Red-eared slider is a turtle species fully adapted to aquatic life and completely dependent on water. It prefers warm and shallow, slowly flowing or permanent fresh water. Because these turtles are poikilotherms, meaning they are unable to regulate their body temperatures independently; they like to climb onto cliffs or rocks by the shore, or onto tree trunks fallen into the water, to warm themselves in the sun.

Juvenile red-eared sliders eat small aquatic animals such as the larvae of aquatic insects and amphibians, molluscs and small fish. Older individuals are more omnivorous, consuming not only animal matter but aquatic plants and, for instance, fruits and berries that have fallen into the water.

The mating season is spring. The female lays the fertilised eggs in a nest it has excavated on land and covers it up after laying her eggs. Depending on the size of the female, the nest contains 2–30 eggs, which incubate into hatchlings in a couple of months. If incubation takes place at a temperature below 27 degrees Celsius, only males will hatch. A higher temperature is required for the eggs to incubate into females. Depending on the length of the summer, one female may lay up to five clutches of eggs at two-week intervals.

Red-eared sliders brumate over the winter at the bottom of ponds or shallow lakes, and sometimes on land under rocks or tree stumps. They become inactive when temperatures fall below 10 °C and their period of rest lasts six months at most (October to April). During that period, they remain motionless and do not eat or defecate. Their metabolism slows by around 80% and they can survive in almost anaerobic conditions for several weeks.

There are three subspecies: T. s. scripta, T. s. troostii ja T. s. elegans.

Punakorvakilpikonna – Trachemys scripta