While much attention is justly focused on the endangered, seafaring loggerhead turtle population that nests here every summer, a less threatened cousin that spends all its time on the island also faces threats from habitat loss and human activity. The Carolina diamondback terrapin (Malaclemys terrapin centrata), with distinctive circular markings on its carapace, inhabits the brackish waters of our salt marshes and tidal creeks, feeding on crabs, snails, fish, oysters and mussels. It's the only turtle species known to prefer brackish water.
Its attraction to crab pots is one threat, sometimes trapping and drowning the animal. Encounters with motorized boats are another potential cause of mortality. Habitat loss from warming and rising water levels, or from human development along estuaries and inlets, is an increasing challenge for diamondbacks, which are found all along the Atlantic coast from Cape Hatteras to Florida. Although not considered endangered, terrapins are an important indicator species for water quality, with populations all along the coast monitored regularly.
The term "terrapin" is applied to land-based turtles, as opposed to marine species like the loggerhead. Carolina terrapins are active nearly all year round, living in burrows dug in mudflats and hibernating there during colder months. Its shell ranges from gray to a light green or brown, and is marked by concentric growth rings that indicate age, which can be measured in decades. One male specimen found on Kiawah had originally been tagged in the 1980's and was found still active and healthy twenty-five years later.
Like their seagoing relations, diamondback females lay their eggs, starting in late spring, in nests dug in sandy banks above the high tide line, which may bring females looking for nesting sites disastrously in contact with vehicular traffic along roads built too close to the water. The nests are often raided by raccoons, foxes and seagulls.
But the good news is that Carolina terrapins have recovered from near-extinction in the early twentieth century, when their pale yellow meat was considered a delicacy. They were eagerly hunted to supply restaurants and fish markets, bringing high prices that climbed even higher as it became more difficult finding them by digging our their hibernation burrows. Today, although legally harvestable, they're thankfully no longer considered suitable for the dining table and no commercial hunting permits have been issued by South Carolina for many years, allowing populations to rebound.
All photographs courtesy John D. Willson, Virginia Tech Dept. of Fish and Wildlife Conservation.