When a Cat Licks Another Cat, It's Not Always a Friendly Gesture. New Study Reveals They May Just Want Their Own Space

Cat owners have long assumed that when one feline grooms another, it's a straightforward sign of affection. A new study is complicating that picture, suggesting that the tongue bath many pet owners find endearing can sometimes function as a subtle power play rather than a gesture of bonding.

The behavior, known scientifically as allogrooming, is common in households with more than one cat and shows up constantly in viral pet videos online. Two cats nuzzling and licking each other reads as tender to most observers. But researchers say the motivation behind the act isn't always what it looks like on the surface.

The investigation traces back to an observation made by Morgane Van Belle, a veterinarian at Ghent University in Belgium. She noticed a repeating pattern between her own cats: one would be resting near a window, and the other would come over and start licking its neck. Shortly afterward, the grooming would turn into nipping, and the cat that had been lounging by the window would get up and move away, leaving its spot to the groomer.

That pattern struck Van Belle as more calculated than affectionate, and it pushed her and a team of colleagues to look more closely at what allogrooming actually accomplishes between cats sharing a home. Rather than relying on assumptions, the researchers set out to gather real-world footage and analyze what preceded and followed each grooming session.

For the research, the team gathered video recordings of allogrooming episodes submitted by 53 households where two cats lived together. The scientists examined traits of the individual cats involved, details of how the grooming itself unfolded, and the behaviors that tended to accompany or follow it, such as biting or one cat retreating from a shared space. The findings were published in May in the journal Applied Animal Behaviour Science.

By tracking what happened immediately after grooming sessions, the researchers were able to see whether the interaction ended peacefully or whether it triggered tension, such as one cat displacing the other from a favored resting place. That before-and-after approach let them distinguish grooming that appeared to strengthen social bonds from grooming that seemed to serve a more self-interested purpose, like claiming territory or resources.

The results add nuance to how scientists and pet owners alike interpret everyday cat behavior. Not every lick is a peace offering, and a session of mutual grooming that ends in a nip and one cat walking away may reflect an underlying negotiation over space rather than simple companionship. Researchers note that allogrooming likely serves multiple, sometimes overlapping functions depending on the individual cats and their relationship, meaning a single grooming session can't always be read the same way twice.

The study is expected to inform further research into feline social dynamics, particularly in multi-cat households where competition for resources like windowsills, food, and attention from owners can create friction beneath seemingly amicable behavior. For now, experts suggest that owners who see one cat groom another should pay attention to what happens next, since the aftermath may reveal more about the relationship than the grooming itself.

Source: Smithsonian Magazine