Water moccasins, also known as cottonmouths, are venomous, semi-aquatic snakes inhabiting the southeastern United States. There is common curiosity regarding their movement patterns in water, particularly their ability to swim beneath the surface. This article will explore the unique aquatic behaviors of water moccasins, detailing how they navigate water and the circumstances under which they might submerge.
Understanding Water Moccasin Swimming
Water moccasins exhibit a distinctive swimming posture. When moving across the water’s surface, they typically display a significant portion of their body above the waterline. This buoyancy allows them to swim with most of their body and often their entire head clearly visible. This contrasts with non-venomous water snakes, which usually swim with only their heads exposed, keeping the rest of their body submerged.
Their ability to maintain this high-riding position is largely attributed to their capacity to hold air within their lungs, acting as a natural flotation device.
While their primary mode of movement in water involves staying on the surface, water moccasins are capable of submerging. However, submergence is not their preferred method of travel through aquatic habitats. They will occasionally dive underwater, but it constitutes a temporary action rather than a sustained swimming strategy.
Key Identification Features in Water
Identifying a water moccasin in its aquatic environment can be important for safety. One of the most noticeable features is their head position, which is often held high above the water, sometimes at a distinct upward angle, similar to a “periscope.” Their head is typically blocky and triangular, though this shape can be challenging to discern accurately from a distance. Water moccasins generally have a dark coloration, ranging from olive to dark brown or black, often with darker bands or blotches that may become less distinct with age. A highly specific defensive behavior, if approached, is the “cottonmouth” display, where the snake opens its mouth wide to reveal a stark white interior as a warning.
Why Water Moccasins Submerge
While water moccasins predominantly swim on the surface, they do submerge under specific conditions. One common motivation for diving underwater is hunting, as they may submerge briefly to ambush aquatic prey. They are known to feed on fish, amphibians, and other small aquatic animals, and a submerged position can provide a stealth approach.
Submerging also serves as a defensive mechanism or an escape tactic when water moccasins feel threatened. They may dive to evade perceived predators or to retreat from disturbances in their immediate environment.
Additionally, submergence can play a role in thermoregulation, allowing the snake to cool down in warmer waters or during periods of high ambient temperatures. They might also seek refuge or hide from view by submerging themselves under submerged logs, rocks, or dense aquatic vegetation.