By: Elliott Chu

The massive Otodus Megalodon sharks—the ocean’s largest-ever meat-eaters—ran hot. Now, studies show that their rise and fall might have been because of their warm-bloodedness. Research shows that because they were warm-blooded, the sharks needed lots of prey to give themselves enough energy to survive. Because of their voracious appetite, they ate enough fish to drive the population into scarcity. Without enough fish to eat, the sharks slowly became extinct.

Chemical measurements of the O. Megalodon teeth suggest the sharks had higher body temperatures than surrounding waters. Analyses on the carbon and oxygen in the teeth revealed that sharks needed to maintain a high body temperature, unlike other fish. The warm-bloodedness trait helped the megalodons become swift, fearsome apex predators. The megalodons grew to about 20 meters, making them one of Earth’s biggest carnivores.

The megalodon’s body was gigantic, so it needed to maintain a high metabolism to survive. In order to do so, the sharks had to eat lots of food. “Massive sharks may have been particularly vulnerable to extinction when food became scarce,” says Robert Eagle, a marine biogeochemist.

Mammals, which are warm-blooded, can boost their metabolisms and maintain their body heat even in colder environments. Some families of fish, either existing or extinct, have a similar trait that lets them keep some body parts warmer than the surrounding water. “Jacking up the temperatures of some body parts are some ways that sharks evolved to be giant,” says Jack Cooper, a paleobiologist.

The Megalodon evolved around 23 million years ago. It went extinct between 3.5 and 2.6 million years ago. Great white sharks emerged late in megalodon’s reign, roughly 3.5 million years ago. They competed for food with their massive cousins. Being smaller than the megalodon and being cold-blooded, the great white sharks need less food to survive. This competition helped drive the megalodons to extinction.