A University of Sussex study has shown horses use visual cues to work out what may be going on in a stable mate’s head – and one of the most important factors for communication is the direction of its ears.
Each horse was individually led to a point where it was released and allowed to choose between two buckets. On a wall behind the buckets was a life-sized photograph of a horse’s head facing either to left or right.
The researchers found if either the ears or the eyes of the horse in the picture were obscured, the horse being led made a random choice between the two buckets. However, if the ears and eyes were visible, then the horse used these directional cues to guide their choice.
Miss Wathan said: “Previous work investigating communication of attention has focused on cues that humans use – body orientation, head orientation and eye gaze, but no one had gone beyond that.
“We found in horses ear position was also a crucial visual signal. In fact, horses needed to see the detailed facial features of both eyes and ears before they would use another horse’s head direction to guide their choice.”
She added most people who lived and worked alongside animals with mobile ears already realised the ears were important in communication, but it had taken science “a while to catch up”.
“We naturally have a humancentric view of the world and as we can’t move our ears they get rather overlooked in other species.”
Prof McComb said the study showed animals other than primates were aware of subtle differences in facial expression and could use these to guide the decisions they made.
“Fine-scaled facial movements can indicate important changes in attention and emotional state and are likely to be crucial in determining social behaviour in a wide range of animals,” she said.
The researchers’ paper, “The eyes and ears are visual indicators of attention in domestic horses”, is published in Current Biology.