Why Do Dogs Sniff Butts? 7 Fascinating Things to Know About Backside Smells | Pupford

I remember being a young dog sitter and taking the dog on a walk, seeing him sniff a dog’s butt, and alarmingly wondering to myself ‘WHY do dogs sniff butts’?!

I was 10 years old and thought it was hilarious, of course, but also could tell it probably was for a specific reason. Well, fast forward a couple of decades, and current me is going to amaze you (and 10-year-old-me) with all the facts about dogs and butt sniffing!

While I’ll do my best to hold in as many butt jokes and puns (was that one already?! 😜), there are some seriously amazing reasons as to why our pups love to sniff each other’s backsides!

Here’s what we will cover:

1. Dog’s sense of smell compared to humans
2. The Jacobson’s organ (aka vomeronasal organ)
3. Pheromones
4. Things dogs learn by sniffing butts
5. Should you let dogs sniff each other’s butts
6. What if your dog doesn’t sniff other dogs
7. Where human pheromones are and how it compares to dog-dog butt sniffing

Let’s get our butts in gear and learn all about it! 🍑

Related Reading: Why Do Dogs Eat Poop?

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DOGS AND BUTT SNIFFING, AN OVERVIEW

Let’s answer the main question first because that’s what you came here for!

Dogs sniff each other’s butts to learn information about the other dog. That’s the basic reason!

Of course, we’re gonna go more in-depth than that, but there’s your “tweetable” answer.

Now, here are 7 things we’re going to learn about in this article as it pertains to your dog, their butt, another dog’s nose, your dog’s nose, and another dog’s butt. You can skip to #4 if you’d like, but I promise points 1-3 are fascinating and will help you understand the entire butt-sniffing picture!

1. Dog’s sense of smell compared to humans
2. The Jacobson’s organ (aka vomeronasal organ)
3. Pheromones
4. Things dogs learn by sniffing butts
5. Should you let dogs sniff each other’s butts
6. What if your dog doesn’t sniff other dogs
7. Where human pheromones are and how it compares to dog-dog butt sniffing

Let’s explore each of the 7 points a bit further!

Related Reading: 15 Funny Things Dogs Do & Why

1- DOG’S SENSE OF SMELL COMPARED TO HUMANS

Dogs are much better than humans at many things. Catching things with their mouths, loving unconditionally (don’t have time for that philosophical conversation right now), and of course, smelling.

A dog’s sense of smell is about 100,000 times stronger than ours.

That is in large part due to olfactory receptors. Olfactory receptors are protein-coupled receptors that play a critical role in how we recognize and understand the smells around us.

Humans have about 5 million olfactory receptors.

Dogs have about 150 million! 😲

The sheer volume of receptors is part of why dogs are so skilled at pulling in and making sense of the smells around them. Plus, dogs typically are using about ⅓ of their brain to understand smells around them, while we humans only use about 1/20 of our brains for smell-related functions.

But, that’s not the only reason… ⬇️

2- THE JACOBSON’S ORGAN (AKA VOMERONASAL ORGAN)

Much of your dog’s top-notch smell sense is thanks to what’s called the Jacobson’s organ, or the vomeronasal organ.

While humans are typically believed to have the Jacobson’s organ, its function is debated and most agree it doesn’t serve a sensory function.

Dogs on the other hand very much have, use, and rely on Jacobson’s organ in how they interact with the world around them. This is especially true when it comes to chemical communication (aka butt sniffing, but we will get there).

The vomeronasal organ, aka Jacobson’s organ, is located inside the nasal cavity just above the roof of the mouth. When the vomeronasal organ interacts with certain chemical smells, it relays that information to the brain.

(I won’t get any more technical than this, but I suggest you do some research if you’d like to learn more about the ins and outs of our dog’s nose/smelling from a scientific standpoint.)

Essentially, the vomeronasal organ plays a role specific to receiving, understanding, and interpreting chemical signals put off by other animals, especially those of the same species.

I promise this is leading into why dogs sniff each other’s butts, so stay with me here!

3- PHEROMONES

Pheromones are chemicals that animals produce that change the behavior of and signal information to another animal of the same species.

What does that really mean..?

Think of them as messages that are secreted by our dogs to other dogs through chemical smells. And where do those messages get released?!

You guessed it… The butt! Well, more specifically through the anal glands, near your dog’s butt.

Related Reading: Dog Scooting On Their Butt? Here's Why

They are also released in dogs’ ears, but dogs typically don’t sniff there because head-to-head interactions are often perceived as threatening.

And now, let’s tie in the vomeronasal organ. That organ is especially important for sensing and interpreting pheromones compared to everyday “normal” smells.

So let’s break it down. ⤵️

1. Every time your dog poops they secrete pheromones through their anal glands
2. While we typically don’t smell the pheromones (because we smell the stinky poop), they do have their own stinky smell
3. Those pheromones then become “part” of your dog’s smell profile
4. Dogs smell each other’s pheromones (with help of the vomeronasal organ) to learn about each other

Okay, so that is certainly an oversimplified explanation, but you should get the point!

Every dog has a unique makeup of pheromones that are secreted with each bowel movement.

So, that leads to the main question… What are in those pheromones, and what can dogs learn from sniffing each other’s specific scent profiles?

4- WHAT THINGS CAN DOGS LEARN BY SNIFFING EACH OTHER'S BUTTS?

Dogs sniff each other’s butts to learn about each other. That’s this entire article boiled down to one sentence!

But, of course, the next question is, what can dogs learn about each other when sniffing each other’s backsides?

Oh, and it’s interesting to note that part of dogs’ unique smell system enables them to focus on the dog’s pheromones and not the smell of poop/stinky stuff only. So interesting!

Here are some pieces of information your dog learns when they sniff another dog’s butt:

• The dog’s gender
• The dog’s sexual status (intact vs spayed/neutered, in heat, etc.) and subsequently if they would be a good mating partner
• The dog’s age
• If the dog is sick or generally healthy
• The dog’s mood and whether they may be aggressive, happy to play, etc.
• Whether they’ve met before (seriously)
• And even what the dog may have been eating recently

STOP and think about that for a moment. What we humans perceive as a kind of weird behavior (the butt sniffing) is actually a tool your dog uses to get to know the other dogs around them!

When you first meet someone you typically ask where they live, where they grew up, what they do for work, if they have kids, and other pleasantries.

Our dogs don’t have to ask, they just learn it all through sniffing each other!

And that leads us to the next section… ⤵️

5- SHOULD YOU LET DOGS SMELL EACH OTHER’S BUTTS?

In most cases (more later on why I say most), you should let your dog sniff other dogs’ butts. It is a vital part of their interaction and how they get to know each other.

Many dogs will actually calm down and relax more around other dogs once they’ve had a chance to investigate those pheromones! It’s like how you open up more and relax once you’ve at least gotten to know the basics of a new colleague.

I did say in most cases though because some dogs don’t handle the sniffing well. This is especially true for dogs that are shy, anxious, or nervous around other dogs.

For example, my dog Sunny can be slightly uneasy with all the sniffing because she has hip dysplasia and it makes her nervous when dogs go near her hips (understandably).

So, keep an eye on your dog’s body language and see how they are handling each interaction. While good rear-end sniffing should be encouraged and allowed, it isn’t a requirement if your dog isn’t comfortable with it.

6- WHAT IF YOUR DOG DOESN’T SNIFF OTHER DOGS

Many people wonder then, what happens if my dog doesn’t really sniff other dogs’ butts?

That’s okay! You don’t have to force them to.

Dogs are unique creatures and each behaves, interacts, and even sniffs differently than others. And while most dogs do sniff other dogs, it’s not a problem if your dog doesn’t!

7- WHERE HUMAN PHEROMONES ARE AND HOW IT COMPARES TO DOG-DOG BUTT SNIFFING

Now that you know all about why dogs sniff butts, you might be wondering about pheromones and sniffing in relation to humans?

Well, humans secrete most of our pheromones in our armpits and crotch.

And since most dogs can't really reach our armpits, they’ll go for a sniff of people’s crotch area.

At least now I can have an explanation for people when my dog shoves their head in a stranger’s crotch! 🤦

RECAP OF WHY DOGS SNIFF BUTTS

Dogs are peculiar creatures with extremely sensitive noses. Dogs use their heightened sense of smell to learn loads of information about the dogs (and people) around them.

To recap, here are things your dog can learn when they sniff another dog’s butt!

• The dog’s gender
• The dog’s sexual status (intact vs spayed/neutered, in heat, etc.) and subsequently if they would be a good mating partner
• The dog’s age
• If the dog is sick or generally healthy
• The dog’s mood and whether they may be aggressive, happy to play, etc.
• Whether they’ve met before (seriously)
• And even what the dog may have been eating recently

Learning all about our dog’s behavior and what makes them tick can help us raise better-behaved dogs! For a deeper dive into dog body language (butt sniffing is part of it), head here to access the Dog Body Langauge Course taught by Traci Madson CPDT-KA.

What’s your funniest dog butt-sniffing story?! Tell us in the comments below!