All aquatic turtles have webbed feet which help them displace water with each stroke of their legs. More than 200 modern species of turtles live in the warmer parts of the world, populating every continent except Antarctica and occurring in every ocean except the Arctic. Over two-thirds of all turtle species live in freshwater. North Carolina's turtle population includes both the smallest and largest species in the world. Terrapins, often called Diamondbacks because of the angular rings on their shells, are the only turtles in the world that live exclusively in brackish water.
Female terrapins are much larger than males, more so than any other North American turtle.
Tortoises are strictly terrestrial with blunt, clubbed shaped feet suited for walking on land. Most of the nearly 50 tortoise species live in hot, dry regions of the southern parts of the world. Their dome-shaped shells and elephantlike feet with short toes and no webbing differentiate them from the aquatic turtles and terrapins who have flatter shells and longer toes joined by a fleshy web. The only tortoise native to the U.S. is the Gopher Tortoise which can be found in the sandy-soiled regions of southern South Carolina, Georgia, Florida, and Louisiana. Whether aquatic or land dwellers, almost half of the world's testudines are at risk because of habitat degradation, hunting, and environmental pollution.