Thresher sharks use their long, sickle-shaped tail fins to whip and stun schooling fish, but the behavior is rarely witnessed.
The accompanying footage, captured last week by O’side Whales in Oceanside, Ca., shows a large thresher shark whipping its tail fin above the surface alongside a whale-watching boat, to the delight of passengers.
"One of the most incredible encounters you can have offshore!” O’side Whales boasted via social media. "That unmistakably long tail makes the thresher shark one of the most unique sharks in our local waters.”
The Pacific common thresher shark can measure to 18 feet, thanks largely to its tail fin. (Click here if video player does not appear below.)
Sightings are rare but thresher sharks are sometimes hooked by fishermen
or spotted free-jumping high above the surface.
The sharks boast small mouths and prey largely on schooling anchovies, sardines, and squid. They're not considered dangerous to humans.
This article originally appeared on For The Win: Tail-whipping shark thrills boaters on whale-watching excursion
