"Together these data show that sheep have advanced face-recognition abilities, comparable with those of humans and non-human primates".
Researchers at the University of Cambridge trained eight sheep to recognize the faces of four celebrities from photos shown on a computer screen. Morton, who studies Huntington's disease, uses them as a stand-in for humans, in part because "sheep have large brains with humanlike anatomy".
Morton and her team are now studying sheep that have been genetically modified to carry the gene mutation that causes Huntington's disease.
As with some other animals such as dogs and monkeys, sheep are social animals and can recognise other sheep as well as familiar humans. That's what scientists discovered through testing sheep by showing them celebrity portraits.
"My 2001 paper looked very carefully at this with a wider range of stimuli, more sheep and more conditions", he said. After training the sheep again showed two images - a person studied celebrities and the unknown person - and eight times out of ten they came to the celebrities with all the enthusiasm. However, their ability to recognize human faces from photos alone is novel. "Our study gives us another way to monitor how these abilities change", Morton said.
When the handler's face was shown, sheep picked it seven out of 10 times. However, the ability of sheep to identify faces was unclear.
The study feeds into ongoing research on treating neurodegenerative diseases such as Huntington's, in which face perception can be impaired. Maybe they just didn't like that the non-familiar lacked a reward, for example. Perhaps a test like this could help study these sheep's "cognitive decline".