Cambridge University researchers were able to train sheep to identify the faces of actors Jake Gyllenhaal and Emma Watson, former US President Barack Obama and BBC newsreader Fiona Bruce.
Scientists showed how they could be taught to recognise screen-shot images of celebrity faces using food rewards.
Sheep learnt to recognise Barack Obama after being shown his photo a few dozen times, said a study Wednesday which suggested our four-legged friends may be smarter than we think. They wanted to see whether the farm animals could correctly identify the same celebrities when pictured from different angles.
The paper notes the possibility that the sheep in the experiment having extensive contact with humans might potentially have led to making them human face experts. If it approached the wrong image, a buzzer sounded and no reward was given.
But even so it shows sheep aren't quite as dumb as people like to make out. They were naturally familiar with their handlers, having spent up to two hours a day with them, so when a photo of the handler was swapped with that of the celebrity, they successfully picked it seven times out of ten.
In a fifth, and final task, the sheep were shown a photograph of their day-to-day handler - who they know well but have never seen a picture of - next to that of an unknown person. "My guess is that the ability of sheep to recognize human faces is a by-product of selection to discriminate between different sheep faces", he says.
She added: "Sheep are long-lived and have brains that are similar in size and complexity to those of some monkeys".
The face recognition ability of sheep could now be used to investigate Huntington's disease and other human brain disorders that affect mental processing, said the researchers.
Finally, the researchers looked at whether sheep were able to recognise a handler from a photograph without pre- training.
"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".
A reward of cereal pellets was dispensed when a sheep crossed an infra-red beam in front of the celebrity image.
After establishing the animals' ability to recognise the celebrities, researchers set them a new task.
First they checked the unfamiliar of the two faces presented, then the handler's image, and then the unfamiliar face again before making a decision to choose the handler.
An incurable neurodegenerative disease that typically begins in adulthood, it begins by affecting motor co-ordination, mood, personality and memory, as well as other symptoms including impairments in recognising facial emotion.
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