Extinction of megalodon shark may have increased whale sizes

A recent paper from PLOS ONE produced results that show the megalodon (the largest shark that has ever lived) became extinct approximately 2.6 million years ago.

There has been a lot of controversy surrounding the extinction of Carcharocles megalodon despite its widespread fossil record. Scientists believe they may have been up to 18 feet long although no entire shark has been found. Megalodon teeth have been found frequently along with mysticete fossils, suggesting that they perhaps preyed upon baleen whales (mysticetes).

The authors used the same methodology that has been previously used to estimate the extinction date of the dodo bird. These results contradict previous theories that the megalodon became extinct at a much later date and even that the shark still exists today. The most recent megalodon records of this species from databases and scientific literature were analysed and the time of its extinction was calculated using optimal linear estimation.

Interestingly, the modern mysticete composition differs to those that were contemporaneous with Carcharocles megalodon. The paper illustrates that the time of megalodon’s extinction coincided with the establishment of gigantic sizes of baleen whales. Its absence would have made way for the primitive baleen whales, which were smaller compared with their counterparts today. Body size correlates with ecological functions and so this may have resulted in additional niches being occupied by baleen whales.

It is fundamental to study the extinction of apex predators like the megalodon as they can trigger a cascade of effects through entire food webs and impact ecosystem composition and function. Knowing when a species became extinct can help better understand the consequences of loosing the ocean’s top predators. In modern marine systems, apex predators particularly large sharks, are declining rapidly throughout the world’s oceans.

Photo credit: Prehistoric Wildlife

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Lucy Grable

Lucy Grable

MSc Species Identification and Survey Skills student at Reading Uni | BSc Marine Zoology | Website Editor MARINElife | Zanzibar humpback whale researcher|Marine wildlife enthusiast

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