Blanding's Turtle Emydoidea blandingii - Special Concern

Family: Emydidae

Description: The Blanding’s Turtle is a medium-sized turtle with a large, domed carapace. Adults have carapace lengths ranging from 5–9 inches (13–23 cm). The carapace is typically dark and covered in small flecks of yellow. The plastron is light yellow to tan in coloration with several dark blotches on each of the scutes, with a single hinge just behind the front limbs. This hinge raises the plastron, allowing individuals to retract their head and neck into the protective shell. The top of the head is similar in patterning to the carapace, and the lower jaw, throat, and neck are solid yellow. Additional characteristics include a long neck, protruding eyes, and a notched upper jaw. Males are typically smaller than females and have a longer tail and a slightly concave plastron.

Habitat: Blanding’s Turtles can be found in wetlands or other permanent bodies of water with little or no flow, high amounts of vegetation, and sandy substrates.

Natural History: Blanding’s Turtles are omnivores, often feeding on fish, frogs, carrion, invertebrates, and plant material. Though large, these turtles are agile swimmers and capable of chasing down prey in the water. Blanding’s Turtles are active during the day and often bask on logs, banks, and clumps of vegetation. This turtle is primarily aquatic, although they will travel long distances overland. Individuals overwinter in mud and organic material at the bottom of aquatic habitats and may also estivate during periods of warm temperatures. Most breeding activity takes place in the early spring and continues through May. Courtship involves a series of steps that can last several hours and includes males chasing, mounting, biting, and attempting to stimulate females to reproduce. Females dig nests that are 7 inches (18 cm) deep in sparsely vegetated sandy upland habitats and lay eggs from May to June. Clutch sizes range from 5–12 eggs (an average of 8). Eggs hatch in two months, and the sex of juveniles is determined by the temperature of the nest. Sexual maturity may take 14–20 years, with males often reaching maturity at faster rates than females.

Species Distribution: Blanding’s Turtles are primarily distributed across the Great Lakes regions, extending from the Sandhills of western Nebraska, east through Iowa and Minnesota to northern New York. Few, isolated populations exist surrounding this region.

South Dakota Distribution: It is possible that few, isolated, peripheral populations of this species were once present in the southeastern corner of the state, but no documentation of this species has been reported in recent decades. If Blanding’s Turtles were once present in southeastern South Dakota, they are likely extirpated. A large population of Blanding’s Turtles is known from the Sandhills near Valentine, Nebraska, and it is possible that Blanding’s Turtles may eventually be documented from the Sandhills region in south-central South Dakota.

South Dakota Status: This species is monitored by the South Dakota Natural Heritage Program. Any observations of this species should be reported to South Dakota Game, Fish and Parks (report observation).

Remarks: The species is named after William Blanding, an early naturalist from Philadelphia. The only verifiable record of this species is from a specimen collected in the Big Sioux River near Sioux Falls in 1963. Given that Blanding’s Turtles are primarily recognized as occurring in wetland habitats, rather than rivers, it raises questions about whether this record from the Big Sioux River in Sioux Falls represents a wild individual or a released pet.

Distribution Map
Age in years of Most Recent Record
5 10 15 20 25 30 35 40 45 50 55 60 65 70 75+
Phenology of Blanding's Turtle (Emydoidea blandingii)
Blanding's Turtle (Emydoidea blandingii)
Blanding's Turtle (Emydoidea blandingii)
Blanding's Turtle (Emydoidea blandingii)
Blanding's Turtle (Emydoidea blandingii)
Blanding's Turtle (Emydoidea blandingii)