A species of tropical fish can differentiate between human faces, a study has found – the first time fish have been found to possess such powers of recognition.
Archerfish, distinguished by their ability to spit water jets to shoot prey out of the air, can accurately recognise one face from another during staged testing, a joint study from the University of Oxford and Queensland found.
The fish were trained individually to select faces on a monitor in view of their tank and pick out a face they had learned from 44 new faces by spitting a jet of water at the correct image.
The archerfish picked out the correct face 81 per cent of the time.
During the tests the fish were able to identify the faces through detailed feature recognition, even when the shapes and colours of faces were altered.
It was previously believed that only certain mammals, and primates in particular, had facial recognition capabilities due to the large size of their brains. Certain species of birds have also been found to “possess neocortex-like structures”, which aid with human facial recognition.
However, results of the study, which was published in the journal Scientific Reports, suggest that, despite having tiny brains, some fish may have highly-developed visual discrimination capabilities.
Dr Cait Newport, research fellow at the University of Oxford and co-author of the study, said: “Being able to distinguish between a large number of human faces is a surprisingly difficult task, mainly due to the fact that all human faces share the same basic features.
“If you consider the similarities in appearance between some family members, this task can be very difficult indeed.”
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