake

Another cottonmouth look-alike is the banded water snake. As its name suggests, this nonvenomous species has distinctive bands or stripes running horizontally down its body. Its coloration can range from brown to gray or black.

Banded water snakes occupy some of the same aquatic habitats as cottonmouths throughout the southeastern United States. When approached, they may flatten their bodies, shake their tails, and strike aggressively, much like a cottonmouth.

Here are some ways to tell a banded water snake apart from a cottonmouth:

Banded Water Snake Cottonmouth
– Distinct stripes on body – No stripes, solid body pattern
– Pointed tail tip – Blunt tail tip
– Round pupils – Vertical pupils

The banded water snake can be positively identified by its conspicuous stripes, pointed tail tip, and round pupils. The cottonmouth lacks stripes, has a blunt tail tip, and vertical pupils.

The Brown Water Snake

The brown water snake is yet another harmless snake that is sometimes mistaken for the venomous cottonmouth. As its name indicates, it has a brown, tan, or reddish-brown body with darker brown or black blotches down its back and sides.

Brown water snakes occupy aquatic habitats throughout much of the eastern and central United States. If cornered, they may flatten their bodies, shake their tails, and bite aggressively, much like a cottonmouth would.

Here are some ways to distinguish a brown water snake from a cottonmouth:

Brown Water Snake Cottonmouth
– Dark brown blotches on back – No distinct pattern, uniform color
– White or yellow belly – Dark belly
– Round pupils – Vertical pupils

The brown water snake can be identified by its dark blotches on the back, light-colored belly, and round pupils. The cottonmouth lacks distinct blotches and has a uniformly colored, dark belly and vertical pupils.

The Plain-bellied Water Snake

The plain-bellied water snake is a brownish, grayish, or olive-colored snake with indistinct, darker crossbands or flecks along its back. As its name suggests, its belly is a uniform cream or yellowish color.

Plain-bellied water snakes are found from the Great Lakes down into the southern United States, often in the same wetland habitats as cottonmouths. When threatened, they may flatten themselves, vibrate their tails, and bite, much like cottonmouths.

Here are some key differences between the plain-bellied water snake and the cottonmouth:

Plain-bellied Water Snake Cottonmouth
– Faint dark bands/flecks on back – No distinct bands or markings
– Plain yellow or cream belly – Dark belly
– Divided anal plate – Undivided anal plate

The plain-bellied water snake can be positively identified by its indistinct back pattern, yellowish belly, and divided anal plate. The cottonmouth lacks obvious bands on its uniformly colored body, has a dark belly, and a single, undivided anal plate.

Key Identification Tips

When trying to distinguish a cottonmouth from similar-looking harmless species, here are a few key identification tips to remember:

  • Check the pupils – Cottonmouths have vertical, cat-like pupils while the other water snakes have round pupils.
  • Look for body stripes or bands – The banded water snake has obvious stripes while the cottonmouth has a uniform body pattern.
  • Note the tail shape – Cottonmouths have a blunt tail tip while some look-alikes like the banded water snake have pointed tail tips.
  • Observe the head shape – If threatened, cottonmouths tend to have a much more flattened, triangular head.
  • Inspect the belly – Cottonmouths have uniformly dark bellies unlike the plain, lighter bellies of most water snake species.
  • Examine anal plates – Cottonmouths have a single anal plate while water snakes have divided anal plates.

While several harmless species bear a resemblance to the venomous cottonmouth, paying close attention to key physical features and behaviors can help reliably distinguish look-alike snakes. When in doubt, it’s best to avoid getting too close and give any suspicious snake plenty of space.


In summary, while the cottonmouth has a distinctive appearance, there are several nonvenomous snakes throughout the southeastern United States that are often mistaken for this pitviper, including:

  • The northern water snake
  • The banded water snake
  • The brown water snake
  • The plain-bellied water snake

However, by carefully examining features like markings/color patterns, tail shape, pupils, head shape, belly color, and anal plates, a harmless water snake mimic can be confidently differentiated from a cottonmouth.

Being able to accurately identify snake species is an important safety skill for those spending time around bodies of water in cottonmouth territory. Proper identification allows you to assess potential risks and determine if avoidance or removal is necessary. When viewing any snake from a safe distance, take the time to carefully observe its features before deciding if it poses a threat.

With over 40 species of snakes found in the southeastern United States, mistakes in identification are common. Don’t rely on just one characteristic – look at the full picture when differentiating a cottonmouth from similar-looking water snakes. A few minutes of careful observation could prevent an unfortunate and unnecessary snakebite.