The northern water snake, or Nerodia sipedon, is a large water-dwelling snake that inhabits the northeastern United States and southeastern Canada. Its resemblance to some venomous snakes often leads to its destruction. Northern water snakes are not poisonous, but their bite can be painful and leave the victim susceptible to infection. These snakes are essential to environmental balance since they prey on several forms of vermin and are food for a variety of predators.
Northern water snakes come in several colors, but most have a dark band across their necks, splotches along their bodies, and crescent-shaped markings in contrasting colors. Their backs are typically brown, red, black, or gray, and their undersides are shades of gray, buff, or white. Northern water snakes grow to over 4 feet (122 cm) in length. They are sometimes mistaken for cottonmouth or copperhead snakes and killed, although they are not dangerous to humans.
These snakes live in North American waterways such as rivers, ponds, lakes, and streams. The northern water snakes are both nocturnal and diurnal, hunting at night and in the daytime. During the day, the northern water snake searches for food away from shore. At night, these snakes patrol the banks of the water they swim in, looking for minnows in vegetation. Northern water snakes also hunt on land, preying on small mammals.
The northern water snake’s diet is extremely varied—they eat amphibians, other reptiles, small mammals, fish, and birds. These aquatic snakes hide near beaver lodges and in plants such as cattails, Virginia creeper, and poison ivy, lying in wait for frogs, turtles, and leeches. The northern water snake can leap high into the air to snatch low-flying birds such as mallards.
Predators of the northern water snake typically include sizable mammals such as raccoons, opossums, and foxes. Other snakes such as copperheads and rat snakes prey on northern water snakes. Large birds such as herons, cormorants, and owls include northern water snakes in their diets.
When grasped by a human or animal, the northern water snake attacks in return, repeatedly biting and releasing a musky odor along with excrement. Although the bite is not poisonous, northern water snakes do inject an anticoagulant that causes the wound to continue bleeding. In some cases, this bite can lead to bacterial infection.
The northern water snake generally thrives in its aquatic habitat and assists in keeping ecological balance by consuming the vermin that would otherwise overrun its habitat. This natural instinct is usually a benefit to humans since the voles, mice, and rats this snake preys upon are both disease vectors and damaging to gardens and crop fields.