One minute your two cats are curled up together, one licking the other’s head. The next, there is a hiss, a swat, and someone storms off. It is confusing: were they friends or not? Research on cat grooming suggests both can be true, and it explains why the licking so often ends in a scuffle.
Why cats groom each other
Grooming another cat is called allogrooming. For a long time it was seen mainly as a sign of affection between cats that get along. That is still part of the picture: cats that groom each other often sleep together and play together. But researchers have found that it is not always friendly.
What the research found
The 1998 study was carried out in a confined group of cats, so the author presented his idea as a hypothesis. Together, though, the two studies point the same way: grooming can be friendly, tense, or both.
Friendly or tense? The signs
| Usually friendly | Signs of tension |
|---|---|
| Both cats relaxed, often lying together | One cat leans heavily over the other |
| Grooming is shared, back and forth | Always the same cat grooming |
| Ends with sleeping or calm separation | Ends with hissing, chasing or one cat leaving fast |
| Ears forward or relaxed | Flattened ears, lip licking, head shaking |
| Both seek each other out later | One cat avoids the other or hides |
If you are not sure whether your cats’ wrestling afterwards is play or a real fight, our guide are my cats playing or fighting? breaks down the body language.
What to do
- Watch the whole interaction. Note who grooms whom, how it ends, and whether one cat starts avoiding the other.
- Interrupt calmly if tension builds. Toss a toy away from both cats or make a soft noise to break it up before it escalates. Do not put your hands between them.
- Double up on resources. RSPCA Australia advises one of each resource per cat plus one extra, in separate locations: food, water, litter trays, resting places and hiding spots.
- Play with each cat. The RSPCA lists the opportunity to play and express hunting behaviour as a core need for every cat in the home.
- Give each cat a safe place. The RSPCA lists a safe place as an essential need. Shelves, cat trees and hiding spots also let a cat move away without being cornered.
FAQ
Why do my cats groom each other and then fight?
Grooming can be friendly, but research suggests it is also a way cats manage tension. A 1998 study found aggression in about 35% of grooming interactions, so a swat afterwards is common.
Does grooming mean my cats like each other?
Often, yes, especially when it happens while they rest together. But tense grooming, where one cat leans over the other and the groomed cat looks uncomfortable, is not a sign of a close bond.
Why does my cat bite the other cat’s neck while grooming?
Grooming is mostly aimed at the head and neck. A gentle nip can happen, but repeated hard bites followed by chasing suggest tension rather than affection.
Should I stop my cats from grooming each other?
No. Only step in, calmly, if the grooming regularly ends in real fights or one cat is clearly stressed.
When is it a real problem?
When one cat hides, stops eating, toilets outside the tray, or either cat is injured. See your vet and consider a qualified behaviourist.
Sources
- van den Bos R. The function of allogrooming in domestic cats (Felis silvestris catus); a study in a group of cats living in confinement. Journal of Ethology, 1998;16:1-13. PDF
- Brussels Times. Belgian researcher uncovers the disturbing truth behind why cats groom each other, July 2026 (on the Ghent University study by Morgane Van Belle). Read
- RSPCA Australia. What do I need to know about multi-cat households? Read
- Live Science. Why do cats lick each other? Read
This article is for general information and is not a substitute for advice from your veterinarian or a qualified behaviourist.
