Diamondback terrapins are kind of a mix between a land turtle and a sea turtle. They live in the marsh, which is a brackish water area. Brackish water is a coastal vegetated area that is influenced by the ocean tides, so the water isn’t as salty as ocean water. They spend some of their day in the water and other parts of the day on land.

The shells of a Diamondback terrapin are flat and streamlined, but high and domed at the same time. They can pull inside their shells for protection, but it’s a tight fit. The feet of a terrapin are also a mix between a sea turtle and a box turtle. They have webbed feet with claws on them that help them swim as well as scurry up muddy marsh banks.

Out in the marshes, Diamondback terrapins eat fiddler crabs and periwinkle snails. Much like the gopher tortoise, diamondback terrapins are also keystone species. Periwinkle snails are an invasive species, meaning they’re not originally from the United States.  These snails eat the Spartina grass (marsh grass), and are capable of turning healthy marshes to mud flats in a matter of days. In coastal areas, the marshes help keep the nearby land above water.

The way to tell a male from a female is by looking at their size. Males are much smaller than the females, only about 4-6 inches long and females are 8-10 inches long. The females need to be bigger because they carry eggs.

Threats for these turtles are cars and crab traps. Female terrapins come out of the marshes to lay their eggs. They look for the highest, driest ground they can find, which is usually near the side of the road. Sometimes they don’t like the side of the road they are on, so they will cross the road to look for a better place to put their eggs. By crossing the roads, they are more likely to be hit by cars. For mostly males and juvenile terrapins, they can get stuck in crab traps, which are submerged underwater, they can’t get out and they can drown.