"Painted Turtle" is also the name of an imprint of Wayne State University Press.

Painted Turtle
Painted turtle
Conservation status
Least Concern  (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Testudines
Family:	Emydidae
Subfamily:	Deirochelyinae
Genus:	Chrysemys Gray, 1844
Species:	C. picta
Binomial name
Chrysemys picta (Schneider, 1783)
Subspecies
C. p. bellii C. p. dorsalis C. p. marginata C. p. picta
Synonyms
Testudo picta Schneider, 1783

The painted turtle (Chrysemys picta) is a turtle, endemic to southern Canada and the United States, belonging to the Emydidae family. Chrysemys is a monotypic genus; however, four distinct subspecies of painted turtle occur. The painted turtle looks similar to other turtles such as the sliders and the cooters, both of which are also North American. The painted turtle is small, measuring 10 to 26 centimeters (4 to 10 in) and weighing 300 to 500 grams (11 to 18 oz) (depending on sex). It has a smooth, flat, oval, and keelless carapace (shell) and a base skin color of black to olive. One of the distinguishing characteristics of this turtle is the red, orange, or yellow "painted" pattern on its legs, tail, neck, and face.

Spanning from southern Canada south to Louisiana and from the Eastern U.S. seacoast to the Western U.S. seacoast, the painted turtle's range is vast. Each subspecies inhabits partially isolated regions, the formation of which are believed to be caused by the last recession of glaciers from the north. The fossil record for this turtle is well established, as remains from many areas within its current range have been found and dated to as far back as 16,300,000 to 13,600,000 BP. It inhabits slow moving streams, rivers, lakes, and ponds (again with each subspecies having its own preferences). Populations usually contain a 1:1 female to male ratio with older turtles being more common than younger ones.

The painted turtle is diurnal, and feeds on many different plants and animals. Its principal predator is the raccoon but birds of prey, snakes, alligators, humans, and rodents also prey upon the species. Winter is spent in hibernation mainly at the bottom of a river-bed, although other locations such as underneath banks of dirt may suffice. It moves frequently between wetlands, largely based on environmental and meteorological conditions. The painted turtle is a rapid grower until sexual maturity is reached (2 to 4 years for males and 6 to 10 years for females) and may live 40 years.

Taxonomy

Subspecies of the painted turtle^[1]

Common name	Scientific name	Synonyms	Authority
Western painted turtle	C. p. bellii	Emys bellii Emys oregoniensis Chrysemys nuttallii Chrysemys pulchra Chrysemys cinerea var. bellii Chrysemys treleasei Chrysemys picta bellii	Gray, 1831 Harlan, 1837 Agassiz, 1857 Gray, 1873 Boulenger, 1889 Hurter, 1911 Bishop & Schmidt, 1931
Southern painted turtle	C. p. dorsalis	Chrysemys dorsalis Chrysemys cinerea var. dorsalis	Agassiz, 1857 Boulenger, 1889
Midland painted turtle	C. p. marginata	Chrysemys marginata	Agassiz, 1857
Eastern painted turtle	C. p. picta	Testudo cinerea Chrysemys cinerea	Bonnaterre, 1789 Boulenger, 1889

The painted turtle is the only recognised species of the genus Chrysemys, although turtles of the genus Pseudemys are very similar, causing some to combine the two.^[2] The Chrysemys turtles (of which there are four distinct races) live exclusively in North America.^[3] The painted turtle was originally described in 1783 by Johann Gottlob Schneider as Testudo picta.^[1]

There has been much debate over the taxonomic classification of Chrysemys, Pseudemys, and Trachemys turtles. In 1964, the three, based on skull and foot morphology, were condensed into one genus, with each making up its own subgenus. However, three years later, further skull and shell examination revealed that classifications to be incorrect. At the same time, the late J. Alan Holman, a paleontologist and herpetologist, pointed out that although all three subgenera were often found in the same bodies of water and had similar mating patterns, there were no records of hybridization among any of them. In conjunction with the previous two observations, cytological, biochemical, and parisotological studies of the early to mid 1980s have indicated that Chrysemys, Pseudemys, and Trachemys should remain three separate genera.^[4]

Description

The painted turtle is 10 to 26 centimeters (4 to 10 in) long^[5] and has a smooth, flat, oval, and keelless carapace.^[6][7] The carapace is olive to black with darkness being related to substrate darkness (the lighter the substrate, the lighter the painted turtle's carapace is likely to be and vice versa).^[8] The plastron (belly) is yellowish and has a black or red-to-brown markings in the middle. The skin of the turtle is black to olive but the neck, legs, tail, and face have red and yellow stripes (however, the face has exclusively yellow stripes).^[5][7] Behind each eye is a large, yellow spot and streak. The chin has two wide yellow stripes that meet at the tip of the jaw.^[8] The upper jaw (the philtrum) is an inverted "V" shape and has two tooth-like projections on either side facing down.^[9] Compared to adults, the hatchlings have a proportionally larger head, eyes, and tail and is more vibrantly colored.^[10] Also, the carapace of hatchlings is nearly circular (something not true in adults).^[11]

Compared to males, the female painted turtle is larger in overall size but has a shorter, thinner tail, and has shorter foreclaws.^[5][6][7] Females weigh 500 grams (18 oz) while males weigh 300 grams (11 oz).^[12] The painted turtle's karyotype is composed of 50 chromosomes.^[7]

Each subspecies displays slightly different characteristics and attributes. Male eastern painted turtles (C. p. picta) are 13.1–16.5 cm (5.2–6.5 in) and females are 14.3–17.1 cm (5.6–6.7 in) in length. The carapace is green and has a yellow stripe down the middle. The shell plates (which are on the carapace) are edged with yellow lines and the edge of the entire carapace is red.^[13] It also has a small, faint mid-dorsal stripe and its plastron is plain yellow or lightly spotted. The western painted turtle (C. p. bellii) is the largest subspecies of painted turtle ^[14] with a maximum carapace length of 25 centimetres (9.8 in).^[15] The reticulated (net-like) pattern of light lines on its carapace is its defining characteristic.^[14] Also, most of the plastron is covered in a dark coloration that begins in the seems and spreads outward. The mid-dorsal stripe is either missing or faint as in the eastern painted turtle.^[14] The southern painted turtle (C. p. dorsalis), the smallest subspecies,^[16] measuring between 10 to 14 centimetres (3.9 to 5.5 in) in length^[17] and has a red or yellow mid-dorsal stripe and either a spotless or near spotless tan plastron.^[16] The midland painted turtle's (C. p. marginata) carapace (10 to 25 centimetres (3.9 to 9.8 in))^[18] is bordered by a dark coloration and the plastron contains a dark figure which varies in shade and, unlike the one found in the western painted turtle, does not extend out along the seams. Its mid-dorsal stripe may be poorly developed or missing.^[19]

Distribution and habitat

The painted turtle is unique in that it is the only turtle found across the entire North American continent.^[14] It reaches southern Quebec, New Brunswick, Nova Scotia, and British Columbia in the north and the coast of Louisiana in the south. It also lives on the eastern coast of the United States, from Maine to Georgia, west to the state of Washington.^[14]

The eastern painted turtle (C. p. picta) is found in southeastern Canada south to Georgia and, from there, west to Alabama. The western painted turtle (C. p. bellii), ranges from western Ontario south to British Columbia, Missouri, Oklahoma, Colorado, Wyoming, Idaho, and Oregon. It is also found scattered throughout the southwestern United States and in Chihuahua.^[14] The southern painted turtle (C. p. dorsalis) lives in southern Illinois south to the Gulf Coast of Louisiana and northeast through central Mississippi.^[16] The midland painted turtle (C. p. marginata) ranges from the southern reaches of Ontario and Quebec south the central United States to Tennessee and Alabama. It also exists eastward through Pennsylvania, Virginia, West Virginia, North and South Carolina, Maryland, and into New England.^[16]

The painted turtle lives in bodies of water with slow moving currents. This includes: ponds, marshes, lakes, and creeks (also called streams). These locations require soft bottoms, adequate basking sites, and the presence of aquatic vegetation. In areas along the Atlantic coast, these turtles have been seen in brackish waters.^[20] In addition to these basic requirements, the four subspecies each seek different attributes in their habitat. The eastern painted turtle is extremely aquatic and seems to only leave the immediate area of a body of water to seek a more suitable habitat. This (often short) migration can involves hundreds of turtles at once.^[21] The western painted turtle lives in a variety of places including the normal streams and lakes, but also locations such as pasture ponds and roadside pools. It can be found at altitudes as great as 1,800 metres (5,900 ft) (observed in the Rocky Mountains).^[15] The southern painted turtle is found almost exclusively in calm water, usually ponds (some of which only a few centimeters deep). There also may be a slight difference in habitat preference between the young and adults of this subspecies.^[17] The midland painted turtle is similar to the southern painted turtle in that it seeks out quiet waters, usually shores and coves. It likes shallows that contain dense vegetation and happens to be quite tolerant of industrial pollution.^[22]

Population features

Within its range and preferred habitat, the painted turtle is almost always the most abundant species of turtle.^[23] Population densities vary widely depending on the weather condition, specific habitat type, and the latitude (dry periods and more southern latitudes are conducive to larger densities while cold periods and more northern latitudes result in the opposite). Estimates range anywhere from 9.9 to 838 individuals for every 1 hectare (2.5 acres) of water. River and large lake populations are often more dispersed because distant travel is common.^[23]

Adult sex ratios of painted turtle populations usually hover around 1:1, but yearly or monthly fluctuations are common.^[24] These slight changes tend to favor males, but observations have shown that some populations contain more females. One well studied population near the northern range limit has a sex ratio of 1:4 (four females for every male).^[25] Hatchling sex ratios have been studied, but results are difficult to determine for two reasons: the eggs are temperature dependent (thus even numbers are not naturally produced) and nesting sites within a population that have both male-producing and female-producing temperatures may be disparate.^[26]

In a given population, older turtles are likely more common than younger ones. Again, gauging the ratios is problematic because juveniles are more difficult to find and catch than adults. Each of the current methods used to determine age distribution in painted turtle populations yields a different result.^[26] The probability of a painted turtle surviving from egg to one year of age is just 19%. From one year to the next, the survival rate among juvenile females is 45% and among adult females the rate is about 95%. Across the board, male survival rates are lower.^[27] Factors that can effect the age distribution of a painted turtle population include natural disasters. Hurricanes for instance can destroy most or all of the nests of a given season, resulting in proportionally more adults and juveniles than hatchlings in the subsequent year.^[27] Age disparity in a population may also be caused by the constant moving of painted turtles to and fro neighboring wetlands.^[26]

Discovery of Painted turtle fossils by age and location^{[28][nb 1]}

Age	Approximate years BP	Location(s) found (alphabetical)
Barstovian	16,300,000 to 13,600,000	Nebraska
Clarendonian	13,600,000 to 10,300,000	Kansas
Hemphillian	10,300,000 to 4,900,000	Nebraska
Blancan	4,750,000 to 1,808,000	Kansas, Nebraska, and Texas
Irvingtonian	1,800,000 to 300,000	Kansas, Maryland, Nebraska, and Oklahoma
Rancholabrean	300,000 to 11,000	Alabama, Georgia, Illinois, Indiana, Kansas, Maryland, Michigan, Mississippi, Nebraska, Nova Scotia, Oklahoma, South Carolina, and Virginia

Evolutionary history and fossil record

The four subspecies of painted turtle have evolved due to partial geographic isolation (each independently adapted to its different surroundings).^[14] It has been suggested that, after the receding of ice from the last ice age, painted turtles were divided into three different populations: C. picta, which inhabited the southeastern Atlantic coast; C. dorsalis, which occupied the southern Mississippi River Valley area; and C. bellii, in the southwestern United States.^[19] Despite this, the populations were not completely isolated, thus completely different species did not evolve. The retreat of the glaciers resulted in an overall northern movement by all three of the painted turtle populations. As a result, C. dorsalis and C. bellii met in Missouri where hybridization produced the fourth contemporary subspecies: C. marginata (which likely originated near the Tennessee River Valley).^[19]

Ecology and behavior

The painted turtle is most active from March to October, yet, even in the north, individuals can be seen basking in February during periods of warmth.^[29] It is diurnal, becoming active at sunrise when it basks (for thermoregulation) for several hours before feeding.^[30] After that, another period of basking follows, than another period of foraging continues into the early evening.^[31] Nighttime is spent sleeping at the bottom of the turtle's pond or small creek, or perched on a part-way submerged object.^[30] All ages of painted turtle have been observed basking for warmth: sometimes 50 or more individuals can be seen on one log at a time. Also, other species of turtle have been seen basking with painted turtles.^[32] Three major periods of basking exist: one in the early morning, one during midday, and another in the early afternoon with each one lasting about 2 hours. The months of most frequent basking is April through September. Air and water temperatures are used throughout the day to maintain a high body temperature. The optimum body temperature range for the painted turtle is between 17 and 23 °C (63 and 73 °F).^[32] Interestingly, laboratory tests have revealed that when a painted turtle has a bodily infection (caused by a bacteria for example), it is capable of adjusting its behavior so that its body temperature will be about 4 to 5°C higher than normal. Apparently the painted turtle has the capability of developing a fever to fight off the infection.^[32]

Dormancy through winter lasts five or six months in the north, but in other locations the period is not as long. There is evidence that, in the far south of its range, the painted turtle may not even hibernate at all,^[21] however, the overwhelming majority of populations do. Throughout hibernation, during periods of warmth, the painted turtle can become active, until the cold temperatures return. The painted turtle can hibernate in various locations: on the bottom of a body of water, within the burrow of a muskrat, underneath banks of dirt, or on land in woods or pastures. When hibernating underwater, a painted turtle can be as deep as 2 metres (6.6 ft), but usually shallower, and may bury itself as deep as 95 centimetres (37 in) in the soft mud.^[33] During hibernation, the body temperature of the painted turtle averages 6.2 °C (43.2 °F). The turtles generally emerge from early March to mid-April (depending on how long cold temperatures persist), when the ice cover of the water-body (if indeed it hibernated in water) has completely disappeared.^[33]

Predators

Painted turtles are preyed upon by a variety of animals.^[23] Its nests are destroyed or raided by thirteen-lined ground squirrels, chipmunks, woodchucks, gray squirrels, skunks, badgers, two types of fox (Urocyon and Vulpes), fish crows, garter snakes, raccoons, and humans.^[23]

Young turtles fall prey to rice rats, muskrats, mink, raccoons, snapping turtles, three types of snake (Agkistrodon, Coluber, and Nerodia), bullfrogs, two types of large fish (Micropterus and Ictalurus), herons, and water bugs. Adults are taken by alligators, raccoons, bald eagles, osprey, and red-shouldered hawks. Painted turtles defend themselves when attacked or handled by kicking, scratching, biting, or urinating.^[23]

Diet

The painted turtle eats a large array of food items with feeding habits depend largely on water temperature. In the spring, when the water reaches 15 to 18 °C (59 to 64 °F), it begins feeding for the season. However, when the water temperature surpasses 30 °C (86 °F) (usually in July or August), the individuals will not forage. Finally, in September, eating ceases at the same range it began in the spring.^[34] The painted turtle hunts along the bottom of small rivers, streams, and ponds and among clumps of algae and aquatic vegetation. The turtle quickly juts its heads in and out of aquatic plants to stir potential prey items out into the open water, where they are pursued.^[34] The painted turtle also skims the surface of the water with its mouth open to catch fine particulate matter. Large prey is held in the mouth and torn up with the forefeet.^[34]

The painted turtle eats plants and animals either alive or dead ^[34] and each subspecies has its own unique diet.^[35] The eastern painted turtle's diet is the least studied of the four subspecies. It is known to be omnivorous and take in a number of different plants and animals with most of the fish consumed being either already dead or injured. The eastern painted turtle prefers to eat in the water, but it has been observed eating on land.^[35] The western painted turtle is omnivorous and its proportionate consumption of plants and animals changes seasonally. During early summer (specifically the month of June), 60% of this turtle's diet is insects. Yet in late summer (September), 55% of its diet is plants.^[36] Also of note, white water-lily seeds are consumed by this turtle in high numbers. The hard-coated seeds remain viable as they pass through its digestive system, which suggests that the western painted turtle is a significant disperser of water lily seeds.^[36] The southern painted turtle is omnivorous and its diet changes with age. Adults of this subspecies obtain 88% of their food from plants while immature specimens consume 13% of their food from plants. The most common plants eaten by the adults are duckweed and algae and dragonfly larvae and crayfish constitute most of the animal prey. The reversal of feeding habits due to age has also been observed in the False map turtle.^[37] The midland painted turtle is also omnivorous, eating mostly aquatic invertebrates and plants. It mostly eats insects, Non-vascular plants, and vascular plants.^[38]

Movement

The painted turtle often travels vast distances (sometimes several kilometers in one trip) either between neighboring wetlands or linearly along a creek.^[39] Individuals have been observed crossing their entire wetland (for some, a 2.4 hectares (5.9 acres) body of water) every day.^[40] Due to heat and overgrowth of vegetation, some individuals will move from shallow marshes to more permanent ponds or lakes during the summer months.^[39] Prolonged heat and drought may also lead the turtle to estivate, and, in extreme cases, die.^[40] Field research and the repeated capturing of painted turtle individuals has revealed that, overall, males travel up to 26.0 kilometres (16.2 mi) between captures, females the second most at 7 to 8 kilometres (4.3 to 5.0 mi) between captures, and juveniles of either gender the least, traveling less than 2 kilometres (1.2 mi) between captures.^[39] Male painted turtles have the largest range because they must seek their mates and are more likely to move between wetlands.^[40]

The painted turtle, through the use of visual recognition, has homing capability.^[39] Many individuals are able to return to their collection point after being released somewhere else, a trip that may require them to traverse over land. One experiment was done in which 98 specimens were placed varying distances away from their home wetland. Of the original number, 41 returned. When living in a single, large body of water, the painted turtle can home from a maximum of 5.8 kilometres (3.6 mi) away. It has also been hypothesized that pregnant females may use some simple form of homing to locate a proper nesting sight.^[39]

Life cycle

Depending on their size, males reach sexual maturity at about 2 to 4 years old, and females from about 6 to 10.^[41] Increased food access (and thus growth) is a factor in the earlier maturation of males. The size and age at maturity of the painted turtle increases with the latitude at which it is found.^[42] The painted turtle mates after emerging from hibernation, throughout spring and summer^[12] and into early fall.^[43] Spermatogenesis (which begins earlier and ends later in southern populations)^[44] begins in March; the minimum temperature required for initiation is 17 °C (63 °F).^[41] The female's ovarian cycle begins in July or August, and ovulation takes place the following spring.^[43]

The courtship ritual occurs in water and begins when the male follows a female until he meets her face to face.^[12] He then strokes her face and neck with his front claws, a gesture that a receptive female will return. This process is repeated several times, with the male retreating from and then returning to the female until she swims to the bottom, where copulation occurs.^[12][43] The courtship ritual and mating act both take place at water temperatures between 10.0 and 27.8 °C (50.0 and 82.0 °F).^[20] The female has the ability to store sperm, which can be used for up to three clutches in a season, in her oviducts.^[45] As males are smaller than females, they are not dominant during the mating ritual.^[12]

Nesting of the eggs starts in late May and lasts until mid-July. The majority of nests are constructed in the late afternoon and early evening (after the hottest part of the day), but for a female to construct one earlier is not unusual.^[46] When preparing to dig a nest, the female sometimes presses her throat against the ground of potential sites, perhaps feeling for their moisture, warmth, texture, or smell, although the behavior is as yet unexplained. She may begin by preparing several false nests,^[47] a behavior also exhibited by wood turtles.^[48] The female accumulates so much sand and mud on her hind feet while digging that her mobility can be reduced, making her vulnerable to predation. Vulnerability of the eggs is a concern when several females make their nests in close proximity. The process of digging and preparing the nest may take up to four hours to complete.^[47] The nests are vase-shaped and are dug in sandy soil by the female, using only her back claws.^[43][47] The optimum female body temperature during nest construction is 29 to 30 °C (84 to 86 °F).^[47]

Nests are exposed to the south and often occur within 200 metres (660 ft) of water, but may be as far away as 600 metres (2,000 ft) depending on the age of the mother; younger females often nest closer to water. The female may return to the same nesting site several year in a row. The size of the nest varies widely depending on the size of the female and the geographical location.^[47]

Egg production of subspecies of painted turtle^{[47][nb 2]}

Subspecies	Range	Average
C. picta picta	1–11	4.9
C. picta marginata	3–17	7.6
C. picta dorsalis	1–11	4.2
C. picta bellii	4–23	11.9

While laying the eggs, the female will moisten the area with bladder water.^[47] If conditions are unsuitable for nesting, i.e., if it is excessively hot or dry, the female can delay her egg laying. The elliptical eggshells are flexible, white, and porous.^[50] The gender of painted turtle fetuses is temperature dependent and is determined during the middle third of incubation. Temperatures between 23 and 27 °C (73 and 81 °F) produce males, and anything above or below that females.^[43] It does not appear that the female chooses nesting sites based on what the subsequent sex of the hatchlings will be.^[10] In the wild, eggs incubate for between 72 and 80 days before hatching,^[43] while under artificial conditions they incubate for between 65 and 80 days (with the mean for both circumstances being 76 days).^[51] The female can lay up to five clutches each year, but the average number is two. It has been found that northern painted turtles produce larger but fewer clutches. A positive correlation exists between female size, clutch size, and egg mass and width.^[49] Studies suggest that larger eggs have a better chance of producing viable offspring than smaller ones.^[44] As many as 30–50 percent of a population's females will not produce any eggs in a given mating season.^[47]

Hatching occurs in August and September, but not all of the offspring will emerge from the nest immediately; hatchlings may overwinter in the nest and emerge the following spring,^[43] this is especially common in the northern part of the turtle's range where, despite seeking shelter within the nest, subzero temperatures result in high hatchling mortality rates. Compared to adults, the baby painted turtle has a proportionally larger head, eyes, and tail and is more brightly colored.^[10] Also, the carapace of hatchlings is nearly circular.^[11]

Growth starts when the turtles first start feeding: usually 7–10 days after hatching. The young painted turtle grows rapidly, sometimes doubling in size in the first year with smaller ones growing more rapidly than larger ones. Young C. picta bellii, the largest subspecies, are the fastest growers.^[52] Likely due to differing environmental conditions and diet, growth rates may change from population to population in the same area. Overall, females grow more rapidly and reach a larger size than males. For both genders, growth slows down sharply once maturity is reached (growth may even stop completely).^[53] In the wild, painted turtles aged 40 years have been found.^[34]

Conservation

Humans are the largest threat to the painted turtle populations and are responsible for the most turtle deaths per year.^[23] Deaths result from highway collisions, intentional killing by anglers, unsafe use of pesticides, and improper care while kept as pets.^[23] Eggs and young have reportedly been sold to pet shops in the lower Mississippi Basin, individuals of all ages have been consumed by humans for food, and eggs have been used as fish bait.^[54] Optimum painted turtle habitat is shrinking yearly, as is the case with most other North American turtle species,^[27] yet there are few laws protecting the turtle.^[55] Consequently, populations of painted turtles in British Columbia are endangered (Pacific Coast population) or of "special concern" (Intermountain-Rocky Mountain population).^[56][57]

Despite these problems, the painted turtle is the predominant North American turtle species, spanning most of North America and having high population densities throughout most of its range. High reproduction rates and its ability to survive in habitats effected by humans (i.e., polluted wetlands and even artificially made ponds) have allowed it to achieve and maintain high numbers in the wild.^[55]

References

Notes

Footnotes

Bibliography