Paleontologists have figured out why megalodons died out

A team of paleontologists led by Jeremy McCormack of the Max Planck Institute for Evolutionary Anthropology have found evidence that competition with great white sharks may have contributed to the extinction of the megalodon, the largest shark that ever lived on Earth.

Found in oceans around the world from 23 to 3.6 million years ago, Otodus megalodon grew up to 20 meters long and weighed up to 103 tons, making them perhaps the most powerful predators in history. And the famous great white shark reaches a length of only 6 m and weighs about 2,200 kg. However, recent studies of zinc isotopes in the teeth of modern and fossil great whites and megalodons have shown that both species fed similarly.

Isotopic analysis is a very powerful tool for understanding dietary intake because differences in ratios isotopes of one or another element make it possible to trace the sources of food consumed by the animal, and the place in the food chains. It also allows inferences to be made about the animal's lifestyle and helps shed light on mysteries such as interspecies competition for prey.

Studying teeth sharks early Miocene (20.4 to 16 million years ago) and early Pliocene (5.3 to 3.6 million years ago), and then comparing them with modern sharks, scientists discoveredthat modern and ancient zinc isotope measurements were nearly identical.

The megalodon ancestor from the Miocene (about 16 million years ago), the species Otodus chubutensis, had a low ratio of zinc isotopes. And in the samples of megalodons that lived in the Atlantic Ocean about 5 million years ago, the proportion of zinc increased markedly. This means they were no longer at the top of the food chain.

A low amount of zinc suggests that a significant part of the diet is muscle tissue. And accordingly, the more prey the predator has, the less it should have the proportion of this isotope in the body. Less zinc means higher in the food chain.

Fossil white sharks from the time of megalodon contain the same low levels of zinc as the ancient species Otodus chubutensis. This means that white sharks did not eat less and worse over time - they took a dominant position in the food chain.

Paleontologists concluded that both sharks competed for the same prey, such as whales or other large ocean creatures. The size of the megalodon and its energy requirements, with a decrease in the amount of available prey, became a serious threat to the survival of the species and eventually led to its extinction.