Whales

 Leviathan

This 16-meter long predator was a direct competitor with the Megalodon.

Its bite was even stronger than Megalodon's.

Some people say Leviathan was scarier than Megalodon.

Basilosaurus

The Basilosaurus was an early eel-shaped whale.

Ambulocetus

Ambulocetus was the origins of the whales

Its ears only functioned underwater.