Big fish don't always eat small fish. Until about three million years ago, the king of the seas was the megalodon (Carcharocles megalodon), a huge shark up to 20 meters long. But something happened then that made it extinct, leaving its crown to the great white shark (Carcharodon carcharias). Some theories blame climate change for the extinction. Others point to the decline of their main prey, whales. A third group of scholars points to the emergence of new competitors for resources, such as the early ancestors of killer whales. But analysis of the teeth of large fish from the past and present now raises another possibility: great white sharks and megalodons competed for the same food, and the former won.
