Diamondback Terrapins are the official state reptile of Maryland, which is fitting as they prefer the brackish waters of the Chesapeake Bay. They can be identified by the distinctive diamond-shaped pattern on their shells.
Some quick facts about Diamondback Terrapins.
The US Fish and Wildlife Service provides some great information about the Diamondback Terrapin.
Video of Diamondback Terrapins nesting.