The painted turtle is generally considered to be a diurnal species (2) (4), spending its nights sleeping on the bottom of a water body, although nocturnal activity has been observed in some parts of its range. This species tends to become active around sunrise, and starts the day by basking for several hours on anything that extends from the water, including logs, rocks and sand bars. Basking sites are commonly shared with other painted turtles, with as many as 50 individuals basking on a log at one time, sometimes with other turtle species. The rest of the day is spent both basking and foraging (2).
The painted turtle is omnivorous, and eats almost any plant or animal, dead or alive (1) (2). However, aquatic insects, crustaceans, plants and algae form the bulk of its diet (3). Rather than adopting a sit-and-wait strategy, the painted turtle usually actively forages for food along the bottom of the water body (2) (3), flushing prey out of hiding by making exploratory strikes into vegetation using its head and limbs. In order to swallow, this species must have its head submerged (3). Young painted turtles are carnivorous at first (2) (3) (6), but become more herbivorous as they mature (2) (6).
In the northern parts of its range, the painted turtle is most active from March to October, hibernating for the remainder of the year, whereas southern populations may be active during any month. During hibernation, the painted turtle can usually be found submerged in water, down to a depth of two metres, buried in the soft substrate at the bottom (2).
The male painted turtle generally reaches maturity at between two and four years of age, and the female between six and ten years (1) (2). Courtship and mating in the painted turtle usually occur from March to mid-June, although they can occur later in the year (2). The female painted turtle is capable of storing sperm to fertilise clutches later in the season (2).
Nesting time varies depending on the location, running from April to mid-July in Louisiana, May to July in Arkansas, and June to July in more northern parts of the painted turtle’s range. The female painted turtle uses its hind feet to dig a flask-shaped nest (2), and may dig several test sites before completing a final nest cavity. Nests are generally dug in loamy or sandy soil in open areas, and are usually found within 200 metres of water (2).
A female painted turtle lays between one and five clutches per season, with two being the most common (1) (2), although not all females reproduce each year (1) (2) (3). Clutch sizes vary depending on the subspecies and the location (1), ranging from 1 to 23 eggs per clutch (1) (2). The white to cream eggs are elliptical in shape (2), and are incubated for between 62 and 80 days (1). Young from clutches laid late in the season may overwinter within the nest until the warmer weather returns (2) (4) (6).
The sex of painted turtle hatchlings is determined by the temperature at which they are incubated (2) (3), with cooler temperatures producing predominantly males, and temperatures of 29 to 32 degrees Celsius producing all females (2).
Painted turtle nests are subject to a high level of predation, with raccoons, snakes, rodents and humans being among the top predators (2). Young turtles are also at risk from predation by frogs and large wading birds (2) (3), while adult painted turtles can be taken by alligators, birds of prey and raccoons (2).