Why Do Cats Smell Each Other’s Butts? 3 Common Reasons

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Image depicting one cat engaging in scent investigation by sniffing the rear end of another cat, a natural behavior that facilitates communication and recognition among felines.

People tend to greet each other with a handshake, hug, or high-five, but many cat owners will have witnessed a much more intimate exchange between cats when they meet each other. Rather than meow a polite hello, after a cursory head sniff, bunt, or rub, many cats head straight for a sniff of the other cat’s butt!

Quick Overview

01

Cats have an amazing sense of smell, having at least 40 times more scent receptors in their noses than people.

02

The vomeronasal organ present in the roof of cats’ mouths detects pheromones, which are chemicals cats use to communicate with each other.

03

Cats sniff each other's butts to get information about each other, such as sexual status and to determine if they have met before.

In this article, we will discuss cats’ amazing sense of smell, explore three reasons why they smell each other’s butts, and let you know if you need to worry about this perplexing behavior.

Also Read: Why Do Cats Put Their Butt In Your Face? A Vet Explains

Super Sniffers

Image capturing a curious cat engaging in scent investigation, using its acute sense of smell to explore its surroundings.

Cats use their incredible sense of smell to hunt prey, avoid toxins, and communicate with other cats.

Although cats have the same basic senses that we do, smell is by far the most important in the feline world. Your cat’s button nose doesn’t just make them look adorable—it contains more than 200 million olfactory (scent) receptors, which is 40 times more than humans!

Cats also have a specialized vomeronasal organ in the roof of their mouths (also known as the Jacobson’s organ) which picks up pheromones. Pheromones are chemicals released from glands on cats’ bodies that act as a form of communication between kitties.

If you have seen your cat pulling a bizarre, grimace-like expression with their mouth partly opened and lips curled after sniffing something, you have witnessed the Flehmen response (which directs scent particles to the Jacobson’s organ for analysis).

Domestic cats share this incredible sense of smell with their wild ancestors, and use it in all areas of their lives, from hunting prey and avoiding toxins to detecting and communicating with other cats.

Let’s explore why cats use their superior olfactory system to sniff the butts of other cats.

1. To Identify Individuals

Tabby cat smelling on the butt of a young blue tabby maine coon

By sniffing butts, cats can tell if they have met before based on the unique scent of all cats.

Cats have two anal glands (also known as anal sacs) that sit just inside the anus at approximately the four o’clock and eight o’clock positions. These scent glands empty when cats poop, releasing a noxious, smelly substance into the rectum and onto the feces.

If you have ever had the misfortune of catching a whiff of the pungent smell of the secretions produced by these glands, you know firsthand that it is pretty revolting! However, these secretions are important in territorial marking.

A study has shown that the contents of feline anal glands vary between individuals, but the makeup of the secretions is highly conserved in any one cat, meaning cats can use the smell to identify each other. By sniffing the bums of a fellow feline, cats can tell if they have met before, or if this is a new cat in the neighborhood.

Also Read: Why Is My Cat Sniffing Everything All Of A Sudden?

2. To Show Dominance

cat smelling another cat's butt outdoors

In the cat world, the first cat to sniff the other’s butt might be doing so in a display of dominance.

There are many forms of communication between cats, sometimes it is very easy to tell from observing cats’ interactions that an individual is trying to display their dominance as they are overtly aggressive in their body language and behavior.

There are also more subtle ways that cats try to exert their dominance over each other, such as being the first to initiate butt-sniffing when two cats meet. The dominant cat might growl or hiss after sniffing and end the interaction, or might allow the more submissive cat to sniff their bottom in return.

Also Read: 5 Things Your Cat’s Butt Can Tell You About Their Health

3. To Discover Mating Status

Charming image of an adorable cat sniffing another cat, demonstrating a common feline behavior used for social interaction and communication.

Cats can learn about about another cat by sniffing their bums. including finding out if a female is receptive to mating.

As mentioned already, pheromones are important chemical messengers released by several glands in cats’ bodies. Although pheromones are usually shared between cats when they rub their faces, heads, and necks on each other, there are also pheromone-producing glands around the tail base and anal area.

Cats also use pheromones in their urine to convey messages about territory, sexual status, and to express stress or fear. Therefore, by sniffing another cat’s rear end, cats can discover a wide range of information about the other individual. For example, male cats can learn if a female cat might be receptive to mating.

Also Read: Why Do Cats Scream When Mating?

Should I Stop My Cat From Sniffing Another Cat’s Butt?

Image of a cat wearing an action camera, capturing a unique perspective as it sniffs another cat, showcasing feline social interactions in an innovative way.

Unless one cat is bullying or hurting another, it’s best to allow them to communicate freely, including sniffing each other’s butts.

There is no need to stop your cat from sniffing another cat’s butt as long as the interaction appears amicable. Cats might return to sniff each other’s butts several times during an encounter, interspersed between head rubbing, bunting, or licking each other. There is no need to interrupt if these signs of a friendly meeting are occurring.

If one cat is persisting despite the other appearing frightened, distressed, or trying to prevent their bottom from being sniffed, then you should try to distract the cats to allow the submissive one to escape.

Also Read: How To Clean A Cat’s Butt In 6 Simple Steps

Final Thoughts

sniffing the butt of another cat

Sniffing butts might seem weird to us humans, but it is an excellent communication tool for cats.

Cats tend to get up close and personal when greeting each other. After an initial head sniff and rub, they often head straight for the other cat’s butt to investigate that area. Cats have an amazing sense of smell and can use the smelly liquid made by feline anal glands to identify other cats and determine if they have met them before.

Sniffing each other’s rear ends also can allow cats to detect pheromones, which give information such as sexual status and readiness to mate. Cats can also display dominance over each other by being the first to sniff the other’s butt in an encounter.

Also Read: Why Do Cats Raise Their Butts When You Pet Them?

Frequently Asked Questions

Why do cats open their mouths when they sniff a butt?

Cats have an organ called the vomeronasal organ (or Jacobson's organ) on the roof of their mouths. This is a specialized scent organ primarily used to analyze pheromones, especially those in feline urine. The cat flicks scent particles onto the organ using their tongue with the mouth held slightly open producing a bizarre facial expression known as the Flehmen reflex.

Can cats identify each other by sniffing butts?

Yes, cats certainly can identify each other by sniffing each other‘s bottoms. A study has shown that the composition of the strong-smelling fluid produced by cats' anal glands varies between individual kitties, but is highly conserved in any one cat, meaning that cats can use their amazing sense of smell to identify if they have met each other before by sniffing butts!

What can a butt sniff reveal?

Cats can learn a lot about each other from a butt sniff, which explains why they carry out this odd cat behavior. The tone of the encounter is set early on, as usually, the more dominant individual will sniff the other cat’s butt first. Cats can identify each other, as well as learn information about the other cat’s sex, readiness to mate, and if they are suffering from fear or stress.

View Sources
Cats.com uses high-quality, credible sources, including peer-reviewed studies, to support the claims in our articles. This content is regularly reviewed and updated for accuracy. Visit our About Us page to learn about our standards and meet our veterinary review board.
  1. Miyazaki T, Nishimura T, Yamashita T, Miyazaki M. (2018). Olfactory discrimination of anal sac secretions in the domestic cat and the chemical profiles of the volatile compounds. Journal of Ethology. 36(1):99-105.

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About Dr. Louise Barnes MRCVS

Louise spent the first few post-grad years in Lancashire, treating a mix of farm animals and pets. After moving to Cambridgeshire, she worked in a hospital looking after small animals and had a special focus on dermatology. Louise is currently doing some locum work as well as writing behavior and nutrition articles for Cats.com.

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