For around 20 million years, the megalodon ruled the oceans - a gigantic shark up to 20 meters long. But then the giant suddenly disappeared. Researchers have long puzzled over its extinction. With a new method, a possible cause is now coming into focus.
Up until a few million years ago, a huge shark was up to mischief in the world's oceans: the megalodon (Otodus megalodon) could reach a length of up to 20 meters. The largest great white sharks alive today are only about a third as big with a total length of six meters. But then Megalodon disappeared 3.6 million years ago, after a reign of around 20 million years. Its extinction has long been considered a mystery. Now researchers have discovered new clues - and of all things the smaller white shark could have played a role.
Researchers found clues in the teeth of the sea predators. An international research team examined modern and fossil shark teeth from around the world - including teeth of megalodons and modern and fossil great white sharks - for the ratio of stable isotopes of the element zinc. This new method can be used to determine which place in the food chain (trophic level) an animal occupied. The researchers wanted to find out what interactions there might have been between the shark species and their ecosystem.
"Our results show that both the megalodon and its ancestor were indeed apex predators, feeding high up in their respective food chains," says Michael Griffiths, a professor at William Paterson University, according to a statement from the Max Planck Institute for evolutionary anthropology in Leipzig. "But what's really remarkable is that the zinc isotope values of early Pliocene shark teeth from North Carolina suggest that the trophic levels of early great white sharks and the much larger megalodon largely overlap."
This suggests that the megalodon competed with great white sharks for food. "Our results suggest at least some overlap in the prey hunted by both shark species," said Kenshu Shimada, a professor at DePaul University in Chicago. "Although the topic deserves further research, our results highlight the possibility of foraging competition between megalodon and the early Pliocene great white sharks."
The extinction of the megalodon could therefore have something to do with competition from the great white shark, the researchers write in their study published in the journal "Nature", but also with other competitors such as toothed whales, which were not the subject of the analysis. However, other factors such as climate change or the disappearance of prey may also have contributed to ending the reign of the basking shark.