Why Do Dogs Sniff Each Other's Butts?

It can’t possibly smell that good ... 🤢

dogs sniffing each other's butts

It’s unavoidable. The first thing your dog does when she sees another dog is start sniffing his butt.

If you’re wondering why dogs prefer to meet nose-to-butt instead of face-to-face, you aren’t alone.

Especially since watching the whole thing probably feels a bit awkward (at least to you, anyway).

The Dodo spoke with Dr. Vanessa Spano, a veterinarian at Behavior Vets in New York City, who explained why dogs love to smell each other’s butts so much.

Why dogs sniff other dogs’ butts

It turns out your dog can learn quite a bit about another dog from their — ahem — butt, which is why she always wants to just dive right in!

“Dogs' anal sacs contain a high concentration of apocrine glands,” Dr. Spano told The Dodo. “Apocrine glands produce chemicals, called pheromones, which relay social information.”

And since your pup has such a strong sense of smell, she learns a lot about everything and everyone just from sniffing.

So if your dog meets another dog during a walk, she’ll probably try to beeline right for his bum.

When she does, she’ll start sniffing under his tail, since that’s where the pheromones are released.

“Upon sniffing the recipient dog's emitted pheromones, these olfactory cues are perceived by your dog's brain,” Dr. Spano explained.

She’ll use those cues to figure out how she feels about the other dog, like whether or not she likes him, feels comfortable around him or is afraid of him.

Do dogs get bothered by other dogs smelling their butt?

Even though this is a pretty standard greeting for dogs, not all pups will be cool with your dog sticking her nose up there.

“The recipient may have underlying fear or anxiety related to unfamiliar dogs,” Dr. Spano explained. “Another main reason [the recipient doesn’t like it] could be that the dog who is doing the sniffing does not interpret social cues appropriately and is actually very pushy about this.”

If you’ve ever found yourself stuck in a conversation with someone who doesn’t get that you aren’t in the mood to chat, it’s kind of like that.

In the event that the other dog in question really doesn’t like that your dog is sniffing his butt, the interaction can go south pretty quickly.

If the other dog is afraid of your dog or has aggression, he may start showing signs like:

  • Backing away
  • Tucking his tail
  • Freezing
  • Barking
  • Growling
  • Lunging
  • Biting

“If the recipient dog is showing more subtle signs of discomfort first, like backing away, yawning, or showing the whites of his eyes, but the dog doing the sniffing does not understand these social body language cues appropriately and instead keeps sniffing or attempting to interact,” Dr. Spano said, “the recipient dog may realize these subtle signs of fear are not enough to get the sniffing dog away from him and instead escalate to the clearer signs of barking, growling [or] lunging.”

When to stop your dog from smelling another dog’s butt

If your dog just doesn’t realize that another dog wants to be left alone, you should definitely step in.

“If you recognize that your dog is very pushy about going up to other dogs and persistent about sniffing their hind ends, this may indicate that [she herself] actually has social anxiety about other dogs, [or she] just does not interpret social cues appropriately,” Dr. Spano explained.

According to Dr. Spano, you can’t assume the other pet parent will always know if his dog has inter-dog anxiety or aggression (or that he would automatically avoid these situations if he did).

Instead, you have to make sure your dog develops a proper understanding of social cues and good etiquette, and you yourself should know when to remove your pup from an encounter, if necessary.

“You must take responsibility yourself and avoid unfamiliar [dog-on-dog] interactions until your dog learns how to politely greet other dogs on leash,” Dr. Spano said.

If you want to do this right, you and your dog should work with a reward-based trainer or a veterinary behaviorist.

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