An illustration reveals the massive extinct shark megalodon, Otodus megalodon, preying on a seal on this image obtained by Reuters on June 27, 2023.
| Photo Credit: Reuters
The megalodon, a huge shark that was the scourge of the ancient oceans and is a star in trendy film theaters, is called for its “large tooth” – and for good motive. Its serrated enamel – as much as about 7 inches lengthy (18 cm) – might tear by way of any prey in the deep blue sea.
Those enamel now are offering a fuller understanding of this extinct predator, with an analysis of the mineral make-up of their enamel-like tissue confirming that megalodon was heat-blooded – a trait scientists suspect contributed each to its super success and eventual downfall.
Researchers estimated that megalodon, which reached at the least 50 ft (15 meters) and probably 65 ft (20 meters) lengthy whereas searching marine mammals together with whales, boasted an general common physique temperature of about 81 levels Fahrenheit (27 levels Celsius) and will maintain it at about 13 levels F (7 levels C) above that of the surrounding seawater.
This might have made megalodon a extra dynamic predator – a sturdy swimmer in a position to digest meals in an energetically environment friendly method and, importantly, tolerate colder water, letting it broaden its vary to just about worldwide.
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Most fish are chilly-blooded – ectothermic – with physique temperatures matching the surrounding water. But a few are heat-blooded – endothermic – producing their very own physique warmth. Examples embrace sure sharks together with the largest trendy one, the nice white.
“The only comparable living species today in terms of both diet and body temperature are the great white shark and, to a lesser extent, the mako shark. Though, as shown in our study, megalodon was quite a bit warmer than both of these modern apex predators, which makes megalodon unique,” mentioned geochemist and paleoclimatologist Michael Griffiths of William Paterson University in New Jersey, lead writer of the analysis revealed in the journal Proceedings of the National Academy of Sciences.
The research discovered that megalodon, whereas heat-blooded, had a decrease physique temperature than whales.
“One theory is that they were regionally endothermic – that some parts of their body were warmer than other parts, whereas body temperature is higher and more uniform across the body in most large mammals,” UCLA atmospheric and oceanic scientist and research co-writer Robert Eagle mentioned.
Megalodon, maybe the largest shark of all time, appeared about 23 million years in the past, then disappeared about 3.6 million years in the past amid declining ocean temperatures and sea ranges.
Warm-bloodedness might have been helpful for megalodon in cooling waters.
“Yet, the fact that the species became extinct suggests the probable vulnerability – or the cost – of being warm-blooded because warm-bloodedness requires constant high food intake to sustain high metabolism,” paleobiologist and research co-writer Kenshu Shimada of DePaul University in Chicago mentioned.
“It is quite possible that there was a shift in the marine ecosystem due to the climatic cooling that caused the sea level to drop, altering the habitats with the populations of the types of food megalodon depended on, such as marine mammals, possibly becoming scarce, leading to the extinction of megalodon,” Shimada added.
Scientists beforehand had suspected megalodon’s heat-bloodedness however the research offered the first empirical proof. The researchers analyzed geochemical traits in fossil megalodon enamel to find out the temperature at which minerals in enamel-like tissue fashioned – an indicator of physique temperature.
After being overshadowed for many years in standard tradition by the nice white – assume the 1975 blockbuster Jaws and its limitless progeny – megalodon is now in the highlight due to the 2018 movie The Meg and its upcoming sequel Meg 2: The Trench.
“Megalodon is primarily represented only by teeth and a handful of vertebral specimens in the fossil record,” Shimada mentioned. “Contrary to novels and movies that portray megalodon as a super-sized, monstrous shark, the fact is that we still don’t even know exactly how it looked or how it lived. This is exactly why the ‘science of Megalodon’ continues to be an exciting academic field.”
