Crocodiles (family crocodylidae) or true crocodiles are large semiaquatic reptiles that live throughout the tropics in africa, asia, the americas and australia. the term crocodile is sometimes used even more loosely to include all extant members of the order crocodilia, which includes the alligators and caimans (family alligatoridae), the gharial and false gharial (family gavialidae) among other extinct taxa. although they appear similar, crocodiles, alligators and the gharial belong to separate biological families. the gharial, with its narrow snout, is easier to distinguish, while morphological differences are more difficult to spot in crocodiles and alligators. the most obvious externa...

Source: Wikipedia