photo

The Thrashing Thresher Shark

Preview A thresher shark uses its unusual tail fin for swimming and hunting.
(Mark Harris, Flickr)

A thresher shark’s long tail fin helps not only its swimming ability, but also its ability to hunt. It can use the fin to herd and trap schooling fish by swimming in increasingly smaller circles before striking the fish with its tail. This strike usually assails from above instead of sideways, a rare technique on the shark’s part that allows them to stun multiple fish at a time. Most carnivorous sharks only kill one fish at a time and are comparatively less efficient. Even though it is an expert hunter, the thresher shark is shy and harmless to humans and is unlikely to attack them.