The Thresher - The Shark with a Whip

To see a common thresher shark from the front you may think that it looks a lot like many other sharks. The streamlined, torpedo-shaped body and classic dorsal fin fit the profile perfectly. However, once you see that massive tail the thresher shark is unmistakable.

Pelagic thresher shark - Photo: Discovery

The thresher shark’s massive caudal fin isn’t just for looks, either. When hunting, the thresher will use its tail to slap the water around schools of fish to corral them. There have also been several reports of threshers using their tails like whips to stun or kill prey.

There are three species of thresher sharks. As its name suggests, the common thresher is the most widely distributed species and it is also the largest, reaching lengths of over 20 feet and weights of over 1,000lbs. The pelagic thresher is the smallest at about 10 feet long and less than 200lbs. The third species is the bigeye thresher, which features eyes that can be up to four inches in diameter for hunting in deep waters with little light.

Most thresher sharks prefer open ocean; depending on size and species they feed on a large variety of marine life, but prefer schooling fish such as mackerel and tuna as well as squid. Adult threshers rarely have any natural predators of their own.

Despite their large size and that fearsome tail, threshers pose little or no danger to humans. There has only ever been one reported attack by a thresher shark on a person and just a handful of attacks against boats. All of these attacks we most likely provoked, as the thresher is still highly prized by sport fishermen despite all species being nearly endangered.