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Why Do Dogs Sniff Butts? Everything You Did (And Didn’t) Want To Know

why do dogs sniff butts

The age-old question of why dogs sniff butts has likely crossed every pet owner’s mind. Butt sniffing is a canine’s social ritual for a meet and greet. So the next time your pup circles and ecstatically sniffs another dog’s butt, they’re just saying hi.

Sniffing the rear end is a pretty good way for canines to foster friendliness. Sometimes the odor from your dog’s rear end, which gives your pup their distinct scent, can get overbearing. A quick wash-down with a gentle dog shampoo should fix the smelly issue.

So long as both dogs have relaxed body language and aren’t annoyed, you can allow them to sniff each other’s butts. But let’s look at five reasons dogs indulge in butt sniffing.

Why Do Dogs Sniff Butts? (5 Reasons)

Dogs sniff each other’s butts to familiarize themselves with one another through their scent. Thanks to a keen sense of smell, dogs can find out almost anything about the other dog. This includes their gender, health, the dog food they’ve been eating, and their mood, all in a brief whiff.

The anal glands located in a pair at a canine’s rear end are responsible for dogs’ incessant sniffing at each other. A study of 17 dogs showed that these sacs released odiferous proteins that played a huge role in chemical communication.

Sniffing the butt is a perfectly normal canine behavior that should be allowed, particularly for well-socialized dogs.

In dog terms, butt sniffing is really good manners. Dogs who are anxious or aggressive around other dogs typically will not allow any dog to sniff their butts.

Dogs aren’t the only mammals that communicate through anal sac secretion. The behavior is seen in other animals like cats, and even undomesticated animals engage in the behavior. This suggests that smelling the butt is an evolutionary occurrence in dogs, deeply encoded in their DNA.

5 Reasons Dogs Sniff Butts

1. A Form of Greeting

Butt-sniffing is the official canine handshake, and both unfamiliar and familiar dogs engage in it as a greeting. When two dogs allow each other to sniff their back ends, all is well and good in their interaction, and they’ll likely be friends.

Some reactive dogs approach others with too much energy, causing the other dog to jump into defense. If your pup approaches intimidatingly, you’ll notice a lot of stiffness, aggression, and refusal to be sniffed by strange dogs.

2. Chemical communication between dogs

Dogs have more than 100 million olfactory receptors, with the bloodhound having a record-breaking 300 million receptors. This makes a canine’s sense of smell about 10,000 times stronger than that of humans. Dogs also have vomeronasal receptors that respond to undetectable odors like pheromones.

Owing to their powerful noses, dogs communicate chemically through their back ends. A dog will learn about another’s temperament, gender, reproductive status, health, and mood with a quick butt whiff.

The anal sacs containing all this helpful information shouldn’t have an overbearing odor unless inflamed. Anal diseases in dogs appearing as swollen glands may be why your dog smells like fish and need medical care.

3. It Helps Canines Remember Each Other

Each dog has a distinct scent released through anal sac secretions. This is why your dog can’t resist sniffing some other dog’s poop while you’re out for a walk.

When dogs sniff each other’s behinds, they identify the other dog by scent and will remember them. Think of it as humans being good with faces, except in this case, they’re good with butts.

4. Sniffing Their Own Butt to Self-soothe

Sniffing and licking the butt may be a soothing mechanism for your dog. If your dog is nervous, they may also lick their private parts and paws, which releases endorphins, making them feel better. Sniffing the butt due to anxiety will occur with other signs like pinned back ears, yawning, and pacing.

This can also indicate an impaction or a source of discomfort or pain in the area.

5. Rear-End Sniffing for Politeness

Dogs also have their form of etiquette, and how they sniff each other is one of them. If a dog approached another head-on, that would be a sign of aggression that could lead to a nasty fight. Dogs approaching each other from their butts is a way of showing politeness and lack of aggression.

How dogs sniff each other’s behinds can offer clues on who’s the more dominant one. The dominant dog will typically initiate the sniffing and smells the less dominant one for a longer time. When their turn comes, less dominant dogs will sniff for a shorter time if they’re allowed to in the first place.

Why Do Dogs Sniff Human Private Areas?

Dogs sniff human private parts to get more information about the person. Sweat glands located around the crotch, the apocrine glands, give canines all types of data like health, mood, age, and sex.

Crotch-smelling is one of the many embarrassing (for the owner) dog behaviors. While apocrine glands are also found in the armpits, dogs can’t reach them and will focus on those around the crotch instead.

Dogs are particularly keen to sniff the privates of people that recently delivered, had intercourse, or are menstruating due to the higher pheromone levels. This behavior can be corrected by training your dog to sit when guests visit. You can also advise visitors to offer their hand for the dog to sniff.

Why Do Dogs Sniff Each Other’s Private Areas?

Why Do Dogs Sniff Each Other’s Private Areas?

Dogs sniff each other’s privates to relay information about themselves. While dogs have apocrine glands all over the body, the glands with the highest concentration of pheromones are in their genitals and anal area.

Sniffing another dog’s privates will give the information they need to know about that dog, such as sex and mood. Male dogs are notorious butt and crotch sniffers in public to determine whether a female dog is ready to mate.

Why Do Dogs Sniff You?

Dogs sniff their owners to feel closer to them because they catch a whiff of their scent. Your pooch may also appear to lick the air as they attempt to lick you to show affection. They choose your stinkiest belongings, like socks and shoes, because they’re the richest in scent.

Dogs also sniff you to find out where you’ve been. This is always the most noticeable when you return home with another dog or animal’s smell on you.

Your dog can also sniff you more intensely when they notice anything out-of-the-ordinary with you. It may be hormonal changes due to pregnancy or a health condition like high/low blood sugar. Some people who own service dogs are familiar with the stare their dogs give when something is off.

Why is My Dog Constantly Sniffing My Other Dog?

Dogs will sniff the other household dogs to communicate with them through the anal gland secretions and apocrine glands in the genitals. Your dog may be in heat, and your male dog sniffs their genitals and behind to decipher the pheromones released. Sometimes dogs also sniff other dogs in areas that may be injured or diseased.

Another unfortunate reason your dog is sniffing your other dog is that they can smell a disease. Studies have shown that dogs can smell different types of cancers in humans, and the same applies to other dogs. For example, you may see your dog sniffing another dog’s ears when they have an ear infection or sniffing and licking another dog’s wounds.

Dogs also sniff each other to show affection, mostly accompanied by affectionate cobbling. Your two dogs are familiar with each other, so the bum sniffing is unlikely to be a dominant thing.

Why Do Dogs Smell Other Dogs’ Poop?

Another dog’s poop contains anal secretions that give them a distinct scent causing dogs to love smelling each other’s poop. By sniffing their stool, your dog will know which other dog crossed their path.

Poop sniffing can easily turn into poop-eating in dogs that eat objects indiscriminately (pica). These dogs find the droppings aromatic and delicious and may even roll in another animal’s poop.

Why Do Dogs Sniff Each Other’s Faces?

Dogs touch noses and sniff each other’s faces to show friendliness and affection. It also indicates dominance when submissive dogs push their nose against or under the dominant ones to show submission. Their highly sensitive nose can make dogs sniff another’s face to see if they’ve been eating something.

Dogs can lick their nose as they sniff another dog as a sign of submission. While dogs sniffing each other’s faces is harmless, be sure to watch out for the dog’s body language. Aggressive behavior like growling or fearful behavior like a tucked tail is your cue to step in.

Final Thoughts

Dogs sniff other dogs’ butts as a way to greet them. A dog’s bum communicates several pieces of information like their health, mood, gender, and reproductive status. The behavior is mostly harmless unless either dog has signs of aggression, discomfort, or fear. Canines allowed to sniff it out are more likely to form strong bonds and remember each other.


Tamsin De La Harpe


Tamsin de la Harpe has nearly two decades of experience with dogs in rescue, training, and behavior modification with fearful and aggressive dogs. She has worked closely with veterinarians and various kennels, building up extensive medical knowledge and an understanding of canine health and physiology. She also spent two years in the animal sciences as a canine nutrition researcher, focusing on longevity and holistic healthcare for our four-legged companions.

Tamsin currently keeps a busy homestead with an assortment of rescue dogs and three Bullmastiffs.

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