Newsroom > News > Press Releases > Tiny scales reveal Megalodon was not as fast as believed, but it had a mega-appetite explaining its gigantism
July 11, 2023 /
Posted in: College of Science and Health /
CHICAGO — A new study reveals the iconic extinct Megalodon, or ‘megatooth shark’, was a rather slow cruiser that used its warm-bloodedness to facilitate digestion and absorption of nutrients.
DePaul University paleobiology professor Kenshu Shimada and coauthors propose radically new interpretations of the lifestyle and biology of
Otodus megalodon, the fossil shark that lived nearly worldwide roughly 15 to 3.6 million years ago.
The new study, which overturns conventional wisdom about the swimming speed of Megalodon, appears in the international scientific journal
The new study is based on the discovery of tiny scales, more precisely called ‘placoid scales,’ of O. megalodon within rock pieces surrounding a previously described tooth set of the fossil shark from Japan.
“Our big scientific findings come from ‘tiny evidence’ as small as grains of sand,” Shimada said.
Inferred to be partially warm-blooded or regionally endothermic — similar to large active modern predacious sharks like the makos and great white sharks —
O. megalodon was traditionally assumed to be an active fast swimming shark. However, the new study reveals that its tiny placoid scales are not equipped with narrowly-spaced ridges or ‘keels’ characteristic of fast-swimming sharks. “This led my research team to consider
The new study also leads to a new paradox. Although strong support for the presence of regional endothermy in
O. megalodon exists based on
another recent study in which Shimada also played a key role, the question was how the fossil shark expended the high level of metabolic heat resulting from its warm-bloodedness without being an active swimmer.
Upon reviewing the literature, the research team noticed another possible function of endothermic body physiology that had been neglected in the biological context of
O. megalodon — i.e., facilitating digestion as well as absorbing and processing nutrients. “It suddenly made perfect sense,” said Shimada. “Otodus megalodon must have swallowed large pieces of food, so it is quite possible that the fossil shark achieved the gigantism to invest its endothermic metabolism to promote visceral food processing.”
The new study with radically new ideas about the biology and lifestyle of
O. megalodon, “Tessellated calcified cartilage and placoid scales of the Neogene megatooth shark,
Otodus megalodon (Lamniformes: Otodontidae), offer new insights into its biology and the evolution of regional endothermy and gigantism in the otodontid clade,” is published in Historical Biology and is freely downloadable for a limited time