THEY RECOGNISE FACES
It might strike you as an odd thing to do, but scientists at the University of Queensland and the University of Oxford have taught archerfish to recognise humans faces. They positioned a computer screen above an aquarium tank and trained the fish to spit water at a particular face, giving them food whenever they hit the right target. When they were shown dozens of other faces, the archerfish kept on shooting at the ones they’d learned to associate with food.
Distinguishing between faces is a complex task involving spotting subtle differences in the same set of features (two eyes, a nose and a mouth). Obviously, archerfish didn’t evolve a specific ability to recognise human faces, but the study shows that even without a big brain fish can recognise slight differences in their surroundings, presumably including other things that are important to them, such as predators and prey.