I Finally Found Out Why Dogs Smell Butts So Much

Written by Austin S.
Updated: October 14, 2022
© Marek Rybar/Shutterstock.com
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I must admit that dogs have a lot of strange behaviors. But one definitely stands out— smelling butts! You must have seen your canine friend smelling each other’s butts at least once or twice. This is weird right? 

And it gets even more disturbing when you see dogs smelling human butts. Why do they do this?

In this article, we’ll answer the question that has always been on your mind about this behavior. And you’ll also learn how you can curb your dog from smelling your guests’ butt.

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Reasons Why Dogs Smell Butts So Much

As a Form of Greeting

While humans would proceed to shake hands and hug each other as a form of greeting, dogs can’t do this. Instead, they replaced these human greeting habits with smelling each other’s butts. 

This behavior is absolutely natural and instinctive to a dog. It is a basic form of dog-to-dog communication. Smelling each other’s butt is a chance for dogs to relieve their stress when encountering other dogs and achieve calm.

The anal secretions from a dog establish which dog will be dominant and set the foundation of the canine relationship.

In most cases, the alpha dog initiates the greeting (sniffing) while the passive one waits for its turn. Dogs may growl during the butt-sniffing to indicate when the other dog should stop sniffing. Sometimes, if a dog doesn’t want to share its information, it may sit down with its tail covering its anus.

Dogs use their exceptional sense of smell to pick up biochemical compounds released by other dogs. When your dog sniffs, she can understand the mood and personality of the new dog. Dogs determine if another dog is a friend or a foe by this initial butt-smelling.

why do dogs sniff butts
A French bulldog and a beagle greet each other by sniffing butts at the park.

©Spiky and I/Shutterstock.com

Gather Information About the Other Dog

Yes, as surprising as it sounds, dogs smell each other’s butts to gather or retrieve information from other dogs. This is because a dog’s butt conveys an array of information unique to each dog. 

This results from the presence of two small anal glands found in the rectum. Each sac contains oil and sweat glands that secrete strong-smelling compounds called pheromones. These pheromones contain scents that are unique to each individual, like fingerprints.

These pheromones give information about the sex of the dog and what the dog fed on. These compounds give clues about a dog’s emotional state. A male dog can be able to detect if a female dog is in heat and ready for mating.


Another unique reason why your dog smells butt is that dogs have a good scent memory. As mentioned above, every dog has a unique scent, and this scent is concentrated at the butt.

So, you may always find your dog smelling the butts of other dogs. This is because dogs smell each other’s butt to determine if they’ve met or are just meeting for the first time.

Dogs are able to associate a scent with a memory or an experience. So a dog’s scent can inform your dog about the previous experience they’ve had, and your dog responds in turn— playfully, with aggression, or in fear.

Also, if two dogs have been separated for a while, and they finally reunite, both dogs smell each other’s rear end to identify one another again.

Reproductive Behavior

Dogs also smell each other’s butt as a reproductive behavior. When a female dog is in heat, it secretes various body hormones like estrogen. Estrogen smell concentration is highest in a female dog’s rear end. Male dogs approach a female dog and smell her butt.

If a female dog is interested and wants to mate, she smells his butt in turn. This is the beginning of the reproductive display that leads to mating.

However, if a female is not in heat, or she is in heat but doesn’t want to mate with the mail, she curls her tail up tightly and covers her vagina and anus. But if the female dog’s tail has been docked (cut off), she sits and covers her anus or vagina or fights the male off.

Dog nose against white background
Dogs use their noses to paint a mental picture of their world and the creatures — including humans — that populate it.


The Power of a Dog’s Nose

One of a dog’s superpowers is its smelling ability. What’s the power of a dog’s nose? Dogs have a very keen sense of smell that greatly surpasses a human’s ability to smell.

Let’s dive into the facts, your dog’s nose contains 150-300 million olfactory receptors, whereas the human nose has just 5 million receptors. Do you think you have a very sensitive nose? Your dog’s sense of smell is 100,000 times more sensitive than yours. 

Do you know a dog can sniff a drop of blood in an Olympic-sized pool?

Dogs interact with their environment with all their senses, but it uses its olfactory senses the most. About 30% of a dog’s brain is dedicated to detecting, identifying, and locating odors.

Dogs are able to gather current and historical information about their environment. They can also locate the source of any smell. This ability is crucial for a dog’s survival. It enabled it to locate food, danger, or mates for reproduction. 

Do you know that when dogs wander in the woods or forest, they rarely get lost? This is because of their strong sense of smell. They urinate on landmarks as they proceed and then retrace their steps by locating the landmarks with their sense of smell.

Humans train dogs to take advantage of their olfactory abilities. Dogs have been used in the detection of drugs and explosives. Research studies show dogs can be used to detect cancer and other illnesses before they manifest.

A Dog’s Second Olfactory System

Dogs have a second olfactory system. This should explain why they have such an acute sense of smell. Dogs have a specialized organ called Jacobson’s organ. This organ is found inside your dog’s nasal cavity, and it opens into the roof of your dog’s mouth behind its incisors.

The Jacobsen’s organ is designed purposely for chemical communication with the brain. Its nerve cells detect odors that would have been otherwise undetected by the nose.

These include compounds or secretions in another dog’s butt.

Both the nose and the Jacobsen’s organ are responsible for the dog’s exceptional sense of smell.

Are Some Dogs More Prone To Sniffing Than Others?

Smelling butt is a prominent behavior in all dog breeds. However, butt-smelling tendency differs between dog genders. 

According to research published by the Journal of the International Society for Anthropology, it has been discovered that male dogs smell butts more than females.

This is explainable because male dogs are generally more active than females. They need to confirm if the female is in heat for mating. And in a pack, male dogs are usually dominant. And, as mentioned above, the dominant dog does the smelling first.

My Dog Doesn’t Smell Butts. Should I Be Worried?

If your dog doesn’t smell butts, there could be various reasons. It could be that your dog isn’t social, or she’s scared, shy, and doesn’t want to meet new dogs.  This could be a result of past negative experiences.

However, you need to confirm if your dog’s sense of smell is still intact, especially if this is a sudden change in your dog’s behavior. Take your canine friend to the vet for a medical check-up to ensure she’s in good health.

Why Your Dog Smells Your Butt

Your dog smelling your butt or other people’s butt can be pretty embarrassing. Why do they do this? First, your dog doesn’t know that’s not how to greet humans. Since butt sniffing is how dogs greet one another, your canine friend is just trying to be friendly and welcome you or your guest.

However, humans also have a lot of hormonal concentration in their genitals. And this odor can be detected as well when your dog smells your butt.

When your dog smells your butt or a stranger’s, she can determine four main things:

  • The sex of the individual
  • If the individual is menstruating or not
  • If the individual is pregnant or gave birth recently
  • The hygiene of the individual
Diabetic dog treats
You can train your dog not to sniff human butts through positive reinforcement.

©Natalia Bostan/Shutterstock.com

How To Stop Your Dog From Smelling People’s Butts

Even though your dog has the best intentions for smelling your butt or your stranger’s, it is still an embarrassing experience. 

So, to stop your canine friend from smelling your guests’ butt, you can do these few things:

  • Train your dog to be calm, and sit whenever someone new enters your house. Practice the obedience-for-treats technique. Reward your dog with treats whenever it does this.
  • Inform your guests beforehand to offer their hand for sniffing if your dog charges to smell them.


While it is perfectly normal for you to shake and hug a friend or a co-worker, dogs smelling each other’s butt is also a natural instinctive behavior. This is not a behavior you can eliminate. However, you can train your canine friend to refrain from smelling people’s butts.

Dogs are fascinating creatures, and we have many more interesting posts dedicated to them. You can check them out below:

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The Featured Image

why do dogs sniff butts
Two dogs gently sniffing and greeting each other in an autumn meadow.
© Marek Rybar/Shutterstock.com

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About the Author

Growing up in rural New England on a small scale farm gave me a lifelong passion for animals. I love learning about new wild animal species, habitats, animal evolutions, dogs, cats, and more. I've always been surrounded by pets and believe the best dog and best cat products are important to keeping our animals happy and healthy. It's my mission to help you learn more about wild animals, and how to care for your pets better with carefully reviewed products.

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