The biggest shark ever was Otodus megalodon, now extinct, which could grow up to 50 feet long. And there may as well not even be a second place, as that's twice as big as any other shark. How did this shark get so big, and what makes it so different? For one thing, O. megalodon reproduced with eggs like other fish, but it does not lay eggs. Rather, the eggs hatch inside the mother, who gives birth to them later on. That allowed for larger baby sharks, but wasn't the best environment for some of them.
A new study, published today in Historical Biology by DePaul University paleontologist Kenshu Shimada and colleagues, suggests that cannibalism in utero may have helped set up the rise of the largest meat-eating shark of all time. The researchers suggest that a biological connection existed between having large, hungry babies, a metabolism that ran warm and increases in size—with the appetites of baby sharks driving their mothers to eat more and get bigger, which led the babies to get bigger themselves.
It's not that unborn sharks developed a taste for meat by eating eggs and sibling in utero, at least not that alone. Read about the evolutionary forces that could have driven megalodon to such great size at Smithsonian.
(Image credit: Smithsonian Institution)
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