How Sensitive is Your Dog’s Nose?

We all know dog’s have a good sense of smell. Of their senses, some may argue it’s the most powerful and maybe even the most important. A testament to this is how well dogs that are blind and deaf get around thanks to that powerful nose. We have a friend with an older Australian Shepherd that is an outdoor farm dog. He is deaf and blind, but if the owner didn’t tell you, you would never know until you tried to call him to you and he doesn’t respond. While he stares right past you, he always knows where you are and never runs into things. If you watch him closely, you will see he is leading with his nose. It truly is remarkable. And he is happy as can be; the owner said his personality never changed as he lost two of his senses and is still the same happy dog as he always was. This is just one example of how sensitive a dog’s nose is.

So Just How Sensitive is Your Dog’s Nose?

The best way to understand their sensitivity is to look at some fact comparisons. Humans have around six million olfactory receptors in our noses. These are the cells that receive and create a signal to our brain so that we can process smells.

Dogs have over 300 million olfactory receptors!

That means their noses have 50 times the number of receptors than we do – no wonder they can smell so well! This equates to their noses being around 100 million times more sensitive than ours.

But what does this look like? It means their noses are powerful enough to detect a scent diluted to one part per trillion. There is no man-made instrument that can detect scents as well as a dog’s nose.

Dogs also can smell separately with each nostril. They brain combines the two “images” to give them a better idea of where the smell is coming from.

Another interesting fact about a dog’s nose is that they can tell how old a scent is. This is how they track smells on the ground. They do this through the ability to detect the reductions in smells as time passes! Pretty incredible!

You would think these numbers mean dogs are the clear winners when it comes to scent—and we certainly find their nose useful for things like cancer detection, search and rescue, bomb sniffing and more. Yet there have been studies that question dog’s supreme nose status. One such study, published in the Applied Animal Science Journal in 2017 found that cats may actually be better at distinguishing between a larger variety smells than dogs. Cats, in case you were interested, have around 45-80 million olfactory receptors, though some could possibly have up to 200 million!

But dog noses are still awesome, and more research is coming out all the time about just how cool they are. In fact, a new study released February 2020 from Lund University and Eötvös Loránd University showed that dogs are actually able to detect heat signatures from other mammals and objects! The dogs were trained to choose between a warm (31 C) object and an ambient-temperature object placed 1.6 meters away. All three dogs successfully chose the warm object in double-blind experiments. Looking at a larger group of dogs, they found that the left somatosensory cortex (which is responsible for detecting temperature, among other functions) in the dog’s brain, responded to a warm thermal stimulus. Current research does not conclude how far a dog’s thermal detection reaches, but they do believe dog’s use it to help them “sniff out” prey.

Like many mammals, dogs also have a vomeronasal organ that allows them to smell pheromones released by other dogs, which they use as part of their body language and behavioural patterns.

Why Knowing your Dog’s Nose Sensitivity Matters

Sure, it’s fun to do scent work or Earthdog competitions with your dog. Or maybe you love to play “hide and seek” with toys, treats or even you as the hidden object your dog is looking for. It’s wonderful that we can use dogs to help detect illness and find people, drugs or bombs. But in our daily life it’s also good to be aware of just how sensitive a dog’s nose for their own health and wellbeing.

A lot of domestic dogs suffer from allergies—it seems like more and more each day. Asthma and other environmental allergies are big problems for a lot of pet owners. If your dog is wheezing, having trouble breathing, itchy, etc., it’s always good to go to the vet and have them tested for allergies, BUT it’s also good to take a look at what is being used in your home.

Do you have candles, incense, or air fresheners going constantly? Imagine what those smell like to your dog! Do you use harsh chemicals to clean without proper ventilation? Maybe you just painted and forgot to air out the room – it may not seem too strong to you – but it definitely is to your dog. It’s good to take notice of these things and see if there are ways we can make our dogs more comfortable in our homes. Think of their nose as a fine-tuned, delicate instrument that needs to be taken care of.

And of course, if you haven’t thought of it before, now that you know your dog has all that power in those cute little nostrils, explore the idea of letting them use those instincts for sports like scent work or volunteer search and rescue. Giving your dog a job that allows them to use their instincts makes for a happy and more contented buddy that will get into less trouble at home because he will have had some mental and physical exercise. Plus, it’s really cool to watch that nose go to work!