Physogaleus were prehistoric sharks from the Eocene Epoch. They were one of the most fearsome creatures of their time, and their only true predator was the huge and ferocious ancient whale, Basilosaurus.
They were around 2 metres long and ate mostly fish, but they would attack other animals, like the primate Apidium.
Physogaleus made an appearance in the 2003 book version of Sea Monsters: A Walking with Dinosaurs Trilogy, where it it is attracted to dead Dorudon, killed by the Basilosaurus.
In Walking With Beasts, in the episode Whale Killer, the Physogaleus (although unidentified) played a minor role. In the beginning of the episode, at least two are eaten by a Basilosaurus, and later, in the mangrove swamp, one kills and eats an Apidium in a savage ambush attack (as seen on the picture) Later on in the episode, a few of these sharks pass by Moeritherium in the water; though they are no threat to the strong and bulky herbivore.