A crocodile is any species belonging to the family Crocodylidae (occasionally classified instead as the subfamily Crocodylinae). The phrase can also be used more loosely to include all members of the order Crocodilia: i.e. the true crocodiles, the alligators and caimans (family Alligatoridae) and the gharials (family Gavialidae). The crocodiles, colloquially called crocs, are huge aquatic reptiles that live throughout the Tropics in Africa, Asia, the Americas and Australia. Crocodiles tend to assemble in freshwater habitats like rivers and lakes and wetlands and occasionally in brackish water. Some species, notably the Saltwater Crocodile of Australia, Southeast Asia and the Pacific islands often lives beside the coastal areas as its name implies. It is also known to venture far out to sea. They typically feed on a wide variety of vertebrates like fish, reptiles, and mammals, sometimes with invertebrates like mollusks and crustaceans, depending on species. They are an antique lineage, and are believed to have changed small since the time of the dinosaurs.
Crocodiles are the most higher of all reptiles despite their prehistoric look. Unlike other reptiles they have a four-chambered heart, diaphragm and intellectual cortex. Their outside morphology on the other hand is a sign of their aquatic and predatory lifestyle. A crocodile’s bodily traits allow it to be a successful predator. They have a smooth body that enables them to swim faster. They also insert their feet to their sides while swimming, which makes the animal even faster, by decreasing the amount of water resistance. They have webbed feet, although not used to propel the animal through the water, this allows it to make fast turns and sudden moves in the water or start swimming. Webbed feet are an advantage in shallower water where the animals sometimes move around by walking.
Crocodiles are extremely fast over short distances, even out of water. They have very powerful jaws and sharp teeth for tearing flesh, but cannot open their mouth if it is held closed, hence there are stories of people escaping from the long-snouted Nile crocodile by holding its jaws shut. Indeed, zoologists will often restrain crocodiles for study or transport by taping their jaws or holding their jaws shut with large rubber bands cut from automobile inner tubes. All huge crocodiles also have sharp welters and powerful claws. They have partial lateral movement in their neck, so on land one can find protection by getting even a small tree between the crocodile's jaws and oneself.
Crocodiles eat fish, birds, mammals and infrequently smaller crocodiles. Wild crocodiles are protected in many parts of the world, but they also are farmed commercially. Their hide is tanned and used to make leather goods such as shoes and handbags, whilst crocodile meat is also measured a delicacy in many parts of the world. The most usually farmed species are the Saltwater and Nile crocodiles, while a hybrid of the Saltwater and the rare Siamese Crocodile is also bred in Asian farms. Farming has resulted in an increase in the Saltwater Crocodile population in Australia, as eggs are usually harvested from the wild, so landowners have an incentive to keep crocodile habitat. Crocodiles are more closely related to birds and dinosaurs than to most animals classified as reptiles, the three being included in the group Archosauria ('ruling reptiles').
