Megalodon sharks were warm-blooded with body temp of 27˚C, proves study

A new geochemical analysis of fossilized teeth confirms the Megalodon shark was warm-blooded.
Sade Agard
Megalodons, which went extinct 3.6 million years ago, are believed to have grown to lengths of 50 feet.
Megalodons, which went extinct 3.6 million years ago, are believed to have grown to lengths of 50 feet.

Alex Boersma/PNAS 

The colossal Megalodon—the largest marine predator to have ever existed—was warm-blooded, according to a recent analysis of fossilized teeth published in the Proceedings of the National Academy of Sciences on June 26.

The new research illuminates how the 50-foot-long Megalodon shark, which thrived in the world's oceans from 23 million to 3.6 million years ago, managed its body temperature. Additionally, the findings hold promise in unraveling the mysteries surrounding its eventual extinction.

Proof that the Megalodon was warm-blooded

Scientists had previously theorized that the Megalodon, also known as Otodus megalodon, was warm-blooded, similar to certain modern sharks. However, these conclusions were based mainly on deductions rather than concrete evidence. In this latest study, researchers have presented the first empirical proof of the extinct shark's warm-blooded nature. 

Megalodon sharks were warm-blooded with body temp of 27˚C, proves study
An upper tooth from a megalodon (right) dwarfs that of a white shark.

To investigate the "Megalodon Endothermy Hypothesis," the researchers employed a cutting-edge geochemical technique. Their approach combined clumped isotope thermometry and phosphate oxygen isotope thermometry methods.

"Studies using these methods have shown them to be particularly useful in inferring the thermo-physiologies of fossil vertebrates of 'unknown' metabolic origins by comparing their body temperature with that of co-occurring fossils of 'known' metabolisms," explained the lead author Michael Griffiths from William Paterson University in a press statement.

Clumped isotope thermometry is a technique that uses the tendency of certain heavier isotopes, like carbon-13 and oxygen-18, to bond together in minerals based on the temperature at which they formed. 

By analyzing the degree of clumping, scientists can determine the temperature at which the mineralization process occurred. 

Some present-day sharks, such as mako and great white sharks, are known for having regional endothermy, where certain parts of their bodies can stay warmer than the surrounding water. Previous research has indicated that their average body temperature can range from 22.0 to 26.6 degrees Celcius (˚C), potentially 10 to 21˚C higher than the ocean's temperature. 

The new study proposes that the Megalodon, in comparison, had a higher overall average body temperature of approximately 27˚C. 

What killed the Megalodon shark?

The Megalodon's capacity to control its body temperature is a significant evolutionary trait because the development of warm-bloodedness is believed to have played a crucial role in driving its massive size.

Earlier studies conducted by Griffiths and his team have indicated that Otodus megalodon was a prominent top apex predator, occupying the highest tier of the marine food chain.

According to the researchers, the considerable metabolic demands of sustaining warm-bloodedness might have affected the species extinction.

"Because megalodon went extinct around the time of extreme changes in climate and sea level, which impacted the distribution of and the type of prey, our new study sheds light on the vulnerability of large marine apex predators, such as the great white shark, to stressors such as climate change," said Griffiths, underscoring the need for conservation efforts to protect modern shark species.