northern diamond-backed terrapin (Malaclemys terrapin terrapin)
This is a moderate-sized estuarine turtle reaching a maximum carapace length of about 9 inches. The carapace is smooth, with the rear half of the shell the widest part. The carapace (upper shell) is gray, brown, yellowish green, or nearly black, and has brown concentric circles alternating with gray, black, or yellow. The plastron (lower shell) is yellowish to greenish, and often has an irregular pattern of black flecks; it may have a dark brown blotch in each scute and the margins of the scutes may be outlined with thin black lines. The skin is usually gray with an irregular pattern of small to large, comma-shaped flecks on the head and limbs. The eyes are black and the "lips" are yellow. The female is significantly larger than the male. This species breeds and lays eggs in the spring and summer. Mating always occurs in the water. Nests are usually constructed in sand, but may also be in fill dirt. These turtles usually overwinter in the mud in channels and tidal flats. This is the the only truly estuarine reptile in Virginia, and the only species in the family Emydidae that possesses a nasal salt gland used for excreting excess salts.
This species is found in the Chesapeake Bay and on the ocean side of the Eastern shore and southeast Virginia. It may be found in coastal rivers as far as tidal influence. It inhabits brackish water, saltwater estuaries and tidal marshes. It is sometimes seen in the Atlantic Ocean.
This species feeds mainly on estuarine mollusks, such as mud snails, but it will also eat crustaceans and worms.