Painted turtle

Appearance

The painted turtle's shell is 10–25 cm long, oval, smooth with little grooves where the large scale-like plates overlap, and flat-bottomed. The color of the top shell varies from olive to black. Darker specimens are more common where the bottom of the water body is darker. The bottom shell 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. As with other pond turtles, such as the bog turtle, the painted turtle's feet are webbed to aid swimming.

The head of the turtle is distinctive. 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. The turtle's upper jaw is shaped into an inverted "V", with a downward-facing, tooth-like projection on each side.

The hatchling has a proportionally larger head, eyes, and tail, and a more circular shell than the adult. The adult female is generally longer than the male, 10–25 cm versus 7–15 cm. For a given length, the female has a higher top shell. The female weighs around 500 g on average, against the males' average adult weight of roughly 300 g. The female's greater body volume supports her egg-production. The male has longer foreclaws and a longer, thicker tail, with the anus located further out on the tail.

Distribution

Within much of its range, the painted turtle is the most abundant turtle species. Population densities range from 10 to 840 turtles per hectare of water surface. Warmer climates produce higher relative densities among populations, and habitat desirability also influences density. Rivers and large lakes have lower densities because only the shore is desirable habitat; the central, deep waters skew the surface-based estimates. Also, lake and river turtles have to make longer linear trips to access equivalent amounts of foraging space.

Adults outnumber juveniles in most populations, but gauging the ratios is difficult because juveniles are harder to catch; with current sampling methods, estimates of age distribution vary widely. Annual survival rate of painted turtles increases with age. The probability of a painted turtle surviving from the egg to its first birthday is only 19%. For females, the annual survival rate rises to 45% for juveniles and 95% for adults.

The male survival rates follow a similar pattern, but are probably lower overall than females, as evidenced by the average male age being lower than that of the female. Natural disasters can confound age distributions. For instance, a hurricane can destroy many nests in a region, resulting in fewer hatchlings the next year. Age distributions may also be skewed by migrations of adults.

Status

The species is currently classified as Least Concern by the IUCN but populations have been subject to decline locally.

Habitat

To thrive, 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, and the shores of lakes. The subspecies have evolved different habitat preferences.

⤷ The eastern painted turtle is very aquatic, leaving the immediate vicinity of its water body only when forced by drought to migrate. Along the Atlantic, painted turtles have appeared in brackish waters.
⤷ The midland and southern painted turtles seek especially quiet waters, usually shores and coves. They favor shallows that contain dense vegetation and have an unusual toleration of pollution.
⤷ The western painted turtle lives in streams and lakes, similar to the other painted turtles, but also inhabits pasture ponds and roadside pools. It is found as high as 1,800 m.

Food

The painted turtle hunts along water bottoms. It quickly juts its head into and out of vegetation to stir potential victims out into the open water, where they are pursued. The turtle holds large prey in its mouth and tears the prey apart with its forefeet. It also consumes plants and skims the surface of the water with its mouth open to catch small particles of food.

Although all subspecies of painted turtle eat both plants and animals, their specific diets vary.

⤷ The eastern painted turtle's diet is the least studied. It prefers to eat in the water, but has been observed eating on land. The fish it consumes are typically dead or injured.
⤷ The midland painted turtle eats mostly aquatic insects and both vascular and non-vascular plants.
⤷ The southern painted turtle's diet changes with age. Juveniles' diet consists of 13% vegetation, while the adults eat 88% vegetation. This perhaps shows that the turtle prefers small larvae and other prey, but can only obtain significant amounts while young. The reversal of feeding habits with age has also been seen in the false map turtle, which inhabits some of the same range. The most common plants eaten by adult southern painted turtles are duckweed and algae, and the most common prey items are dragonfly larvae and crayfish.
⤷ The western painted turtle's consumption of plants and animals changes seasonally. In early summer, 60% of its diet comprises insects. In late summer, 55% includes plants. Of note, the western painted turtle aids in the dispersal of white water-lily seeds. The turtle consumes the hard-coated seeds, which remain viable after passing through the turtle, and disperses them through its feces.

Predators

Painted turtles are most vulnerable to predators when young. Nests are frequently ransacked and the eggs eaten by garter snakes, crows, chipmunks, thirteen-lined ground and gray squirrels, skunks, groundhogs, raccoons, badgers, gray and red fox, and humans. The small and sometimes bite-size, numerous hatchlings fall prey to water bugs, bass, catfish, bullfrogs, snapping turtles, three types of snakes, herons, rice rats, weasels, muskrats, minks, and raccoons. As adults, the turtles' armored shells protect them from many potential predators, but they still occasionally fall prey to alligators, ospreys, crows, red-shouldered hawks, bald eagles, and especially raccoons.

Painted turtles defend themselves by kicking, scratching, biting, or urinating. In contrast to land tortoises, painted turtles can right themselves if they are flipped upside down.

Evolution

The painted turtle is the only species in the genus "Chrysemys". The parent family for "Chrysemys" is Emydidae: the pond turtles. Emydidae is split into two sub families; "Chrysemys" is part of the Deirochelyinae branch. The four subspecies of the painted turtle are the eastern, midland, southern, and western.

The painted turtle's generic name is derived from the Ancient Greek words for "gold" and "freshwater tortoise"; the species name originates from the Latin for "colored". The subspecies name, "marginata", derives from the Latin for "border" and refers to the red markings on the outer part of the upper shell; "dorsalis" is from the Latin for "back", referring to the prominent dorsal stripe; and "bellii" honors English zoologist Thomas Bell, a collaborator of Charles Darwin. An alternate East Coast common name for the painted turtle is "skilpot", from the Dutch for turtle, "schildpad".Although its evolutionary history—what the forerunner to the species was and how the close relatives branched off—is not well understood, the painted turtle is common in the fossil record. The oldest samples, found in Nebraska, date to about 15 million years ago. Fossils from 15 million to about 5 million years ago are restricted to the Nebraska-Kansas area, but more recent fossils are gradually more widely distributed. Fossils newer than 300,000 years old are found in almost all the United States and southern Canada.