Sniffing the air like that is a bad sign

31 May 2024, 10:12 a.m. by Tracey McLennan

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The sense of smell is a dog’s primary sense and they have the ability to pick up scents that we are simply unaware of. That’s because dogs have around 300 million scent receptors in their noses and we have about six million. Not only that – the part of their brain that handles smells is about 40 times bigger than the same part of a human brain.

Many dogs will use their incredible noses to pick up the scent of wildlife or birds on the air – as well as any other scents floating around. Dogs can learn to use their sense of smell to locate anything from pheasants for hunters to explosives for the police. There were even dogs trained who could sniff out Covid-19 infections and the dogs were said to be more accurate than lateral flow and PCR tests.

There is research that indicates that sniffing on a walk will help to lower a dog’s pulse rates even if they are moving. Many dog behaviour experts recommend taking dogs for slow walks on longer leads and allowing the dogs to choose the direction and pace based on what they are sniffing. These scent-based walks help to satisfy dogs and often leave them calmer when they get home than a thrill-filled outing of ball chasing and playing with their friends.

So . . . why is it a bad sign??

With all of this information, I bet you are wondering about the title of this blog. Sniffing sounds like the best thing ever , doesn’t it? I certainly think it is.

But – there is a lot of misinformation around about dogs including about their amazing scent abilities.

I kid you not, somebody once said to me.

When dogs go still, close their mouth, and sniff the air, it’s a bad sign. It means they’re going to be aggressive.

The person was serious about it and told me that they’d seen it happen lots of times.

It was a brief conversation and I don’t know how experienced she was with dog behaviour. But – one reason that dogs often close their mouths to sniff is if they are intent on finding where the source of the smell is. It is easier for them to find whatever they are smelling if they breathe only through their nose.

You don’t need to take my word for it, you can test it out for yourself really easily. The next time you’re out with your dog and they have been running enough to make them pant, pause for a couple of minutes and press some pieces of food into the bark of a tree. Press them low enough down that your dog will easily be able to reach them. It’s important that your dog can find and then eat the food.

When you are finished, let your dog search out the pieces of food. Watch them while they search. What you will almost certainly see is your dog closing their mouth when they are searching. You may see their nose move too as they work to find the food. If you watch quietly and listen, you’ll hear them making strong sniffing sounds.

The closed mouth and intense sniffing you’ll have seen is all about your dog getting more information through their nose and nothing to do with aggression.

What seems to worry some people about dogs closing their mouth to sniff is that there is almost always an intensity about it and I think that the intensity is what makes people concerned.

If somebody has made you worried about your dog's sniffing, let me help. Sign up to my free online course called The High Prey Drive Challenge that you can sign up to join today.

When sniffing is not calming

For sure, sniffing is not always calming. Look at this video of one of my dogs sniffing in some long grass. She is not remotely calm and her sniffing is of the sort that worries some people because it is intense and predatory. She is trying to find mice using their scent.

The sort of sniffing that she is doing is not at all calming for her. Instead, it is highly arousing and doing it pushes her to move faster and to push through barriers in her search for the mice.

Sniffing and predation

For many dogs, predation starts with sniffing. Some people call it searching, others hunting. What you call it doesn’t matter at all but being able to recognise it and distinguish it from more casual, calming sniffing is important.

It is important because while intense, predatory sniffing does not mean that your dog is going to bite you – or be unfriendly toward other dogs – what it can mean is that your dog is about to take off by themselves to try and find the prey they can smell.

If you want to learn more about predation in dogs – something that is often called prey drivehave a read of my blog on the subject.

I have carried out and published some research in this area and what I found was that 88% of dogs enjoy hunting. Those dogs were described as living to hunt or doing it often - so there is a high chance that your dog will too. In fact, it could be that if your dog regularly chases wildlife or birds and if that is a problem for you, that you could prevent the chasing by getting your dog hunting with you instead.

How to get your dog hunting with you

One of my favourite ways of getting dogs to be enthusiastic about hunting with me rather than off on their own is to hide little pieces of food when my dog isn’t watching and then let them sniff those pieces of food out.

Once your dog understands the game, it often becomes valuable enough to them that they’ll come away from wildlife scent to play it – like my dog is doing in this video.

If you would love more help with your dog’s prey drive, I would be delighted to help you understand more about it – and about what you can do to work with your dog so that you both have easier and more fulfilled walks. I have a free online course that you are more than welcome to click here and sign up for. You’ll get the course sent to you in a series of emails so that you can digest each part before moving onto the next bit.

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Woman with short hair and a purple top walks through stunning countryside carrying a pink dog lead

Hi - I'm Tracey.

I am the founder of Best Dog Learning and Stuff and a massive prey drive enthusiast. I've lived with high prey drive dogs for over 20 years and I love them. I run the awesome High Prey Drive Club where I help my members learn to have fabulous walks and happy lives with their high prey drive dogs.

I am a published researcher in my field with both my original research and my review of the literature looking at prey drive in dogs being published in the respected journal Applied Animal Behaviour Science.

I am the author of Canine aggression: Rehabilitating an aggressive dog with kindess and compassion.

I want to show you how easy and fun it can be to have a high prey drive dog.

If you'd like help with your dog, I'm ready to help you right now.

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