WHITE SHARKS WOULD HAVE COLLABORATED TO MEGALODON’S EXTINCTION
Megalodon is recognized by researchers as the largest shark that ever existed in the seas of planet Earth. However, its teeth larger than the palm of a hand, its mouth as big as a train door, and its length reaching 18 meters may not have been enough against its smaller relatives, the white sharks. At least that’s what a recent study published in Nature Communications shows.
The two species coexisted during the Pliocene period — between 2.6 million and 5.3 million years ago — and likely hunted the same prey. “Our new study shows that in the Pliocene the diet of the great white shark was very similar to that of the megalodon, indicating that our data do not contradict the hypothesis of competition between species,” said professor of paleobiology at DePaul University and co-author of the study, Kenshu Shimada.
For co-author and University of William Paterson professor Michael Griffiths, white sharks may have had an important advantage. “Because they were smaller, they possibly didn’t need as much food as megalodons,” said Griffiths. This would have given great white sharks a competitive advantage if they were feeding on the same prey as the sea giant.
To reach their conclusion, the scientists needed to analyze the presence of different zinc isotopes preserved in the enamel of collected teeth. As reported by CNN, it was the first time that this type of diet-related signature was proven in fossilized shark teeth, with 13 teeth from extinct species and 20 teeth from modern species being analyzed by the team.
Zinc is a key element for the development of organisms and plays a fundamental role in bone evolution. The ratio of heavier and lighter zinc isotopes shows what types of animal matter sharks used to feed on. “The ratio between the different isotopes changes as you move up the food chain,” explains Griffiths.
In other words, according to the study, if the megalodon fed on the great white shark, its higher position in the food chain would be reflected in the zinc analysis. However, the two species were found to have similar zinc patterns, suggesting that their diets were similar.
The research also indicates that the similar feeding between the two species does not necessarily mean that there was direct competition between the megalodon and the great white shark, as the two may have specialized in different prey, but they also shared similar foods.
Most reconstructions show this prehistoric fish as a gigantic great white shark. “The megalodon is usually portrayed as a huge, monstrous shark in stories and movies. But in reality we know very little about the extinct animal,” Shimada told CNN.
Even with the well-founded competition hypothesis, the team of researchers does not rule out the possibility that the extinction of megalodons occurred due to other factors, such as climate change and the collapse of their prey.