The megalodon, this extinct giant of the seas, may not have been the stocky colossus we thought. A new study suggests that this legendary predator had a longer and more slender body, resembling more a lemon shark than a great white shark.
This revision of the megalodon's morphology is based on a thorough analysis of fossils and comparisons with more than 170 species of sharks, both modern and extinct. Researchers used fossilized vertebrae to estimate the size and shape of this marine monster, challenging previous hypotheses based on simplistic analogies with the great white shark.
A new method to estimate the size of the megalodon
Scientists examined a partial megalodon spinal column discovered in Belgium, measuring about 11 meters (36 feet). By comparing these remains with the body proportions of numerous shark species, they estimated that this specimen was about 16 meters (52 feet) long, with a head of 1.8 meters (5.9 feet) and a tail of 3.6 meters (11.8 feet).
By extrapolating from even larger vertebrae found in Denmark, researchers calculated that some megalodons could reach up to 24 meters (79 feet) in length. This estimate makes it one of the largest marine predators to have ever existed, rivaling the blue whale in size.
This method, based on comparisons with more than 170 species of sharks, both modern and extinct, offers a more accurate approach than previous hypotheses. It allows for a better understanding of the actual proportions of the megalodon, without being limited to simplistic analogies with the great white shark.
A body adapted to deep-sea swimming
Unlike the great white shark, whose stocky body is designed for bursts of speed, the megalodon would have had a more hydrodynamic morphology. This slender shape, similar to that of lemon sharks or whale sharks, would have allowed it to move more efficiently over long distances in the oceans.
a) Silhouettes of the lemon shark (Negaprion brevirostris), the great white shark (Carcharodon carcharias), and the common porbeagle (Lamna nasus) in lateral (gray) and dorsoventral (black) views.
b) Hypothetical morphologies of the sharks in (a) after applying a fineness ratio of 6.15.
c) Conceptual and highly hypothetical reconstruction of Otodus megalodon with a fineness ratio of about 6.08, superimposed on a silhouette of its reconstructed spinal column. Silhouettes of human swimmers illustrating its relative size.
This adaptation is essential for a predator of this size, as a massive body would have made swimming too energy-consuming. Researchers estimate that the megalodon moved at a moderate speed, reserving its accelerations for hunting prey. This swimming strategy would have allowed it to cover long distances without exhausting its energy resources too much.
This slender morphology also suggests that the megalodon was an enduring predator, capable of tracking its prey across vast oceanic expanses. This characteristic, combined with its imposing size, made it a formidable hunter, perfectly adapted to its role as a superpredator of prehistoric seas.
The implications of this discovery
This new vision of the megalodon sheds light not only on its appearance but also on its lifestyle. A longer and thinner body suggests that it covered vast distances to hunt, rather than relying on quick and brutal attacks. This predation strategy would have been essential for an animal of this size.
Moreover, researchers estimated that newborns were already 4 meters (13 feet) long at birth, making them the largest babies in the history of fish. This impressive size would have allowed them to quickly escape predation and become formidable hunters from a young age. This reveals a remarkable evolutionary adaptation to ensure the survival of young megalodons.
This study also raises questions about the reasons for the megalodon's extinction. Competition with other predators, such as the great white shark, may have played a key role. These new data allow for a better understanding of the ecological dynamics that shaped prehistoric oceans and their biodiversity.
To go further: How do scientists estimate the size of extinct animals?
Paleontologists often use partial fossils, such as vertebrae or teeth, to estimate the size of extinct animals. By comparing these remains with modern species, they can extrapolate the missing dimensions. This method, although imperfect, offers reasonable estimates in the absence of complete skeletons.
For the megalodon, researchers analyzed fossilized vertebrae and compared them to those of modern sharks. By studying the proportions between the head, trunk, and tail, they were able to reconstruct the general morphology of this giant predator. This approach relies on statistical data and mathematical models.
However, these estimates remain subject to margins of error, as body proportions can vary between species. The discovery of new fossils, particularly more complete skeletons, would allow for refining these calculations and better understanding the actual anatomy of the megalodon.
Article author: Cédric DEPOND