Horses use a silent form of communication that involves moving, and paying attention to, eyes and ears, a new study has found.
The research, published in the journal Current Biology, shows how animal ears don't just move to better hear sounds. The movements have meaning to other horses.
"Most significantly, our results demonstrate that animals with large, mobile ears can use these as a visual cue to attention," co-authors Jennifer Wathan and Karen McComb wrote.
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Human ears aren't mobile, so scientists in the past hadn't paid much attention to ears as a means of communication in other animals.
As Wathan, a researcher at the University of Sussex, explained in a press 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."