A new study by a team of shark experts challenges the common assumption that megalodon, the largest shark ever, was a giant version of the modern great white shark.
Megalodon’s body shape
Megalodon (Otodus megalodon) was one of the most formidable predators in Earth’s history, reaching lengths of up to 24 meters and weighing more than 50 tons. However, its appearance and lifestyle have been largely based on speculation, as no complete skeleton has ever been found. Only its teeth and some vertebrae have been preserved in the fossil record.
For decades, scientists have used the great white shark (Carcharodon carcharias) as a model for megalodon’s body shape, assuming that they were closely related and had similar adaptations. However, a new study published in Palaeontologia Electronica by 26 shark experts from around the world challenges this view and proposes a different reconstruction of megalodon based on new fossil evidence and biomechanical analysis.
The study’s lead author, Kenshu Shimada, a paleobiologist at DePaul University in Chicago, says that using the great white shark as a template for megalodon is problematic because it relies on “tenuous assumptions” about their evolutionary relationship and scaling factors.
Shimada and his colleagues reexamined a partial fossilized vertebral column of megalodon housed in a Belgian museum, which was previously used by another team of researchers to estimate its body length at 15.9 meters. The new study found that this specimen was incomplete and missing many vertebrae at both ends of the column. Moreover, the study found that megalodon’s vertebrae were relatively thin and weak compared to those of great white sharks, suggesting that it had a more slender body shape and less muscular power.
According to Shimada, megalodon’s body shape was more similar to that of modern thresher sharks or pelagic sharks, which are long and streamlined for efficient swimming over long distances. He estimates that megalodon could reach up to 24 meters in length, making it 20 percent longer than previously thought.
Megalodon’s hunting strategy
The study also implies that megalodon had a different hunting strategy than great white sharks, which are known for their ambush attacks on seals and other prey from below. Great white sharks rely on their powerful muscles and fast acceleration to deliver devastating bites with their serrated teeth, often severing limbs or causing massive blood loss.
Megalodon, on the other hand, may have been more of a pursuit predator, chasing down large whales and other marine mammals over long distances. Its teeth were not serrated but smooth-edged, indicating that it used them to grasp and hold onto its prey rather than slicing through flesh. Megalodon may have also used its massive body size to ram or crush its prey with brute force.
Charles Underwood, a co-author of the study and a paleontologist at Birkbeck, University of London, says that megalodon’s hunting style was “less of an ambush predator” and “more straight pursuit”. He adds that megalodon “wouldn’t be hovering over the sea floor waiting for a whale to move above it and then slamming into it from below”.
Megalodon’s extinction
Megalodon ruled the oceans for about 20 million years, from the early Miocene to the late Pliocene epochs. However, it went extinct around 3.5 million years ago, leaving behind only its fossilized teeth and vertebrae as clues to its existence.
The exact cause of megalodon’s extinction is still debated, but some possible factors include climate change, competition with other predators, and decline in prey availability. The study suggests that megalodon’s body shape and hunting strategy may have also contributed to its demise, as it was less adaptable to changing environmental conditions than its smaller and more agile relatives.
Shimada says that megalodon’s extinction is “a reminder that even the most seemingly invincible animals are ultimately vulnerable to environmental changes”.