Human ears are much more likely to receive information than send it ("what your earrings say about you" quizzes notwithstanding). A horse's swiveling ears, however, play an important role in communication, according to a new study in the journal Current Biology. Ear posture, say researchers at the University of Sussex, England, is an under-studied area of communication, because our lobes don't convey much -- but for horses, ears tell another story.
The position of an equine ear is a "crucial visual signal that other horses respond to," says University of Sussex communication expert Jennifer Wathan, in a press release. "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."
In a series of tests, the Sussex scientists led a horse to a pair of buckets, and then let the animal pick. Plastered to the wall behind each bucket was a life-size picture of a horse's head, facing the bucket to the left or right. When the researchers covered up the photo's eyes or ears, the horse in question selected a bucket seemingly at random. When presented with an entire horse head image, on the other hand, the horse chose his or her bucket deliberately, using the photo's ears and eyes as guides.
Horses, like chimpanzees, elephants and dolphins -- and humans -- live in "complex and fluid" social groups, Wathan points out. Without ways to convey information -- be it the wag of a tongue or the wiggle of an ear -- life in these social groups would be impossible.
"Most people who live and work alongside animals with mobile ears would agree that the ears are important in communication, but it has taken science a while to catch up," Wathan says. "We naturally have a human-centric view of the world and as we can't move our ears they get rather overlooked in other species."