What is it about?

Otodus megalodon was a gigantic shark that went extinct around 3.6 Mya. It could grow to the enormous size of at least 15 m long, making it one of the largest apex marine predators since the Mesozoic. Here, we test hypotheses relating to its extinction by providing quantitative estimates of its body temperature, thereby constraining its thermal physiology.

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Why is it important?

We found that O. megalodon had body temperatures significantly elevated compared to other sharks, consistent with it having a degree of internal heat production as modern warm-blooded (endothermic) animals do. High metabolic costs associated with having at least partial endothermy may have contributed to its vulnerability to extinction compared to other shark species that persist until this day.


The geochemical technique our research team employed was previously used to determine the thermophysiology of some dinosaurs. Our new study demonstrates that it can be applied also to marine vertebrates such as sharks, particularly hard mineralized anatomical components like teeth. Although warm-bloodedness in O. megalodon was previously suspected, our new study represents the first empirical evidence supporting the idea on the basis of geochemistry. This new study represents strong teamwork among paleobiologists and geochemists and was primarily funded by the U.S. National Science Foundation. The results generated would not have been possible without the significant contribution of undergraduate researchers, most of which are from traditionally underrepresented communities.

Michael Griffiths
William Paterson University of New Jersey

Read the Original

This page is a summary of: Endothermic physiology of extinct megatooth sharks, Proceedings of the National Academy of Sciences, June 2023, Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.2218153120.
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