Terrapin – any omnivorous aquatic turtle of the family Emydidae. A terrapin’s shell is flatter than that of a tortoise; this allows it to travel through water with the least resistance. The shell is composed of an outer layer of horn for protection and an inner layer of bone. The shell and skin are very sensitive.\r\rTerrapins’ jaws are composed of bone, covered with a hard layer of horn which comes to a sharp edge. There are no teeth but the hard horny jaws are effective for biting and tearing.\r\rHearing in the terrapin is essentially non-existence but it has good sight. The sense of smell is keen and used for finding food, both on land and in the water.\r\rTerrapins can breathe quite freely when on land by alternately contracting two muscles in the flanks and two in the front of the body. By this means, the lungs are expanded and contracted, air being sucked in and pushed out. In the water, the terrapin breathes by using the lining of the throat and two sacs in the cloacae, which allow air to pass through them.\r\rTerrapins like company. They live in large numbers in the wild.