Dogs have multi-functional nostrils.
When we inhale and exhale through our noses, air travels through the same passageway. When it comes to dogs, their nostrils can work independently from each other. A fold of tissue just inside their nostrils separates the odour into two different paths—one for olfaction (smelling), which breaks down the odour to tell the dog every single detail about that scent, and one respiratory, for breathing. Dogs can move their nostrils independently – smelling in stereo – and this helps them to determine the direction of a scent.
Dog noses are wet for a reason.
If you’ve ever wondered why your dog’s nose is usually wet it’s because the moisture helps to capture scents and hold onto them. Molecules of scent stick to the moist, exterior tissue of the nose. There they can dissolve, and travel to the vomeronasal organ for closer analysis The vomeronasal organ is a specialised sac designed specifically for the processing of scent molecules. It is situated above the mouth and along the floor of the nose, covered in tiny hairs to encourage the molecules along.
Dogs have incredible scenting ability. Dogs can smell 10,000 to 100,000 times better than the average human! Alexandra Horowitz, a dog-cognition researcher at Barnard College, shared this interesting example: If we are able to detect a teaspoon of sugar in our morning coffee, a dog is able to detect that same teaspoon of sugar in a million gallons of water. "Let's suppose they're just 10,000 times better. If you make the analogy to vision, what you and I can see at a third of a mile, a dog could see more than 3,000 miles away and still see as well." James Walker, former director of the Sensory Research Institute at Florida State University. Or as psychologist and dog book author Stanley Coren would explain it “let’s say you have a gram of a component of human sweat known as butyric acid. Surprisingly, humans are quite good at smelling this. If you let it evaporate in the space of a 10-story building, many of us would still be able to detect a faint scent upon entering the building. Not bad, for a human nose. But consider this: If you put the 135-square-mile city of Philadelphia under a 300-foot-high enclosure, evaporated the gram of butyric acid and let a dog in, the average dog would still be able to detect it!
You cant fool your dog
Research indicates that it’s quite likely that dogs can smell fear, anxiety, even sadness. The flight-or-fight hormone, adrenaline, is undetectable by our noses, but dogs can apparently smell it. To dogs, stress or anger manifests as a cloud of hormones. In addition, fear or anxiety is often accompanied by increased heart rate and blood flow, which sends tell-tale body chemicals more quickly to the skin surface. Trying to mask your strong feelings with a casual smile may fool your friends, but it’s not going to fool your best friend.
Dogs don’t exhale through their nostrils.
If you peer closely at your dog’s nose, you’ll see that there are slits on either side. That’s where the air comes out whenever your dog exhales! By separating incoming and out-going sniffs, odours don’t need to jostle with the air already in the nose for access to the lining of the nose, and the exhales create little currents of air which swirl yet more scent molecules around, allowing them to be inhaled and processed. If you ever watch dogs sniffing in the dust on dry ground, you can see it happening!
Dogs notice all the skin that we shed daily
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Humans actually shed 50 million skin cells every minute. Though we can’t physically see these microscopic “snowflakes” coming from our bodies, dogs are able to smell every single one. That’s why they can track and find people who have been lost on mountains or in disasters. Every human has a unique scent fingerprint, and that’s pretty much everything a dog needs to tell one person from another. “To our dogs, we are our scent,” Alexandra Horowitz, Inside of a Dog: What Dogs See, Smell, and Know.
Dogs sniff to get to know each other.
The nose is the best tool a dog has to get an idea of who his new friends are. All that butt sniffing that you’ve witnessed among pooches is normal. Dogs can find out the age, sexual status and even the health and diet of another dog just through some exploratory sniffing! Greetings sometimes start face to face, but quickly end up on the other end of the dog, where there's loads of info for the sniffing.
Dogs send “pee-mail”
Stanley Coren: “Dogs read about the world through their noses, and they write their messages, at least to other dogs, in their urine.” It’s tempting to drag your dog along on a walk when he’s sniffing everything annoyingly slowly, but give him chance to read the neighborhood gossip column, and let him do a little writing while he’s at it.
A dog’s scenting ability is extraordinary
Dogs’ sense of smell is incredibly acute. Drug sniffer dogs are able to detect a plastic container packed with marijuana submerged in a petrol tank filled with petrol! Cancer-sniffing dogs have been known to ‘insist’ that a spot on a patient’s skin contained melanoma cells, even though doctors had already pronounced it cancer-free – and subsequent biopsies prove the dog to be correct. A dog specially trained for water searches has been shown to be able to detect the location of a canister of pork dropped in a lake a mile long and half a mile wide, with the water 5m deep … and a further 1m layer of silt on the bottom that the canister had sunk into!
In dogs, the nose is the fastest route by which information can get to the brain. Scent is the dog’s most primal sense. The receptors in the dog’s nose connect directly to nerves in the specialised olfactory bulbs in his brain. These olfactory bulbs make up around an eighth of the dog’s brain mass … proportionately greater than the size of brain given to humans’ visual processing centre. The processing of scent information occurs directly in the brain structures involving emotion and instinct, giving dogs an immediate and visceral perception of the world around them.
Dogs can smell time
The past can appear to your dog in tracks left by passers-by, or by the warmth of a recently parked car, or the residue of where you have been, and what you have done recently. Lamposts and trees are the bulletin boards by which dogs know who has passed in the neighbourhood, how they are feeling and what they have eaten. And the future is in the breeze, alerting dogs to the approach of someone or something long before they can be seen.
Sniffing is hard work!
When a dog is scenting something he sniffs at around 5 times per second – it takes a great deal of physical fitness to move the diaphragm that quickly, and a lot of concentration to process the information – hence why dogs find scentwork so tiring and finish a session in a state of satisfied relaxation.
Puppy Power
The sense of smell is the puppy’s only major sense for the first few weeks of life, and he has to find his mum, his food and his siblings using smell – not sight or hearing.
Top five best scenting dogs
1. Bloodhound
2. Basset Hound
3. Beagle
4. German Shepherd
5. Labrador Retriever
Did you think a bloodhound’s ears were designed that way just to make him look like a canine Sherlock Holmes? Think again … as the dog moves along the ground with his head down the long, flappy ears help to disturb the scent molecules and fan up odours to his nose.
