A Crocodile can be any of the 14 species of large, water-loving reptiles in the family Crocodylidae (sometimes classified instead as the subfamily Crocodylinae). The term is also used more loosely to include all members of the order Crocodylia: that is, the true crocodiles; the alligators and caymens (family Alligatoridae); and the Gharial (family Gavialidae).
The crocodiles, often just called crocs, are reptiles that live in a large portion of the tropics in Africa, Asia, the Americas and Australia. Crocodiles tend to live in slow-moving rivers and feed on a wide variety of living and dead mammals and fish. Some species, notably the saltwater crocodile of Australia and the Pacific Islands, have been know to venture far out to sea.
Contrary to popular belief, only three species of crocodile (the Saltwater, the Mugger and the Nile) and one of alligator (the nearly-extinct black caimen) have been known to stalk or attack human beings for food. Large specimens of these four are extremely dangerous. Saltwater Crocodiles in northern Australia take careless tourists on a regular but rare basis, once every few years.
Crocodiles are very fast over short distances, even out of water. They have extremely powerful jaws and razor-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. All large crocodiles also have sharp and powerful claws. Crocodiles are ambush hunters, waiting for fish or land animals to come close, then attacking in a rush. As cold blooded predators, they can survive long periods without food, and rarely need to actively go hunting. Despite their slow appearance, crocodiles are top hunters in their chosen environment, and various species have been observed attacking and killing lions, large ungulates and even sharks.
The largest species of crocodile is the Saltwater Crocodile, which lives in northern Australia and throughout South-East Asia and is the largest reptile currently living on Earth. Confusingly, in northern Australia it is common to refer to the Saltwater Crocodile as an "alligator", which it is not, and to the smaller Freshwater Crocodile as a "crocodile". This is possibly because the long-snouted Freshwater Crocodile or "freshie" does look a bit like a miniature Nile Crocodile, while in comparison the "saltie" could be said to look like the far less dangerous American Alligator. So the Alligator River in the Northern Territory is in fact named after the Saltwater Crocodile. This is why some northern Australians will claim that alligators not crocodiles are the dangerous ones.
Crocodiles in the wild are protected in Australia and many other parts of the world, but they also are farmed commercially in special crocodile farms, and their hide is tanned into leather and used to make handbags, boots, and the like, while crocodile meat is considered a delicacy by connoisseurs.