Scientists at the University of Cambridge, led by Professor Jenny Morton, have discovered that sheep can recognize human faces. While you probably won't see any sheep taking the witness stand to finger criminals, the discovery came from a serious neurological study aimed at gaining a better understanding of neurodegenerative disorders in general and Huntington's disease in particular.

Sheep have a reputation for being remarkably dim with a penchant for behavior bordering on the suicidal, but Morton says that being long-lived social animals with large brains, sheep have face-recognition abilities comparable to humans and monkeys. This makes them very good models for neurological research.

Though the eye is often compared to a camera, vision is actually a very complex process. This is especially true when it comes to facial recognition. For humans, primates, and even sheep, faces are an important means of identification and social interaction. The problem is, recognizing someone's face isn't easy. How one sees a face changes from moment to moment and situation to situation. Faces change subtly over time, we see them from different angles, lighting is never constant, and many other factors come into play.

To overcome this, the brain doesn't store one static image of a face and then try to match it. Instead, facial memory is associative. That is, the brain identifies various parts of a face, then tries to associate them with other parts like an identikit until a match is made. The memory doesn't store the face, but only the parts and how they are related to one another.

This is why it's often impossible to visualize the face of someone one knows well, yet it's possible to pick out a familiar face in a crowd without even trying. This complex mechanism makes facial recognition an excellent tool for understanding neurodegenerative diseases.

At Cambridge's Department of Physiology, Development and Neuroscience, Morton's team placed eight sheep in a specially designed pen. This pen included a workstation with two computer screens and two treat dispensers. On the screens, the scientists flashed images of four celebrities: BBC journalist Fiona Bruce, Jake Gyllenhaal, Barack Obama, and Emma Watson. When the ovine lab subjects chose a famous face, they broke an infrared beam and were rewarded with food.

In addition, images of four non-celebrities were flashed on the screen. If the sheep chose one of these, a buzzer sounded and no treat was dispensed. Eventually, the sheep learned to associate the celebrities with food and would choose them eight out of 10 times. In later tests, the faces were shown at an angle. The sheep had more trouble picking out the right faces, but performance dropped by only 15 percent, which is the same success rate as for human subjects.

One unexpected discovery was that the sheep were able to pick images of their handler's face without any pre-training. When the handler's face was placed in the test queue, the sheep did a double-take, then chose the handler seven out of 10 times.

"Anyone who has spent time working with sheep will know that they are intelligent, individual animals who are able to recognize their handlers," says Morton. "We've shown with our study that sheep have advanced face-recognition abilities, comparable with those of humans and monkeys.

"Sheep are long-lived and have brains that are similar in size and complexity to those of some monkeys. That means they can be useful models to help us understand disorders of the brain, such as Huntington's disease, that develop over a long time and affect cognitive abilities. Our study gives us another way to monitor how these abilities change, particularly in sheep who carry the gene mutation that causes Huntington's disease."

The research was published in Royal Society: Open Science.

The video below outlines the study.

Source: University of Cambridge