The megalodon (Otodus megalodon), extinct for 3.6 million years, is often depicted as a monstrous, oversized shark in science fiction novels and films, including Megajaws (2018) and Megajaws 2 (2023). But now researchers have discovered that the animal was not as large as previously thought.
In a study published this Monday (22) in the journal Palaeontologia Electronica, a team of 26 scientists from several countries, including Brazil, discovered that the megalodon was slimmer than previous studies suggested.
Until then, research estimated that the species reached a length of between 15 and 20 meters. Since the megalodon is known primarily from its teeth and vertebrae in an incomplete fossil record, the modern great white shark has traditionally served as a model for its body size.
This model led researchers to conclude that Megalodon was round and chunky, like great white sharks. However, when comparing the extinct shark's fossil vertebrae with those of living relatives of the lamniform sharks, the authors found that this was not the case.
“Our team reexamined the fossil record and found that Megalodon was slimmer and possibly even longer than we thought,” study lead author Phillip Sternes, a biologist at the University of California at Riverside in the United States, said in a statement Explanation . “So a better model might be the modern mako shark.”
Sternes says that the team which includes Brazilians João Paulo CB da Silva, researcher at the Federal University of Paraíba (UFPB); and Hugo Bornatowski, professor at the Federal University of Paraná (UFPR) measured the entire vertebral skeleton of a living great white shark with a CT scanner and compared it with the previous reconstruction of the megalodon spine. The results suggest that the prehistoric creature was not just a larger version of today's great white shark.
However, the megalodon is still one of the largest sea predators that has ever existed. A slimmer, more elongated body suggests that the animal also had a longer digestive canal. Sternes explains that in this case the creature may have had increased nutrient intake and may not have needed to be fed as often as previously thought.
2 of 2 UC Riverside biologist and first author of the study, Phillip Sternes, holds a Megalodon tooth Photo: Douglas Long/California Academy of Sciences UC Riverside biologist and first author of the study, Phillip Sternes, holds a Megalodon tooth Megalodon Photo : Douglas Long/California Academy of Sciences
“With a greater ability to digest its food, it could have survived longer without hunting,” the researcher suspects. “This means less predation pressure on other marine life. If I only had to eat a whale every now and then, whale populations would remain more stable over time,” he explains.
Why is Megalodon extinct?
One hypothesis put forward by scientists to explain the extinction of megalodons is the natural reduction in their prey. However, Sternes believes that one of the factors that contributed in part to the change in shark size was the emergence of the great white shark, which may have been more agile and evolved into an even better predator than the megalodon. “This competition for food may have been an important factor in its disappearance,” he speculates.
Scientists previously reported incomplete vertebrae of a megalodon with a total vertebral length of 11.1 meters. However, another study found that the same fossilized individual was only 9.2 meters long, including the head.
“It was a 'Eureka' moment when our research team noticed the discrepancy between the two previously published lengths for the same Megalodon specimen,” reported coleader of the new research Kenshu Shimada, a professor of paleobiology at DePaul University in Chicago ( UNITED STATES). ). ).
The discovery changes what is known about megalodon behavior, ancient sea life and the reasons for shark extinction. “In the future, any meaningful discussion about the body shape of O. megalodon may require the discovery of at least one complete or nearly complete skeleton of the species in the fossil record,” says Jake Wood, coauthor of the study.
“Despite the great scientific progress in our new study, the fact that we still don't know exactly what O. megalodon looked like stimulates our imagination,” says Shimada. “A persistent mystery like this makes paleontology, the study of prehistoric life, a fascinating and exciting scientific field.”