Plain-Bellied Watersnake

Nerodia erythrogaster
Other Common Name
Yellow-Bellied Watersnake; Yellow-Bellied Water Snake

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


A medium-sized, heavy-bodied, dark-colored, semiaquatic snake with a plain yellow belly. It is mainly gray, greenish gray, or brownish black, with little or no pattern. The belly is plain yellow or occasionally orange. The young are strongly patterned with brown dorsal and lateral blotches that may be joined to form transverse bars.

Similar species: The blotched watersnake (Nerodia erythrogaster transversa), a subspecies, occurs in southwestern and western Missouri. It is gray or greenish brown with brown blotches along the back and sides; the belly is plain yellow with a wash of orange, especially under the tail. In summer, it often ventures away from water onto land. Watersnakes are often confused with the venomous western cottonmouth and needlessly killed. Cottonmouths are more heavy-bodied, with a larger, chunky head and a facial pit between the nostril and eye; they are darker and have a light line from the eye to the corner of the mouth.


Length: 30 to 48 inches.

Habitat and conservation

This species is prefers the quiet waters of swamps, sloughs, oxbow lakes, and ponds. Individuals bask on logs in shallow water, on branches above the water, or along the shore. As with most other watersnakes, this species is pugnacious when cornered and will strike or bite viciously. It also excretes a foul-smelling musk from glands at the base of the tail and will smear this substance and feces onto a captor.


Foods include fish, toads, frogs, tadpoles, salamanders, and crayfish.

Plain-Bellied Watersnake Distribution Map
Distribution in Missouri

Throughout southeastern Missouri, north along the Mississippi River floodplain to Pike County. The blotched watersnake subspecies occurs in southwestern and western Missouri.

Life cycle

This species is apparently active from late March through October. Courtship and mating occur in April and early May. Like other watersnakes, this species gives birth to live young, and larger females bear larger litters. The young are born during August and early September, with 10–30 in a litter.

Human connections

Snakes stir our imaginations and figure prominently in our myths, religions, and stories. We humans have invented many unfair and incorrect myths that make them seem the embodiment of evil. Learn to separate truth from fiction, and overcome your prejudices.

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.