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Canadian Herpetological Society Société d'Herpétologie du Canada |
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Midland Painted Turtle
Chrysemys picta marginata
Family: Emydidae
The Midland Painted Turtle is a sub-species of the Painted Turtle (Chrysemys picta).
COSEWIC status:- Special Concern
- Special Concern
- Least Concern
Description
Midland Painted Turtles have a smooth, gently rounded carapace (upper shell) that is dark green to black in colour with red markings on the sides. The plastron (lower shell) is usually tan to yellow and often has a dark, irregularly shaped blotch in the center. The head and the limbs are black to green with yellow and red stripes. Individuals can reach a maximum carapace length of 19.5 cm, but most are much smaller than this. Hatchlings have an average carapace length of 2.5 cm and resemble adults in colour and pattern, but with a keeled carapace and proportionately larger head, legs and tail.
Similar Species
The Midland Painted Turtle can easily be confused with the Western Painted Turtle and The Eastern Painted Turtle, although the distributions of these species have limited overlap in Canada. The front edges of the scutes (scales) on the carapace of the Eastern Painted Turtle have a yellow-olive colour band which forms more-or-less straight bands across the carapace, while the scutes of the Midland Painted Turtle are in alternating rows and rarely have thick colour bands along the front edges. Western Painted Turtles lack red stripes on the head and neck and have a bright orange or red plastron with a larger irregular dark blotch in the centre. No other Canadian turtle species have red markings at the edge of the carapace. Northern Map Turtles have a similar striped pattern on the head and limbs, but lack red stripes, have a keel down the center of the carpace, and the rear margin of the carapace is serrated. The exotic Red-eared Slider also lacks the red markings at the edge of the carapace and the rear margin of the shell is lightly serrated.
Distribution
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Painted Turtles have the widest range of any freshwater turtle in Canada, occurring from British Columbia to Nova Scotia. The Midland Painted Turtle is found in central and southern Ontario east of Lake Superior, and in southern Quebec. In the United States, the Midland Painted Turtle occurs south of Ontario and Quebec to Tennessee and northern Alabama.
Habitat
Painted Turtles prefer shallow aquatic habitats with slow-moving water, soft bottoms, aquatic vegetation, and abundant basking sites. Typical habitats include swamps, marshes, permanent or temporary ponds, creeks, rivers and lakes. Females nest in sandy or gravelly soils in open-canopy habitats with high sun exposure, such as in forest clearings, meadows, shorelines, rock outcrops, agricultural fields and the shoulders of roads. The nest sites are typically within 200 m of a water body. Painted Turtles overwinter at the bottom of water bodies or under submerged undercut banks.
Biology
In Canada, Midland Painted Turtles are dormant during the winter and are active from late March or April until October or early November, depending on latitude. Females nest from late May to early July. The female excavates a nest cavity and deposits 3–17 (average 8) elliptical eggs. The number of eggs laid varies with age and size of the individual and the number of clutches laid (females usually reproduce every year, but may lay more than one clutch of eggs). The eggs hatch in the fall, approximately 2.5 months after they were laid, but hatchlings often overwinter in the nest before emerging the following spring. Painted Turtle hatchlings are capable of supercooling and are freeze-tolerant, allowing them to survive sub-zero temperatures as low as −10°C in the nests. The sex of the offspring depends on incubation temperature; warmer incubation temperatures produce females and cooler temperatures produce males. In Canada, female Painted Turtles reach sexual maturity at 12–15 years of age, and males mature at 7–10 years of age. Painted Turtles can live for over 50 years in the wild, and possibly much longer. Painted Turtles are omnivorous and forage primarily during the day for invertebrates, small vertebrates like fish or frogs (possibly mainly taken as carrion) and a variety of plant material. Painted Turtles bask regularly throughout the active season, especially on sunny days. Individuals may make use of multiple wetlands over the course of the year, and home ranges can be several kilometres in length.
Threats
Wetland loss has resulted in decline and extirpation, primarily in southern parts of the Canadian range, and ongoing habitat loss continues to threaten this species. Painted Turtles are especially susceptible to mortality on roads, particularly during the nesting period when females are making overland movements. Since Painted Turtles are relatively long-lived, even low rates of road mortality can result in population decline. Nest predation by subsidized predators (e.g. Raccoon, Skunk) can be a serious threat in areas where these nest predators are hyper-abundant. Other threats include illegal collection for food or as pets, introduction of exotic or invasive species, mortality and injury from fishing by-catch (including drowning in commercial fishing traps), and chemical contamination of aquatic habitats. Climate change poses a potentially serious future threat to Canadian turtles.