A cataclysmic die-off nearly wiped out all sharks 19 million years ago

Sharks are often considered one of the most finely-tuned animal groups on the entire planet. Over a huge timeline, sharks have managed to not only persist but typically thrive. Sharks lived alongside the dinosaurs tens of millions of years ago, and while species have come and gone, the sharks we see today aren't all that dissimilar from those that were prowling the waves when colossal dinosaurs were stomping around on dry land. They have incredible staying power, but new research suggests they endured an incredibly difficult period in the not-so-distant past.

In a new paper published in the journal Science, a pair of researchers explain how they accidentally stumbled upon what appears to be evidence of a mass shark extinction some 19 million years ago. The event dramatically reduced shark populations, leading to a huge drop in population numbers as evidenced by a reduction of fossils in ocean sediment. Over 90% of shark fossils suddenly disappear in the open ocean fossil record around that time, with over 70% of shark species completely vanishing.