New research could have us all re-writing the script on our assumptions of the largest shark that ever lived, because it turns out that – rather than feasting exclusively on other predators at the top of the ancient food chain – the Otodus megalodon (or the megalodon, for short) – tended to be far less particular, snacking on species at all levels of the web.

Evidence of this stark contradiction to popular belief has been published this week in the scientific journal Earth and Planetary Science Letters after international research led by a team from Goethe University in Frankfurt carried out a newly developed scientific analysis of the chemical element zinc in numerous fossil megalodon teeth.

Here’s what we know. The megalodon was the largest predatory fish the Earth’s history has ever witnessed; measuring up to 24 metres in length (longer than a truck with a trailer, says the German researchers), and weighing up to 100 tonnes. 

Its large mouth was equipped with hand-sized, triangular teeth which could bite with the force of an industrial hydraulic press.

Between 20 and 3 million years ago, it ploughed through the world’s ocean in search of prey in order to feed its estimated required 100,000 kilocalories each day.

Until now, it has been the wide scientific assumption that this was obtained primarily from whales. But scientists at Goethe University, alongside those from France, Austria, and the USA have discovered that the megalodon had a far broader prey spectrum than previously thought.

So, how did researchers come to this conclusion? To begin, they extracted the element zinc from the fossil megalodon teeth, an element which occurs in various heavy atomic variants (known as isotopes).

Zinc is absorbed through food, with less of the heavier isotope zinc-66 being stored in muscles and organs than the lighter isotope zinc-64.

Fish that eat other fish (which eat other fish themselves) can incorporate ‘significantly less zinc-66 into their tissue’, while those that hunt them as prey incorporate even less. By comparing the teeth of various prehistoric and modern shark species with each other and with another animal species, researchers have been able to gain a better insight into predator-prey relationships from 18 million years ago.

The large teeth came primarily from fossil deposits in Sigmaringen and Passau where, some 18 million years ago in the relatively shallow inlet of the sea less than 200 metres deep, where various other shark species alongside the megalodon.

“Sea bream, which fed on mussels, snails, and crabs, formed the lowest level of the food chain we studied. This was followed by smaller shark species such as requiem sharks and ancestors of our modern-day whales, dolphins, and other cetacean species,” said Dr Jeremy McCormack from the Institute of Geosciences at the Goether University.

“Larger sharks – such as sand tiger sharks – were even higher up the food chain, and the top was occupied by large sharks such as Araloselachus cuspidatus and the Otodus sharks, which include megalodon.

“Megalodon was certainly flexible enough to feed on marine mammals and large fish – depending on availability, both from the top of the food chain and from the lower levels.”

Rather than a species with a diet strictly specialised in marine mammals, the paleontologist suggests that the megalodon was an “ecologically versatile generalist.” Comparisons between the fossils from Sigmaringen and Passau, for example, have shown the Passau individuals ate more prey from the lower levels of the food pyramid, indicating regional differences in the prey spectrum or temporal changes in prey availability.

Applying the zinc analysis method to teeth fossils is a new and emerging science that has since been used to yield conclusive evidence not only for prehistoric shark and whale species, but also for herbivorous ancient rhinos and even modern-day sharks.

“This method can give us many more exciting insights into the lifestyles of prehistoric animals and provide clues to how marine communities have changed over geological time. Most importantly, it has shown us that even ‘super-feeders’ are not immune to extinction,” said Kenshu Shimada, a paleobiologist at DePaul University in Chicago and co-author of the study.

The 2025 study ‘Miocene marine vertebrate trophic ecology reveals megatooth sharks as opportunistic supercarnivores’ has been published in Earth and Planetary Science Letters.

Previous studies – including one led by McCormack – had shown that the appearance of the modern great white shark was, at least partly, responsible for the extinction of Otodus megalodon.

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