A paper in the journal PLoS ONE about the hunting strategies of pelagic thresher sharks (Alopias pelagicus) has shown that the animals do use their tales to stun prey. The behavior was investigated at Pescador Island in the Philippines over 5 months in 2010, using a video camera to record the predation. After analyzing the footage of the 25 hunting event observed, the researchers found that “tail-slaps occurred with such force that they may have caused dissolved gas to diffuse out of the water column forming bubbles,” and conclude that:

“The evidence is now clear; thresher sharks really do hunt with their tails.”