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How Thresher Sharks Use Their Enormous Tails to Hunt

This is a beautiful video to watch.

Scientists have previously confirmed that thresher sharks use their massive tails to hunt. But for the first time, footage has been captured of the sharks using their tails in an actual hunt, and we all get to check it out thanks to the Times video above.

A landmark 2010 paper in the Journal of Fish Biology featured the results of underwater filming of threshers from 2007 to 2009, during which 34 baited feeding events were caught on camera. According to the authors, every single event was initated with the top part of the shark's caudal (tail) fin. The study used long lines with bait attached to initiate the feeding events, and the sharks took two different approaches in their strikes: the first, described as sinuisodal, was observed to be more common but only successful half the time; the second, a lateral strike, was slightly less common but nearly always successful.

This caught young thresher shows just how big their tails can be, via WDFW

So while the evidence that threshers use their tails in hunts was pretty clear, what that behavior looks like in a wild hunt was less well understood. Now, divers in the Philippines have caught footage of threshers hunting sardines. As the Times's James Gorman explains, the sharks were observed to swim quickly at a school of sardines and then suddenly stop, flipping their tails over their backs to create an underwater shock wave that stuns the fish long enough to be eaten.

It's beautiful to watch. More than that, it's an incredible combination of physiological and behavioral evolution. It's an interesting chicken-and-egg questions, too: Did the tail, which can be about half the length of the shark's body, evolve in response to tail hunting behavior? Or did the behavior follow the evolution of the tail? Without more research, it's as yet unknown, which makes it all the more fascinating.

@derektmead