Although Blanding's turtles are now thought to be closely related to European pond turtles (Emys obicularis) and box turtles (Terrapene), they were once thought to be most closely related to chicken turtles (Deirochelys) because of similarities in the skull and neck vertebrae and similar feeding habits.
Future survival of Blanding's turtle populations mainly depends on the condition and availability of wetland habitats. This species has been given legal protection in certain states. In the lower Great Lakes basin, however, they appear to be maintaining populations. As with many other species that must migrate to suitable nesting locations, fragmentation caused by roads results in the death of many turtles every year. Because this species is slow-maturing, juvenile as well as adult survivorship must remain high to ensure this species' survival (Harding 1990, 1997). Blanding's turtles are considered lower risk by the IUCN and they are a species of special concern in Michigan.
US Federal List: no special status
CITES: no special status
State of Michigan List: special concern
IUCN Red List of Threatened Species: lower risk - near threatened
Blanding's turtles are omnivores. Their favorite food items are crustaceans but they also feed on insects, leeches, snails, small fish, frogs, and occasionally some plants. Food is captured with a rapid thrust of this turtle's long neck, similar to the feeding actions of the snapping turtle (Chelydra). Feeding mostly occurs underwater and food seized on land is generally carried to the water for swallowing. Prey is either swallowed whole or if it is too large it is held by the jaws and shredded into smaller pieces by the front claws.
Blanding's turtles are found from southwestern Quebec and southern Ontario west to Minnesota and central Nebraska and south to central Illinois. The Great Lakes region is currently a stronghold for this species (Harding, 1997). There are disjunct populations along the eastern seaboard as well, including in New York, Massachusets, Rhode Island, New Hampshire, southern Maine, and Nova Scotia (Ernst, Lovich, and Barbour, 1994).
Biogeographic Regions: nearctic (Native )
Blanding's turtles are found in and around shallow weedy ponds, marshes, swamps, and lake inlets and coves most of the year. They prefer slow-moving, shallow water and a muddy bottom with plenty of vegetation (Harding 1990).
Habitat Regions: temperate ; terrestrial ; freshwater
Terrestrial Biomes: forest
Aquatic Biomes: lakes and ponds
Average lifespan
Status: captivity: 12.8 years.
Blanding's turtle are medium sized turtles with a carapace length ranging from 15.2 to 27.4 cm. These semi-aquatic turtles have moderately high, domed carapaces. They are elongate and smooth, lacking keels or sculpturing. The carapacial scutes display distinct growth annuli most prominently seen in juveniles. Coloration between individuals is highly variable. The carapace is black or gray with any variation of scattered light yellow or whitish flecks or dots. The light spots and flecks predominate in some individuals while others are almost solid black. The plastron is yellow in color with a dark blotch in the outer corner of each scute, and has a V-shaped notch near the tail. In males, the plastron is moderately concave while females posses a flatter plastron and a narrower tail. Blanding's turtles have a hinge located between the pectoral and abdominal scutes, which allows for partial closing of the plastral lobes. The hinge may be practically non-functional or nearly as effective as that of the box turtle (Terrapene). The head is rather flat with a short, rounded snout. These turtles seem to have a permanent "smile" due to the notch in the upper jaw. As with the carapace, the top and sides of the head vary in coloration from black, brown, or olive with yellowish spots or mottling. Contrasting greatly with the rest of the turtle, the chin, throat, and underside of the long neck are bright yellow. The hatchlings of this species have a gray, black, or brown carapace that is 3 to 3.5 cm long. A single light spot is seen in the center of each scute. The plastron has a central black blotch outlined in a yellowish color and the plastral hinge is not yet functional. Immature turtles are often more brightly marked than adults and possess a proportionately longer and thinner tail.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry
Turtle eggs and hatchlings have a variety of predators to which they have virtually no defenses. Raccoons, skunks, and foxes are the major predators on the eggs, but they also prey upon the hatchlings and juveniles. Other predators to the young include large fish, frogs, snakes, wading birds, and crows. Adult turtles depend on their shells for protection on land and in the water rely on their strong swimming abilities to either escape to deeper waters or conceal themselves on the bottom. Rarely will the Blanding's turtle bite as a defense. It is an extremely gentle organism that can rarely be induced to bite.
Mating activities begin when a courting male approaches a female, quickly mounts her carapace, and clasps its edges with his claws. To keep the female withdrawn, the male either bites at her head and forelimbs or presses down on her snout with his chin. The male may also swing his head back and forth or up and down over the female's head or blow a stream of bubbles across the top of her head. The pair will either sink to the lake bottom, float near the surface, or hang on to vegetation until fertilization is complete.
Blanding's turtles reproduce through internal fertilization with copulation taking place in the water. Mating can occur between April and November but is most concentrated in April and May. Less than half of the adult female population will reproduce in a give year. Mostly in June, females may travel considerable distances from the water to find suitable nest sites to lay their eggs. They prefer open, sunny spots in well-drained but moist sandy soil, but when lacking preferred areas, lawns, gardens, or gravel road edges will be used. Females dig a nest cavity approximately 17 cm deep and 7 to 10 cm in diameter at the mouth using alternating movements of the hind feet. They lay 6 to 21 flexible, elliptical shaped eggs measuring about 3.6 cm long. Most hatchlings will emerge 50 to 75 days later, depending on the temperature and moisture in the nest, in August or early September. Because Blanding's turtles have temperature-dependent sex determination, eggs incubated below 25 degrees C produce nearly all males and those incubated above 30 degrees C are nearly all females. The nest must first remain free of any predator attacks and then hatchlings must often travel a considerable distance to reach suitable aquatic habitat. Since few young are ever encountered in the wild, it is presumed that the hatchlings are extremely unlikely to survive the initial weeks away from the nest. These long-lived turtles will reach sexual maturity in 14 to 20 years and reproduce for approximately the next 40 years. Although Blanding's turtles generally reach 60 years of age some individuals may live to be up to a century old.
Key Reproductive Features: gonochoric/gonochoristic/dioecious (sexes separate)
Average number of offspring: 8.
Average age at sexual or reproductive maturity (male)
Sex: male: 4380 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 6500 days.
Blanding's turtle (Emydoidea blandingii)[1][5] is a semi-aquatic turtle of the family Emydidae. This species is native to central and eastern parts of Canada and the United States.[2] It is considered to be an endangered species throughout much of its range.[8] Blanding's turtle is of interest in longevity research, as it shows few or no common signs of aging and is physically active and capable of reproduction into eight or nine decades of life.[9][10]
There are differences of opinion as to the genus for this species; both Emys and Emydoidea occur in published sources in 2009, 2010, and 2011.[1][4]
Both the specific name, blandingii, and the common name, Blanding's turtle, are in honor of American naturalist Dr. William Blanding (1773–1857).[11]
Blanding's turtle is a medium-sized turtle with an average straight carapace length of approximately 18 to 23 cm (7.1 to 9.1 in) with a maximum of 25.5 cm (10.0 in). A distinguishing feature of this 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'.
Blanding's turtle takes 14–20 years to reach sexual maturity. Mating probably occurs in April and early May with nesting beginning in early June and lasting throughout the month.[12] The clutch size varies from region to region. In New York, the clutch size ranges from 5–12 eggs with an average of eight.
Blanding's turtle overwinters under or near water, in mud, or under vegetation or debris. This is known as brumation. During the nesting season, a female Blanding's turtle may be found more than a kilometer from where it hibernated. It is omnivorous, eating crustaceans and other invertebrates, fish, frogs, crayfish, carrion, berries, and vegetable debris. It is capable of catching live fish. Based on the extreme lack of aging symptoms and lack of age related decline, these turtles are considered a negligibly senescent species.[9]
Blanding's turtle is a timid turtle and may plunge into water and remain on the bottom for hours when alarmed. If away from water, the turtle will withdraw into its shell. It is very gentle and rarely attempts to bite. It is very agile and a good swimmer.
The geographic range of E. blandingii centres on the Great Lakes, and extends from central Nebraska and Minnesota (where it twice failed to become the state reptile)[13] eastward through southern Ontario and the south shore of Lake Erie as far east as northern New York. In Nebraska, this turtle is uncommon in the eastern portion of the state, but common to abundant in the Sand Hills region lakes, ponds, and streams. There are also isolated populations in southeastern New York (Dutchess County), New England, and Nova Scotia.[14]
Its general habitat is wetlands with clean shallow water. It is known to bask on logs, and will wander far from water, particularly when nesting. It generally nests 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 habitat, or new food sources, as do elder turtles.
The primary threat to Blanding's turtle is habitat fragmentation and destruction as well as nest predation by unnaturally large populations of predators.[2] It is listed as an endangered species on the IUCN Red List[2] as endangered in some U.S. states, and as either threatened or endangered throughout Canada, though in the U.S. it has no federal status. International trade in the Blanding's turtle is restricted, as the species is listed in Appendix II of the Convention on International Trade in Endangered Species (CITES) meaning that international trade is regulated by the CITES permit system.[3]
This species can also be adversely affected by prescribed burns. During fall and late spring hatchlings move overland and it is recommended that prescribed burns should be avoided during these times.[15]
The U.S. states in which it is considered endangered are Indiana,[16] Illinois, Missouri,[17] Maine, New Hampshire, Massachusetts, and South Dakota.[18] It is considered threatened in New York and Iowa.[19][20] In Michigan, Blanding's turtle is also fully protected as a special concern species;[21] making it unlawful to kill, take, trap, possess, buy, or sell.[22] In Lake County, Illinois, a long term species recovery program has been underway since 2009.[23]
In Canada, the Great Lakes-St. Lawrence River population in Ontario and Quebec is federally threatened[24] and the Nova Scotia population is endangered.[25] Conservation and recovery efforts in Nova Scotia have been in place for two decades and rely on habitat and life history monitoring based on the work of researchers and volunteers. Habitat protection has proven crucial. The population in Kejimkujik has been placed under the highest level of protection; the McGowan Lake population was initially protected by Bowater but has since been taken over by the Province. In Pleasant River, Nova Scotia Nature Trust protects four separate segments of critical habitat.[26]
{{cite journal}}: CS1 maint: multiple names: authors list (link) Blanding's turtle (Emydoidea blandingii) is a semi-aquatic turtle of the family Emydidae. This species is native to central and eastern parts of Canada and the United States. 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 few or no common signs of aging and is physically active and capable of reproduction into eight or nine decades of life.
