"Psst, Flicka, the hay's in that bucket!"
Though talking horses like Mr. Ed may be pure fiction, horse communication is real, new research suggests.
Horses communicate to their buddies with a cocked head, perked ears and a side-eye gaze, according to a study that was published yesterday (Aug. 4) in the journal Current Biology. The study is one of the first to investigate in-depth how these social animals communicate.
"Our study is the first to examine a potential cue to attention that humans do not have: the ears," study co-author Jennifer Wathan, a psychologist at the University of Sussex in England, said in a statement.
Plenty of nonhuman animals have revealed their interesting communication skills to curious scientists. Dolphins converse via an elaborate system of clicks and whistles, have signature whistles that act like names, and can remember old friends' "names" decades after first encountering them. Many great apes communicate by gaze, body language, vocalizations and even scent. Ravens gesticulate with their beaks and wings. And elephants gesture with their tusks. [The 5 Smartest Non-Primates on the Planet]
Most studies in animals, however, assumed the creatures communicate like humans via body language and gaze. Researchers also assumed that animals with eyes on the sides of their heads, such as horses, didn't use gaze to communicate.
But horses are social animals that constantly need to communicate with each other, whether to alert group mates to the presence of a predator or to share news of a tasty food source.
To understand how horses communicate, Wathan and her colleagues took photos of horses when the animals were paying attention to something. In some of the photos, the horses were given masks that obscured their eyes or ears. Other photos left the creatures' eyes and ears exposed.
Next, the team placed the photos such that the images were "looking" at one of two buckets of food, then brought in real horses.
When the photographed horse's entire face was visible, the real horse usually went straight to the food bucket the horse replica was looking at. The horses seemed to use head orientation to guide their decisions.
But if the horse in the photo had masked eyes or ears, the real horses went to either bucket an equal number of times, suggesting the animals couldn't interpret much information from the photos.
"We found that in horses, their ear position was also a crucial visual signal that other horses respond to," Wathan said in a statement. "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 findings suggest that horses use the eyes and the ears to communicate. In addition, the new research shows that even animals with eyes on the sides of their heads can communicate via gaze.