How Horses 'Talk' to Each Other: Communication with Eyes and Mobile Ears

Horses are smart for animals, communicating to others of their kind with bodily expressions. Now, scientists have taken a closer look at how horses "speak" to one another, and found that they're sensitive to the facial expressions and attention of other horses, including the direction of the eyes and ears.

In the past, researchers believed that animals to the sides of their heads could not glean information based on the direction of one another's gaze. This latest study, though, seems to challenge that.

In order to learn a bit more about horse communication, the researchers took photographs to document cues given by horses when they were paying attention to something. The scientists then used these photographs as life-sized models for others horses to look at as they chose between two feeding buckets. In each case, the horse in the photo was paying attention to one of the buckets and not the other.

"Our study is the first to examine a potential cue to attention that humans do not have: the ears," said Jennifer Wathan, one of the researchers, in a news release. "Previous work investigating communication of attention in animals has focused on cues that humans use: body orientation, head orientation, and eye gaze; no one else had gone beyond that. However, we found that in horses their ear position was also a crucial visual signal that other horses respond to. In fact, horses need to see the detailed facial features of both eyes and ears before they use another horse's head direction to guide them."

The scientists found that horses rely on the head orientation of their peers to locate food. Yet the ability to read each other's interest level is disrupted when parts of the face are covered up with masks.

"Horses display some of the same complex and fluid social organization that we have as humans and that we also see in chimpanzees, elephants, and dolphins," said Wathan. "The challenges that living in these societies create, such as maintaining valuable social relationships on the basis of unpredictable interactions, are thought to have promoted the evolution of advanced social and communicative skills. There is a general interest in studying species with this social structure."

The findings are published in the journal Current Biology.