Turtles along with tortoises and terrapins are placed in the order Chelonia. The aquatic species are usually called turtles and the terrestrial members are known as tortoises. Turtles are normally slow moving and non-aggressive animals. They do not have teeth. Instead, jaws are armed with horny plates that help in chewing food. The body is covered with a protective bony shell. The upper portion of the shell is called carapace and the lower portion is known as plastron. The limbs are flattened laterally and toes are webbed. Some species of turtles have paddle-like flippers with two or three protruded claws. The fore flippers are used in propulsion, whereas, the hind flippers serve for digging nest. Males can be identified from females by their usually concave plastrons. The majority of turtle species are found in or near the tropics. Breeding takes place in water and it happens usually once annually. The female goes on the land for laying eggs. For that purpose, a hole is made by the hind legs in the ground near the bank. During lying time, the female hangs her tail in the hole and lays egg one by one. With the help of hind legs, she picks the eggs up and meticulously allows them to slide to the ground. After depositing the egg, the hole is filled up and she returns to the water. The eggs are hatched by the heat of the soil alone. The freshwater turtles have a flattened disc-like shell covered with soft skin. The other characteristics include retractile head and neck, paddle-like limbs and three claws on each limb.