Amazing powers of sheep

Sheep have a similar visual recognition system to that of humans

		By Helen Briggs BBC News Online

Sheep may be brighter than we think.

According to British scientists, they probably experience some degree of emotion and could even be capable of conscious thought.

This astonishing verdict is based on the ability of sheep to remember old faces, be it a member of the flock or even a shepherd.

Sheep may be capable of using the same system (as humans) to remember and respond emotionally to individuals in their absence

Dr Keith Kendrick

"The way the sheep's brain is organised suggests they must have some kind of emotional response to what they see in the world," Dr Keith Kendrick, of the Babraham Institute, Cambridge, told BBC News Online.

"It does beg the question that sheep must potentially be able to think about individuals that are absent from their environment," he said.

New studies have revealed that sheep can remember up to 50 sheep faces as well as familiar human faces, such as their shepherd.

They do this using a similar neural mechanism, and a similar part of the brain, to that of humans. Memories only start to fade after about two years of absence.

Horses may have similar powers...

One inference is that sheep are capable of conscious thought at some level, says Dr Kendrick.

"We [humans] are obviously capable of conscious perception of faces using this exact same system in the brain as is present in the sheep," he told BBC News Online.

"Therefore, it would be surprising if they were not capable of some level of consciousness using that same system."

Old faces

The Cambridge team made their discovery by presenting sheep with 25 pairs of similar faces.

Click here to see a sample pair of sheep faces

The animals were trained to associate each of the pair with a food reward, learning to recognise individual faces.

The scientists then measured activity in regions of the sheep's brain associated with visual recognition.

As in humans, these reside in the temporal and frontal lobes of the brain, including a greater involvement of the right hemisphere.

They found that sheep could remember 50 other sheep faces, even in profile.

...but possibly not cats and dogs

The farm animals were then shown two old faces - a sheep and a shepherd.

Even after two years apart, the sheep still responded to the faces, calling out in recognition.

The specialised face-processing system in the sheep brain offers advantages for long-term recognition of many individuals that are similar to those for humans, say the Babraham researchers.

"In humans, analogous brain regions and neural circuits are activated equivalently when we see or form mental images of the faces of specific individuals," they write in the journal Nature.

"This suggests that sheep may be capable of using the same system to remember and respond emotionally to individuals in their absence."

Medical applications

The team says the work has implications for medicine, as well as animal husbandry.

It could shed light on a rare human condition where people are unable to recognise faces.

The remarkable memory of sheep could extend to other farm animals.

Goats, cattle and horses probably have a similar ability to recognise faces, says Dr Kendrick.

But dogs and cat have poorer visual systems and may not be as well equipped.

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