The diamondback terrapin (Malaclemys terrapin) inhabits the coastal brackish and saltwater marshes of the eastern and southeastern U.S. It is a medium-sized turtle, with males reaching approximately 5 inches in shell length and females significantly larger. largest, 9 inches. Generally, the shell and skin coloration of a terrapin is gray to whitish, with varying patterns of black spots and stripes. Some even have black “moustaches.” Occasionally, yellow spots are found on the carapace scutes and there may be an orange tinge to the marginal scutes of some individuals.
When aquatic turtles are capped, they are generally not known to live. Still, be careful when handling large females because of their large heads and powerful jaws.
Aquatic turtles belong to the family Emydidae, which encompasses several freshwater turtles, such as painted turtles, slider turtles, map turtles, and many others. Among them, the diamondback terrapin shares its closest relationship with the map turtles found within the genus Graptemys.
Aquatic turtles are popular among North American tortoises because they live exclusively in saltwater-fed habitats. Adults are often seen in salt marsh streams during the tide, but are less obvious during high tides, a time when large predators such as sharks are more likely to enter the habitat. Turtle biologists suspect that terrapins spend high tide hiding in the grass and mud of salt marshes, where they also feed on periwinkle snails. Hatchling terrapins appear to live in grassy marshes closer to shore and spend their early years hiding in shallow water, mud, and under mats of dead grass.
Read more here
