The diamondback terrapin turtles all have concentric diamond-shaped markings on the scutes (plates) of their top shells.
The markings vary greatly in color and pattern among the seven subspecies. They are typically shades of gray, black, and brown. Females are considerably larger than males. Both sexes have large webbed feet. These provide them with the strong swimming abilities required in an environment with tidal fluctuations and powerful currents.
The diamondback terrapin’s territory spans the Atlantic and Gulf Coast states from Maine to Texas and they are especially populous in the Carolinas.
Unique among North American turtles in that they tolerate both fresh and salt water, diamondback terrapins prefer the brackish waters of tidal marshes, estuaries, and coastal rivers. (Other indigenous turtles are exclusively either freshwater or marine-dwellers.) Although no natural populations exist in purely freshwater habitats, terrapins are highly aquatic, spending more of their time in the water than basking on land.
These creatures evolved over 200 million years ago.
The earliest known fossil remains, found at Edisto Beach, near Charleston, date back to the Pleistocene epoch (1.65 million years ago).
The name “terrapin” is derived from an Algonquin word. It described edible turtles, and their popularity as a delicacy extended well into the 1960s. During the years when they were in the greatest demand, an average of 45,000 turtles were caught and shipped to market.
Humans no longer pose the greatest threat to terrapins (discounting loss of habitat, pollution, etc.).
Raccoons, foxes, crows and gulls are all nest predators. Wading birds and predatory fish, like sharks and dolphins, all prey on larger terrapins.
The terrapins, in turn, are voracious carnivores. They prey on crabs, snails, shrimp, fish, mussels, clams, worms, and insects. A particular favorite is the periwinkle snail, easily crunched between their strong jaws. They are mobile predators, stalking and rapidly striking their quarry, especially during high marsh tides. Diamondback terrapins have long frontal claws. Their claws dig nests and tear food into bite-sized chunks which they consume only while under water.
For details on other water activities offered by H2O, visit h2osports.com.
By Master Naturalist Kathleen McMenamin Vicars