Nerodia erythrogaster

Superregnum: Eukaryota
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Cladus: Craniata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Classis: Reptilia
Cladus: Eureptilia
Cladus: Romeriida
Subclassis: Diapsida
Cladus: Sauria
Infraclassis: Lepidosauromorpha
Superordo: Lepidosauria
Ordo: Squamata
Subordo: Serpentes
Infraordo: Caenophidia
Superfamilia: Colubroidea

Familia: Colubridae
Subfamilia: Natricinae
Genus: Nerodia
Species: Nerodia erythrogaster
Name

Nerodia erythrogaster (Forster, 1771)

Neotype: USNM 126890, adult ♀, collected by T.M. Beckett on 19 March 1948. [designated by Conant (1949: 10)]
Type locality: not given, restricted by neotype designation to “near Parker's Ferry, Edisto River Swamp, Charleston County, South Carolina”, by Conant (1949: 10).

Combinations

Coluber erythrogaster Forster, 1771: 364 [original combination]
Tropidonotus erythrogaster — Holbrook, 1842: 33 [subsequent combination]
Nerodia erythrogaster — Baird & Girard, 1853: 40 [subsequent combination]

References
Additional references

Makowsky, R., Marshall, J.C., McVay, J., Chippindale, P.T. & Rissler, L.J. 2010. Phylogeographic analysis and environmental niche modeling of the plain-bellied watersnake (Nerodia erythrogaster) reveals low levels of genetic and ecological differentiation. Molecular Phylogenetics and Evolution 55(3): 985–995. DOI: 10.1016/j.ympev.2010.03.012 Paywall Reference page.

Links

Uetz, P. & Hallermann, J. 2022. Nerodia erythrogaster. The Reptile Database. Accessed on 28 May 2022.
Hammerson, G.A., Frost, D.R. & Santos-Barrera, G. 2007. IUCN: Nerodia erythrogaster (Least Concern). The IUCN Red List of Threatened Species 2007: e.T63854A12722399. DOI: 10.2305/IUCN.UK.2007.RLTS.T63854A12722399.en. Accessed on 28 May 2022.

Vernacular names
English: Plain-bellied Water Snake

Nerodia erythrogaster, commonly known as the plain-bellied water snake or plainbelly water snake, is a familiar species of mostly aquatic, nonvenomous, 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.[2] 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.[3] This species exhibits geographically defined phenotypic variation which results in a number of different subspecies.[4] Adults vary in size from 24 to 40 inches (76–122 cm) in total length.[5] Juvenile snakes have banding patterns similar to banded water snakes, but can be identified by their unmarked bellies.[6]
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 in their geographic range.[6]
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.[5] They tend to spend more time in terrestrial habitat than other water snake species. They hibernate during the coldest months of the winter.[6]

The species gets most of its food from the water. They feed primarily on fish, crayfish, salamanders, and frogs. 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.[6][5]
Reproduction

This species bears live young (ovoviviparous) like other North American water snakes 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.[6] In 2014 a captive female produced two healthy offspring via parthenogenesis.[7]
Predators and defense

The plain-bellied water snake is prey to both terrestrial and aquatic predators. Reported predators include largemouth bass, kingsnakes, cotton mouths, and several species of egrets, and hawks. 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.[6]
Taxonomy

These six subspecies of N. erythrogaster have been historically recognized, including the nominotypical subspecies. 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."[8][9]

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.[10] 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.[6]
References

Hammerson, G.A.; Frost, D.R.; Santos-Barrera, G. (2007). "Nerodia erythrogaster". IUCN Red List of Threatened Species. 2007: e.T63854A12722399. doi:10.2305/IUCN.UK.2007.RLTS.T63854A12722399.en. Retrieved 19 November 2021.
"Nerodia erythrogaster Plainbelly Water Snake". Animal diversity web. Retrieved 30 July 2020.
Gibbons, Whit (2004). North American watersnakes : a natural history. Michael E. Dorcas. Norman: University of Oklahoma. ISBN 0-8061-3599-9. OCLC 53814672.
Makowsky; Marshall, J.C.; McVay, J.; Chippindale, P.T. & Rissler, L.J. (2010). "Phylogeographic analysis and environmental niche modeling of the plain-bellied watersnake (Nerodia erythrogaster) reveals low levels of genetic and ecological differentiation". Molecular Phylogenetics and Evolution. 55 (3): 985–995. doi:10.1016/j.ympev.2010.03.012.
Moore, Chas. "Plain-bellied water snake". Outdoor Alabama. Retrieved 30 July 2020.
Gibbons, Whit & Dorcas, Mike (2005). Snakes of the Southeast. University of Georgia Press. ISBN 978-0820326528.
Smith, Jules D. (20 September 2015). "Captive Snake Gives Second Virgin Birth in Two Months". themarketbusiness.com. Retrieved 22 September 2015.
"Nerodia erythrogaster (FORSTER, 1771)". The Reptile Database, reptile-database.org.
Makowsky, Robert; Marshall Jr., John C.; McVay, John; Chippindale, Paul T. & Rissler, Leslie J. (2010). "Phylogeographic analysis and environmental niche modeling of the plain-bellied watersnake (Nerodia erythrogaster) reveals low levels of genetic and ecological differentiation". Molecular Phylogenetics and Evolution. 55 (3): 985–995. doi:10.1016/j.ympev.2010.03.012. PMC 3322375. PMID 20302955.

Finlayson, C. Max (2018), "Ramsar Convention Typology of Wetlands", The Wetland Book, Dordrecht: Springer Netherlands, pp. 1529–1532, retrieved 202 Further reading

Conant, R. 1975. A Field Guide to Reptiles and Amphibians of Eastern and Central North America, Second Edition. Houghton Mifflin. Boston. xviii + 429 pp. ISBN 0-395-19977-8 (paperback). (Natrix erythrogaster, pp. 142–144 + Plate 20 + Map 103.)
Schmidt, K.P., and D.D. Davis. 1941. Field Book of Snakes of the United States and Canada. G.P. Putnam's Sons. New York. 365 pp. (Natrix erythrogaster, pp. 224–225.)
Smith, H.M., and E.D. Brodie Jr. 1982. Reptiles of North America: A Guide to Field Identification. Golden Press. New York. 240 pp. ISBN 0-307-13666-3 (paperback). (Nerodia erythrogaster, pp. 154–155.)
Wright, A.H., and A.A. Wright. 1957. Handbook of Snakes of the United States and Canada. Comstock. Ithaca and London. 1,050 pp. (in 2 volumes) (Natrix erythrogaster, pp. 477–490, Figures 141.-143., Map 39.)