The order Crocodilia contains the alligators and caimans (family Alligatoridae, the true crocodiles (family Crocodylidae) and the gharials (family Gavialydae). They inhabit the warmer parts of the world. Crocodiles are adapted to fresh and marine water as well as terrestrial life. The body is covered with hard horny scales or scutes and the skin is soft between the scales. The other characteristics include short and powerful legs, five toes on each forefoot and four on the hind foot. The eyes of crocodilians are protected by a flap of skin. The broad and thick tongue can not protrude. Each jaw -has a row of sharp teeth. Crocodilians have well developed smell, sight and hearing. The penis of the male is located at the cloaca. The copulation takes place in water. The female normally mates only once in a year. She lays hard shelled eggs in a nest. The nest is prepared by the female along the bank of the river, lake or in other suitable place. The chalky-shelled eggs are oval in shape and their number varies from 20 to 100 or more depending upon the species. The female remains in the vicinity of nest and helps the emerging young by breaking open the eggs. The mother also assists in carrying the hatchlings into the water.