Cottonmouths and the
Harmless look-a-like Snakes

 

 

Cottonmouth
vs.
Northern Water Snake

The most notable thing about the eastern cottonmouth in Virginia is its very limited distribution within the state. In recorded Virginia history, the venomous cottonmouth has only been found in the following counties/cites: Chesterfield Co., Prince George Co., Surry Co., Sussex Co., Chesapeake City, Newport News City, Suffolk City, Virginia Beach City & York Co.

* Click on a thumbnail to see a larger version
 
Young eastern cottonmouths with yellowish tail tips.
Baby cottonmouth with yellow tail tip
Juvenile cottonmouth with yellow tail tip
Juvenile cottonmouth with yellow tail tip
   

Eastern cottonmouths are born alive with a bright yellowish to yellowish green tail tip. The yellow tail tip is used as a lure for frogs, lizards and other prey items. This brightly colored tail tip fades to black as the snake ages. The color of cottonmouths is a yellowish olive to black with about 13 black crossbands that are wide on the sides and narrow as they approach the backbone. Some of the crossbands may be broken, not meeting at the backbone. The outer edges of the bands are usually black. Crossbands get darker as they approach the tail. Older adults may be a uniformed dark color, usually black, without a discernable pattern.

The name "cottonmouth" refers to the manner in which the cottonmouth notifies other animals including humans of its presence. Opening of the mouth and flashing the inner white lining is not an aggressive action, it simply makes the cottonmouth more visible. Despite common folklore, cottonmouths do not chase after people.

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The eastern cottonmouth is very buoyant and usually swims across the surface of the water. All other water snakes found in Virginia swim with just a small portion of their neck and head above the water surface. Keep in mind that all of our water snakes, including the eastern cottonmouth can swim completely submerged.

The eastern cottonmouth is a pit-viper, as are all three of Virginia's venomous snake species (northern copperhead, eastern cottonmouth and timber rattlesnake). The "pit" in pit-viper refers to the heating sensing pit located between the eye and the nostrils on the snake's head. In addition to the heat sensing pit all three venomous snakes in Virginia have vertical pupils. All harmless snakes in Virginia have round pupils and lack the heat sensing pits. Another characteristic of all Virginia's venomous snakes is the single row of scales on the underside of the tail after the anal plate (vent).

While close inspection of a snakes face and/or its bum is a definitive way to distinguish a venomous snake from a harmless species, it requires one to get dangerously close to a potently dangerous animal. It is far better to learn the pattern and coloration of a few snakes so that specimens may be identified from a safe distance.

Cottonmouths primarily feed on fish and frogs, however they also play a pivotal role in controlling rodent populations. Without cottonmouths and other rodent eating snakes there would be a drastic increase in crop/food damage and rodent spread diseases. While cottonmouths are venomous they are placid snakes that only bite if stepped on or otherwise threatened. If you see a cottonmouth, leave it alone and rest assured it will do its best to avoid you.

 

Cottonmouth vs. species most commonly misidentified as cottonmouths

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Eastern Cottonmouth vs. Northern Water Snake

Northern water snakes are one of our most abundant snakes and can be found near any body of water that supports fish and/or frogs. Unfortunately, harmless northern water snakes are frequently misidentified as "cottonmouths". This occurs at an alarming rate even well outside the range of the cottonmouth.

Northern water snakes have a body color of brown to gray with varying amounts of white, red and yellow. Their pattern consists of closely positioned crossbands. The crossbands break up about halfway down the length of the snake and form a series of rectangular, alternating blotches near the backbone and on the sides. Some northern water snakes can be a uniformed brown to grayish color without a discernable pattern.


A couple reduced patterned northern water snakes. Click to enlarge

 

Venomous Eastern Cottonmouth

Harmless Northern Water Snake

Very Limited Distribution and Population
Very Abundant State Wide Distribution and Population
Hour-glass pattern outlined in black
 

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Eastern Cottonmouth vs. Brown Water Snake

Juvenile brown water snakes are patterned the same as adults. This snake has a relatively long head which is wider than the neck. Active during the day and often seen basking on overhead vegetation over the water. Brown water snakes primarily feed on catfish.

Venomous Eastern Cottonmouth

Harmless Brown Water Snake

Very Limited Distribution and Population
Limited Distribution
Hour-glass pattern outlined in black. Rectangular blotch pattern on the side and back Blotches do not touch.

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Eastern Cottonmouth vs. Red-bellied Water Snake

Juvenile red-bellied water snakes are boldly patterned with a pattern similar to a juvenile northern water snake, but usually with a pinkish base color. Adults are reddish brown to chocolate brown. Subadults or young adults may retain traces of a juvenile pattern.

Venomous Eastern Cottonmouth

Harmless Red-bellied Water Snake

Very Limited Distribution and Population
Limited Distribution
Hour-glass pattern outlined in black
Reddish brown solid color

 

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