The Northern diamondback terrapin is known for its diamond-shaped markings on its shell and is the only turtle species in North America that inhabits brackish waters. They can inhabit these waters because of a special gland that helps to remove excess salt from their bodies by secreting tears high in sodium chloride.

Diamondback terrapins also have webbed feet and muscular legs that make them strong swimmers, especially in brackish waters where they may experience strong tides or currents. The terrapin’s diet consists of hard-shelled prey, like aquatic snails, crabs, mussels, and clams, which they can crush with their strong jaws.

Diamondback terrapins are a species of special concern in New Jersey because of their declining populations due to habitat loss and traffic accidents.