The two apex predators occupied similar places in the food chain. And the mighty and much larger megalodon ultimately lost out.

Scientists are still wondering how such a mighty animal like the terrifying megalodon disappeared from the face of the earth. Between 23 and 3.6 million years ago, this prehistoric monster shark, which could grow up to 20 meters in length, ruled the oceans. In comparison, the largest white sharks reach a length of only six meters. Yet the latter inhabit the oceans to this day and megalodon is extinct. And the great white shark may be partly to blame, it suggests a new study†

Diet and Competition

Meanwhile, many factors have been discussed to explain the gigantism and extinction of megalodon. Its diet and competition are often identified as the main causes. Researchers are now building on this in a new study. Although many of the fossil remains of megalodon have unfortunately not survived the test of time, we do have some large, triangular teeth, which a research team has subjected to a thorough inspection.

Zinc content

The researchers analyzed the zinc content in megalodon fossil teeth and compared it to that of modern-day white sharks. This zinc content, which can be found in tooth enamel – the protective layer on the teeth – reveals an animal’s diet over a long period of time. And from that, researchers can determine again where it occupies in the food chain.

A tooth of the extinct megalodon next to that of the great white shark. In particular, notice the huge difference in size. Image: MPI for Evolutionary Anthropology

The researchers make an interesting discovery. Because the zinc isotopes studied reveal that megalodon and the white shark occupied the same position in the food web. And so they were probably big competitors. “Remarkably, the zinc content suggests that the early white shark’s position in the food web largely overlaps with that of the much larger megalodon,” said study co-author Michael Griffiths. This implies that the two apex predators probably targeted the same prey and regularly had to compete against each other.

Confirmed

These findings confirm previous theories that the great white shark had a hand in the megalodon disappearance. Some scientists have already pointed an accusing finger at the great white shark. Great white sharks, with their signature serrated-edged teeth, surfaced about 6 million years ago. At first only in the Pacific, but around 4 million years ago they had actually colonized all the oceans. It would mean that great white sharks and megalodon lived side by side for a while. And that would have become too much for the megalodon; the white shark was too strong a competitor.

Incidentally, the entire life of megalodon already consisted of competition. An earlier study by the same researchers shows that unborn megalodons may have been guilty of cannibalism. The embryos may still go for a walk and regularly treat their brothers and sisters who are in the other womb to a visit. The strongest embryos then eat their unborn brothers, sisters and the unfertilized eggs. The result is that only a few embryos survive and are born significantly larger; this is how baby megalodons with a staggering length of two meters were born.

Thanks to the study, we are getting a little better understanding of what ultimately killed the impressive shark. And that the great white shark may have been at least partly to blame for this seems increasingly plausible. “While additional research is needed, our results appear to support theories of dietary competition between megalodon and white sharks,” said study researcher Kenshu Shimada.

In addition, the study shows that analysis of zinc levels in tooth enamel can effectively reveal the diet and position in the food web of long-extinct animals. “This method could now be applied to other fossil animals,” said study researcher Jeremy McCormack, “including our own ancestors.”