The evolutionary history of crocodilians is a very ancient one, reaching back to the Triassic period. The oldest known true Crocodilians (now extinct) dates back 200 million years .

The common term crocodile was arrived from the Greek word “krokodeilos”, meaning lizard. Even though modern Crocodilians features primitive external morphology, they are the most advanced of all reptiles.

The family ‘Crocodilians’ are normally divided into three groups considered as subfamilies. These subfamilies are the Alligatorinae (7 Caiman species and Alligators), Gavialinae (one specie, Gharials) and Crocodylinae (12 species) to which the Nile crocodile specie (Crocodylus Niloticus) belong. The Nile crocodile is thus one of the 12 Crocodylus species considered to be the “True Crocodiles”.