We all know horses can pick up on our moods - but a new study has found they can also recognise our facial expressions.
Scientists at the University of Sussex found that when horses were shown a picture of an angry face, their heart rate increased and they moved their heads to look at the image with their left eye. Horses are known to turn their heads to the left when viewing threatening or negative stimuli.
There were 28 horses in the study, which were recruited from five yards in Sussex and Surrey between April 2014 and February 2015.
Each horse was shown photos of happy and angry men they had never seen before, and their behavioural and physiological responses were measured.
“We have known for a long time that horses are a socially sophisticated species, but this is the first time we have seen that they can distinguish between positive and negative human facial expressions,” said Amy Smith, a doctoral student in the university’s mammal vocal communication and cognition research group.
“The reaction to the angry facial expressions was particularly clear – there was a quicker increase in their heart rate, and the horses moved their heads to look at the angry faces with their left eye.”
Previous research has shown a number of species, including dogs, view negative events with their left eye. Information from the left eye is received in the right hemisphere of the brain, which is where threatening stimuli is processed.
Amy said there are several possible explanations for their findings.
“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 explained. "Alternatively, individual horses may have learned to interpret human expressions during their own lifetime.”