Megalodon was slimmer than depicted in films, study finds

A new study shows that Megalodon, a gigantic shark that died out 3.6 million years ago, was more slender than previous studies suggested. This discovery changes scientists’ understanding of Megalodon behavior, ancient marine life and why sharks became extinct.

The megalodon or megatooth shark is commonly depicted as a large monster in popular culture, with recent examples in the science fiction films “The Meg” (2018) and “Meg 2: The Trench” (2023). Previous studies speculate that the shark probably reached a length of at least 50 feet and possibly up to 65 feet.

However, Megalodon is only widely known from its teeth and vertebrae in the fossil record – a rather incomplete data set from which to draw hypotheses. Thus, the modern great white shark was traditionally used as a model for Megalodon bodies in earlier studies. This pattern led researchers to conclude that the shark was round and stocky like great whites.

“Our team re-examined the fossil record and found that Megalodon was thinner and perhaps even longer than we thought. Therefore, a better model might be the modern mako shark,” said Phillip Sternes, a biologist at UCR and first author of the article. “It would still have been a fearsome predator at the top of the ancient marine food chain, but it would have behaved differently based on this new understanding of its body.”

For the new study published in the journal Electronic paleontology, A team of 26 scientists from around the world, co-led by Kenshu Shimada, a professor of paleobiology at DePaul University and Sternes, took inspiration from differences in previously estimated body lengths of megalodon.

“It was a eureka moment when our research team realized the discrepancy between two previously published lengths for the same Megalodon specimen,” Shimada said.

The team then looked at a new comparison of Megalodon vertebrae fossils with those of related lamniform sharks. “We measured the entire vertebral skeleton of a living great white shark with a CT scan and compared it to the previous reconstruction of the Megalodon spine,” Sternes said.

“It was still a giant predatory shark. But the results strongly suggest that Megalodon was not simply a larger version of the modern great white shark.”

A revised understanding of Megalodon’s body type would in turn affect scientists’ understanding not only of the giant shark itself, but also of its impact on the ecology and evolution of marine ecosystems that have shaped today’s oceans.

There is no doubt that the Megalodon is one of the largest marine predators to have ever lived. But a thinner, more elongated body would suggest that Megalodon also had a longer digestive canal. Sternes explained that in this case, the sharks might have benefited from better absorption of nutrients and might not have had to eat as often as previously thought.

“With an increased ability to digest its food, it could have gone longer without needing to hunt. This means less predation pressure on other sea creatures,” Sternes said. “If I were to eat just one whale every once in a while, whale populations would remain more stable over time.”

Some shark scientists have hypothesized that a natural decline in prey numbers led to the extinction of megalodons. However, Sternes has another theory, partly supported by the revised understanding of its form.

“I think there was a combination of factors that led to the extinction, but one of them may have been the emergence of the great white shark, which was perhaps more agile, making it made an even better predator than Megalodon,” Sternes said. “This competition for food may have been a major factor in its disappearance.”

The research team of shark experts from the United States, United Kingdom, Austria, France, Japan, Mexico, Brazil and Australia believes that a revised understanding of marine life ancient would have a cascading effect on the oceans still visible today.

“Now that we know it was a slimmer shark, we need to re-examine its lifestyle, how it actually lived and what caused its death,” Sternes said. “This study represents a major stepping stone for others to follow up on.”