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Megalodon, the apex predator that once ruled Earth's oceans.
Latest research cited by CNN in the National Academy of Sciences' journal sheds light on the fearsome Megalodon shark: Megalodon, one of the most formidable sharks to have ever lived on Earth, is not the 'cold-blooded predator' as widely misunderstood (literally).
Specifically, the Megalodon shark is a warm-blooded species.
'We discovered that the Megalodon shark has a significantly higher body temperature compared to other shark species, indicating an internal heat generation similar to modern warm-blooded animals' - Co-author Robert Eagle, Professor of Marine Science and Biogeography at the University of California, USA, stated on CNN.
Using a novel geochemical technique on Megalodon fossilized teeth, scientists found that this extinct shark had warm blood, with a body temperature approximately 7 degrees Celsius higher than the estimated seawater temperature at that time.
This revelation dispels a long-held misconception that Megalodon sharks are cold-blooded. According to Americanoceans.org, sharks are cold-blooded animals, also known as ectothermic creatures. This means their body temperature is regulated by the surrounding water temperature, not by their own metabolism. Despite being cold-blooded by nature, sharks exhibit a high adaptability to ocean life, with some species capable of adjusting their body temperature to some extent.
In reality, scientists had previously hypothesized that Megalodon is a warm-blooded species, and this recent study is the first to provide concrete evidence for that assertion.
Researchers found that the warm-blooded characteristic played a role in unraveling the biggest mystery of the Megalodon shark: its colossal, fearsome size (1); simultaneously shedding light on the reasons behind its extinction, highlighting the vulnerability of large marine predators to environmental changes (2).
(1). Colossal and Fearsome Size of Megalodon
Believed to be at least 15 meters long, Otodus Megalodon, also known as Megatooth shark, was one of the largest predators in the sea since the Mesozoic Era and went extinct approximately 3.6 million years ago, according to Eagle.
Researchers observed how carbon-13 and oxygen-18 isotopes found in ancient shark fossilized teeth were tightly linked, providing data that could reveal the body's warmth. From this discovery, they inferred that the average body temperature of Megalodon was around 27 degrees Celsius.
According to the study, Megalodon is a locally endothermic species, meaning they can regulate temperature in specific parts of their body. This enables them to maintain a relatively stable body temperature, making them more dynamic and efficient predators in the ocean.
Senior research author Kenshu Shimada, a paleontologist at DePaul University in Chicago, USA, suggests that warm-blooded traits could be a key driver behind Megalodon's colossal size and overall hunting prowess.
'A large body enhances prey-catching efficiency over a broader spatial range, but sustaining this requires a significant amount of energy. We know Megalodon had sharp teeth and a massive bite force used to prey on marine mammals, based on its fossilized record. The new research aligns with the idea that the evolution of warm-bloodedness was a prerequisite determining the colossal size of Megalodon,' answered Kenshu Shimada to CNN.
(2). Extinction of the Megalodon Shark
For a creature of such magnitude, constantly expending excessive energy to regulate body temperature may have contributed to its decline as global climate conditions changed. Researchers note that the Megalodon extinction coincided with a cooling Earth temperature.
Paleontologist Shimada states: 'The permanent disappearance of Megalodon demonstrates the vulnerability of warm-blooded species because they require continuous food intake to sustain robust metabolism. There likely was a shift in the marine ecosystem due to cooling climate, causing sea levels to drop, altering the habitat of Megalodon's prey like marine mammals, ultimately leading to the extinction of this super shark species.'
Michael Griffiths, the lead author of the study, a professor of environmental science, geochemist, and paleontologist at William Paterson University in New Jersey, USA, notes that compared to other apex predators, Megalodon was much larger and, therefore, more susceptible to disruptions in prey populations.
However, delving further into ancient shark research can still provide scientists with a better understanding of the challenges that similar marine species face today.
'One significant implication of this study is highlighting the vulnerability of large predators at the top of the food chain, such as modern large white sharks' - Professor Michael Griffiths concludes.
Source: CNN, Americanoceans.org
