shark are often imagined as lethal predator with row of razor - crisp tooth and capable of zipping through the water at mellow speeds . But it seems in the instance of the famous prehistoric shark Otodus megalodon , only one of those assumption hold true .
In a studypublishedin Historical Biology , a team of researchers describe very modest O. megalodon scales found in Japan . These George Sand - grain - sizedplacoid musical scale , or denticle , show up in elasmobranchs , a group of Pisces that let in shark and rays . Unlike bony fish scales , placoid scales stay the same size through the animal ’s life .
“ Because of the assumption that O. megalodon must have been at least partially warm - blooded , the fossil shark was previously envisioned to be a fast - swimming , participating predator , ” say Kenshu Shimada , a paleobiologist at DePaul University in Chicago , in an e-mail to Gizmodo .
An artist’s illustration of O. megalodon pursuing a seal.Illustration: Alex Boersma/PNAS
“ However , the novel study that examine the fogey scales of O. megalodon advise that it likely swam much slower than previously thought or was probable an ‘ medium swimmer ’ at best in the shark populace , ” he add .
The extinct shark could grow a astonishing 65 feet farsighted , and thrived in ocean around the world from 15 million years ago until about 3.6 million long time ago . Newborn someone were about six feet long ( about the sizing of some full - grown world ) , and thespecies probably participated in filial cannibalism , by which siblings would eat sibling , allow only the survivor to grow into adulthood .
O. megalodon was a lamniform , take a shit it a relative of modern sharks like the thresher shark , mako shark , and , of course , the great bloodless shark , whichmay have campaign its big relatives to extinction .
O. megalodon’s fossil placoid scales.Photo: Kenshu Shimada
The researchers found that O. megalodon ’s placoid scales miss the ridges ( called “ keel ” ) present in rapid shark , bespeak that the apex marauder was more an episodic speedster than a full - fourth dimension racer .
O. megalodon was still a rattling piranha of the Pliocene ocean , but it belike used “ outburst of faster swim for prey capture , ” Shimada said in a DePaul University discharge , rather than always moving at such a clip .
The fogey scale are associated with a set of 73 tooth from an individual O. megalodon that was recover in Japan in the later 1980s . The shark ’s corpse remained scatter on the seafloor as it decomposed , leaving the scales to be discovered millions of twelvemonth afterwards .
With the specie moving slower than previously cogitate , the researchers pondered where the sharks put their metabolic heat .
“ Our enquiry team realise that , just like some mod shark that are partly warm - full-blood , it likely used the organic structure heat to warm up its stomach and intestine to facilitate digestion and nutrient absorption , ” Shimada say in an email . This makes sense because O. megalodon must have swallowed declamatory piece of meat , and its physical structure heat must have render an additional encouragement to ease food processing . ”
In other words , because the quick - blooded shark moved slowly , it put its free energy towards eating a bunch . Megalodons — they’re just like us !
More : Two Bull Sharks Swam Up the Mississippi River All the Way to St. Louis
Apex predatorsGreat white sharkIchthyology
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