Why did megalodon go extinct? New study outs unexpected culprit (2024)

The great and mighty megalodon was one of the biggest fish to ever have lived, insofar as we know, and was likely the apex predator of its time. This giant of the “megatooth shark” family roamed the oceans until a few million years ago. It was the king of the seas – and then it was gone.

Why? One recent theory suggested that megalodon died off during a mass extinction event caused by a supernova 150 light years away that irradiated and heated our planet 2.6 million years ago. Research indicated that the radiation would have penetrated into the deep seas and persisted for years, killing animals en masse. Indeed, what other than cosmic catastrophe could have vanquished a marine monster of that magnitude?

One snag is megalodon went extinct as much as a million years before the supernova, paleontologists estimate.

Now a new study published Tuesday in Nature Communications supports the theory that one culprit lending to megalodon’s extinction was the great white shark, whose ancestors plied the seas in parallel with the megatooth sharks.

It isn’t suggested that great whites attacked megalodon in shark packs, though it has recently been postulated that some shark species do in fact form faux-cooperative relationships as they hunt. Megalodon’s problem lay elsewhere.

The megalodon was a titan among sharks: it could reach as much as nearly 60 feet (18 meters) in length and weigh as much as 50 tons, paleontologists suggest. It had a fearsome bite, but size comes with a price.

The greatest great whites were about a third of its size, today averaging about 15 feet in length. Think of it this way: what is zippier, an elephant or a hyrax?

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One of multiple causes of megalodon’s extinction may have been competition over food, explain Jeremy McCormack of the Max Planck Institute for Evolutionary Anthropology and colleagues, as deduced from analyzing zinc isotopes in the enamel of fossil shark teeth as an indication of diet.

Note the challenge inherent in elucidating what animals ate millions of years ago, even when one finds telltale bite marks that can’t be anything else on the prey’s skeletal remains. That is extremely rare.

Shark skeletons are made of soft cartilage, not bone, and most of what survives in the fossil record of sharkdom is teeth. When teeth grow, as they do throughout a shark’s life, they incorporate the essential mineral zinc that they get from their food, the team explains.

The team managed to demonstrate that dietary zinc isotope signals are preserved in the shark teeth over deep geological time, and could shed light on what they ate and on the sharks’ position in the ecology.

Crucially to their thesis, they deduce that two different species of megatooth shark – one being said megalodon – and great whites coexisting in the Early Pliocene occupied roughly the same position in the food chain (the same “mean trophic level”).

In other words, the ecological footprint of these sharks overlapped; they were likely vying for food, including marine mammals such as cetaceans and seals; and the wee great white – everything being relative – was plausibly nimbler than the monstrous megalodon.

Combine that competitive pressure with other elements, including climate and environmental changes, possibly the collapse of prey populations, and megalodon abruptly died off while the great white prevailed, they suggest.

Did the great white outcompete the megalodon to the point of its extinction? One cannot say that for sure, but being more agile in the sea could have translated into a killer advantage when the seals and meals grew scarce, and the great whites may have played a part in the Meg’s extinction.

And thus, great whites continue to speed through the seas, and very occasionally attack people, and models of them may star in “Jaws” knockoffs to this very day, while megalodon is gone except in cheesy sci-fi flicks.