Blanding's turtle (Emydoidea blandingii) is a semi-aquatic turtle native to North America. It is considered to be an endangered species throughout much of its range. Blanding's turtle is of interest in longevity research, as it shows little to no common signs of aging and is physically active and capable of reproduction into eight or nine decades of life.
A distinguishing feature of Blanding's turtle is the bright yellow chin and throat. The carapace, or upper shell, is domed, but slightly flattened along the midline, and is oblong when viewed from above. The carapace is speckled with numerous yellow or light-colored flecks or streaks on a dark background. The plastron, or lower shell, is yellow with dark blotches symmetrically arranged. The head and legs are dark, and usually speckled or mottled with yellow. Blanding's turtle is also called the "semi-box" turtle, for although the plastron is hinged, the plastral lobes do not shut as tight as the box turtles'.
The range of Blanding's turtles centers on the Great Lakes and extends from central Nebraska and Minnesota eastward through southern Ontario and the south shore of Lake Erie as far east as northern New York. There are also isolated populations in southeastern New York (Dutchess County), New England, and Nova Scotia. These turtles live in wetlands with clean shallow water and nest in open grasslands, usually far away from water.
Blanding's turtles spend most of their life in water. They are very agile and good swimmers. These turtles do come out on land to bask on logs and will wander far from water, particularly when nesting. They generally nest in sunny areas, with well-drained soil. Younger turtles may bask on sedge and alder hummocks. Young will often travel far in search of mating sites, new habitats, or new food sources, as do elder turtles. Blanding's turtles overwinter under or near water, in mud, or under vegetation or debris. This is known as Brumation. During the nesting season, females may be found more than a kilometer from where they hibernated. Blanding's turtles are generally solitary creatures but may tolerate other turtles in the same ponds or lakes. They are diurnal hunters and feed both in the water and on land. They are timid creatures and may plunge into the water and remain on the bottom for hours when alarmed. If away from water, the turtle will hide in its shell. They are very gentle and rarely attempt to bite.
Blanding's turtles are omnivores. They eat crustaceans and other invertebrates, fish, frogs, crayfish, berries, vegetable debris, and carrion. They can even catch live fish.
Blanding's turtles have a polyandrous mating system; this means that females mate with more than one male in a single breeding season. Mating probably occurs in April and early May. Nesting begins in early June and lasts throughout the month. The female excavates a nest in a sunny area and lays 3-19 eggs; after that, she covers the nesting hole. Blanding’s turtles usually nest in the same place every year. The incubation period lasts around 80-128 days. Baby turtles weigh 6-10 grams at birth and are completely independent. They will reach reproductive maturity at 14-20 years of age.
The main threats to Blanding's turtle include habitat fragmentation and destruction as well as nest predation by unnaturally large populations of predators. These turtles also suffer from road mortality and commercial trapping for food and for the pet trade.
According to the IUCN Red List, the total population size of Blanding's turtle is unknown. However, there is an estimated population of the species in Nebraska consisting of over 130,000 mature individuals. Currently, Blending's turtle is classified as Endangered (EN) on the IUCN Red List and its numbers today are decreasing.
Blanding's turtles play an important role in keeping their ecosystem healthy as they feed on a wide variety of food, including animals, plants, and carrion.