Look at That Face!

A horse named Icaro is the boss of the barnyard on the farm where he lives in East Sussex, England. According to his owner, Nicola Cramond, Icaro knows how to let his fellow horses know who’s in charge: He makes a “snarky face” by pinning his ears back and narrowing his eyes.  

“Horses are expressive,” says Cramond, who has raised the animals for more than 20 years. A new study supports her observation. Scientists recently discovered that horses make a variety of faces. In fact, they have 17 distinct facial expressions. In comparison, people make 27—the most known of any animal.

A horse named Icaro is the boss of the barnyard. He lives on a farm in East Sussex, England. His owner, Nicola Cramond, says Icaro knows how to let his fellow horses know who’s in charge. He pins his ears back and narrows his eyes. That’s his “snarky face.”

“Horses are expressive,” says Cramond. She’s raised horses for more than 20 years. And a new study supports her view. Scientists recently found that horses make a number of faces. In fact, they have 17 different facial expressions. Compare that with people, who make 27—the most known of any animal.

Horses aren’t the only animals whose facial expressions have been studied. In addition to studying humans, behavioral scientists have also looked at the faces made by cats, dogs, and chimpanzees. “Facial expressions have an enormous impact on social interaction,” says Bridget Waller. She’s a psychology researcher and the director of the Center for Comparative and Evolutionary Psychology at the University of Portsmouth in England. 

Waller explains that facial expressions can tell animals what other members of their species are thinking. This helps them avoid conflicts, strengthen bonds, and show intentions to play, mate, or groom. In other words, facial expressions help animals “predict what others are going to do next and act accordingly,” she says.

Horses and humans aren’t the only creatures whose facial expressions have been studied. Behavioral scientists have also looked at cats, dogs, and chimpanzees. Why study animal faces? “Facial expressions have an enormous impact on social interaction,” says Bridget Waller. She’s a psychology researcher and the director of the Center for Comparative and Evolutionary Psychology at the University of Portsmouth in England.

Waller explains that facial expressions carry a lot of information. They can tell animals what other members of their species are thinking. This helps them avoid conflicts and strengthen bonds. It also helps show if they want to play, mate, or groom. In other words, facial expressions help animals “predict what others are going to do next, and act accordingly,” she says.

To understand whether horses made facial expressions, scientists first needed to know more about the animals’ anatomy. Most muscles in the body attach to bones in order to move a body part, like an arm or a leg. But in horses and other mammals, facial muscles attach to the undersurface of skin. Previously, little was known about how these muscles work. That’s because scientists had focused mostly on studying muscles essential to survival—like those used to eat—instead of those used to make facial expressions.

Wathan and her team examined the face of a dead horse. They studied the facial muscles to see how they were attached to the skin. That way they could determine how each muscle contracts and relaxes to move the skin. From this information, the researchers created a virtual map of a horse’s facial muscles (see Making a Face).

Next, Wathan and her team recorded videos of horses in different situations. They visited local farms and stables. They even visited horses having veterinary procedures. That way they could record facial expressions that might occur during a stressful or painful situation. “We tried to capture all the facial movements horses could make,” says Wathan.

Scientists wanted to understand if horses made facial expressions. But first, they needed to know more about the animal’s structure. Most muscles in the body attach to bones. That way, they can move a body part, like an arm or leg. But in horses and other mammals, facial muscles attach to the underside of skin. Scientists knew little about how these muscles work. They had mostly studied muscles needed to survive, like those used to eat. They hadn’t focused on muscles used to make facial expressions.

Wathan and her team looked at the face of a dead horse. They studied the facial muscles to see how they were attached to the skin. That helped them figure out how each muscle contracts and relaxes to move the skin. From this information, the researchers made a virtual map of a horse’s facial muscles (see Making a Face).

Next, Wathan and her team took videos of horses in different settings. They visited local farms and stables. They even visited horses having veterinary treatments. That way, they could record facial expressions that might happen when a horse is feeling stress or pain. “We tried to capture all the facial movements horses could make,” says Wathan.

Then the team went through the painstaking process of carefully watching 15 hours of footage, noting every distinct muscle movement they observed. “Being able to interpret horse faces is something that humans aren’t born with,” says Wathan. “It comes with a lot of experience.” The researchers assigned a code to each expression. The code identified which muscles were responsible for the movement.

Not only did the scientists confirm 17 separate expressions, they also discovered that horses share 10 of the same facial-muscle expressions with people. “The number
of similarities between horses and humans was surprising,” says Wathan. “This suggests that these facial expressions may be very old behaviors that were present in our last common ancestor. Or they may have evolved in humans and horses in response to similar pressures.”

The team gathered 15 hours of video. Then they carefully watched all of it. They noted every different muscle movement they saw. “Being able to interpret horse faces is something that humans aren’t born with,” says Wathan. “It comes with a lot of experience.” The researchers gave a code to each expression. The code showed which muscles triggered the movement. 

The scientists didn’t just spot 17 different expressions. They also found that horses and humans share 10 of the same facial-muscle expressions. “The number of similarities between horses and humans was surprising,” says Wathan. “This suggests that these facial expressions may be very old behaviors that were present in our last common ancestor. Or they may have evolved in humans and horses in response to similar pressures.”

The next step in Wathan’s studies is to link horses’ facial movements with the emotional states that might cause them. Translating horses’ facial expressions could help people understand the animals’ emotions—something they can’t tell us directly. This could be important to veterinarians when an animal becomes ill. It could also help animal owners trying to solve behavioral problems—like when Icaro acts out by “bullying” other horses.  

“We need new methods that allow the animals to tell us what they’re feeling,” says Wathan. One way scientists hope to connect expressions with emotions is by studying which hormones the animal releases at the moment it makes a facial movement, she says. For instance, when a dog seems like it’s smiling, its brain could be releasing endorphins. These chemicals in mammals’ bodies are partly responsible for feelings of happiness.  

Wathan’s studies aren’t finished. The next step is to link horses’ facial movements with the emotions that might cause them. Horses can’t tell us how they’re feeling directly. But their facial expressions could help people understand horses’ emotions. This could be important to veterinarians when animals become ill. It could also help animal owners solve behavioral problems—like when Icaro acts out by “bullying” other horses. 

“We need new methods that allow the animals to tell us what they’re feeling,” says Wathan. One way scientists hope to connect expressions with emotions is by studying hormones. Wathan says that scientists could look at which hormones the animal releases when it makes a facial movement. For example, a dog seems like it’s smiling. At that moment, its brain could be releasing endorphins. These chemicals in mammals’ bodies can cause feelings of happiness.

Some studies also suggest that humans have the ability to accurately interpret some animal emotions by just looking at facial expressions (see Decoding Doggy Emotions). But to know for sure, scientists say that more research needs to be done. 

Of course, for longtime horse lovers like Cramond, Icaro’s owner, the discovery that horses’ faces communicate how they feel comes as no surprise. “People who are around horses all the time are wondering what the fuss is about,” she says.

Can humans just look at an animal’s facial expression and tell what it’s feeling? Some studies suggest that they can, at least with some animal emotions (see Decoding Doggy Emotions). But scientists don’t know for sure. They say that more research needs to be done.

The discovery that horses’ faces show how they feel made headlines. But longtime horse lovers like Cramond, Icaro’s owner, aren’t surprised. “People who are around horses all the time are wondering what the fuss is about,” she says.