Why Do Dogs Smell Each Other?

May 2, 2018

If you have a dog or if you’re simply a good observer, you will have noticed that when dogs meet each other, they start to sniff each other, especially in the anal area. Even though this behavior can seem a bit disgusting from a human perspective, there is a motive behind it. Let’s find out the reasons why dogs smell each other.

Dogs smell backsides in order to socialize properly

The first fact to take into account is that a dog’s sense of smell is very developed – between ten and a hundred thousand times better than ours. 

So, when dogs smell each other’s backsides, what they are actually doing is collecting information about their fellow dogs. For example:

two dogs

  • Gender.
  • Physical state and mood.
  • What they ate recently.

Doing this means they are able to socialize properly because they collect information about their peers when smelling each other.

Even if it seems like a somewhat disgusting behavior to us, it’s normal that dogs smell each other’s backsides. But this behavior has a very specific motive. It’s the way in which dogs decode chemical information secreted by their anal glands. This allows them to socialize properly with their peers.

Dogs establish chemical communication through the secretion of their anal sacs

So, when dogs sniff each other, they are establishing what is called “chemical communication.”

Actually, the anal glands release this smell that gives this information. These sacs are located on each side of the anus; they produce the secretions that the dogs’ powerful sense of smell knows how to decode very well.

George Preti, chemist at the Monell Chemical Senses Center in Philadelphia, U.S.A., carried out a study in 1975 about these glands’ secretions. He determined the main chemicals that composed them: a compound of trimethylamine and various fatty acids.

Every animal has a certain diet and distinct emotional and immunological systems. Therefore, each one gives off a specific smell. 

How dogs decode the chemical information that they get from smelling each other

But how do our four-legged friends decode the chemical information that they find when smelling the backsides of other dogs?

This topic has a lot to do with the Jacobson organ, or vomeronasal. We can define this as an auxiliary olfactory system that can detect the distinct chemical compounds, generally pheromones. It directly transmits this information to the brain.

Located between the nose and the mouth of dogs and other vertebrates, specifically in the vomer bone, this organ allows dogs to communicate when decoding their physical and emotional states. 

While this organ is considered vestigial in humans, recent studies have been carried out that try to determine if it still has any function and if it’s comparable to the same organ in other species.

More information about dogs’ sense of smell

dogs smell snow

Besides the fact that smell is a very developed sense in dogs, it should also be pointed out that these animals have a large olfactory memory. This makes it possible for them to remember, for example, the smell of other dogs and recognize it years after meeting them.

Dogs have an amazing sense of smell that allows them to sniff every particle that travels through the air. This transcends normal communication with their fellow dogs, other animals, and their environment. Humans have taken advantage of this skill for many years.

Dogs have been trained to detect:

  • Drowning bodies in the sea.
  • Survivors of catastrophes buried under rubble.
  • Drugs camouflaged by criminals.
  • Explosives.
  • Distinct types of cancer in people.
  • Situations of hypoglycemia in diabetic patients.

A dog is much more than man’s best friend.