An Underwater Sailor

The elegant sailfish is a swift seafarer: it's capable of swimming at speeds as high as 60 miles per hour in short bursts.

The oversized dorsal fin that gives the sailfish its name is usually kept folded down to the side while the fish is swimming, but it's hoisted up when the fish feels threatened or in the course of a hunt. Sailfish hunt cooperatively, encircling a school of anchovies or sardines and leaping dramatically to herd the baitfish into a tightly packed, panicked ball. Then the predators move in. If the ball begins to disperse, the sailfish dramatically raise their sails like capes to frighten the prey and herd them together again.

Image: Boyce Image