About dog noses
A dog’s nose is probably their most important sensory organ. Apart from helping them find delicious (or stinky) food and avoid prey, it acts as a social media tool, a 3-D visualiser, a matchmaking tool, and so much more!
Some dog behaviour around sniffing is quite peculiar, especially if seen in the human context (as is our inclination). However, understanding why our dogs need to sniff can help us decode that. But first, let’s see a quick comparison between human and dog noses.
Dog noses are way more complex than human noses — their noses can have up to 300 million olfactory receptors, compared to our measly 5 million. Although dog brains are smaller than human brains, the brain area devoted to the sense of smell is about 40 times larger than in humans. Dogs also have more types of olfactory receptors and more olfactory neurons (specialised cells that detect odour) than humans. Therefore, their sense of smell is highly evolved as compared to ours. Dog noses are 1000 times more sensitive than human noses (did your dog hate your ex or their perfume; who knows?), allowing dogs to sniff out diseases and drugs, feel and smell heat, and even tell the time based on the changes in the smells around a room as the day progresses (feel silly about trying to hide a piece of cheese from your dog now?).
With this in mind, let’s look at some fun facts about dog noses and understand how our dogs’ sense of smell leads to some ‘weird’ behaviour.
Dogs can breathe in and out, simultaneously
Pay attention to your breath — it goes in, then goes out, and this repeats, but the two actions never happen simultaneously. You’re either breathing in or breathing out. Your dog, however, can breathe in and out simultaneously. This creates a continuous circulation of air when they sniff, allowing them to smell things better while respiring well.
Our dogs’ noses have the ability to separate air — a portion goes to the smell-sensing (olfactory) area, and the other goes to the lungs. Therefore, they need not pause breathing to decode a scent, and vice versa!
Dogs have a ‘second nose’
Dogs possess an organ called the Vomeronasal or Jacobson’s organ. It is located near the roof of the mouth in the nasal cavity and connects to a separate part of the brain from the rest of the nose. It can detect specific compounds and influences several canine behaviours. Dogs use this to detect pheromones, which help find potential mates, and puppies use this to find the source of their mother’s milk.
Dogs can smell in 3-D and even in the past
Your keen sense of smell doesn’t feel all that keen now, huh? Dog nostrils work the same way as human eyes — each nostril can take smells independently. Odour profiles from each nostril are combined by the dog’s brain to give them a complete picture of their surroundings and tell them where smelly objects (food/prey/etc.) are located.
Due to how sophisticated dogs’ noses are, they can detect slight changes in odour molecules at a particular spot over a period of time. This allows them to recognise what happened there in the past and figure out where prey or other objects of interest might have gone from there.
Now that we know how powerful and extraordinary dog noses are, let’s try to understand some dog behaviours and traits from the all-factory sense. Yes, all-factory, because the nose is where a dog processes their entire world most thoroughly. It makes sense, then, that their very first action upon coming across new things is to get a big whiff of the scent.
There’s a place a few metres down the road from my home, which I like to call the bulletin board. Literally every dog on this street pees (and poops) there, and every time there’s a dog around, you know they’ll sniff for sure. This is a behaviour that’s markedly different from human behaviour. However, from a dog’s point of view, it’s just social media.
When they pee, they’re leaving a post for other dogs to see how they’re doing — their latest meal, mood, fertility and health status, etc. When they sniff another dog’s pee (or butt), they’re merely scrolling and reading other dogs’ posts (by contrast, if we sniff pee, we’ll only sniff pee). It’s a great way to keep up with the neighbourhood.
This is why dogs are so fascinated with vehicles — many vehicles have new scents from far-off places, especially of other dogs. It’s perfectly okay to let your dog sniff vehicles on their walk — it’s hot gossip from the world for them. Just be careful not to let them sniff hot parts of those that have just been parked.
Some dogs also lick their noses after they’ve smelled something. This takes the scent particles stuck on the surface of the nose to the roof of their mouth — near the Jacobson’s organ and helps them process the smell better.
Wet nose (Vet knows?):
Most of the world associates dogs with wagging tails and wet noses. Wet noses serve two purposes — better function and cooling. A dog’s nose gets wet either by licking or coming in contact with a moist surface during sniffing or due to mucus secretion. Mucus causes odour particles to stick to the surface of the dog’s nose, letting them smell better. The glands that secrete mucus also produce a clear fluid that cools the dog’s nose through evaporation.
While cooling is a function of the wet nose and it aids the dog in maintaining body temperature, the dog’s nose also has a heating function — it heats up inspired air so that it is closer to body temperature, making it easier for the lungs to function.
A wet nose is typical in dogs, but an overly wet nose may indicate health issues, especially if the nasal discharge is thick or has a weird colour. This may merely be allergic or may indicate a more extensive problem.
On the other hand, a dry nose may not always indicate health issues and is not a reliable indicator of dehydration (please see how to check for dehydration in this blog). Brachycephalic breeds — short-snouted dogs — commonly have dry noses. If your dog has a dry nose but seems generally okay, you need not worry. However, a dry nose accompanied by lethargy, loss of appetite, cracks and sores, or other signs of illnesses is a cause for concern, and you should consult your vet. Do not use human moisturisers on your dog’s dry nose; use only what your vet prescribes.
Before ending this blog, we should take a quick look at the nosey neighbourhood. You must have noticed that your dog has whiskers. These vary in length and are distributed on the sides of the nose, along the front of the snout (and in a few more strategic areas of the face). They help the dog figure out the size, shape and speed of nearby objects by transmitting information to sensory cells based on subtle changes in air currents. Dog whiskers are not ornamental and should not be cut! Doing so can cause your dog to be less spatially aware.
While all dog breeds have a sophisticated sense of smell, some are better at sniffing than others. Hounds and working dogs like German Shepherds and Labradors have a sharper sense of smell and are appropriately employed as sniffer dogs. Regardless of skill and simply because of how pivotal your dog’s nose is in navigating their world, let them sniff, especially on walks! Sniffing engages the brain and serves as mental enrichment too.
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