Harmless · Native to the United States

Plain-bellied water snake

Nerodia erythrogaster (Forster, 1771)

Also called yellow-bellied, red-bellied or copperbelly water snake
Data updated October 2026

Plain-bellied water snake resting on a log at the water's edge, its back dark olive-gray with no pattern
Fig. 1 — Adult on a log at the edge of a cypress swamp. Adults are dark gray, olive or brown above with little or no pattern.
Plain-bellied water snake belly showing an unmarked yellow-orange underside
Fig. 2 — The belly is plain yellow to orange or red with no spots, the key field mark.

At a glance

A heavy-bodied water snake with a plain, unmarked yellow, orange or red belly and a dark back. It eats more frogs than most water snakes and often wanders over land far from water. It is harmless but bites and musks when handled.

01

Identification

Adults are dark gray, greenish gray, olive or brownish black above, usually with little or no pattern, although some western and southwestern adults keep faint blotches. The belly is the giveaway: plain yellow, orange or red, with no spots or half-moons. In the copperbelly form of the Midwest the back is nearly black and the belly bright orange-red. Scales are keeled. Young snakes look very different from adults: pale gray to pinkish-brown with large, alternating dark blotches on the back and sides, which fade during their second year.

  1. 01Plain, unmarked belly. Yellow to orange or red underside with no dark spots, unlike most other water snakes.
  2. 02Dark, nearly patternless back. Adults are uniform gray, olive or brown above. Juveniles are boldly blotched.
  3. 03Round pupils, no facial pit. A slimmer head than a cottonmouth, with no light line from the eye to the corner of the mouth.

Commonly confused with

Cottonmouths are heavier with a bigger, chunkier head, a facial pit, vertical pupils and a pale line from the eye to the mouth corner. Young plain-bellied water snakes look like northern or southern water snakes but lack belly markings. Never handle a snake you cannot identify.

02

Size

01 ft2 ft3 ft4 ft Typical adult · about 38 in (97 cm)

Most adults are 30 to 48 inches (76–122 cm) long. Missouri gives an occasional maximum of about 64 inches (163 cm). Females grow larger than males but have proportionally shorter tails.

03

Range & habitat

Shallow, seasonally flooded bottomland forest wetland with fallen logs
Fig. 3 — Shallow and seasonal wetlands with lots of frogs are favored habitat.

The plain-bellied water snake has a wide range across the southeastern and south-central United States, through the Coastal Plain and lower Piedmont of the Southeast to the Mississippi Valley, Texas and Oklahoma, and north into the lower Midwest. It is absent from the Appalachian Mountains and peninsular Florida but occurs in north Florida. It prefers quiet water: swamps, sloughs, oxbows, slow rivers and creeks, floodplains, flooded bottomland woods, ponds, lakes and drainage ditches, and it is strongly tied to temporary wetlands. It is less aquatic than other water snakes and often turns up in woods well away from water.

State guides: Texas · Oklahoma · Florida

04

Diet & predators

Plain-bellied water snakes eat a larger share of frogs and toads than most water snakes, which mainly eat fish. Adults take frogs, toads, tadpoles, salamanders, fish and crayfish, hunting both in wetlands and in the surrounding woods. Young snakes eat mostly small fish. Like other water snakes they seize prey in their jaws rather than constricting.

Feeds on

  • Frogs and toads
  • Tadpoles and salamanders
  • Fish
  • Crayfish

Preyed on by

  • Herons and other predatory birds
  • Raccoons and other predatory mammals
  • Other snakes (newborns)
  • Large frogs and fish (newborns)
Frog in shallow water among plants
Prey — frogs.
Great blue heron wading in a wetland
Predator — wading birds.

05

Behavior & seasons

Plain-bellied water snakes are active from about late March through October, with most leaving winter retreats in April and early May. They bask on logs, branches over the water, stumps and shorelines. They are more at home on land than most water snakes: in summer they often travel overland between wetlands, cross roads on rainy nights and, when alarmed, may flee onto land instead of into the water.

When cornered they strike and bite readily, and if picked up they smear a foul-smelling musk. Winter is spent in mammal and crayfish burrows, rock piles and crevices, levee riprap and rotting stumps and logs.

06

Reproduction

Courtship and mating take place in spring, mostly April and May. Females give birth to live young in August and early September. Litters usually hold about 10 to 32 young, with bigger females having more. The young mature at about three years old, and individuals can live nearly 15 years.

07

Conservation

Across most of its range the species is common and widespread, and Louisiana considers its populations stable. It is protected in Georgia. The exception is the copperbelly water snake of the Midwest: its northern population, north of the 40th parallel in Indiana, Michigan and Ohio, was listed as Threatened under the U.S. Endangered Species Act in 1997 after steep declines. Because it depends on frogs and shallow seasonal wetlands, wetland loss is its main threat.

Keep reading

Sources

Data updated October 2026 · How we build these pages