Cathy GaitIf you’re a loving pet parent, you can help but to have noticed a particularly vexing behavior in your best canine friend. Every time he meets another dog, he promptly sniffs the other’s butt. What is so attractive about that rear end, anyway? And isn’t there a better way?
As it turns out, butt-sniffing is more polite! Let’s take a closer look at this odd greeting.
Why Do Dogs Sniff Other Dog’s Butts?
I’m guessing that most of the time, you don’t sniff another person’s butt, so why would your dog? Well, there are actually a few reasons your dog is interested in the junk in another dog’s trunk. These concern your dog’s superior sense of smell and canine etiquette.
Butt Sniffing = The Nose Knows
One of the biggest reasons dogs sniff other dogs’ butts has to do with their olfactory system. This refers to the system that governs your dog’s sense of smell, but it goes way beyond that.
Just to give you an idea of how powerful a dog’s nose is, they have some 300 million olfactory receptors in their noses. That compares with only about five million in humans. From our perspective, our beloved best friends have super sniffers!
But there’s more still. Inside a dog’s nose is a unique organ called the vomeronasal organ, or as it is probably more commonly known, the Jacobson’s organ. This organ is referred to as the ‘second nose,’ and it’s located in the nasal cavity near the roof of the dog’s mouth.
The Jacobson’s organ is wired to a different part of your dog’s brain than his nose, which plays a vital role in butt-sniffing. Jacobson’s organ is what can detect the so-called undetectable odors such as pheromones.
Butthole Pheromones and Chemical Communication
These pheromones and other compounds are released by special glands in your dog’s anus. These are called the anal sacs or anal glands. Through the secretions released by the anal glands, your dog actually experiences a form of chemical communication with other dogs.
Compounds in a dog’s anal glands can allow your dog to gather information about a new friend. In fact, the anal gland parfum — ahem, for lack of a better term — is as unique as a fingerprint.
While humans can smell the secretions from the anal sacs, that scent is usually covered by your dog’s poop. Unless you get really close (I don’t recommend it), you’re unlikely to detect the odor, and you won’t be able to perceive all the valuable information your dog will from the scent.
These chemicals can give your dog information about this new dog’s reproductive status. They also give your dog information about the other dog’s diet, health status, temperament, gender, and much more. These pheromones can even give your dog information about another dog’s emotional state.
From just a quick sniff, your dog will know if his new friend is aggressive, calm, excited, or in a playful mood. Your dog will also store that dog’s particular eau d’butt, as it were, in his memory, so he will know the next time these two dogs meet that they’ve met before, and he’ll remember which of them is dominant.
What Does Butt-Sniffing Have to do with Dog Behavior?
Great question and the answer is a lot!! When two dogs meet, they will typically sniff each other’s butts, and this allows them to determine which one of them is the dominant dog and which is the submissive dog.
It’s the foundation of canine relationships, and it’s part of why you should let them sniff away unless they’re overly aggressive. They’re much less likely to fight once they know who’s who in the canine hierarchy.
The dominant dog will typically initiate the sniffing while the submissive one waits his turn. The dominant dog will also often growl after he is done sniffing. If the submissive dog begins to sniff first, he may stop and retreat. He knows his place in the butt-sniffing order.
If your dog is more introverted, he may choose to limit the information he gives out by sitting down and clamping his tail over his rectum. That allows him to reduce the odor he emits.
Dogs sniffing rear ends also helps to calm them down. It’s an innate ritual that actually relieves stress and soothes your best friend.
Should You Allow Your Dog to Sniff Other’s Butts?
You might ask, “why do dogs sniff each other in the rear end as opposed to other areas like the ears?” There are, after all, scent glands behind your dog’s ears that convey similar information.
Part of the reason dogs sniff each other’s butts instead of the ears is that approaching a dog face-to-face is more aggressive. That’s why butt-sniffing is preferable to ear-sniffing. You’ve probably noticed this in the anxious way your dog approaches another dog’s butt.
As long as your dog and the other dog are both healthy, well-socialized, and under pet-parent supervision, you should let them sniff to their heart’s content. The more ‘getting-to-sniff-you’ action they get with each other, the more likely they are to become friends.
Of course, some dogs can get pretty intense with their butt-sniffing, so you should watch their body language to make sure they are both tolerating it well. If one dog seems to be overdoing it or feeling stressed, it’s better to pull them away from one another.
It’s also a good idea to make sure you only allow your dog to sniff in pairs. An orgy of butt-sniffers — I know it’s hard to imagine — is likely to result in some dogs getting overexcited, which can lead to fights.
Final Thoughts
The answer to the question, “why do dogs sniff butts” is to learn everything they can about a new dog. Butt-sniffing is a form of hand-shaking between dogs. But the butt conveys much more information than a mere handshake ever could.
From the scent of another dog’s butt, your dog will know much about where that other dog has been, what he’s eaten, how he feels, and if he’s in the mood for a sexual romp. The two dogs will also determine who is dominant and who is submissive, and once they’ve done that, they have a foundation upon which they can build a lasting friendship.
I’m glad it doesn’t work this way in humans, but for Fido, there’s nothing like a good butt sniff!
