Recent research reveals that the ancient megalodon shark was not a cold-blooded killer, but rather a warm-blooded predator capable of regulating its body temperature. By studying the isotopes in its tooth enamel, scientists have determined that the megalodon could maintain a body temperature approximately 13 degrees Fahrenheit higher than the surrounding water, a remarkable feat compared to other sharks of its time.
While the megalodon was undoubtedly a formidable predator, the analysis of tooth minerals provides insights into how it maintained its body temperature. However, this unique ability might have played a role in its extinction during the changing marine ecosystems of the Pliocene Epoch.
A team of environmental scientists from the University of California, Los Angeles (UCLA), UC Merced, and William Paterson University conducted a study shedding light on the megalodon’s warm-blooded nature and its impact on its survival. Through the analysis of isotopes found in the tooth enamel of the extinct shark, which disappeared approximately 3.6 million years ago, the researchers concluded that the megalodon could keep its body temperature around 13 degrees Fahrenheit (or 7 degrees Celsius) higher than the surrounding water.
This temperature difference exceeds that of other sharks living alongside the megalodon and classifies the megalodon as a warm-blooded species. Published in Proceedings of the National Academy of Sciences on June 26, the study suggests that the energy expenditure required for temperature regulation might have contributed to the megalodon’s demise. Furthermore, these findings have implications for understanding current and future environmental changes.
Lead researcher Robert Eagle, an assistant professor of atmospheric and oceanic sciences at UCLA, and a member of the UCLA Institute of the Environment and Sustainability, stated, “Studying the factors that led to the extinction of a highly successful predatory shark like the megalodon can provide valuable insights into the vulnerability of large marine predators in today’s ocean ecosystems, which are currently experiencing the effects of ongoing climate change.”
Megalodons, believed to have reached lengths of up to 50 feet, belonged to a group of sharks known as mackerel sharks, which includes the great white and thresher shark. Unlike most fish, which are cold-blooded and have body temperatures matching that of the surrounding water, mackerel sharks possess the ability to keep parts or all of their bodies warmer than the water—a characteristic referred to as mesothermy and regional endothermy.
Unlike fully warm-blooded mammals, sharks store heat generated by their muscles. The absence of soft tissues in ancient shark fossils has made it challenging to determine to what extent the megalodon was warm-blooded or endothermic, but various pieces of evidence have suggested mesothermy in this species.
To overcome this challenge, the researchers focused on the megalodon’s teeth, the most abundant remains found in fossil records. Teeth consist mainly of a mineral called apatite, containing carbon and oxygen atoms. Isotopes, which can be “light” or “heavy” forms of these atoms, reflect environmental factors during the formation of apatite. Analyzing the isotopic composition of fossil teeth provides insights into an animal’s habitat, diet, and, in the case of marine vertebrates, the chemistry of the surrounding seawater and the animal’s body temperature.
Randy Flores, a UCLA doctoral student and study collaborator, explained, “The isotopes preserved in teeth’s minerals can be thought of as a kind of thermometer, one that retains its reading for millions of years. Teeth form in the tissue of an animal while it’s alive, allowing us to estimate the temperature at which they formed and approximate the animal’s body temperature during its lifetime.”
Since most ancient and modern sharks cannot significantly raise their body temperatures above that of the surrounding seawater, the isotopes in their teeth indicate temperatures similar to the ocean temperature. However, in warm-blooded animals, the isotopes reflect the additional heat generated by the animal’s body, resulting in tooth temperatures warmer than the surrounding seawater.
By comparing the isotope values of the megalodon’s teeth to those of other contemporary sharks, the researchers identified the extent to which the megalodon could warm its own body. They collected teeth from the megalodon and other sharks from five locations worldwide and analyzed them using mass spectrometers at UCLA and UC Merced. Using statistical modeling, the team estimated the seawater temperatures at each collection site, finding consistent evidence in the megalodon’s teeth that demonstrated its impressive ability to regulate its body temperature.
The megalodon’s warmer body allowed it to swim faster, tolerate colder waters, and inhabit various regions worldwide. Paradoxically, this evolutionary advantage may have contributed to its downfall. The megalodon existed during the Pliocene Epoch, which occurred from 5.33 million years ago to 2.58 million years ago, a period of global cooling that led to sea level changes and ecological shifts incompatible with the survival of the megalodon.
Flores suggests, “Maintaining the energy levels required to sustain the megalodon’s elevated body temperature would have demanded an insatiable appetite, which might not have been sustainable during a time of changing marine ecosystems, where it potentially had to compete with newcomers like the great white shark.”
Co-leader of the project, Aradhna Tripati, a professor of Earth, planetary and space sciences at UCLA and a member of the Institute of Environment and Sustainability, noted that future research will aim to apply the same approach to studying other species. She stated, “Having confirmed the presence of endothermy in the megalodon, we now wonder how frequently it was found in apex marine predators throughout geological history.”
Reference: “Endothermic physiology of extinct megatooth sharks” by Michael L. Griffiths, Robert A. Eagle, Sora L. Kim, Randon J. Flores, Martin A. Becker, Harry M. Maisch IV, Robin B. Trayler, Rachel L. Chan, Jeremy McCormack, Alliya A. Akhtar, Aradhna K. Tripati, and Kenshu Shimada, 26 June 2023, Proceedings of the National Academy of Sciences.
DOI: 10.1073/pnas.2218153120
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Frequently Asked Questions (FAQs) about Megalodon’s warm-blooded nature
Q: What did the recent research reveal about the megalodon shark?
A: The recent research revealed that the megalodon shark was a warm-blooded predator capable of regulating its body temperature, as indicated by isotopes in its tooth enamel.
Q: How did scientists determine the megalodon’s body temperature?
A: Scientists analyzed the isotopes in the megalodon’s tooth enamel, which act as a “thermometer” preserving the temperature at which the teeth formed. The isotopic composition indicated that the megalodon could maintain a body temperature around 13 degrees Fahrenheit higher than the surrounding water.
Q: Why is the megalodon being warm-blooded significant?
A: Being warm-blooded allowed the megalodon to move faster, tolerate colder water, and inhabit different regions worldwide. It was a unique characteristic compared to other sharks of its time.
Q: What implications does this discovery have?
A: The discovery suggests that the energy expenditure required for temperature regulation might have contributed to the megalodon’s extinction during the changing marine ecosystems of the Pliocene Epoch. It also provides insights into the vulnerability of large marine predators in the face of ongoing climate change.
Q: What were the main factors that led to the megalodon’s extinction?
A: The megalodon’s extinction was likely influenced by global cooling during the Pliocene Epoch, resulting in sea level changes and ecological shifts that the species couldn’t adapt to. Additionally, maintaining the energy levels necessary to sustain its elevated body temperature may have been challenging during this period.
More about Megalodon’s warm-blooded nature
- Proceedings of the National Academy of Sciences: Endothermic physiology of extinct megatooth sharks
- University of California, Los Angeles (UCLA): Research News – Megalodon Was No Cold-Blooded Killer – And That Spelled Its Doom
- UC Merced: News – Megalodon: Ancient giant shark was warm-blooded
- William Paterson University: News & Events – Megalodon: Ancient Giant Shark Was Warm-Blooded
5 comments
So megalodon was like a heater in the ocean, huh? That’s rad! No wonder it was such a boss predator. But too bad it couldn’t handle the changing times. Nature can be harsh, man. RIP megalodon, you were one cool shark!
This research is groundbreaking! It’s incredible how studying ancient teeth can unlock secrets about an extinct species. The megalodon’s warm-blooded nature sheds light on its unique ecological role and the challenges it faced. We have so much to learn from the depths of our oceans.
Dang, megalodon was a hot shark! I can’t imagine how terrifying it must have been to encounter one. It’s interesting to think about how its warm-bloodedness affected its behavior and survival. This study shows how climate change can impact even the mightiest predators.
megalodon being warm-blooded is mind-blowing! I love how they used isotopes in the tooth enamel to figure that out. It’s fascinating to think about how this adaptation affected their hunting and survival. Climate change really had an impact on these amazing creatures.
wow, who knew that Megalodon waz all warm-blooded!?!? makes me wonder how it survived in tha oshen. maybe it ate too much and couldn’t keep up wit da changing climate. sad to see such a big predator go!