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

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of semi-

aquatic Aquatic means relating to water; living in or near water or taking place in water; does not include groundwater, as "aquatic" implies an environment where plants and animals live. Aquatic(s) may also refer to: * Aquatic animal, either vertebrate ...

, non-

venomous 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 sti ...

colubrid Colubridae (, commonly known as colubrids , from , 'snake') is a family of snakes. With 249 genera, it is the largest snake family. The earliest fossil species of the family date back to the Late Eocene epoch, with earlier origins suspected. Colu ...

snake Snakes are elongated limbless reptiles of the suborder Serpentes (). Cladistically squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales much like other members of the group. Many species of snakes have s ...

endemic Endemism is the state of a species being found only 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 foun ...

to the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

Description

The plain-bellied water snake is a large, thick-bodied, mostly patternless snake, with a generally beige underside. Some snakes display a thin, white line between the pale belly and their darker top scales. Subspecies can range from dark brown, gray, and olive-green to greenish-gray or blackish in color. Some lighter-colored individuals have dark dorsal patterns. Plain-bellied water snakes can be distinguished from other water snakes by their “plain”, patternless undersides, which vary in color from light reddish hues to beige; this is where they get the common name “plain-bellied”, as they typically have no notable markings on their bellies. There used to be recognized subspecies of the plain-bellied water snake, although scientists often had a hard time differentiating between them. This has led to these subspecies no longer being recognized. The scientific name ''erythrogaster'' comes from the Greek word “''erythros''” (meaning ‘red’) and “''gaster''” (meaning ‘belly’). This species exhibits geographically-distinct, phenotypic variations which result in a number of unique subspecies. Adults vary in size from 24 to 40 inches (76–122 cm) in total length. Juvenile snakes feature patterns similar to banded water snakes, but can be identified by their unmarked bellies.

Distribution and habitat

Plain-bellied water snakes are found in every southeastern state of the

U.S. The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 states and a federal capital district, Washington, D.C. The 48 contiguous ...

, except for the higher elevations in the

Appalachian Mountains The Appalachian Mountains, often called the Appalachians, are a mountain range in eastern to northeastern North America. The term "Appalachian" refers to several different regions associated with the mountain range, and its surrounding terrain ...

(thus excluding them from eastern Tennessee and western

North Carolina North Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, South Carolina to the south, Georgia (U.S. stat ...

). On the east coast, they are found across

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

, north to southeastern

Virginia Virginia, officially the Commonwealth of Virginia, is a U.S. state, state in the Southeastern United States, Southeastern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States between the East Coast of the United States ...

, as well as western

Tennessee Tennessee (, ), officially the State of Tennessee, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Kentucky to the north, Virginia to the northeast, North Carolina t ...

. They are found at lower elevations from

Georgia Georgia most commonly refers to: * Georgia (country), a country in the South Caucasus * Georgia (U.S. state), a state in the southeastern United States Georgia may also refer to: People and fictional characters * Georgia (name), a list of pe ...

and west across the Gulf States, extending as far west as

Oklahoma Oklahoma ( ; Choctaw language, Choctaw: , ) is a landlocked U.S. state, state in the South Central United States, South Central region of the United States. It borders Texas to the south and west, Kansas to the north, Missouri to the northea ...

and

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

. The snakes are almost always found near a permanent freshwater source, usually several feet deep, and not necessarily clear or fast-moving waters, either. They can often be observed resting on branches or foliage directly over the water, for an easy escape route. In their natural geographic range, the snakes are adapted to a

wetland A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...

lifestyle, often found at or near creeks, rivers, swamps, floodplains, lakes, and ponds, as well as man-made reservoirs, dams, and canals.

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. ''Nerodia erythrogaster'' is found no further than (approximately) 318 feet (97 m) away from a freshwater source, but do travel over dry land, around 98–108 feet (30–33 m) in a single day. Unfortunately, their migration leads to high mortality rates on roads, with mortality rates reaching up to sixty percent. They tend to spend more time in terrestrial habitats than other species of ''

Nerodia ''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. Five of the species have recognized subspecies. Descript ...

''. They hibernate during the coldest months of the winter. The species finds the bulk of its prey in the water. They feed primarily on tadpoles, small amphibians, fish, crayfish and other crustaceans, aquatic insects (like water beetles), hatchling turtles and carrion. Because of the amount of time they spend on land, the snake's diet includes a large quantity of

amphibians Amphibians are ectothermic, anamniote, anamniotic, tetrapod, four-limbed vertebrate animals that constitute the class (biology), class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all Tetrapod, tetrapods, but excl ...

, consisting mostly of toads and frogs. Like most other snakes, it will actively hunt for prey, but this species has also been observed submerged underwater and lying in wait for prey to approach. They apprehend and swallow prey alive without the prior use of

constriction Constriction is a method used by several 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 ...

envenomation Envenomation is the process by which venom is injected by the bite or sting of a venomous animal. Many kinds of animals, including mammals (e.g., the northern short-tailed shrew, ''Blarina brevicauda''), reptiles (e.g., many snakes), spiders, i ...

Reproduction

This species bears live young (

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

) like other North American water snakes and

garter snake Garter snake is the common name for small to medium-sized snakes belonging to the genus ''Thamnophis'' in the Family (biology), family Colubridae. They are native to North America, North and Central America, ranging from central Canada in the no ...

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. A typical litter size consists of around eighteen young, but litters may exceed that size; 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 + ) is a natural form of asexual reproduction in which the embryo develops directly from an egg without need for fertilization. In animals, parthenogenesis means the development of an embryo from an unfertiliz ...

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 nigricans'') is a carnivorous, freshwater fish, freshwater, ray-finned fish in the Centrarchidae (sunfish) family, native to the eastern United States, eastern and central United States, southeastern Canada an ...

, kingsnakes, cottonmouths, 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 bird of prey, birds of prey of the family Accipitridae. They are very widely distributed and are found on all continents, except Antarctica. The subfamily Accipitrinae includes goshawks, sparrowhawks, sharp-shinned hawks, and othe ...

. When they feel threatened, plain-bellied watersnakes may attempt to escape and/or respond with threat displays such as striking in the direction of the perceived threat or releasing a foul musk from its cloaca. Unlike the common watersnake, the plain-bellied watersnake 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 (: 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. ...

. 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 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 bluis ...

'' (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 copper-bellied water snake subspecies was designated a threatened species in

Ohio Ohio ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Erie to the north, Pennsylvania to the east, West Virginia to the southeast, Kentucky to the southwest, Indiana to the ...

Michigan Michigan ( ) is a peninsular U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, Upper Midwestern United States. It shares water and land boundaries with Minnesota to the northwest, Wisconsin to the west, ...

and northern

Indiana Indiana ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Michigan to the northwest, Michigan to the north and northeast, Ohio to the east, the Ohio River and Kentucky to the s ...

under the Federal Endangered Species Act.