Megalodon was NOT cold-blooded, study finds
The thought of an 18-metre (59ft) shark with teeth as big as your hand is enough to send a chill down your spine. But megalodon, the largest marine predator that ever lived, was no cold-blooded killer, a study suggests. Analysis by environmental scientists has revealed the terrifying shark was warm-blooded and could regulate its body temperature. Based on analysis of tooth enamel, researchers found the ancient species could maintain a body temperature of about 7C (13F) warmer than the surrounding water. The temperature difference is greater than other sharks that lived alongside the megalodon and is large enough to count the shark as warm-blooded, the experts said. And the discovery could help explain why it went extinct 3.6 million years ago as it needed to use so much energy to stay warm. Previous studies suggest the megalodon reached lengths of at least 50 feet (15 meters) . Lead researcher Robert Eagle, an assistant professor of atmospheric and oceanic sciences at the University of California, Los Angeles, said: Studying the driving factors behind the extinction of a highly successful predatory shark like megalodon can provide insight into the vulnerability of large marine predators in modern ocean ecosystems experiencing the effects of ongoing climate change. Megalodons belonged to a group of sharks called mackerel sharks. Members of that group today include the great white and thresher shark. While most fish are cold-blooded, with body temperatures that are the same as the surrounding water, mackerel sharks keep the temperature of all or parts of their bodies somewhat warmer than the water around them. Megalodons warmer body allowed them to move faster, tolerate colder water and spread out around the world. But it was that evolutionary advantage that might have contributed to its downfall, the researchers wrote. The megalodon lived during the Pliocene Epoch, which began 5.33 million years ago and ended 2.58 million years ago. Global cooling during that period caused sea level and ecological changes that the megalodon did not survive. Randy Flores, who also worked on the study, said: Maintaining an energy level that would allow for megalodons elevated body temperature would require a voracious appetite that may not have been sustainable in a time of changing marine ecosystem balances when it may have even had to compete against newcomers such as the great white shark. The findings were published in the Proceedings of the National Academy of Sciences journal. It follows a study last year that concluded the exact length the megalodon reached was actually . The extinct creature grew to larger sizes in comparatively cooler environments, such as North Carolina and Peru, than in warmer areas, like in Florida and Panama. The findings align with a principle known as Bergmanns rule, where animals found in colder climates are often larger as a greater size allows them to retain more heat. The megalodon, whose name means 'big tooth', is typically portrayed as a super-sized, monstrous shark in novels and films such as the 2018 sci-fi film 'The Meg'. While there is no dispute that they existed or that they were gigantic, the megalodon (officially called Otodus megalodon) is known only from ancient fossilised teeth and vertebrae. Academics are hopeful that , which could conclusively reveal what it looked like.