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This site was created by students in the herpetology class at Towson University. Site last updated: 05/21/07.
Acknowledgements: Herb Harris - Range Maps; Mark Tegges - Photography; Dan Lapascha & Gigi Forester - TU Herpetology Logo
Diamondback terrapin
(Malaclemys terrapin)
Description
The diamondback terrapin is known to have the greatest sexually dimorphic size disparity among North American turtles –females become up to 15 - 23 cm (6 - 9 in.) and males 10 - 14 cm (4 - 5½ in.). A diamondback terrapin has a light gray body dotted with contrasting black spots, a consistently white upper lip, and a carapace that is either deeply or slightly grooved with either huge vertebral keels or slight knobs. The carapace color is highly variable, and some turtles have carapaces that are boldly patterned with dark rings on a ground of light gray or brown, while others have carapaces that are uniform black or dark brown. Plastrons are orange or yellowish to greenish gray. The hind legs are relatively large and the toes are webbed beyond the base of the nails.
Habitat
This species is typically found in saltwater habitats, including brackish channels, lagoons, tidal flats, marshes, estuaries, and coastlines, although it needs access to fresh water as well for drinking purposes. The diamondback terrapin is the only member of Family Emydidae that can survive in such highly saline habitats. The habitat choice of the species allows them to feed on a variety of crustaceans, fish, insects, and mollusks.
Breeding
Consistent with their size difference, female terrapins reach sexual maturity at a later age (6 years) than male terrapins (3 years). Diamondback terrapins breed in the water in the early spring. In the late spring and summer, females will lay 4-18 eggs in the sand above the high tide line. Hatchlings are 2.5 - 3.2 cm (1-1¼ in.) in length and are have more brightly patterned plastrons than adults. Females typically nest several times annually and are known to produce eggs for several years after a single mating. The sex ratio is generally skewed toward females.
Distribution in Maryland
Range map adapted from Harris, 1975.
Links
http://www.uga.edu/srel/diamondback_terrapin.htm