Allogrooming & Allorubbing in Cats

Allogrooming and allorubbing is when cats groom or rub against other cats, animals, objects, or their humans. (Other animals allogroom and allorub, but we’re sticking to cats in this article.) It’s a crucial part in how they communicate and also bond, so understanding why they do it is important to every cat parent. As usual, let’s take a layperson’s deep dive into these fascinating feline behaviors.

Rigsby enjoys a grooming session from a more dominant cat, Elise.

Allogrooming in Cats

Cleanliness & Scent Spreading

Allogrooming is when one animal grooms another animal. For instance, a mother allogrooms her kittens until they’re old enough to do it themselves. While this is normal behavior and seems pretty straight forward, allogrooming outside of kitten-dom seems to be more complex.

The main purpose of grooming is to clean, but it’s pretty apparent that cats that allogroom are not cleaner than cats that live alone. This means it must have a social purpose.

The groomer nearly always approaches the other cat with a vertically raised tail. Most allogrooming is performed around the head and neck, and it occurs in colonies where the cats are familiar with one another. This is one way for cats to spread their scent around the colony.

Rigsby gets a groomed by two males at one time.

Besides cleanliness and scent spreading, what purpose does allogrooming serve? Most scientists believe the grooming is a way of redirecting aggression or showing dominance. The vast majority of interactions in one study, 94%, began with one animal approaching or inviting the other animal and not when animals were already sitting or lying together.

Redirected Aggression & Dominance

Now, there aren’t a ton of studies on cats allogrooming, so the data is a bit limited, but it still gives us some insight.

In one study, for example, 78.6% of more dominant, higher-ranking cats groomed more submissive, lower-ranking cats more often than the other way around. In 1/3 of these interactions, the groomer was aggressive toward cat he or she was grooming, usually right after the grooming.

We already know cats display redirected aggression. When a cat sees something upsetting that it can’t reach, it will redirect aggression to another cat or person. But what evolutionary purpose would this serve as it relates to allogrooming?

The goal of any successful cat colony is harmony and coexistence. Fights not only risk the health of the cats that are fighting, but also the safety of the entire colony. Nothing calls attention from a predator faster than hearing their prey vocalize. It’s possible allogrooming keeps the peace, lessens fights, and helps the colony stay balanced.

Cats in smaller living spaces have higher numbers of allogrooming and less aggressive behavior between cats. And, consider these facts:

Males more often engage in allogrooming than females. In one study on allogrooming, 65.1% were between two males, 31.3% were males with females, and only 3.6% were two females together.
Males also initiated allogrooming 90.4% of the time.

Why does this support the redirected aggression/dominance hypothesis? Because males tend to be more aggressive than females, especially in outdoor colonies where they are more often unaltered.

My Additional Observations on Allogrooming

There are some points I want to make about this based on my opinion and observations:

A purring and cooperative cat, happily tilting its head, and seemingly offering it for grooming, likely enjoys the grooming and there is a level of bonding to that. I’ve seen cats who are very close participate in this behavior, and when the groomer is done, they may nip to finish it, but that’s as far as it goes. While, yes, the dominant cat is grooming, I don’t see this as a sign for any redirected aggression, especially if the two cats are in a room by themselves and just lying together. And again, why would a submissive cat offer it’s head for grooming if it wasn’t some sort of enjoyable experience.
I’ve read that cats will only groom cats they know. That’s simply not true. One thing I always do when there is a new foster cat, especially a kitten, is present the cat to my resident cats Beaker and Dolly. They both always groom the head, and Beaker sometimes the body too.
I’ve seen allogroomers groom sick cats, most interestingly, cats they don’t normally groom. My Beaker groomed my cat Vito’s head the day before I put him to sleep. Beaker would normally not do this and Vito would normally never allow this. It was a sign to me that Vito was not well.
We have no idea why cats get overstimulated. What if they get this way because they interpret the repeated pets from us as us “grooming” a lower ranking member – especially if they are a dominant cat, they may not appreciate this behavior, and may even be confused by it. Just a thought!

Allorubbing in Cats

Allorubbing is when one cat rubs against another’s head, neck or flanks, but cats also rub against humans and objects. Their skin glands release pheromones, allowing them to scent mark and communicate. Cats have multiple skin glands in their face, paws, and around their tail and genital area. Although it’s suspected cats also rub against each other to create a group scent, more research is needed.

I like to think of pheromones as little sticky notes that tell the cat that left them and other cats things like “This is safe,” “Scratch this,” “This is mine.”

Cats use the vomeronasal organ on the roof of their mouths to detect pheromones. If you see your cat smell something and then have their mouth open slightly, this is the flehmen response, and it means your cat is detecting pheromones.

Cats focus on smelling areas around the head and genital area over the flank and tail. It’s likely the glands on the head and anal glands contain the best and most useful information.

Studies have shown that allorubbing occurs more often between females or males and females than males and males. Cats almost always lift their tails to precede an allorub!

Types of Cat Facial Pheromones

Bunting is specifically when cats rub their heads against something. A cat’s head has multiple glands, including pinna (the ear), temporal glands (above the eye), cheek glands, perioral glands (corners of mouth), and submandibular gland (chin). While it’s not clear if different glands release different substances, facial pheromones alone contain 40 different chemicals. Keep in mind, one pheromone contains multiple chemicals.

Scientists have identified five facial pheromones and have synthesized two of them into diffusers and sprays for pet parents.

F1 – We know the components but not the function.

F2 – Males release this pheromone when they rub on objects during mating, likely to tell the females they’re in the mood for love.

F3 – Comforting, released on objects. May indicate territory or that something is safe. This creates a sense of security and reduces anxiety. Feliway makes synthetic versions: Classic Cat diffuser and Classic Cat spray (I prefer the spray).

F4 – Released when cats rub against other cats and humans. Indicates familiarity with that cat or human. Believed to reduce aggression and communicate safety. There are synthetic versions available.

F5 – We know the components but not the function.

One note is Feliway recently released the Optimum Cat diffuser. Although I could not find out what specific pheromones are in it, based on the description, it sounds like a combination of facial pheromones (but don’t quote me;-)). Studies showed positive results with 93% of cat owners reporting enhanced calming.

Mother-Kitten Pheromone

It’s difficult to find a lot of details on it, but mothers release the cat appeasing pheromone (CAP) from the mammary region. It helps kittens feel safe and secure. Feliway makes a synthetic version in the Feliway Multicat diffuser.

Scratching Pheromone

Cats have interdigitate glands in their toes and foot pads which release a pheromone (feline interdigital semiochemical) encouraging a cat to scratch something. The pheromone is released when a cat scratches an object, which is why it’s hard to redirect a cat after they’ve committed to scratching something you don’t want them to. It also explains why once one cat scratches an item, it’s common for others to follow.

My Additional Observations on Allorubbing

Thoughts on things I’ve seen and experienced:

Rubbing seems to be associated with greetings. Cats often rub against their owner’s legs when they return home or when they greet each other.
I’ve rarely seen allorubbing result in aggression, which means it must have a different purpose compared to allogrooming.
When I have a new object or piece of furniture in my house, I’ll often offer it to the resident cats. Usually, they’ll smell it and then rub against it. This could be a combo of saying “This is safe,” + “This is mine.”
There is a lot of debate over whether allorubbing creates a “group scent.” My personal opinion is that it does. The best evidence we have to support this is pod aggression, when a cat returns from the vet and others don’t recognize the cat because it smells funny. A cat should still have its own smell, so why is that not enough to tell the other cats, “I’m back”? I think the smell of other animals likely covers the group scent (or even scent of the home environment), and that is why the cats don’t recognize him or her.
We still have a lot to learn about pheromones and what they communicate. I strongly believe that cats know the health (and even mental) status of other cats through pheromones. I’ve seen them treat sick cats differently. I’ve also seen a cat that no one likes be attacked when sleeping. If body language is the main piece of communication, how is a sleeping cat an issue? This cat could have a pheromone that is communicating something the others don’t like. I wouldn’t be surprised if traits like anxiety or stress impact the pheromones of humans and cats and therefore affect our relationships with them.