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9 Weird Reasons Why Dogs Sniff Cat Bums

Why Do Dogs Sniff Cat Bums

You’ve seen dogs do it to other dogs. 

But this is strange. 

You see your dog sniff a cat’s bum.

What’s the reason behind that action?

Keep on reading to find out:

  • 9 reasons why dogs sniff cat bums.
  • 3 ways cats let dogs know they don’t like it.
  • 7 things dogs learn from sniffing a cat’s butt. 
  • A simple way to use butt sniffing to introduce dogs and cats.
  • And many more…

Why do dogs sniff cat bums?

Dogs sniff cat bums because of instinct. It’s a way of communicating greetings, identification, gathering information, reinforcing bonds, and relieving tension. It lets the dog know the cat’s mood and whether it’s a friend or not.

9 reasons why dogs sniff cat bums

#1: It’s instinct

Every time they meet each other, dogs sniff each other’s butts. 

Did you know that cats also do this?

It’s an instinct for them. 

Both animals have strong senses of smell. 

The AKC tells us that dogs can smell 10,000 to 100,000 times better than humans.

While cats have 40x more scent sensors in their nose than humans. 

According to this study, both animals often rely on their sense of smell. They use it as a way to navigate their social interactions. 

They use their nose to explore the world. 

And oftentimes it’s their way to communicate. 

Want to learn how they do this?

Then keep on reading.

#2: Greeting each other

In other words, it’s their way of shaking hands. 

For us, it may be alarming when dogs sniff our crotches or our bums. 

But for cats and dogs, it’s only polite.

They have two anal sacs below their anus. 

These release their own signature scent molecules and pheromones.

And the butt contains most of their scent. This is why they use it as a way of greeting each other.

Butt-sniffing etiquette

There also seems to be etiquette for butt-sniffing. 

Well-mannered dogs often do this. But they don’t crowd their potential friend. 

But there are rude dogs. These dogs are aggressive butt-sniffers. 

The minute they meet a new dog, they immediately go for a butt sniff. 

And you’ll often see that these dogs get snapped or growled at by the other dog.

The same goes for friendly dogs and apprehensive cats. 

Some over-friendly dogs might even hump cats.

Canines might get a well-timed swipe on their noses. Especially if the cat feels annoyed or threatened.

#3: A way of communication

Dogs Sniff Cat Bums Because It's Their Way Of Communication

ACS informs us that dogs communicate using:

  • Scent.
  • Barking.
  • Facial and body. 

Butt-sniffing is part of their way to communicate using scent. 

This is why dogs who are new to each other engage in this activity. 

They get to know a lot of things about each other. 

Even their mood (which I’ll talk about later).

Another way dogs use scent is through urine marking. 

Have you gone on your usual walk and your dog keeps sniffing particular spots?

They can be:

  • Fire hydrants.
  • Sides of fences.
  • Telephone poles.

These are prime areas where most dogs will pee. 

It’s their way of saying, 

“Hi, I’m Fido. And I have walks here all the time.

And if your dogs pee in the same place on your lawn, they’re saying:

“This is my home. Nobody trespass.”

#4: For identification

A dog’s sense of smell is so powerful that they can identify their humans by their scent. 

So when your pooch sniffs your cat’s bum, it’s their way of learning the individual smell. 

In fact, this study shows that dogs file it away for later. 

Dogs have a scent memory that they can access. Especially when they encounter the same smell later.

They even remember it more if there are positive associations with the scent. 

Gigi’s nose 

My friend’s dog, Gigi often uses this ability to know when her hooman gets home.

Gigi’s a Pug. She has a bit of an attachment issue with my friend’s brother. Their family often jokes that Gigi imprinted on him.

Every time he’d go out, she’d lie down by the door. And put her little nose in the gap between the door and the floor. 

She’d stay there, whine, and wait. 

My friend knew when Gigi scented him. 

Her nose would twitch like an excited worm. Her droopy tail would perk up and curl. It looks like a wagging croissant.

My friend couldn’t even hear her brother’s footsteps. 

But Gigi already knew her hooman was coming back to her. 

You might also want to know: Can Dogs Imprint On Humans? 13 Signs Your Dog Imprinted On You

#5: To gather information

A butt sniff session tells your dog a lot about the cat. 

As I said before, the anal glands secrete their own individual scent and pheromones. 

But what does this tell your dog?

According to VCA, they can learn the following stuff:

  • Age.
  • Sex.
  • Health.
  • Social status.
  • Sexual status.
  • Emotional state. 
  • Physiological status.

So it’s not just a simple butt sniff. 

It’s a very evolved step of their social communication.

“Do cats do this?”

And cats do this to other cats, too!

So don’t worry that your cat gets confused about why your dog’s nose is on their bum.

The NY Post states that cats do it as a way to say “Hello”

And when you see them raise their tail, it’s their most intimate greeting. And they only show their butts to the ones they trust the most. 

#6: To know friend from foe

To Know Friend From Foe

Did you know dogs do this to know who’s friendly or not? 

I already discussed the many different things dogs can know with a bum sniff. 

They also use it as a way to gauge whether or not to continue interacting with the other dog. 

VCA says that for cats this is a way to identify:

  • Health.
  • Compatibility.
  • Whether they’ve met before.

With cats, there are times when they don’t want to have their butt sniffed. 

And they communicate this by covering their bum with their tail.

It means they’re shy and don’t want to interact just yet. 

Note: When your cat hides away from a butt sniff from your dog, get them used to each other first. 

It may be that the cat isn’t used to dogs. It’s important that they get used to each other. Otherwise, you’re not giving them a chance to be friends. 

This is best if you do this while they’re still young. Or they’re already friends with other species.

You can acclimate them using the following steps:

Step 1: Put them in separate but connecting rooms. 

Step 2: Use a barrier, like a baby gate. Or a mesh one. This allows them to get used to each other’s scent and presence. But you’re not burdening them with a meeting. 

Step 3: When the cat and dog show interest in one another, you can let them meet for short periods. 

Step 4: Let them be around each other for longer and longer. Until both have adjusted. And they’re well-behaved when they’re together.

#7: They want to know the cat’s mood

Another reason why dogs sniff a cat’s butt is to figure out their mood. 

It’s one reason why they do it to other dogs, too.

They’re wondering,

“How’s my little cat friend doin’ today?”

“Is he up for a game of catch my tail?”

“Or is he feeling a little lazy and just wants to cuddle?”

Dogs and cats have a unique way of communicating their emotions. 

They might be different species but they can form really special bonds. 

Love adorable dog and cat friends? 

Then watch this video for more cuteness:

#8: It relieves tension

For humans, a bum sniff isn’t exactly an ice breaker. 

But for cats and dogs, this is a way to break the tension. 

Allowing each other to sniff their butt is a way of saying,

“You’re alright, I guess. I’m okay being your friend.”

For them, this is calming. Any misgivings they have will go away once they do this.

But for dogs who are always aggressive butt sniffers, there might be a problem. 

It might be a sign of stress. 

Check your dog if they show these other signs from VCA:

  • Pacing. 
  • Licking.
  • Panting.
  • Barking.
  • Shaking.
  • Whining.
  • Yawning.
  • Drooling.

Cats who hiss and don’t like a bum sniff, don’t feel receptive to friendly advances from your dog. 

#9: To reinforce their bond

It happens a lot. Especially with bonded dog and cat pairs. 

Butt sniffing is a way to make their friendship stronger. By reinforcing their bond. 

It’s their way of saying,

“Oh! It’s my friend. I love my friend.”

This is why you’ll see dog and cat friends who do it. Even though they’ve been together a long time. 

It also happens when 2 friends haven’t seen each other for a bit. And when their fur parents introduce them again, a bum sniff happens. 

You’ll also often see it when they play with each other. 

It’s a way of checking in how the other’s feeling. Because they also sniff butts to tell the other animal’s mood.

Conclusion: Why do cats and dogs smell each other’s butt?

Dogs and cats smell each other’s butt as a way of communication. They use it for greeting, identifying, gathering information from each other. It’s also a way to know each other’s mood if one’s friendly or not, and to relieve tension. Butt sniffing also reinforces the bond between the two animals.

You might also want to check out: 5 Reasons Why Dogs Sniff Their Own Bums + 7 Dangers