Crocodiles, alligators, caimans and the related gharials - are reptiles adapted for an aquatic way of life. They are powerful swimmers, but also spend some of their time on land, basking in the sun. By moving back and forth between water and land, they can keep their bodies at an optimum temperature as the day heats up or the night cools down.
Scientific name: Crocodilia
The shading illustrates the diversity of this group - the darker the colour the greater the number of species. Data provided by WWF's Wildfinder.
Discover the other animals and plants that lived during the following geological time periods.
The Crocodilia (or Crocodylia) are an order of large reptiles that appeared 83.5 million years ago in the Late Cretaceous period (Campanian stage). They are the closest living relatives of birds, as the two groups are the only known survivors of the Archosauria. Members of the crocodilian total group, the clade Pseudosuchia, appeared about 250 million years ago in the Early Triassic period, and exhibited a wide diversity of forms during the Mesozoic era.
The order Crocodilia includes the true crocodiles (family Crocodylidae), the alligators and caimans (family Alligatoridae) and the gharials (family Gavialidae). Although the term 'crocodiles' is sometimes used to refer to all of these, a less ambiguous vernacular term for this group is 'crocodilians'.
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