Diamondback Terrapin

Malaclemys terrapin

The Basics:

• Size: females approximately 10”; males are 4-5”.
• Color: carapace (upper shell) – brown, black, olive, tan or orange; plastron (lower shell) – yellowish to greenish gray; skin is light gray with black spotting pattern.
• Habitat: brackish water habitats like salt marshes, shrublands, dunes, mixed grasslands and tidal creeks.
• When and where to observe:  at locations such as Jamaica Bay Wildlife Refuge and Alley Pond Environmental Center, may see females come ashore to nest in mid-summer (stay at least 150 feet away so that she is not disturbed).

The Details:

Perhaps she just thought that this was a good enough spot for the task at hand.  The summer day was bright and sweltering when she, a female Diamondback Terrapin, and I found ourselves on Jamaica Bay Wildlife Refuge’s West Pond trail.   She crawled out of the patches of little bluestem, stopped on the gravel, and looked up at me in a nonchalant, unbothered manner even though I was sitting on a bench only a few feet away.

Apparently, I must have looked unthreatening because after a few minutes her back legs were busy swishing back and forth to clear off the soil for a nest.

I’m not sure what made her change her mind, but after about five minutes she stopped, looked around, and quietly returned to the clumps of Little Bluestem grass.

Tolerant of salt water, Diamondback Terrapins tend to inhabit salt marshes, shrublands, dunes, mixed grasslands, and tidal creeks like those found at Jamaica Bay or the northern end of Alley Pond Park.   Their common name is a reflection of the diamond-shaped concentric circles on the upper shell (called a carapace) and the Native American word “terrapin” which means “turtle”.

The protective carapace ranges in color – brown, black, gray, olive tan or even orange – while the plastron (lower shell) is usually yellowish to greenish gray, and skin is light gray with a pattern of dark spots.  Female carapaces may measure up to 10” long while males are about half that size.  Diamondback Terrapins have black eyes and webbed feet – very helpful in their aquatic environment.

Diamondback Terrapins spend the winter months tucked away alone or in small groups, buried in creek banks or underwater.  Come late April to early May, they become active again, feeding on a variety of marine invertebrates (worms, crabs, snails) and some aquatic plants.  Spring is also the time for mating if they are mature enough – males are ready to reproduce when they are three years-old, while females need to wait until their sixth year.  On Long Island, mating usually takes place in June to July.

Summer is the most likely time to see a Diamondback Terrapin, particularly on warm days and high tides, when females come ashore to dig holes in the soil with their back legs and deposit 4-15 pinkish eggs with leathery shells.  It is extremely important to not disturb the females – scaring them may mean the abandon nesting activity.

After laying eggs, the nest is covered again with soil, and females head back to deeper water and join males, remaining active until hibernation in November or December.

Eggs hatch in approximately two months with a peak in September, though some eggs will remain in the nest until the following spring (look for small yellow flags along Jamaica Bay’s West Pond trail noting nest locations, part of a Hofstra University study).  Unfortunately, eggs and hatchlings frequently fall victim to predators like raccoons, Norway rats, and ghost crabs.  In fact, they are just one example of the challenges Diamondback Terrapins face.

Problems began in the early 1900s when terrapins were nearly hunted to extinction – seems their meat was so tender and tasty that gourmands couldn’t help but make terrapin soup, evidently a favorite at many posh restaurants.

Oddly enough, their rescue came in the form of an economic disaster.  The Great Depression of the 1930s meant that folks couldn’t afford such luxuries and the subsequent Prohibition years limited access to sherry, a necessary ingredient for terrapin soup.

Diamondback Terrapin populations began to rise and by the 1970s, there was little concern.  Unfortunately, today there are new threats the species faces and their numbers have declined again.

Besides the aforementioned predators (many of which are the outcome of increased human presence), coastal development has not only destroyed their habitat, but also led to more collisions with people, particularly our cars.  Crab traps drown entangled terrapins, and although there are legal protections against their harvest, they are still a popular species in both the pet trade as well as some food markets.

The struggles faced by today’s Diamondback Terrapins prompted the New York State Department of Environmental Conservation to list them as a “Species of Greatest Conservation Need”.   Thankfully, the species has an organization of scientists focused on their preservation in the “Diamondback Terrapin Working Group” formed in 2004.

What can we do to help out the Diamondback Terrapin?

Remember to always keep a distance from nesting females (at least 150 feet away is recommended) and respect trail closures during nesting season, and never collect them from the wild.  If you want to see terrapins up close, head over to the Alley Pond Environmental Center where they have a small aquarium.   Drive carefully when in terrapin habitat and be certain to clean up any garbage to cut down on rats and raccoons that prey upon the hatchlings and destroy nests.

We must all make a contribution to the survival of the Diamondback Terrapin, not only for moral reasons, but ecological ones as well.  If it weren’t for the terrapins feasting on small grass-grazing snails called periwinkles, the vital salt march ecosystem would become barren mud flats.

References:

• The Amphibians and Reptiles of New York State: Identification, Natural History, and Conservation by James P. Gibbs, Alvin R. Breisch, Peter K. Ducey, Glenn Johnson, John L. Behler, and Richard C. Bothner, published 2007 by Oxford University Press.
• Diamondback Terrapin Working Group, accessed on 1/15/2009 at: http://www.dtwg.org/index.html.
• Field Guide to the Natural World of New York City by Leslie Day, published 2007 by Johns Hopkins University Press.
• Species of Greatest Conservation Need (SGCN) by the New York State Department of Environmental Conservation, accessed on 1/15/2009 at: http://www.dec.ny.gov/animals/9406.html.

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