Up to 16m in length, Megalodon was the largest shark ever. It lived only a few million years ago, the time that the earliest humans envolved. Megalodon is a close relative to the present days great white shark, only much bigger. Like the great white, it was probably warm-blooded and preyed on marine mammals. Its favourite food was whale, It attacked its prey near the surface, when it came up for air.
Like with most sharks, only the teeth of Megalodon are being found, because the cartilaginous skeleton of sharks does'nt get fossilized. Megalodons teeth where 21cm long, it really was the top predator of its time.