Nerodia erythrogaster

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.

Nerodia erythrogaster
plain-bellied water snake Nerodia erythrogaster
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Colubridae
Genus:	Nerodia
Species:	N. erythrogaster
Binomial name
Nerodia erythrogaster (Forster, 1771)
Synonyms
Coluber erythrogaster Forster, 1771 Tropidonotus erythrogaster — Holbrook, 1842 Tropidonotus transversus Hallowell, 1852 Nerodia erythrogaster — Baird & Girard, 1853 Natrix fasciata erythrogaster — Cope, 1888 Natrix sipedon erythrogaster — Allen, 1932 Natrix erythrogaster — Clay, 1938 Natrix e. erythrogaster — Conant, 1958 Nerodia e. erythrogaster — Conant & Collins, 1991

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 dispaly 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. Adults vary in size from 24–40 inches (76–122 cm) in total length.[3] Juvenile snakes have banding patterns similar to banded water snakes, but can be identified by their unmarked bellies.[4]

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, and to the borders of eastern North Carolina and western Tennessee. 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.[4]

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 in water or traveling over land. During hot, humid weather, they will travel long distances away from water.[3] They are unusual for a water snake in the amount of time that they are found on land. They hibernate during the coldest months of the winter.[4]

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 includes a large quantity of amphibians. Like most other snakes, it will hunt for prey, but the snake has been observed, sitting in aquatic areas, waiting for prey to approach them. They apprehend and swallow prey alive without using constriction.[4][3]

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 baby snakes in North Carolina,[4] In 2014 a captive female produced two healthy offspring via parthenogenesis.[5]

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.[4]

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."[6][7]

• 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 its tendency to travel over land on roads and highways. Destruction or damage to wetlands is also a threat to the species's habitat. 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.[4]

References

1. 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.
2. "Nerodia erythrogaster Plainbelly Water Snake". Animal diversity web. Retrieved 30 July 2020.
3. Moore, Chas. "Plain-bellied water snake". Outdoor Alabama. Retrieved 30 July 2020.
4. Gibbons, Whit & Dorcas, Mike (2005). Snakes of the Southeast. University of Georgia Press. ISBN 978-0820326528.
5. Smith, Jules D. (20 September 2015). "Captive Snake Gives Second Virgin Birth in Two Months". themarketbusiness.com. Retrieved 22 September 2015.
6. "Nerodia erythrogaster (FORSTER, 1771)". The Reptile Database, reptile-database.org.
7. 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.

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.)