Dog Talk: 6 amazing facts about dogs' noses

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Have you ever wondered how your pet knows when you have a treat stashed away in your pocket? Here are six amazing facts about dog noses that explain their amazing sense of smell.

1. Dogs can breathe in and out – at the same time

Both humans and dogs can breathe through their mouths and noses. However, if you’re a regular human, you will either breathe in or breathe out at any given time.

There are master musicians who learn an art called circular breathing where they breathe in through the nose while simultaneously pushing air out through the mouth. This creates a constant flow of air that helps them play wind instruments like the Australian didgeridoo, Egyptian arghul and Cambodian sralai.

Dogs are natural masters of circular breathing. They keep air circulating all the time, without even working at it.

2. Dog nose design is pawsome

When air enters a canine nose, a fold of tissue just inside splits the airflow into two streams. One flow is dedicated to smelling and the other is dedicated to respiration.

Also, if you look closely, you’ll see dog noses are typically slit along the sides. When the dog breathes out, that air is vented through those slits. The air that’s breathed out creates mini air-turbulence along the sides of the nose. This ensures that the breathed out air won’t be mixed up with the air that’s being inhaled.

The doggy breathing system is so intricate, that scientists have written papers on how it works, under titles such as The Fluid Dynamics Of Canine Olfaction. But basically, all we need to know is that only new air hits the doggy nose straight on. This is important because:

3. Dog noses are basically scent science labs

When it comes to olfaction – the posh word for our sense of smell – dogs have up to 300 million olfactory receptors. We humans have around six million.

On top of that, the bit of the brain that’s dedicated to decoding and interpreting smells is about 40 times bigger in dogs than it is in humans.

Finally, dogs have a vomeronasal organ (aka Jacobson’s organ), a special patch of scent-sensitive cells in the nose that lies just above the roof of the mouth. This detects pheromones, chemicals released by living creatures that signal important information about mood and health.

Humans have a vomeronasal organ too, but scientists aren’t sure how or even if it works. So, if you want to read up on the controversy, check the otorhinolaryngologist journals.

Put it together and it’s no surprise that dogs can smell between 10,000 to 100,000 times better than us. If you put that in terms of sight, it’s like saying that what we can see at 300m, a dog could see just as clearly at 3,000km.

4. Dogs are ace scent locators

Like us, dogs have two nostrils. Unlike us, canine brains analyse what’s coming from each nostril separately. Once the information is analysed, the results are then put together – a process that means the dog can locate the scent exactly in space.

The practical upshot is this: your pet can smell which stall you bought your popiah from and what make of hoisin sauce the hawker used. But even more impressively, the dog can also scent exactly where you’re hiding it.

Being able to place the source of scents exactly is incredibly useful because it means dogs living in the wild can find food easily, even if it’s buried or far away. It also helps them avoid predators who are hiding from view. And when dogs are in a group, they can spot the female dog who is fertile, which puppy is theirs, and more.

5. Dog noses need not be wet – but it helps

It’s commonly said that a healthy dog has a damp nose. However, dog noses aren’t naturally damp. When a dog sleeps, its nose will be dry. However, as soon as they’re awake, your pet will run its tongue over its nose. The reason is because a thin layer of moisture helps to collect scent molecules.

Interestingly, the average dog will produce about a pint of mucus every day, just to keep that hooter running in good condition.

So, if your pet is awake and with a suspiciously dry nose, make sure your pet is properly hydrated. If there’s still a problem, talk to the vet. Note: Sadly, some flat-nosed breeds like Pugs have been so badly bred that they cannot keep their noses lubricated properly. If this is the case with your pet, talk to your vet about moisturiser.

6. Dogs say hello by sniffing butts and groins

When a dog meets another dog, and they’re friendly, there’s a lot of bum-sniffing. Dogs aren’t shy so it’s not a problem. But when your pet unashamedly gooses your friends, the atmosphere might be a little fraught. The thing is that it’s perfectly sensible dog behaviour.

As dogs are optimised for scent, and doggy bottoms and human groins are loaded with glands that produce pheromones, a nose in that awkward place is simply an efficient way to figure out how you’re feeling, how your health is, what you ate last, and more.

Basically, it’s the human equivalent of, “Hello, how are you?” but without having to actually answer the question.