The Painted turtle is the most widespread native turtle of North America. Fossils show that the painted turtle existed 15 million years ago. These turtles have a long, oval, smooth shell with little grooves where the large scale-like plates overlap, and flat-bottomed. The color of the top shell (carapace) varies from olive to black. The bottom shell (plastron) is yellow, sometimes red, sometimes with dark markings in the center. Similar to the top shell, the turtle's skin is olive to black, but with red and yellow stripes on its neck, legs, and tail. Painted turtles have a very distinctive head. The face has only yellow stripes, with a large yellow spot and streak behind each eye, and on the chin two wide yellow stripes that meet at the tip of the jaw. As with other pond turtles, the Painted turtle's feet are webbed to aid swimming.
The Painted turtle is the only turtle whose native range extends from the Atlantic to the Pacific. It is native to eight of Canada's ten provinces, forty-five of the fifty United States, and one of Mexico's thirty-one states. On the East Coast, it lives from the Canadian Maritimes to the U.S. state of Georgia. On the West Coast, it lives in British Columbia, Washington, and Oregon and offshore on southeast Vancouver Island. The northernmost American turtle, its range includes much of southern Canada. To the south, its range reaches the U.S. Gulf Coast in Louisiana and Alabama. In the southwestern United States, there are only dispersed populations. It is found in one river in extreme northern Mexico. Painted turtles need fresh waters with soft bottoms, basking sites, and aquatic vegetation. They find their homes in shallow waters with slow-moving currents, such as creeks, marshes, ponds, rivers and the shores of lakes.
Painted turtles are social creatures and sometimes more than 50 individuals are seen on one log together. These cold-blooded reptiles regulate their temperature notably by basking. Turtles bask on a variety of objects, often logs, but have even been seen basking on top of common loons that were covering eggs. Painted turtles start their day at sunrise, emerging from the water to bask for several hours. Warmed for activity, they return to the water to forage. After becoming chilled, turtles re-emerge for one to two more cycles of basking and feeding. At night, they drop to the bottom of their water body or perch on an underwater object and sleep. During the winter, Painted turtles hibernate. In the north, the inactive season may be as long as from October to March, while the southernmost populations may not hibernate at all. They hibernate by burying themselves, either on the bottom of a body of water, near water in the shore-bank or the burrow of a muskrat, or in woods or pastures. When hibernating underwater, Painted turtles prefer shallow depths, no more than 2 m (7 ft). Within the mud, they may dig down an additional 1 m (3 ft). In this state, turtles do not breathe, although if surroundings allow, they may get some oxygen through their skin.
Painted turtles are omnivores and eat animals and plants. They feed on both living and dead animals. Their diet includes aquatic insects, fish, crustaceans, aquatic vegetation, and algae.
Painted turtles mate in spring and autumn. Females dig nests on land and lay eggs between late spring and mid-summer. While preparing to dig her nest, the female sometimes exhibits a mysterious preliminary behavior. She presses her throat against the ground of different potential sites, perhaps sensing moisture, warmth, texture, or smell, although her exact motivation is unknown. She may further temporize by excavating several false nests. Females can lay five clutches per year each including 4-15 oval, soft-shelled eggs. Incubation lasts 72-80 days in the wild. In August and September, hatchlings break out from their egg, using a special projection of their jaw called the egg tooth. Immediately after hatching, turtles are dependent on egg yolk material for sustenance. About a week to a week and a half after emerging from their eggs, hatchlings begin feeding to support growth. The young turtles grow rapidly at first, sometimes doubling their size in the first year. Females grow faster than males. In most populations males reach reproductive maturity at 2-4 years old, and females at 6-10. Size and age at maturity increase with latitude; at the northern edge of their range, males become mature at 7–9 years of age and females at 11-16.
The main threat to Painted turtles is habitat loss in various forms. Related to water habitat, there is drying of wetlands, clearing of aquatic logs or rocks (basking sites), and clearing of shoreline vegetation, which allows more predator access or increased human foot traffic. Related to nesting habitat, urbanization or planting can remove needed sunny soils. Another significant human impact is roadkill - dead turtles, especially females, are commonly seen on summer roads. In addition to direct killing, roads genetically isolate some populations. In the West, human-introduced bass, bullfrogs, and especially snapping turtles, have increased the predation of hatchlings. Outside the Southeast, where sliders are native, released pet Red-eared slider turtles increasingly compete with Painted turtles. In cities, increased urban predators (raccoons, canines, and felines) may impact Painted turtles by eating their eggs. Other threats include over-collection from the wild, released pets introducing diseases or reducing genetic variability, pollution, boating traffic, angler's hooks (the turtles are noteworthy bait-thieves), wanton shooting, and crushing by agricultural machines or golf course lawnmowers or all-terrain vehicles.
According to IUCN, the Painted turtle 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 and its numbers today are stable.
Due to their diet Painted turtles are important predators of crustaceans, small fish and other invertebrates in aquatic ecosystems they live in.