Why do dogs sniff other dog’s bottoms ?

Why do dogs sniff other dog’s bottoms ?

Dogs are of course renowned for having a superior sense of smell, so it is understandable that it is confusing for dog owners that their dogs often like to greet other dogs by sniffing their bottoms, often getting very up close and personal to do so! As this is something that would be considered to be at best unusual and at worst very rude within the human world, it can be hard for us as people to get our heads around it! In this article, we will look in more depth at why dogs are so keen to sniff the back ends of other dogs, plus what it means when they do this.

The anal glands

On either side of the dog’s anus are two small openings that are called the anal glands, which produce a strong and distinctive odour that is unique to each dog. While we as humans fortunately cannot generally detect the scent of our dog’s anal glands, to other dogs with their superior senses of smell, the scent from the anal glands of other dogs are very distinctive, and provide information to your dog about the other dog or dogs in question.

When a dog gets up close to another dog and sniffs right up against their back end, this can be considered almost as the canine version of leaning into another person to hear them more clearly, and decoding the things that they are saying with greater clarity.

Greetings and exchange of information

When two dogs first meet, be they strangers or friends, often the first thing that they will do is circle each other to pick up each other’s scent, and get their noses up under the tail to pick up information about the other dog. In dog terms, this is comparable to how children might communicate verbally when they first meet; opening straight away with questions such as “who are you?” “Where are you from?” These communications form the basis of the dog’s understanding of each other, their familiarity with each other, and the start of their relationship, however short-lived.

Dogs can also find out from this butt-sniffing greeting information such as what the other dog has eaten, the sex of the dog, if they are spayed or neutered, if the other dog is healthy, and if they are friendly!

Calming and decoding smells

As well as having an amazing sense of smell, dogs have a fantastic scent memory, and will be able to recall and identify the scent of another dog, even if they have not seen them for a long time.

Sniffing the secretions of another dog will tell your dog instantly if they have met this dog before, which will tell your dog if they got on with each other previously, who was dominant, and if this dog is safe and friendly. Even when two dogs live together as part of the same “pack,” when one dog has been away from the other and returns, they will often go through the whole sniffing process, just as they would with a stranger. This tells the dogs where the other dog has been, what they have done, and if anything has changed since they saw each other last!


Butt-sniffing is also a way that dogs can establish who is going to be the dominant dog out of the pair; how they interact with each other while sniffing will start to form the foundations of their ongoing relationship. One dog will usually call a halt to the sniffing before the other, either by retreating or warning the other dog off. Which dog “calls it” and whether or not the other dog respects it, will go a long way towards determining the pecking order between the two dogs.


Because the anal glands give off such a wide range of information about the dog, in some situations, it is in the best interests of the dog to play their cards close to their chests as it were, and limit the amount of information that is available to strangers. This can be witnessed when one dog is sniffing enthusiastically at another dog, and the other dog is keeping their tail firmly clamped down to mask their scent as much as possible, and trying to retreat from the sniffer.


While it might seem that there is very little etiquette involved in something as primal as sniffing another dog’s bottom, there are in fact a lot of social cues and behaviours involved in the process. Some dogs are more enthusiastic sniffers than others, while other dogs are more reticent or speculative, and will not take kindly to another dog getting up close and personal with them. It is important that dogs are able to read each other’s cues where bottom sniffing is concerned, and know when to retreat and allow the other dog their space, lest they might be snapped at for bad manners!

This is something that often takes puppies and younger dogs a while to learn and that can only be learnt through trial and error, which is why it is so important to adequately socialise puppies with other dogs while they are still young and likely to be forgiven for any rookie mistakes or breaches in etiquette.



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