Research published in the journal Nature Communications now strengthens the hypothesis that competition for food was a key factor. Significantly smaller but still surviving sharks could have challenged Megalodon for food.
For the current study, the international research team led by Jeremy McCormack from the Max Planck Institute for Evolutionary Anthropology (MPI-EVA) in Leipzig and the Goethe University in Frankfurt am Main compared the ratio of different zinc isotopes stored in the teeth of modern and fossil shark teeth are. The samples came from all over the world – in addition to teeth from megalodon, those from modern and fossil great white sharks.
The analysis is comparable to the already widely used investigation of nitrogen isotopes in tooth collagen, the organic tissue in the teeth. This provides indications of whether an animal has fed mainly on animal or vegetable proteins. However, the collagen that is required for this is usually no longer present in fossil teeth.
“Both the megalodon and its ancestor were indeed apex predators,” says Michael Griffiths, a researcher at William Paterson University in New Jersey. This finding was to be expected due to the size of even growing animals. What is remarkable from the researchers’ point of view, however, is the composition of the zinc isotopes. “It suggests that the trophic levels of early great white sharks and the much larger megalodon largely overlapped.”
That would mean that the animals hunted the same prey. In the case of today’s great white sharks, these are mainly fish, squid and other sharks. Larger animals are also increasingly preying on marine mammals such as seals and dolphins. Great white sharks also eat carrion, like dead whales.
Today, however, the population of great white sharks, which are native to all oceans, is declining and is considered “highly fragmented”. The animals are usually caught unintentionally in nets and on hooks. On the Red List of the International Union for Conservation of Nature (IUCN) the stock is classified as “vulnerable”.
