Thresher sharks are Lamniformes or mackerel sharks and have a long, elongated upper tail fin. They are strong swimmers often hunting in pairs and can launch themselves completely out of the water.
Their name comes from the way in which they kill prey - smashing fish with their long tails before eating them.
They are not usually dangerous and are unlikely to bite a human being but they are known to ram swimmers with their long pointy noses and have been known to injure divers with their tails when provoked.
The Thresher shark ranges from 16.5 to 20 ft long and lives in open tropical and temperate waters, including the eastern and western Atlantic, the central Pacific, and the Indo-west Pacific.