A tropical fish can tell one human face from another despite lacking a part of the brain that animals considered much smarter use for this task, scientists said Tuesday.
This unsuspected ability was demonstrated in experiments with archerfish, a tropical species best known for spitting jets of water to shoot prey out of the air.
Instead of aiming at bugs, the sharpshooter fish were taught to spit at pictures of human faces displayed on a computer monitor outside their aquarium.
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The fish were first introduced to two faces, and taught to spit at one of them in exchange for a food reward.
The researchers then tested whether the fish would recognize, and spit at, the face they had learned from among 44 new ones.
And they were right more than 80 percent of the time, the team found.
"Even when we did this with faces that were potentially more difficult because they were in black and white and the head shape was standardized, the fish were still capable of finding the face they were trained to recognize," said study co-author Cait Newport of the Oxford University's department of zoology.
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