By Scott Matthew Quint and Gerry Salmon

     When you think of snake misidentification you tend to think about the confusion between Coral Snakes and Scarlet and Scarlet King Snakes. However, the most common snake misidentification that occurs is between the Water Moccasin (Cottonmouth) and virtually any snake found in or near the water. The purpose of this article is to help you identify what is and what is not a Water Moccasin. A secondary aim is to dispel some of the myths of Water Moccasin behavior.

     The Water Moccasin is a dangerously venomous snake found through most of the Coastal Plains, ranging as far north as Virginia. As it's name implies, it is a snake that lives in and around water. There are two subspecies that occur in the Coastal Plains, both are similar in outward appearance and their differences are irrelevant to this article. Aside from the Water Moccasin there are many other aquatic or semi-aquatic snakes in the Coastal Plains, none of which are dangerous. The fact is that there are over 20 varieties of snake in the Coastal Plains that make a living around the water and only one is the Water Moccasin. Many of these snakes have similarities, though, it really doesn't seem to matter how DIS-similar they are to the Water Moccasin because the only criteria that seems to make any difference to the lay-observer is that fact that the snake was near the water.

     When observing snakes near aquatic habitats, they may or may not be Water Moccasins. That being said, it is a conceeded fact that Water Mocasins are very common. However, several of the other species that share its habitat are just as or more common. Be that as it may, some of the snakes observed will be Water Moccasins, so the observer should be careful. Always stick to the principle of not approaching any unfamiliar animal. The snake will not approach you, so your decision will directly determine the dangerousness of the encounter.  It is often rumored that Water Moccasins are extremely aggressive and will chase a humans that comes too near. That complete hogwash.

     Water Moccasins are large-looking snakes. A 30 inch Water Moccasin will look larger than it really is because of its girth. In fact, snakes over 36 inches are uncommon, but eye-witness accounts of them abound. All of the other aquatic snakes (I will group them all under the term "aquatic snakes" even though this is a coarse description) are more slender, though some species of water snake such as the Brown Water Snake (Nerodia taxispilota) can be fairly hefty at large size. Even so, a 36 inch Water Moccasin will be a thicker animal than even a 5 foot water snake. A Water Moccasin seen from a distance away will look like a big snake.

     Water Moccasins behave differently than other aquatic snakes. All will flee given the opportunity, but Water Moccasins will only flee if they sense that they can reasonably get away.

A 30 inch Water Moccasin on a swamp road in SC
Photo by Gerry Salmon

A Water Moccasin displays its mouth and fangs
Photo by W.T.Helfrich

     If the water is close, then  they will often dive for it, even if the threat is between them and escape. I have had them rush around me and over my feet to get to the water. This may be a source of some of the Water Moccasin's rumored (but non-existent) aggressiveness.  Most other aquatic snakes will usually flee away from the threat even if it drives them away from the water.

    However, if a Water Moccasin is caught out in the open, it will coil and display by opening its mouth wide exposing the white liningof its mouth (hence its second name cottonmouth). I believe that this behavior serves two purposes, as a threat and as a practical defense of its head. It would certainly be difficult to grab this animal by the head without being bitten.

     Be advised, though the Water Moccasin is not aggressive, it will readily bite and  bite from a Water Moccasin can be very serious. Their venom is very destructive to the tissue around the bite and bite victims often get nasty bacteriological infections like gangrene.

A  swimming Water Moccasin in SC
Photos by Gerry Salmon

     If you look at the pictures above, you can see that the Water Moccasin is extremely buoyant. Most of it's body is above the surface.  This is a trait of all Pit Vipers.   

     Below are pictures of a Banded Water Snake swimming along a bank. Notice that its body is mostly submerged with only an occasional coil breaking the surface. This is typical of all non-venomous snakes in the coastal plains. Also note how much more slender the water snake is than the Water Moccasin. This snake is of similar length to the Moccasin in the pictures above.

Swimming Water Snake in Currituck County NC
Photo by Scott Matthew Quint

     It is often Difficult to distinguish the Water Moccasin from the various water snakes, especially when the snakes are dry as most are not brightly colored. Always mind the simple rule of not approaching any snake when you are not absolutely sure of its identification.  However if you are concerned about snakes in and around your home or favorite fishing hole, look for the distinguishing characteristics described here.


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