Cottonmouth snakes, also known as water moccasins, are venomous pit vipers found across the southeastern United States. These semi-aquatic reptiles are often a source of concern for people encountering them. While their bites are serious and require immediate medical attention, fatalities from cottonmouth bites are rare when proper medical care is promptly administered.
Understanding Cottonmouth Venom and Risk
Cottonmouth venom is primarily hemotoxic, damaging blood cells and tissues. This can lead to localized pain, significant swelling, bruising, and tissue damage around the bite site. Internal bleeding and blistering may also occur.
While cottonmouth venom can cause substantial harm, it is rarely fatal to humans. Prompt medical intervention, particularly antivenom administration, significantly reduces the risk of severe outcomes. Bite severity depends on the amount of venom injected, as some bites may be “dry bites” with no venom, and the victim’s overall health and the bite’s location. Unlike neurotoxic venoms, cottonmouth venom does not typically cause systemic reactions or neurological effects.
Recognizing Cottonmouths
Identifying cottonmouths helps distinguish them from non-venomous water snakes. Cottonmouths are heavy-bodied snakes, typically 2 to 4 feet long, with some reaching 6 feet. Their heads are distinctly triangular and broad, wider than their necks, and they possess heat-sensing pits between their eyes and nostrils. Their pupils are vertical and elliptical, resembling a cat’s eye.
A characteristic defensive behavior is to coil and open their mouth wide, exposing the stark white interior that gives the snake its name. This display serves as a warning. Cottonmouths are frequently found in or near slow-moving water, swamps, marshes, and streams, though they can wander onto land. When swimming, they often keep their entire body, including their head, elevated above the water’s surface, unlike many non-venomous water snakes.
If a Bite Occurs
A cottonmouth bite typically causes immediate, severe pain, followed by rapid swelling and skin discoloration. Other symptoms include bruising, blistering, and nausea.
Immediately move away from the snake and call 911. While waiting for medical help, gently wash the bite area with soap and water and remove any tight clothing or jewelry from the affected limb. Keep the bitten area still and, if possible, position it at or below heart level. Do not apply a tourniquet, cut the wound, attempt to suck out the venom, or apply ice, as these actions are harmful or ineffective. Antivenom, such as CroFab, is the primary treatment and should only be administered by medical professionals in a hospital setting.
Avoiding Encounters
Cottonmouths typically bite only when threatened or provoked. To reduce encounter risk, wear protective clothing like boots and long pants in their habitats. Be aware of your surroundings, especially near water, and avoid reaching into dense vegetation or logs without visual inspection.
Keeping yards clear of debris, tall grasses, and woodpiles makes an area less appealing to snakes. If you encounter a cottonmouth, give it ample space and do not attempt to handle or disturb it; they usually retreat if given the opportunity.