''Nerodia erythrogaster'', commonly known as the plain-bellied water snake or plainbelly water snake, is a familiar

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of mostly aquatic, non

venom Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a st ...

ous,

colubrid Colubridae (, commonly known as colubrids , from la, coluber, 'snake') is a family of snakes. With 249 genera, it is the largest snake family. The earliest species of the family date back to the Oligocene epoch. Colubrid snakes are found on ev ...

snake Snakes are elongated, limbless, carnivorous reptiles of the suborder Serpentes . Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more j ...

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

to the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

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. The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

, from

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

to southeastern

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth ar ...

on the east coast, to the borders of eastern

North Carolina North Carolina () is a state in the Southeastern region of the United States. The state is the 28th largest and 9th-most populous of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, Georgia and ...

and western

Tennessee Tennessee ( , ), officially the State of Tennessee, is a landlocked state in the Southeastern region of the United States. Tennessee is the 36th-largest by area and the 15th-most populous of the 50 states. It is bordered by Kentucky to th ...

, 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 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. 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 Constriction is a method used by various snake species to kill or subdue their prey. Although some species of venomous and mildly venomous snakes do use constriction to subdue their prey, most snakes which use constriction lack venom. The snake i ...

Reproduction

This species bears live young (

ovoviviparous Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a term used as a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous animals possess embryos that develop insi ...

) like other North American water snakes and

garter snake Garter snake is a common name for generally harmless, small to medium-sized snakes belonging to the genus ''Thamnophis'' in the family Colubridae. Native to North and Central America, species in the genus ''Thamnophis'' can be found from the ...

s. 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 Parthenogenesis (; from the Greek grc, παρθένος, translit=parthénos, lit=virgin, label=none + grc, γένεσις, translit=génesis, lit=creation, label=none) is a natural form of asexual reproduction in which growth and developmen ...

Predators and defense

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

largemouth bass The largemouth bass (''Micropterus salmoides'') is a carnivorous freshwater gamefish in the Centrarchidae ( sunfish) family, a species of black bass native to the eastern and central United States, southeastern Canada and northern Mexico, bu ...

, kingsnakes, cotton mouths, and several species of

egrets Egrets ( ) are herons, generally long-legged wading birds, that have white or buff plumage, developing fine plumes (usually milky white) during the breeding season. Egrets are not a biologically distinct group from herons and have the same build ...

, 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 ...

. 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'' ( Conant, 1963) - plainbelly water snake *'' Nerodia erythrogaster bogerti'' (Conant, 1953) - Bogert's water snake *''Nerodia erythrogaster erythrogaster'' ( Forster, 1771) - redbelly water snake *'' Nerodia erythrogaster flavigaster'' (Conant, 1949) - yellowbelly water snake *'' Nerodia erythrogaster neglecta'' (Conant, 1949) - copperbelly water snake *'' Nerodia erythrogaster transversa'' ( 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 Ohio () is a state in the Midwestern region of the United States. Of the fifty U.S. states, it is the 34th-largest by area, and with a population of nearly 11.8 million, is the seventh-most populous and tenth-most densely populated. The sta ...

Michigan Michigan () is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the List of U.S. states and ...

and northern

Indiana Indiana () is a U.S. state in the Midwestern United States. It is the 38th-largest by area and the 17th-most populous of the 50 States. Its capital and largest city is Indianapolis. Indiana was admitted to the United States as the 19th s ...

under the Federal Endangered Species Act.