As more species are admitted into the “smart” animals club, fish can be overlooked. While some archerfish were able to recognize computer-generated images of human faces in a series of laboratory experiments, there is not a lot of scientific evidence about how well fish can recognize the humans that dive into their watery world.
However, some fish stood out to a team of scientists at a research station in the Mediterranean Sea. Every field season, some local marine life would appear and follow a team of scientific divers. The fish would steal the food that the divers carried to use as experimental rewards. The team suspected that the animals could recognize the specific diver who had previously carried the food, since this fish only followed that person while ignoring the others.
After designing a series of tests, the team found that some of the fish can tell humans apart based on some of their dive gear. The findings are detailed in a study published February 18 in the journal Biology Letters.
Following the leader
To test their hunch, the team from the Max Planck Institute of Animal Behavior in Germany conducted a series of experiments to see if wild fish are telling people apart. The study was conducted in about 26.2 feet of water at a research site in the Mediterranean Sea. Here, populations of wild fish have become habituated to humans. According to study co-author and Max Planck student Katinka Soller, the fish were, “willing volunteers who could come and go as they pleased.”
Training was the first experimental phase. The team tested if the fish could learn to follow Soller. She started by trying to attract the attention of local fish by wearing a bright red vest and swimming about 164 feet. Over time, Soller removed the clues that marked her until she swam in plain diving gear, kept the food hidden, and only fed fish after they…
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