Northern Prairie Wildlife Research Center
Description: This species is a shy, medium-sized (5-7.5 inches, 125-190 mm) turtle. It has a dark brown or black dome-shaped upper shell (carapace) with many yellow spots or streaks. The plastron (underside of shell) is hinged across the forward third and is brownish yellow with large brown or black blotches near the edge of each scute (outermost plate of shell). The Blanding's turtle has a long head and neck and a bright yellow chin and throat, which can be seen from some distance. It may appear to have a black moustache.
Habitat and Habits: This species is semi-aquatic, spending most of its time in shallow water at marsh and pond edges, sloughs and drainage ditches. Blanding's turtles bask on logs and muskrat houses and overwinter in mud at the bottom of marshes and ponds, although activity under ice has been observed. Good habitat includes a muddy bottom and abundant vegetation. It feeds on aquatic plants and crustaceans (aquatic insects, crayfish).
Breeding occurs in late spring. The male displays his yellow throat to the female during mating. She moves onto land to select a nesting site, which is usually sandy, well drained and exposed to the sun. The female lays 6-15 cream-colored eggs, which hatch 10-15 weeks later, usually in September.
Distribution: Formerly widespread, Blanding's turtle is now restricted to several states and provinces in the Upper Midwest. It occurs from Nebraska in the west, east to Michigan, Ontario and Quebec. Scattered populations are found throughout the northeastern United States. This species is considered peripheral or disjunct in South Dakota, with one record from the Big Sioux River in Sioux Falls.
Conservation Measures: Draining of wetland habitats or inundation for agricultural purposes, river channelization and water impoundment have reduced available habitat for the Blanding's turtle in South Dakota and nationwide.