New York Natural Heritage Program
Blanding's Turtle
Emydoidea blandingii (Holbrook, 1838)

Identifying Characteristics [-]
This is a medium to large turtle with a carapace (upper shell) length of 5 to 10 inches (12.5-26.0 cm) (Ernst and Barbour 1972). The black carapace is elongated, domed, and smooth and is speckled with numerous yellow or light-colored flecks or streaks. The plastron (lower shell) is bright yellow, with large, dark, symmetrically arranged blotches on the posterior lateral third of each scute and these blotches may hide the yellow color on older adults. A well-developed hinge lies between the pectoral and abdominal scutes on the plastron, but the hinge may not always be apparent on young turtles (Conant 1951). The head is large, black or dark brown in color, and may have scattered yellow spots. This species has a long neck with a yellow throat and chin. The yellow undersurface of the neck appears at 3 years of age (Vogt 1981). The tail and limbs are dark with some yellow or light brown spots and the hind feet are weakly webbed.

Characters Most Useful for Identification [-]
The bright yellow coloration of the chin and throat is a useful diagnostic characteristic that can be used on both captured and observed individuals.

Best Life Stage for Proper Identification [-]
Adults and juveniles are similar in appearance and can be identified by the yellow chin and throat.

Diet [-]
Blanding's turtles are omnivorous (Graham and Doyle 1977) and will eat food both in and out of the water (Pope 1939, Vogt 1981). For turtles in New England and Michigan, crayfish and other crustaceans were documented to comprise about 50% of the diet, insects 25%, and other invertebrates and vegetable matter 25% (Lagler 1943, DeGraaf and Rudis 1983). Turtles in Missouri are primarily carnivorous, specializing in crayfish, followed by insects. Fish, fish eggs, and frogs have also been documented as food items, with small amounts of duckweed and algae always in association with animal food (Kofron and Schreiber 1985). In Nova Scotia where crayfish are absent, Blanding's turtles eat dragonfly nymphs, aquatic beetles, and other aquatic insects, as well as snails and some fish (Bleakney 1963). The quality of the diet may be the most important factor influencing growth. Evidence suggests that turtles from eutrophic environments grow faster and achieve larger maximum size on a carnivorous diet than do turtles on an herbivorous diet. Size differences between Michigan and Massachusetts populations have been explained by differences in food quality and availability, which affect growth rates (Graham and Doyle 1977). Blanding's turtles have been observed consuming pondweed seeds (Potamogeton sp.), golden shiners (Notemigonus crysoleucas), and brown bullheads (Ictalurus nebulosus) where high nutrient levels from sewage effluent have stimulated the growth of high protein foods in Massachusetts (Graham and Doyle 1977).
Blanding's Turtle Images
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The Best Time to See
Generally inactive during cold winter months in north. Primarily diurnal.

In Massachusetts (Graham 1979), daily activity is bimodal during warmer weather and unimodal when the temperature drops. At 25 C the turtles have a short activity period from 5:00 to 6:00 AM EST, then rest until noon with a larger period of afternoon activity lasting until approximately 5:00 PM EST. When the temperature falls to 15 C the turtles show a continuous 8:00 to 5:00 "workday". However, the amount of total movement, movement per hour, and diet activity is greater at 25 C than 15 C, probably due to metabolism changes associated with changes in body temperature (Graham 1979). In Massachusetts, active dispersal of hatchlings from nests to wetlands occurred primarily in early to mid-morning and in late afternoon (Butler and Graham 1995).
Present Reproducing
The time of year you would expect to find Blanding's Turtle present (blue shading) and reproducing (orange shading) in New York.
Similar Species
  • Eastern Box Turtle (Terrapene carolina)
    Eastern box turtles are similar to Blanding's turtles in that they also have a plastral hinge, but unlike Blanding's turtles, box turtles can close up tightly (Conant and Collins 1998). Box turtles also have a hooked beak (Conant and Collins 1998) and do not have the yellow chin and throat coloration that is characteristic of Blanding's turtles.
  • Spotted Turtle (Clemmys guttata)
    Spotted turtles may be confused with juvenile Blanding's turtles, but this species has fewer, well separated yellow spots and no plastral hinge (Conant and Collins 1998). Spotted turtles do not have the yellow chin and throat coloration that is characteristic of Blanding's turtes and they are also much smaller in size than adult Blanding's turtles.