Sheep can learn to recognize faces

Sheep learned to recognize four celebrities after being shown their pictures, according to a new study published Wednesday, suggesting the woolly animals have face-recognition abilities similar to humans and primates.

In the study published in the journal Royal Society Open Science, scientists trained eight sheep to recognize the faces of ex-US President Barack Obama, "Harry Potter" actress Emma Watson, British TV host Fiona Bruce and American actor Jake Gyllenhaal.

Previous research had already shown sheep can recognize other sheep and familiar humans, but little was known if they can recognize unfamiliar faces from two-dimensional photographs.

In the experiment, scientists trained the sheep using food incentives to recognize the celebrity faces from a frontal photo of each.

They then challenged the sheep by presenting two photographs and rewarded the sheep with food if they chose that of the celebrity. Sheep were able to identify the learned face eight times out of 10.

Researchers also tested whether sheep could still recognize the learned face if it was at a different angle. Sheep were able to perform this task at about 66 percent, which the researchers said was "a magnitude similar to that seen when humans perform this task.”

Finally, a third part of the test had the sheep identify the picture of a known handler, which they were able to do about 72 percent of the time.

A video of the experiment can be watched here. 

"Sheep can not only be trained to recognize unfamiliar human faces, but that they can also recognize the face of a person familiar to them from a two-dimensional image," the research suggested.

Quick and easy facial recognition is an important social skill for humans.

Many animals have the ability to recognize same-species faces, including chimpanzees, macaque, cattle, goats and pigeons.

Other studies have shown some animal species, including horses, dogs, mockingbirds, sheep and macaques, can recognize the faces of individuals from other species.

The sheep study may help research on treating neurodegenerative diseases such as Huntington's, which affects cognitive abilities including facial recognition.

A sheep version of Huntington's has been bred, which has similar brain and social impairments as the human version.

By studying how sheep learn, researchers hope to further understand normal brain function and how it changes with diseases such as Huntington's.