Horses can read human facial expressions, study suggests

A new study suggests horses may be able to read human facial expressions especially anger.

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University of Sussex researchersexamined the reactions of 28 horses to photographs of people making positive and negative expressions.

When the animals saw images of angry faces, theylooked at the picturesmore with their left eyes a behaviour previous studies have shown is associatedwith perceiving negative stimuli, according to the study published in Biology Letters.

That's likely because the left eye processes information for the right hemisphere of the brain,which in turn processesthreats.

What's more, the angry expressions caused the horses to show signs of stress, including an increased heart rate.

"The reaction to the angry facial expressions was particularly clear,"Amy Smith, a doctoral student in theMammal Vocal Communication and Cognition Research Groupat Sussex whoco-led the research, said in a press release.

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The animals didn't have strong reactions to the happier faces, which suggests their facial expression recognition abilities may be defensive in nature, the researchers say.

"This may be because it is particularly important for animals to recognize threats in their environment," Smith said. "In this context, recognizing angry faces may act as a warning system, allowing horses to anticipate negative human behaviour such as rough handling."

Co-author Karen McComb, a University of Sussex animal behaviour professor, has a couple of theories as to why horses have learned to read human emotions.

"Horses may have adapted an ancestral ability for reading emotional cues in other horses to respond appropriately to human facial expressions during their co-evolution," she said.

"Alternatively, individual horses may have learned to interpret human expressions during their own lifetime," she said.

"What's interesting is that accurate assessment of a negative emotion is possible across the species barrier despite the dramatic difference in facial morphology between horses and humans.

"Emotional awareness is likely to be very important in highly social species like horses and our ongoing research is examining the relationship between a range of emotional skills and social behaviour."

AUniversity of Helsinki study about dogslast monthfound similar results.Canines also react moststrongly to angry or threatening expressions.