Researchers at the Max Planck Institute for Animal Behavior in Germany say wild fish can follow divers who feed them — and can even distinguish people by the color of their clothing. The team says the result could change how we think about fish.
What did the experiments reveal? Led by principal author Maelan Thomas, the team conducted a series of experiments at a research station in the Mediterranean Sea. In the first phase, diver Katinka Soller trained two species of sea bream to follow her at a depth of 8 meters over 12 days. She swam a 50-meter route and offered the fish food along the way. During that period, about 20 fish learned to swim alongside their trainer.
Then Maelan Thomas joined her. In dozens of follow-up trials he either wore the same diving gear as Katinka or a different, colorful outfit. In both cases, the two divers—each carrying food—swam in different directions and then returned to the start to repeat the route.
When the divers wore different outfits, the fish followed the trainer who was feeding them. However, when the researchers dressed identically, the bream could not tell them apart, according to the Independent. The team suggests that because the fish had no prior experience with people, they probably relied on visual cues to tell the divers apart. Specifically, the fish used clothing color and patterns as cues.
Thomas points out that nearly all fish have color vision. He thinks the work could make people rethink how smart fish are. The findings were published in the journal Biology Letters.
