This article originally appeared on VICE Indonesia.
Cats and dogs have been known to feel human emotions, sometimes mirroring those by their owners. After all, when browsing through videos and photos of cute animals for our daily dose of happiness, it’s the smiles and hopeful gazes that catch our attention the most.
But some scientists now believe that facial expressions are not an accurate way to read animals’ emotions, because they don’t always correspond with how humans express themselves.
Are animals even capable of crying and smiling in the human sense? If they are, what makes them emotional? If not, how do they feel comfortable expressing emotions?
According to the Smithsonian’s National Zoo Senior Curator Bryan Amaral, animals can actually cry, but not because they feel sad. When animals tear up, it’s usually because their eyes are dry. When animals in the zoo tear up, he immediately calls a veterinarian to make sure it’s not because of an infection or a corneal abrasion.
Professor Ad Vingerhoets from the Tilburg University in the Netherlands said that humans are the only creatures capable of expressing emotion through tears. In his book Why Only Humans Weep: Unravelling the Mysteries of Tears, Vingerhoets wrote that other mammals use a variety of other means to convey signals that they are sad or hurt, like when they are separated from their young.
But it’s not just humans who use facial expressions to convey emotions. Dogs have been known to put on a “cute face” when they want something from humans. A study published in Current Biology gave wolves and domestic dogs a closed container of meat. The wolves attempted only to bust the container open, while dogs made eye contact with humans to communicate their desire.
“Eye contact is a basic mechanism for cooperation. Dogs cannot communicate with language, so instead they use eye contact with humans,” said Alex Benjamin, associate professor of psychology at England’s York University.
A study published in Scientific Reports found that dogs appear to be smiling in positive situations, like while playing or on walks. But scientists are still unsure whether these “smiles” indicate happiness or are simply another means of communication. “There is no data that explains a dog’s smile,” University of Portsmouth researcher Juliane Kaminski said. The debate on animal emotions has been ongoing for over a century. Charles Darwin declared in his 1872 publication The Expression of the Emotions in Man and Animals that humans and animals express emotions the same way. Like how humans cry when they’re sad or laugh when they’re happy.
Although humans like to think that we can read our pets’ facial expressions, we’re probably mistaken. There are more convincing ways to detect animals’ emotions. Researcher Mathilde Stomp, for instance, said horses use grunts to express themselves. Stomp divided 48 horses into two groups: stable horses and outside horses, and found that the “outside” group, which was given the freedom to roam and explore, grunted twice as much as the restricted group.
Stomp concluded that these grunts indicate joy because they grunt similarly when they are eating and playing, instead of when they are agitated by humans.