The diamondback terrapin is a species of turtle native to the brackish costal tidal marshes of the Northeastern and southern United States, and in Bermuda. It has one of the largest ranges of all turtles in North America, stretching as far south as the Florida Keys and as far north as Cape Cod.

The name originally was used by early European settlers in North America to describe brackish-water turtles It retains this primary meaning in America.

The common name refers to the diamond pattern on top of its shell (carapace), but the overall pattern and coloration vary greatly. The shell is usually wider at the back than in the front, and from above it appears wedge-shaped. The shell coloring can vary from brown to grey, and its body color can be grey, brown, yellow, or white.

All have a unique pattern of wiggly, black markings or spots on their body and head. It has large strong webbed feet. Males grow to a carapace length of approximately 13 cm (5.1 in), while the females grow to an average carapace length of around 19 cm (7.5 in). The largest female on record was just over 23 cm (9.1 in) in carapace length. Male diamondback terrapins weigh 300 g (11 oz) on average, while females weigh around 500 g (18 oz). The largest females can weigh up to 1 kg (35 oz). Terrapins are very strong swimmers. They have strong jaws for crushing shells of prey, such as clams and snails. This is especially true of females, who have larger and more muscular jaws than males.

More Info: en.m.wikipedia.org