What the megalodon's extinction can teach us about threats to present day sharks

TRANSCRIPT
The Megalodon: a giant ancient shark that died out around 2.6 million years ago. Fossil evidence suggests it was found across the planet, and at 60 feet long, it was the biggest shark, in fact, the biggest fish-of all time.
But what happened to the Megalodon? Why doesn't it exist today?
Based on their estimated size, it is thought that they needed to eat 2,500 pounds of food every day just to survive - that’s the equivalent of 2 entire cows, or 10,000 quarter pounders. It is thought that the main driver of their disappearance was that they ran out of food.
As the Great Ice Age approached and Earth cooled, shifting tectonic plates were also beginning to close the ancient seaways that used to exist between continents. This altered the currents in the ocean, disrupting the movements and feeding patterns of many of the huge animals alive at the time.
The reliable populations of prey the megalodon depended on, like whales and other marine mammals, started declining, possibly as part of these climatic changes. At the same time, smaller predatory sharks - including the ancestors of modern Great Whites - were becoming better competitors, meaning the megalodon probably just couldn’t catch enough food to sustain itself. Because when you’re as big as two London buses, you can’t survive on sardines.