FLORIDA COTTONMOUTH

Scientific name: Agkistrodon piscivorus conanti

Size

The average size of a mature Florida Cottonmouth is approximately 3 feet in length. Some may grow to 4 or 5 feet in length, and on rare occasion may exceed 5.5 feet. The largest recorded Florida Cottonmouth was 74.5 inches.

Description

The Florida Cottonmouth, often called a Water Moccasin, is a heavy, thick-bodied snake. It is dark olive, brown, or black in color and usually has dark brown bands around the back and sides. These bands usually have serrated, saw-like edges. The bands are often difficult to see, and the snake's body may appears to be completely black. There is a distinctive dark stripe on both sides of the head that starts at the eye and runs backwards along the head. This stripe is outlined on top by a cream-colored pinstripe, and has a contrasting light cream color below it. On the tip of the nose of the Florida Cottonmouth, are two small, dark stripes that start between the nostrils and run down the nose to just underneath the chin. The underside of the body is typically yellowish-white to a dark tan in color with dark blotches on it.

The Florida Cottonmouth has elliptical pupils that look like cat's eyes and like all pit vipers, has a heat sensing-pit between the nostril and eye on each side of its head. The Florida Cottonmouth has a large, triangular head that is wider than the neck when viewed from above.

Young Florida Cottonmouths are brightly patterned and the tip of the tail on young Florida Cottonmouths is yellow or green. The yellow/green tail is used to attract food. It is wiggled in a motion imitating a worm or caterpillar, which attract frogs, lizards, or other prey that the young Florida Cottonmouth eats.

Distribution

In the United States, the Florida Cottonmouth is found in the southeastern states of Alabama, Florida, Georgia, and South Carolina.
Map of US states the Florida Cottonmouth is found in.
Map does not show area of true distribution, only the states in which there is a population.
Actual distribution in any highlighted state may be limited.

Notes

The Florida Cottonmouth is typically found around freshwater such as lakes, ponds, rivers, and swamps. Along with the Eastern Cottonmouth and Western Cottonmouth, it is one of only three venomous water snakes in North America.

When disturbed or threatened, the Florida Cottonmouth with often coil up it's body, open its mouth wide, and show the white inside of its mouth as a defensive warning. The inside of the mouth looks like white cotton, which is where the cottonmouth gets its name. This defensive posture is often called gaping. One interesting fact about this display is that the fangs are typically not erect and showing, but remain retracted. This is a great example of the fact that the Cottonmouth has voluntary control over whether the fangs are erect or not when its mouth is opened.

The Florida Cottonmouth is often thought of as an aggressive snake. This is partly due to the fact that they will often stand their ground, showing their defensive posture, rather than retreat. Truth is, they bite out of defense when they feel trapped or cornered, and are not an aggressive snake that will chase someone down.

Many people wrongly assume that any dark-colored snake near the water is a Cottonmouth. There are many different kinds of water snakes that live in the same areas as the Florida Cottonmouth. There are ways to tell them apart. The Cottonmouth has elliptical pupils, which look like cat-eyes, whereas the other water snakes have round pupils. The Cottonmouth has heat-sensing pits between its eyes and nostrils, like all pit vipers. The other water snakes do not have heat-sensing pits. When the head is viewed from above, the eyes of the Cottonmouth cannot be seen, whereas the eyes of the water snake can be. The Florida Cottonmouth swims with its head well out of the water, whereas water snakes swim with their heads in the water. The dark stripe, running from the eyes back along the sides of the head, can also help identify a Florida Cottonmouth.

Florida Cottonmouth photo
Photo used by permission:
© 2004 John White

Florida Cottonmouth juvenile

Below are some photos of a Florida Cottonmouth that was in a neighbor's yard. I placed it in a 5 gallon bucket and relocated the snake to a safer location. Note the distinct, bold pattern on the juvenile compared to the much more subdued coloring of the mature Cottonmouth.

Florida Cottonmouth juvenile photo
Photo © 2003 David W. George
Taken in New Port Richey, FL on 9/25/03
Buddy and Jen's back yard

For more information on venomous snakes, please see the Venomous Links page.

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