Prehistoric shark jaws. Fossilised jaws of a Carcharodon (or Carcharocles) Megalodon. This prehistoric megatoothed shark was an enormous predator that lived from the Oligocene to Pleistocene epochs (about 25 to 1.5 million years ago), and was thought to attain lengths exceeding 20 metres, and possibly significantly larger. It was related to the modern great white shark, and is thought to have fed on whales, as this is the only source of food that could have provided it with enough meat.