Crocodiles (subfamily Crocodylinae) or true crocodiles are large aquatic tetrapods that live throughout the tropics in Africa, Asia, the Americas and Australia. Crocodylinae, in which all its members are considered true crocodiles, is classified as a biological subfamily. A broader sense of the term crocodile, Crocodylidae, that includes the tomistoma, was excluded in this article since new genetic studies reveal the possibility of tomistoma as a close relative of the gharial. This article applies the term crocodile only to the species within the subfamily of Crocodylinae. The term is sometimes used even more loosely to include all extant members of the order Crocodilia: which includes all members of Crocodylidae, including the tomistoma, the alligators and caimans (family Alligatoridae) and the gharials (family Gavialidae), and the rest of Crocodylomorpha, which includes all of the prehistoric crocodile relatives and ancestors. Although they appear to be similar to the untrained eye, ...