''Nerodia erythrogaster'', commonly known as the plain-bellied water snake or plainbelly water snake, is a familiar species of mostly aquatic, non venomous, colubrid snake endemic to the United States.

Description

The plain-bellied water snake is a large, thick-bodied, solid-colored snake. Subspecies can be brown, gray, olive green, greenish-gray, and black in color. Some lighter colored snakes display dark dorsal blotches. This snake can be distinguished from other water snakes by its plain, unmarked underside varying in color from red to yellow. It gets its common name because it has no marking on its underside. Its scientific name ''erythrogaster'' comes from the Greek word “''erythros''” meaning red and “''gaster''” meaning belly. This species exhibits geographically defined phenotypic variation which results in a number of different subspecies. Adults vary in size from 24 to 40 inches (76–122 cm) in total length. Juvenile snakes have banding patterns similar to banded water snakes, but can be identified by their unmarked bellies.

Natural habitat

Plain-bellied water snakes are found in every southeastern state of the U.S., from Florida to southeastern Virginia on the east coast, to the borders of eastern North Carolina and western Tennessee, and as far west as Oklahoma and Texas. They are not found in the Appalachian Mountain Range, which excludes them from eastern Tennessee and western North Carolina. The snakes are almost always found near a permanent water source. They are usually seen near rivers and floodplains, lakes and ponds and any natural

wetlands A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The ...

in their geographic range.

Behavior and diet

Plain-bellied water snakes are active in the warmest months of the year. During the hottest months of summer, they will be active both during the day and at night. In warmer months, they are typically found basking on logs or near bodies of water, swimming, or traveling over land. During hot, humid weather, they will travel long distances away from water. They tend to spend more time in terrestrial habitat than other water snake species. They hibernate during the coldest months of the winter. The species gets most of its food from the water. They feed primarily on fish, crayfish, other crustaceans, salamanders, frogs, and carrion. Because of the amount of time they spend on land, the snake's diet includes a large quantity of

amphibians Amphibians are four-limbed and ectothermic vertebrates of the class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terrestrial, fossorial, arbore ...

. Like most other snakes, it will hunt for prey, but this species has been observed submerged in water sources waiting for prey to approach them. They apprehend and swallow prey alive without using constriction.

Reproduction

This species bears live young ( ovoviviparous) like other North American

water snakes Different snakes are called water snakes. "Water snake" is also sometimes used as a descriptive term for any snakes that spend a significant time in or near fresh water, such as any species belonging to the family Acrochordidae. They should not be ...

and garter snakes. The snake breeds from April until mid-June in the southeast U.S. The female gives birth during the months from August to September. Large broods have been observed, but a typical litter size is around eighteen. One female was observed with a litter of fifty five hatchlings in North Carolina. In 2014 a captive female produced two healthy offspring via parthenogenesis.

Predators and defense

The plain-bellied water snake is prey to both terrestrial and aquatic predators. Reported predators include largemouth bass,

kingsnakes Kingsnakes are colubrid New World members of the genus ''Lampropeltis'', which includes 26 species. Among these, about 45 subspecies are recognized. They are nonvenomous and ophiophagous in diet. Description Kingsnakes vary widely in size an ...

, cotton mouths, and several species of egrets, and

hawks Hawks are birds of prey of the family Accipitridae. They are widely distributed and are found on all continents except Antarctica. * The subfamily Accipitrinae includes goshawks, sparrowhawks, sharp-shinned hawks and others. This subfamily a ...

. Their usual reaction to threats of being captured are: attempts to escape, biting and releasing a foul odor. Unlike the common water snake, the plain-bellied water snake will leave water and try to escape over land if threatened.

Taxonomy

These six subspecies of ''N. erythrogaster'' have been historically recognized, including the

nominotypical subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

. However, in 2010, Makowsky, et al. determined that there was "little support for the recognized subspecies as either independent evolutionary lineages or geographically circumscribed units and conclude that although some genetic and niche differentiation has occurred, most populations assigned to N. erythrogaster appear to represent a single, widespread species." *''

Nerodia erythrogaster alta ''Nerodia'' is a genus of nonvenomous colubrid snakes commonly referred to as water snakes due to their aquatic behavior. The genus includes nine species, all native to North America. Description ''Nerodia'' species vary greatly, but all are ...

'' ( Conant, 1963) - plainbelly water snake *''

Nerodia erythrogaster bogerti ''Nerodia'' is a genus of nonvenomous Colubridae, colubrid snakes commonly referred to as water snakes due to their aquatic behavior. The genus includes nine species, all native to North America. Description ''Nerodia'' species vary greatly, ...

'' (Conant, 1953) - Bogert's water snake *''Nerodia erythrogaster erythrogaster'' ( Forster, 1771) - redbelly water snake *''

Nerodia erythrogaster flavigaster ''Nerodia'' is a genus of nonvenomous colubrid snakes commonly referred to as water snakes due to their aquatic behavior. The genus includes nine species, all native to North America. Description ''Nerodia'' species vary greatly, but all ...

'' (Conant, 1949) - yellowbelly water snake *''

Nerodia erythrogaster neglecta The copperbelly water snake or copperbelly (''Nerodia erythrogaster neglecta'') is a subspecies of nonvenomous colubrid snake endemic to the Central United States. Description Copperbelly water snakes have a solid dark (usually black but blui ...

'' (Conant, 1949) - copperbelly water snake *''

Nerodia erythrogaster transversa ''Nerodia'' is a genus of nonvenomous colubrid snakes commonly referred to as water snakes due to their aquatic behavior. The genus includes nine species, all native to North America. Description ''Nerodia'' species vary greatly, but all are ...

'' ( Hallowell, 1852) - blotched water snake

Conservation

The plain-bellied water snake is considered a conservation risk because of loss of wetlands and other anthropogenic factors. 35% of wetlands worldwide have been lost from 1970 to 2015. This species is often struck by vehicles while it crosses highways traveling from one water source to another. They are commonly mistaken for cottonmouths and are consequently killed by people averse to snakes. It is not a protected species in the southeastern states. In 1997, the subspecies, copper-bellied water snake was designated a threatened species in Ohio, Michigan and northern Indiana under the Federal Endangered Species Act.