Cottonmouths, also known as water moccasins, are venomous pit vipers native to the southeastern United States. These semi-aquatic snakes display the distinctive white interior of their mouths when threatened. This article discusses their presence in Tennessee, identification, habits, and what to do if encountered.
Cottonmouth Presence in Tennessee
Cottonmouths are found in Tennessee, primarily in the western third of the state. Their distribution extends from the Mississippi River eastward to counties just past the lower Tennessee River, including areas of the northern Highland Rim. Populations also exist in floodplain habitats along the lower Cumberland River and its major tributaries in central Tennessee, such as Montgomery, Cheatham, Dickson, and potentially Davidson counties. They are less common or absent in the eastern mountainous regions of the state.
Identifying Cottonmouths and Their Look-Alikes
Cottonmouths have several key physical characteristics. They possess a thick, heavy body and a distinctly triangular or blocky head, noticeably wider than their neck. A large sensory pit is located between each nostril and eye. Their pupils are vertical, resembling a cat’s eye, and are often obscured by a broad, dark facial stripe.
Cottonmouths are dark olive-brown to almost black, sometimes with crossbands that may become less visible with age. Juvenile cottonmouths have more distinct patterns and a bright yellow or greenish tail tip used to lure prey. Non-venomous water snakes, such as the Northern Water Snake and Banded Water Snake, are mistaken for cottonmouths. These look-alikes have round pupils, a narrower head not significantly wider than their neck, and lack heat-sensing pits. When threatened, non-venomous water snakes may flatten their bodies and heads to appear larger, but their head shape remains less blocky.
Habitat and Behavior
Cottonmouths prefer aquatic and semi-aquatic environments, inhabiting swamps, marshes, slow-moving streams, ponds, and drainage ditches in Tennessee. They are found near permanent water sources, basking on logs, branches overhanging water, or along shorelines. Unlike many non-venomous water snakes that submerge their bodies when swimming, cottonmouths swim with their entire body and head riding high on the water’s surface.
When disturbed, cottonmouths employ a defensive posture rather than immediately striking. They may coil their body and open their mouth wide to reveal the white interior, giving them their common name. They may also vibrate their tail or release a foul-smelling musk. Cottonmouths prefer to flee from perceived threats and are not inherently aggressive; most bites occur when individuals attempt to handle, harass, or kill them.
Safety and Misconceptions
Understanding cottonmouth behavior helps minimize potential encounters and dispel common misunderstandings. In areas where cottonmouths might be present, wear appropriate footwear and remain aware of your surroundings, especially when walking near water or stepping over logs and rocks. Avoid reaching into crevices or under objects where a snake might be concealed.
A misconception is that cottonmouths are aggressive and actively chase people. Studies indicate cottonmouths try to escape when confronted; perceived “chasing” is often the snake moving towards the closest cover, which may be in the human’s direction. Another misconception is assuming all water snakes are cottonmouths, leading to the unnecessary killing of non-venomous species. Venom is energetically costly for snakes to produce, so they reserve it for subduing prey, not for unprovoked attacks.
Responding to a Cottonmouth Bite
While prevention is important, knowing the correct response to a cottonmouth bite is important. If bitten, immediately call 911 or emergency services. Stay calm and move away from the snake to prevent further bites.
While waiting for medical help, keep the bitten limb as still as possible and positioned below heart level. Remove any constricting items like jewelry or tight clothing from the affected area before swelling begins. Do not apply a tourniquet, cut the wound, try to suck out the venom, or apply ice, as these actions can cause more harm than benefit. Professional medical attention is required, as antivenom may be administered in cases of significant envenomation.