Extreme gigantism

Prehistoric shark surprisingly slim, according to researchers

The teeth of a megalodon at an exhibition in Germany

(Bild: dpa/Christoph Schmidt)

It's not good news for directors of gruesome shark films: the extinct megalodon mega-shark may not have been an enlarged version of the bulky great white shark, but a much slimmer creature. This is confirmed by another study.

This would have made the megalodon (technical name: Otodus megalodon) about six times as long as a great white shark. Its size would have been closer to that of a blue whale, and with an estimated weight of around 94 tons, it would also have been almost as heavy. According to the researchers, the megalodon's cylindrical body was probably designed for energy-efficient travel rather than high-speed hunting.

Megalodon as an extreme of gigantism
It probably had little in common with the massive predator seen in lurid films. "Gigantism is not just about getting bigger, but also about developing the right body to survive at that size," explained co-author Phillip Sternes. "And the megalodon was perhaps one of the most extreme examples of this."

The great white shark (pictured) probably bears less resemblance to the Magalodon than assumed.

(Bild: studio5050)

The prehistoric shark became famous through the science fiction films "Meg" and "Meg 2: The Deep", in which such giants emerge from the depths. No complete skeletons of the species, which lived around 15 to 3.6 million years ago and was widespread in the oceans almost worldwide, have yet been found, but mainly individual giant teeth and vertebrae. Scientists therefore have to rely on estimates to determine their size and shape.

Comparison of vertebrae provides new conclusions
Due to their similar serrated teeth, it was long assumed that megalodons and great white sharks were very similar. The team led by Kenshu Shimada from DePaul University in Chicago did not rely on tooth analyses, but compared the fossilized, approximately eleven-metre-long and almost complete spine of a megalodon with that of 165 living and extinct shark species in order to estimate the ratio of head, body and tail.

For this specimen, the scientists estimate a total length of a good 16 meters and a weight of around 30 tons. Based on other, much larger vertebrae found, they also assume that megalodons several decades old could have been more than 24 meters long.

A lemon shark

(Bild: BlueOrange Studio)

The team also looked at the proportions. Great white sharks (Carcharodon carcharias) have a stocky build that is favorable for fast movements, with a broad midsection that tapers sharply towards the tail. The megalodon, on the other hand, was probably something between a lightning-fast predator and a leisurely gliding traveler.

More like an oversized lemon shark
"It did not resemble an oversized great white shark, but rather a giant lemon shark with a slender, elongated body," explained Sternes. This shape makes much more physical sense for such a large animal to be able to move efficiently through the water. Modern basking sharks such as the whale shark (Rhincodon typus) and the basking shark (Cetorhinus maximus) as well as other giant aquatic vertebrates such as whales also have slender bodies.

As a newborn, a megalodon may already have been three and a half to four meters long and thus as large as many adult sharks of today's species. "It is quite possible that megalodon young were already hunting marine mammals shortly after birth," says Sternes.

Only a new find will bring clarity
All of their interpretations are working hypotheses and still preliminary, the researchers also emphasize - ultimately, only the discovery of a complete skeleton will bring certainty. The results support an earlier analysis by the team with Phillip Sternes as first author. Computer tomography scans of the vertebrae of a great white shark and data on the megalodon from earlier studies were used. These results alone suggested that the megalodon was not simply a giant version of the modern great white shark.