Crocodiles are reptiles that still look very much like their ancient ancestors from 300 million years ago. The earliest crocodile ancestors were all terrestrial, before some ventured to feed in the water, or at the water’s edge, but crawled back onto land to bask and lay eggs. Only 23 species of aquatic crocodile relatives (Order Crocodilia) exist today, including those that we call crocodiles, alligators or caimans, and gharials. This group of existing crocodile relatives first evolved about 120 million years ago. The bodies and snouts may be more elongated than their ancestors, but they still have big teeth, four feet with claws and a long tail. Crocodile relatives have large scales on their skin, and large bony plates underneath. By about 65 million years ago, the terrestrial lineage became extinct.
One of the photos here shows that these animals can use their powerful tails to launch their heads and feet entirely above the water’s surface.