Here’s a riddle: How is a fish like a long-distance cyclist? Sure, they both need lots of water. But now researchers have found another parallel: Both huddle in groups, hiding behind their companions’ bodies to save energy., researchers used high-speed cameras and a device that measured the fish’s oxygen consumption to track the movements and energy use of a type of large minnow called a giant danios (When the scientists created a strong, turbulent current, the solo minnows struggled.
But those minnows that clustered together—like a peloton of cyclists at the Tour de France—were sheltered from the harshest turbulence by the individual fish leading the school, as seen in the video above. Fin movements from the leading fish altered the current before it reached the others, creating a calmer zone for the follower fish, who used up to 79% less energy than fish that swim alone.
Many animals use similar principles to shelter from air currents—birds have easier flights when flying in a “V” formation, for instance. The scientists think other critters may be using the same strategy as the giant danios to hide from turbulence, both in the water and in the air. Understanding how fish swim in eddies could also aid in habitat restoration, the team says, helping conservationists engineer more efficient fish passages through dams.