Why did the world’s biggest shark go extinct?

How do you tackle a giant shark with a 3-meter wide jaw, a 16-meter long body and a ferocious appetite? According to an international research team, the answer may be to simply take away its favourite food.

The giant shark species, Carcharocles megalodon is thought to have gone extinct 2.6 million years ago, after roaming the world’s oceans for over 14 million years. New archaeological evidence suggests the disappearance of dwarf whales and seals may have led to its downfall.

C.Megalodon has captured public imagination due to its awe-inspiring size and massive teeth. Its name is derived from ‘big tooth’, as the main archaeological evidence for its existence is its giant teeth. Some Megalodon teeth have been found to be as long as 7 inches!

New fossil evidence of abrasion and punctures caused by Megalodon teeth in small cetacean skulls indicate the giant shark’s appetite for dwarf whales. This is likely due to the difficulty and effort involved in catching larger prey.

The disappearance of Megalodon’s favourite food coincides with a time period characterised by the Northern Hemisphere glaciation, around 3 million years ago. A drive towards cooler climates had a detrimental impact on the coastal environments frequented by small whales.

Furthermore, the emergence of seasonal feeding grounds at high latitudes favoured the development of larger-sized whales capable of migrating to food rich poles. The combination of these two factors led to the extinction of dwarf whales and the rise of larger cetaceans, such as the blue and giant humpback whales.

The lack of smaller whales could have forced Megalodon to hunt for larger whales which are more difficult to catch. Ultimately, it was unable to cope with this change in feeding habits and was driven to extinction.

Researchers however, are still cautious about Megalodon’s appetite for smaller whales over larger ones. Dana Ehret, in an interview with New Scientist magazine, mentioned:

“I’ve seen a specimen from Virginia yet to be published of a fairly large baleen whale found with a Megalodon tooth lying on top of an indentation in the bone”.

Although it is clear that Megaladon have no problems feasting on larger whales, it is still uncertain whether it wasn’t simply just scavenging on their remains instead. More evidence is needed to corroborate Megalodon’s preference for smaller cetaceans over larger ones, and therefore establish this as the key reason for its extinction.

Andris Piebalgs is a PhD student in the Department of Chemical Engineering

Banner Image: Shark silhouette, Elias Levy