Turtles, tortoises or terrapins what they are called depends not only where they live, but also where you live. In the United States we commonly call all of these “turtles” and use the term “tortoise” for strictly terrestrial species, those that live on land. Tortoises have stumpy, elephant-like hind feet and no webbing between their toes. “Terrapins” live in brackish water, water that is only slightly salty. “Sea turtles” live in saltwater. Turtles have been around, 250 million years, since before the dinosaurs, with the same basic body design.
All reptiles with shells are turtles and like all reptiles they are “ectothermic” and use the sun’s heat to raise their body temperature. They breathe air with at least one long, have scales on their skin and claws on their toes. Most reptiles lay eggs, but some snakes and lizards are ovoviviparous and the eggs hatch within the mother’s body and the young are born alive. Turtles lay leathery eggs. They are vertebrates and their ribs and backbone are firmly attached to the inside of the shell…no getting out of that!
Diamondback terrapins, Malaclemys t. terrapin, are believed to be the only turtle in the world that lives in brackish water. They are found from Cape Cod southward along the Atlantic coast to the Florida Keys and westward along the Gulf Coast to Texas.
Diamondback terrapins are named due to the diamond-shaped scutes, or bony plates, on their carapace, the upper shell. Their scutes are unique to each individual, just like fingerprints to humans. Within the scutes are white, green and black concentric circles. The color of the carapace varies greatly from grayish to brown to nearly black. The plastron, lower shell, is yellowish or greenish. The diamondback’s hind feet are large and webbed. Turtles do not have teeth, but their upper and lower jaws form a strong horned beak. Their powerful jaws are heard making a popping noise as they eat periwinkle snails and mollusks in the marsh.
Female diamondback terrapins are much larger than males. Males weigh an average .5 pounds and measure 4 to 5 1/2 inches long. Females weigh 1.5 pounds and are 6 to 9 inches long. Males have long, thick tails, females have shorter tails. Like most turtles, temperature determines the gender of the species. Warmer temperatures result in more females and lower temperatures more males. Studies indicate that at 31oC (87.8oF) the result will be 100% female diamondback turtles and at 26oC (78.8oF) there will be 100% males.
Females don’t mate until they are about 7 years old. Nesting takes place in June and July. They will dig nests, 4-8″ deep, above the high tide level and lay an average of 9 pinkish-white eggs. The eggs will hatch in 9 to 15 weeks. Sometimes there is “delayed emergence” depending on conditions the hatchlings might remain the nest over the winter, surviving on fat reserves, without eating. They emerge in April and feed on mollusks, snails, invertebrates and carrion. Their predators include skunks, raccoons, foxes, gulls, crows, herons, predatory fish and humans. They can live up to 40 years.
Terrapins were once considered a gourmet delicacy and were harvested commercially in the early 1900s. By 1920 they were much sought after costing $90 per dozen. Farms were even established in North Carolina to breed the terrapin in captivity. Turtle, or terrapin, soup was made with sherry and one report attributed alcohol prohibition in the 1920’s leading to decreased popularity of terrapins. Alcohol prohibition and the Great Depression might have actually led to the rebound of the diamondback terrapin population.
Today destruction of wetland habitats, heavy motor boat traffic leading to injury and death from being struck by propellers, entanglement in fishing nets and the threat of drowning in crab traps has led to the diamondback terrapin being listed as a species of special concern in many states, Connecticut included. As of 2015, diamondback terrapins cannot be collected or possessed in Connecticut. In Maryland, it is the official state reptile and it has been the mascot for the University of Maryland since 1932.
You can help by working to protect wetlands, being aware of turtles when boating, be on the lookout when driving especially during the nesting season they might be crossing the road, leave all turtles where they should be – in the wild!
“A turtle travels only when it sticks its neck out.” Korean Proverb
Wildlife Fact Sheet – Diamondback Terrapin
Amphibians and Reptiles of Connecticut and Adjacent Regions by Michael Klemens
Just for Kids – Terrific Turtles