Scientists have confirmed the size of the megalodon: the ancient shark grew to 24 metres
The Megalodon really was monstrously large. Scientists have re-examined the long-lost vertebrae of this ancient shark and confirmed the estimate: the largest specimens could have reached 24.3 metres in length — almost as long as two city buses.
These are the vertebrae of Otodus megalodon, a giant extinct shark that lived between approximately 15 and 3.6 million years ago. The specimen was found in Denmark back in the late 1970s, described in the scientific literature, and was then considered lost within museum collections for decades. The new study has been published in *Palaeontologia Electronica*.
Details
The fossils come from the Gram Formation in Denmark. The specimen is around 10.8 million years old. It was found in a large clay quarry in the late 1970s and scientifically described in the early 1980s.
The vertebrae were subsequently housed at the Geological Museum in Copenhagen, but were lost to view after being moved from the laboratory. Only photographs and old descriptions remained in the scientific literature. It was not until the late 2010s that a museum staff member noticed some mysterious boxes containing fossils in the collection — and so the lost Megalodon vertebrae were rediscovered.
The main significance of the discovery is that it confirmed the size of the largest vertebra: approximately 23 cm in diameter. According to the study’s author, Kenshu Shimada, these are not only the largest known shark vertebrae, but probably the largest fish vertebrae ever recorded.
How the size was estimated from the vertebrae
Teeth are the most commonly found remains of the Megalodon. Vertebrae are much rarer, which is why every such specimen is extremely important.
The size of 24.3 metres was not obtained by direct measurement of the body, but by calculation. Scientists compared the Danish vertebrae with a more complete set of Megalodon vertebrae from Belgium. In the Belgian specimen, the largest vertebra was about 15.5 cm in diameter, and the length of the shark itself was estimated at approximately 16.4 metres. The Danish vertebra turned out to be significantly larger — around 23 cm — and on this basis, the maximum length of the specimen was estimated at 24.3 metres.
The researchers emphasise that this does not mean all megalodons were this enormous. This is the most scientifically sound estimate for the largest known specimens. An article on the biology of the megalodon also states that 24.3 m is an estimate based on the Danish specimen, and that such a shark could have weighed around 94 tonnes.
What else have we learnt about this ancient shark?
Scientists used computed tomography to study the growth lines in the vertebrae. These lines function much like the annual rings in a tree: they can be used to estimate the animal’s age.
According to the new study, the megalodon to which these vertebrae belonged was at least 64 years old at the time of its death. The model also suggests that, theoretically, such sharks could have lived up to 96 years.
Another unexpected discovery: fragments of gill-related structures and tiny scales from another shark – a giant shark – were found in the rock surrounding the vertebrae. The authors believe this may have been the contents of the megalodon’s stomach. If this interpretation is correct, it would be the first such case recorded in the megalodon fossil record.
Why this is important
The megalodon was one of the largest predators in the history of the oceans. Its size is important not only for striking comparisons with buses or whales. Its body size determines how the animal hunted, how much energy it required, where it could have lived, and what impact it had on the ecosystem.
The new study is also significant because it confirms older data which, for decades, had been based almost exclusively on photographs. Scientists now once again have a physical specimen that can be measured, scanned and compared with other finds.
That said, the Megalodon’s appearance remains a matter of reconstruction. The authors of an earlier paper in *Palaeontologia Electronica* noted that no complete skeleton of the Megalodon has been found, so its body shape, length and mass remain estimates that may be refined as new discoveries are made.
Background
Megalodon was an extinct giant shark that lived in oceans around the world during the Miocene and Pliocene epochs. It is often referred to as the ‘monster shark’, but what is scientifically more significant is that it serves as an example of how a marine predator could reach gigantic proportions and dominate food webs.
Most Megalodon finds consist of teeth. These are well-preserved because they are highly mineralised. Vertebrae and other parts of the cartilaginous skeleton are much less likely to survive, which is why such specimens are particularly valuable.
This is precisely why the return of the Danish vertebrae to scientific analysis was such a significant event: it allowed researchers not merely to reiterate an old estimate, but to re-examine it using actual specimens.
Source
Study: Kenshu Shimada et al., “Rediscovery of the associated gigantic vertebrae of the extinct megatooth shark, Otodus megalodon, from the Upper Miocene Gram Formation in Denmark, and comments on its palaeobiological significance and the maximum possible size of the species”, *Palaeontologia Electronica*, 2026.