The River cooter is a species of freshwater turtle native to the central and eastern United States. The name "cooter" may have come from an African word "kuta" which means "turtle" in the Bambara and Malinké languages, brought to America by African slaves. River cooters are relatively large turtles. Their carapace (upper shell) is typically dark greenish-brown usually with a "C" marking facing the posterior. The plastron (bottom shell) is yellow to reddish-orange with a dark pattern between scutes that follows the scute seams (this fades with age). Females tend to grow larger than males and have a smaller tail and more convex plastron. One particularly distinctive feature of River cooters is that they have the ability to breathe underwater through a sac called the cloaca bursae which is based on their tail. This allows them to stay underwater for extended periods of time and makes their behavior harder to study.
River cooters are found from Virginia south to central Georgia, west to eastern Texas, Oklahoma, and north to southern Indiana. They live in a wide variety of freshwater and even brackish locations. Rivers, lakes, ponds and tidal marshes with heavy vegetation provide ideal habitat.
River cooters are generally solitary creatures often seen basking on logs or sun-warmed rocks. They may frequently be found in the company of other aquatic basking turtles (sliders and painteds) sometimes piled up on top of each other. All are quick to slip into the water if disturbed. Diurnal by nature, River cooters wake with the warming sun to bask and forage. They can move with surprising speed in the water and on land. It is not unusual for them to wander from one body of freshwater to another, but many individuals seem to develop fairly large home ranges, which they seldom or never leave. Large webbed feet make these turtles an excellent swimmer, capable of negotiating moderately strong river currents of major river systems. River cooters sleep in the water, hidden under vegetation. In areas that are quite warm they remain active all winter, but in cooler climes can become dormant during the winter for up to two months, in the mud, underwater. They don't breathe during this time of low metabolism but can utilize oxygen from the water, which they take in through the cloaca. River cooters prefer to be well hidden under aquatic plants during the winter dormancy period or while sleeping each night.
River cooters are mainly herbivores. They feed on aquatic plants, grasses, and algae. Younger ones tend to seek a more protein enriched diet such as aquatic invertebrates, crustaceans, and fish. Older turtles may occasionally seek prey as well but mostly partake of a herbivorous diet.
River cooters are polygynandrous (promiscuous) meaning that both sexes have multiple mates. Breeding takes place in early spring. Nesting usually occurs from May to June. The female chooses a site with sandy or loamy soil, within 100 ft (30 m) of the river's edge. She looks for a rather open area, with no major obstacles for the future hatchings to negotiate on their way to the river. The nest is dug with the hind feet. She lays 10-25 or more eggs in one or more clutches. Eggs are ellipsoidal, approximately 1.5 inches (4 cm) long. Incubation time is determined by temperature but averages 90-100 days. Hatchlings generally emerge in August or September and are independent at birth. Female River cooters become reproductively mature at 6 years of age while males attain maturity when they are 13 years old.
River cooters suffer from loss of habitat, predation by animals, slaughter on the highways, and use as a food source by some people. Hatchlings are particularly vulnerable. During their overland scramble to the river, many hatchlings will be taken by avian and mammal predators. Alligators and muskrats await them in the water. Some will be taken and sold to pet stores. Populations are down in some areas, and there have been increasing reports of injured turtles.
According to IUCN, the River cooter is locally common and widespread throughout its range but no overall population estimate is available. Currently, this species is classified as Least Concern (LC) on the IUCN Red List.