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They’re looking at ewe. Sheep have shown an unexpected capacity to recognise straight mugshots of four celebrities, but then to identify those same megastars in side profiles they’d not seen before. Humans and monkeys are the only other creatures known to do this from two-dimensional images.

The eight sheep that took part were trained to familiarise themselves with straight mugshots of four celebrities: former US president Barack Obama, UK newsreader Fiona Bruce, and actors Emma Watson and Jack Gyllenhaal.

The sheep viewed pairs of pictures, one of which was always one of the four celebrities. They “chose” the celeb pic by approaching it, and were rewarded with a cereal pellet in the trough below. They got nothing if they chose the other image.

At first, the celebrity mugshots were paired with black oblongs, then with non-human objects shaped like faces, and finally with mugshots of other people selected because they looked like the celebrities. By the end of training, the sheep correctly picked the celebrity over the stranger 79 per cent of the time.

Next, the researchers showed the sheep the same celebs and a stranger, but now both faces were shown as left- or right-sided profiles. This tested whether the sheep were simply recognising the mugshots as stand-alone images, or actually identifying the people. Again, the sheep excelled, picking out the celebs in 66 per cent of their choices.

Clever sheep

“That’s way more often than by chance,” says lead author of the University of Cambridge, UK. “With the angled face, the percentage drop in recognition was the same as for humans, around 15 per cent,” she says. “I was surprised they did as well as they did.”

For the first time, the study reveals that sheep can mentally take a two-dimensional image of a face and rejig it into a three-dimensional representation, says Morton. That way, they can still recognise the same person even from different angles.

“It’s amazing sheep can quickly learn to recognise unfamiliar human faces presented in different viewing perspectives,” says of the University of Lincoln, UK. “It’s possible this human-like face perception capability is more widespread in the animal kingdom than we previously thought.”

It makes sense that sheep would have this ability, says of the University of Washington in Seattle. He has shown that crows can recognise human faces, even many years after first viewing them. “Sheep life revolves around interacting with shepherds, other keepers and dogs, so knowledge of this important aspect of their environment should be favoured during the domestication process.”

A test for dementia

The finding adds to the mounting evidence that sheep, despite their dim-witted reputation, are highly intelligent. For instance, scientists have known that – though not under such testing conditions as these – since 2001.

Despite its fun appearance, Morton says the research has a serious purpose. She plans to present the same face-recognition challenge to new sheep that have been bred in Australia to develop Huntington’s disease.

One of the major symptoms of Huntington’s, and other forms of dementia, is inability to recognise faces. The “celeb test” should allow Morton to monitor the pace of deterioration in the Huntington’s sheep – and possibly in patients too – plus a way to test new treatments before trying them on people. “We would be able to tell if new treatments reduce the deficits,” says Morton.