Biotic's Gain

A dog’s nose is not simply a better version of ours, it is built to a different design. A labrador carries somewhere around 220 million olfactory receptors against our five or six million, spread over a far larger sheet of sensory tissue, and devotes a much bigger share of its brain to processing what arrives there. Sniffing is a separate action from breathing, with its own airflow path, and a second organ in the roof of the mouth reads chemical signals that have nothing to do with ordinary odour. The practical result is a dog that gathers most of its information about the world through its nose, and reads a lamp post the way we read a noticeboard.

The equipment inside the nose

Behind a dog’s nostrils sits a maze of thin, scrolled bones called turbinates, covered in olfactory epithelium. Folding the tissue this way packs a large sensory surface into a short muzzle. Scent molecules landing on it bind to receptors, and the signal travels to the olfactory bulb, which in a dog is proportionally far larger relative to overall brain size than ours is.

Receptor counts vary with breed and with the length and shape of the muzzle. Bloodhounds are usually quoted at the top of the range, around 300 million. Short-faced breeds have the same basic architecture compressed into less space, and tend to have less of it. This is a difference in degree rather than a different sense, and a pug still smells circles around its owner.

Sniffing is not the same as breathing

When a dog breathes normally, most air goes straight through to the lungs. When it sniffs, the airflow splits, and a portion is diverted into a recess at the back of the nose where the olfactory tissue sits, so scent molecules accumulate there instead of being flushed out on the next breath.

Sniffs come in rapid bursts, several a second. The exhaled air leaves through the slits at the sides of the nostrils rather than straight ahead, which stops the dog from blowing away the very scent it is investigating and helps draw fresh air in from in front. Dogs can also move their nostrils somewhat independently, which gives them a sense of which side a smell is stronger on. A dog working a trail in a zig-zag is not being inefficient, it is reading the edges of a scent plume.

A damp nose is part of the mechanism too. Moisture captures airborne molecules and holds them against the tissue, which is one reason a dog will lick its nose mid-investigation.

The second nose in the roof of the mouth

Dogs also have a vomeronasal organ, sometimes called Jacobson’s organ, sitting above the roof of the mouth and opening behind the front teeth. It handles heavy, non-volatile chemical signals rather than ordinary smells, chiefly those carried in urine and other secretions, and it feeds a separate part of the brain.

That is what is happening when a dog stops dead at a patch of grass, inhales with a slightly open mouth and a faintly odd expression, and sometimes chatters its teeth. It is not tasting anything unpleasant. It is routing a sample to a different sensor. Males do it more often than females, and it is most common around spots other dogs have marked.

What the big numbers do and do not mean

You will see claims that dogs smell ten thousand or a hundred thousand times better than people. Those figures are rough and, more importantly, compound-specific. Sensitivity is measured one substance at a time, and the gap between dog and human is enormous for some molecules and modest for others. For certain compounds trained dogs detect concentrations in the parts per trillion; for others the advantage is far smaller.

The more useful way to put it is that dogs do something we cannot: they pick a single thread out of a tangle. A person walking into a kitchen smells stew. A dog smells the meat, the stock, the onion, the pan it was cooked in and whoever stirred it. Separating components in a mixture, and reading how old each one is, is the real skill.

Why this should change how you walk your dog

If scent is a dog’s main channel, a walk spent being towed briskly past every interesting surface is a walk with most of its content removed. A shorter route with time to investigate usually leaves a dog more settled afterwards than a longer one taken at pace, because sniffing is mentally occupying in a way that trotting along a pavement is not.

Two practical habits follow. Build in deliberate sniffing time rather than treating every pause as disobedience, perhaps a stretch of the route where the lead goes long and the dog chooses. And on days when a proper walk is not possible, scatter a portion of the daily food in the garden or in a towel: ten minutes of searching does more for a bored dog than another lap of the block.

Smell, food and the fussy eater

Dogs have far fewer taste buds than we do, somewhere around a sixth as many, so aroma does most of the work in deciding whether a bowl is worth bothering with. Warming food slightly lifts its smell and often restarts a dog who has been picking at it, and it explains why wet food is frequently more tempting than dry. We went through that in detail in wet food, dry food: what actually makes a dog choose, and the behaviour side sits in our fussy eater guide.

It also means a dog going off its food is sometimes a nose problem rather than an appetite problem, which is worth remembering before concluding that a dog has simply become picky.

Training with the nose rather than against it

Scent work is the easiest hobby to start with a dog of any age, size or energy level, because it asks nothing of the joints and everything of the brain. Hide a treat under one of three cups while the dog watches, then while it does not. Hide food around a room and send the dog to find it. Progress to hiding a single scented item and rewarding the find.

Older dogs often take to this particularly well. Hearing and sight fade before smell does, and a game that runs on the sense still working tends to go down better than one that depends on the senses that are not. There is more on the other two in what dogs actually see and what dogs can actually hear.

Where the Calming Chews sit

Biotic’s Gain Dog Calming Chews contain L-theanine and are a complementary feed, which means they are fed alongside a complete and balanced diet rather than in place of part of it, to the feeding guide on the pack for your dog’s weight. A complementary feed is not a medicine and cannot claim to treat, prevent or cure anything. Whatever is going on with a dog that struggles to settle, the routine, the environment and the amount of mental work in the day are where the real change comes from.

When to speak to your vet

Book an appointment if you notice discharge from the nose, particularly from one nostril only, any bleeding, repeated sneezing or reverse sneezing that does not settle, pawing at the face, swelling around the muzzle, or noisy breathing that is new. A sudden loss of interest in food in a dog that has always eaten well is worth a call too, since it can have causes well beyond the nose.

One thing not to do: never put drops, oils or cleaning products into a dog’s nose on your own initiative. If something needs treating there, it needs a vet to say what.

Biotic’s Gain chews are a complementary feed for dogs, fed alongside a complete and balanced diet. They are not a medicine and are not intended to diagnose, treat, prevent or cure any condition. If your dog is unwell, is on medication, or you have any concerns about their health or behaviour, speak to your vet.