Northern Watersnake

Nerodia sipedon sipedon

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Photo of a northern watersnake rearing back in grass on land.
The northern watersnake is Missouri's most common watersnake.
MDC Staff
Other Common Name
Northern Water Snake; Banded Watersnake; Common Water Snake; Midland Watersnake (ssp. pleuralis)
Family

Colubridae (nonvenomous snakes) in the order Squamata (lizards and snakes)

Description

The northern watersnake is a gray to reddish-brown snake with numerous dark brown, reddish-brown, or blackish crossbands along the front third of the body. The bands become blotches in the latter part of the body. The belly is cream-colored or yellowish with numerous black and reddish half-moon markings or spots. As with other watersnake species, the scales along the back have keels, causing the snake to feel rough. For defense, watersnakes bite viciously (but they are not venomous) and secrete a strong-smelling musk from glands at the base of the tail.

Similar species: The midland watersnake (N. sipedon pleuralis), another subspecies, occurs in the southern third of Missouri. It is tan or reddish brown with brown or reddish-brown bands. Some are orangish with brown markings. It prefers clear, cool, gravel-bed streams. The subspecies overlap and interbreed, so some show traits of both. Watersnakes are confused with the venomous western cottonmouth and needlessly killed. Cottonmouths are heavier-bodied with a larger, chunky head; have a pit between the nostril and eye; are darker; and have a light line from each eye to the corner of the mouth.

Size

Length: 24 to 42 inches.

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Photo of a northern watersnake, closeup on head.
Northern Watersnake
Like other watersnakes, the northern watersnake can defend itself by biting viciously, but it lacks venom.

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Photo of a northern watersnake in shallow water.
Northern Watersnake
The northern watersnake is gray to reddish brown with dark brown crossbands.

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Photo of a northern watersnake rearing back on a dry gravel surface.
Northern Watersnake
The northern watersnake, like our other nonvenomous snakes, has round, not vertical, pupils.

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Photo of a northern watersnake among fishes in shallow water.
Northern Watersnake
The northern watersnake and other watersnakes actually improve game fishing.

FG-0072_Northern_Water_Snake.mp4

Video of a northern watersnake in the wild.

Northern Watersnake wrapped in a cord

Northern Watersnake wrapped in a cord
Northern Watersnake wrapped in a cord
My first snake of the year was a reminder of what litter can do to our ecosystems. DeSoto

Midland Water Snake

Snake swimming away from shoreline. The water makes its reddish color more pronounced.
Midland Water Snake in Lake Springfield Park

Northern watersnake

A gray snake with red markings on its back makes its way through leaf litter and branches
Northern watersnake near the KATY Trail at Weldon Spring
Habitat and conservation

This is Missouri’s most common species of watersnake. Individuals bask on branches overhanging water or on logs or rocks along the water’s edge. In hot weather, they are nocturnal. They hide under rocks or other objects along the edge of rivers and ponds. They live in and near a wide variety of aquatic habitats: creeks, rivers, sloughs, ponds, lakes, and swamps.

Foods

Watersnakes eat fish (mostly nongame species), frogs, tadpoles, toads, and salamanders. Game fish are too agile for watersnakes to catch, unless the fish is injured or diseased.

Northern Watersnake dist map
Distribution in Missouri

Found throughout the northern and western two-thirds of the state. The midland watersnake subspecies lives in the southern and eastern third. The two overlap and intergrade.

Status

Locally, this snake is sometimes called “banded water snake” or “common water snake.” More confusing yet, there is another species of watersnake (Nerodia fasciata confluens) that is officially called broad-banded watersnake. Herpetologists create official common names that correspond precisely with scientific names. Because these official common names and the common names used by regular people don’t always agree, it is best to use scientific names when identification must be precise.

Life cycle

This species is active from early April until October. Courtship and mating occur in the spring, and gestation may last 3-4 months. The young are born live during August and September. A litter can contain 6-66 young, usually averaging 20-25. The young are light gray or tan, contrasting with dark brown or black crossbands and blotches, and at birth they are about 7-10 inches long. Some females may produce a litter every other year.

Human connections

Watersnakes were formerly killed under the mistaken belief that they ate game fish. In reality, they improve fishing by eating dead or dying fish (preventing the spread of fish diseases), by reducing fish overpopulation, and by providing food for game species (large game fish eat young watersnakes).

Ecosystem connections

As predators, watersnakes control populations of the animals they consume. But snakes are preyed upon themselves. Their defenseless newborns are eaten by animals ranging from large frogs and fish to other snakes and birds and mammals. Adults are eaten by predatory mammals and birds.