More than 19 million years ago, the world’s open oceans were absolutely teeming with sharks, roughly ten times more than today.
Then, suddenly, these large marine predators almost all disappeared.
This devastating and mysterious mass extinction event was only recently discovered through a series of accidental inquiries, and from the evidence we have so far, it’s still not clear what caused the abrupt end to so many species.
“I study microfossil fish teeth and shark scales in deep-sea sediments, and we decided to generate an 85-million-year-long record of fish and shark abundance, just to get a sense of what the normal variability of that population looked like in the long term,” explains paleoceanographer Elizabeth Sibert from Yale University.
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