The carapace of this species can reach more than 40 cm (16 in) in length, but the average length ranges from 15 to 20 cm (6 to 8 in). The females of the species are usually larger than the males. They typically live between 20 and 30 years, although some individuals have lived for more than 40 years. Their life expectancy is shorter when they are kept incaptivity. The quality of their living environment has a strong influence on their lifespans and well being.
These turtles are poikilotherms, meaning they are unable to regulate their body temperatures independently; they are completely dependent on the temperature of their environment. For this reason, they need to sunbathe frequently to warm themselves and maintain their body temperatures.
Reptiles do not hibernate, but actually brumate; while they become less active, they do occasionally rise to the surface for food or air. Brumation can occur to varying degrees. In the wild, red-eared sliders brumate over the winter at the bottoms of ponds or shallow lakes. They generally become inactive in October, when temperatures fall below 10 °C (50 °F). During this time, the turtles enter a state of sopor, during which they do not eat or defecate, they remain nearly motionless, and the frequency of their breathing falls. Individuals usually brumate underwater, but they have also been found under banks and rocks, and in hollow stumps. In warmer winter climates, they can become active and come to the surface for basking. When the temperature begins to drop again, however, they quickly return to a brumation state. Sliders generally come up for food in early March to as late as the end of April.
In the wild
The red-eared slider originated from the area around the Mississippi River and the Gulf of Mexico, in warm climates in the southeastern United States. Their native areas range from the southeast of Colorado to Virginia and Florida. In nature, they inhabit areas with a source of still, warm water, such as ponds, lakes, swamps, creeks, streams, or slow-flowing rivers. They live in areas of calm water where they are able to leave the water easily by climbing onto rocks or tree trunks so they can warm up in the sun. Individuals are often found sunbathing in a group or even on top of each other. They also require abundant aquatic plants, as these are the adults’ main food, although they are omnivores. Turtles in the wild always remain close to water unless they are searching for a new habitat or when females leave the water to lay their eggs.