WHEN CATS PLAY, THEY MIRROR ONE ANOTHER’S FELINE FACES

Animal play is a mix of fun, fairness, chaos, and serious business. The diverse ways in which animals engage in play with each other continue to captivate people—from researchers and citizen scientists to anyone curious about what animals are doing, thinking, and feeling while they play. After all, animals across many species “just wanna have fun.”

It’s a given—cats, dogs, and a host of other animals love to play with their companions in all sorts of ways, and they have a great time doing it.

For play to stay fun, it’s crucial that individuals, whether they’re wrestling or zooming around in excitement, are able to signal their intentions clearly. Play often involves behaviours that are also seen in aggression, predation, and reproduction, so players need to communicate something like, “I want to play, not fight, hunt, or mate with you.” Similarly, if play gets a little too rough or intense, they need to reassure their playmates with signals like, “This is still play—I’m not trying to hurt you” or even apologize, saying something like, “Sorry I bit you too hard or mounted you—let’s keep playing.”

Play is a sensory kaleidoscope. When canids, felids, and other animals engage in play, they often use behaviours like vigorous biting, mounting, and body-slamming—actions that can easily be misunderstood by those involved. Research shows that many animals, including companion dogs, make a conscious effort to play fair by following what could be called “the golden rules of play”: ask first and communicate clearly, mind your manners, admit when you’re wrong, and be honest. By adhering to these rules, animals are able to carefully navigate play, ensuring that things like rough-and-tumble games don’t spiral into real fights.

Cats use facial expressions to get along, have fun, and play fair

The play behaviours of companion cats are gaining increasing attention, making it easier to distinguish between when cats are playing and when they are fighting. When cats seem to be “going crazy” during play, they’re just being their natural, playful selves—not exhibiting any signs of aggression or psychopathy. Cats use facial expressions during play and even mirror each other’s facial cues to maintain a playful mood, signal consent to continue playing, and keep the interaction positive.

Researchers filmed cats interacting and categorized their encounters as either affiliative (e.g., grooming, resting together, sniffing noses, or tail positioning) or non-affiliative (e.g., behaviours like staring, slow approaches, defensive posturing, and fighting-related actions like biting and swatting). To study facial expressions, they used the Cat Facial Action Coding System (CatFACS), analyzing 48 distinct facial markers. Machine learning models were then employed to classify the interactions as either affiliative or non-affiliative and to determine whether the cats were mimicking each other’s facial expressions using a technique called type matching.

The results of this detailed and labor-intensive study are both fascinating and significant. In simple terms, the data show that cats mirror each other’s facial expressions, which helps them play fairly and get along.