Nov 30 2015

How Your Dog “Sees” The World Through Smell

Can you smell that? No? Well that is because our human noses only have 5 million olfactory receptors. Five million may seem like a lot of receptors, but not when you compare it to or feline friends who have 80 million receptors in those tiny little noses. And though our cats may win the night vision competition, the clear winner when it comes to sniffing out the perfect scent are our dogs, whose noses have 250 million receptors, give or take a few million depending on the breed.


To be able to cram all these smelling receptors inside the nose we have bony scroll-shaped plates, turbinates, which are covered with a thick spongy membrane containing the receptors. In our human noses if one removed the turbinates and lay them out flat it would take up an area of about one square inch (roughly a postage stamp) where as our dog’s turbinates unrolled would take up 60 square inches (roughly a sheet of paper).


Turbinates inside the nose

At the Fraser Valley Animal Hospital in Abbotsford, we have a special scope that allows us to look inside the nose. This scope helps us find things like a piece of grass, nasal mites, or a tumor. It allows us to take biopsies to help diagnose why a pet may have nasal discharge.

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Examining the back of the nose

So how much better can our dogs smell? Well because nobody has developed a great study to determine exactly how much better our dogs smell we can only make an educated guess based on the number of receptors and the amount of brain real estate dedicate to smelling. As well the ability to smell varies between the breeds, with the flat-faced dogs like Winston being low on the smelling totem pole, and blood hounds being one of the best sniffers. But it is estimated that a dog can smell 1000 to 10,000 times better than the average human. What does that mean? Well here are an analogy that really make it obvious how smelling is our dog’s superpower. If you are able to smell ½ teaspoon of sugar in a cup of coffee, well your dog could smell that same ½ a teaspoon of sugar dissolved in an Olympic size swimming pool.

All this sniffing is how your dog gets his “news”. When Brutus sniffs another dog he is finding out everything about that dog, the sex, what he ate, who the dog interacted with, and what mood he is in. Yes there is no faking it with our dogs they truly can smell fear.

This amazing ability to sniff has made our canines a very helpful companion in our human world. We have trained our dogs to be drug sniffers, bomb sniffers, as well as being able to detect certain forms of cancer when sniffing a person’s breath. One study showed that dogs detected colorectal cancer from a person’s breath with a 98 percent accuracy, which was more accurate than the standard medical test presently used. Maybe there is something to be said about a “Lab” test!

So next time you are taking your dog for a walk and you are tempted to drag him away when he is stopping to sniff and pee every couple of feet, remember he is just picking up the local gossip and leaving a note of his own through “pee-mail”.

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