Painted turtle with a yellow-orange plastron

Painted Turtle (Chrysemys picta) is a reptile that is common in southern Canada, the United States, and northern Mexico and is related to other water turtles such as sliders and cooters. This turtle lives in ponds, lakes, marshes, and in slow-moving rivers that have soft, muddy bottoms. The maximum carapace size, or shell length, for painted turtles is 10 inches (250 mm), or 25 cm. Its shell is used to protect it from its predators.

Mating begins shortly after the turtles have emerged from hibernation when the water temperature is still low. Mating may also occur in the fall. The breeding season typically lasts from late spring to early summer. Males begin to breed when they reach maturity, usually at 70-95mm plastron length when they are three to five years old. Females take longer to mature (4–5 years) and are larger at maturity. The courtship ritual of adult painted turtles is a rare and beautiful sight, rarely seen in the wild. Possessing a broader, thicker tail and a smaller (about 80 percent the size of an adult female of the same age), more elongated body shape, the male painted turtle swims to face the female nose-to-nose, prior to fertilizing her ova, and uses his comparatively hugely over-sized front claws to tickle the cheeks of the female rapidly up-and-down in a vibratory manner, in about one-second bursts, with the "palms" of the forefeet facing outward. Different subspecies of painted turtle can and do interbreed - the offspring exhibit an intergradation of the characteristics of the parent races. Painted turtles are amniotes which requires females to nest on land. Females prefer soft, sandy soil with good exposure to the sun for their nest site. Nests are dug with the turtle's hind feet, usually within 200 meters of water. The nest is no deeper than 10 to 12 centimeters. The females will lay 4 to 15 oval, soft shelled eggs, in a conical flask-shaped hole. The eggs are elliptical, white to off-white and are mostly smooth with slight pits. Female turtles may lay up to five clutches of eggs per season although typically, they will lay only one or two clutches. Once the eggs are laid the mother will cover the hole with dirt or sand and leave the nest unattended. Painted turtle eggs hatch 72 to 80 days after they are laid. Once the young hatch and dig out of the nest, they are immediately independent.

Aquariums used to house a painted turtle should be sized at at least 40 gallons per adult, but a 20 gallon, or 30 gallon breeder tank is great for babies, or hatchlings. They must have an accessible land area (commercially made turtle ramps are available at most pet stores) to bask on and to completely dry out on. The tank should be cleaned at least a couple of times a month and right size filtration system should be purchased and kept clean and well-supplied with filter media. A UVA/UVB light is critical to the health of basking turtles. Turtles require heat and sunlight (either natural or artificial) to properly digest food and develop their shells and beaks. Fluorescent UVA/UVB lamps are not suitable for turtles. Turtles in cooler times of year need some heat in addition to the UV light, but a UV light will provide enough heat if the water is 60 F. Exposure to sunlight or artificial heat sources must not be arranged carefully since overheating can kill a turtle within minutes. Always provide a sufficient amount of clean, shaded cooler water to which the turtle can retreat. Keep a turtle habitat fitted with an effective barrier such as a firmly-attached, 1/2-inch wire mesh cover with a sturdy frame which your baby or young child, cat or dog cannot dislodge.

Painted turtles are vulnerable to predation throughout their development and into adulthood. Many animals such as raccoons, several types of squirrels, chipmunk, woodchucks, skunk, badger, foxes, fish crows, garter snakes, deer, ants, beavers, and humans will prey on turtle nests. Newly hatched turtles are eaten by rats, muskrat, mink, raccoons, snapping turtles, snakes, bullfrogs, large fish and herons. Adult turtles are preyed upon by alligators, snapping turtles, raccoons, bald eagles, osprey, and red shouldered hawks. Humans pose many threats to painted turtles through habitat destruction, the use of pesticides, vehicles on roadways, intentional killing by anglers, and through improper care while kept as pets. When a painted turtle feels threatened, it may kick and scratch, bite and urinate. Painted turtles that have avoided predators and disease have been known to live longer than thirty years in the wild.

Source: Wikipedia (All text is available under the terms of the GNU Free Documentation License)

For more information (background, pictures, experiments and references): The Painted Turtle