If Your Dog Could Talk: the sense of smell, a superpower.

By Pascale Saravelli, canine educator and co-director at Social Dogs Mallorca.

“Please... let me stop and sniff. It's how I make sense of the world.”

There are two ways to start a walk with your dog. The first is simple: you open the front door and begin walking.

The second... is what actually happens.

You walk a few metres and, suddenly, your dog stops. They lower their nose to a small patch of grass and remain perfectly still. Five seconds. Ten. Fifteen. You wait, the leash slightly taut. You check your phone, reply to a message, or glance at the time. Then you look up and wonder, "What could possibly be so interesting there?"

The answer is as simple as it is surprising. Probably far more than you could ever discover during the entire walk. Because while you see nothing more than a patch of grass... your dog is exploring an invisible universe.

We like to think we're sharing the same walk. But the truth is that we're moving through two completely different worlds. Ours is a world of images. We recognise faces, colours, buildings, and landscapes. Theirs is a world made primarily of molecules. While we look at a park, a dog perceives an immense cloud of chemical information that we aren't even aware exists.

It's not that dogs have a "better" nose. They have a nose designed to answer completely different questions.

When we walk into a café, we notice the aroma of coffee, freshly baked bread, or the perfume of the person who has just come in. Our brain blends all those scents together into a single impression of the environment.

A dog experiences something entirely different. They can separate much of that mixture and analyse many of its individual components. It's similar to walking into a room where everyone is talking at once. We hear a general murmur.

Dogs can distinguish many of those conversations individually. Scientists call this ability olfactory discrimination, and it is one of the most remarkable features of the canine olfactory system.

The explanation begins with the nose itself.

Humans have approximately five to six million olfactory receptors. Dogs have between 125 and 300 million, depending on the breed.

The Bloodhound, widely regarded as the ultimate scent-tracking specialist, is among the breeds with the highest number of olfactory receptors. But the difference doesn't end there. The region of the brain dedicated to processing smells is proportionally about 40 times larger than ours. Dogs not only detect far more information—they also devote much more brainpower to interpreting it. That is why, for a dog, sniffing is not simply a pastime. It is one of the primary ways they understand the world.

There is another common misconception worth challenging. We often say that a dog "smells a tree" or "smells a person." In reality, dogs do not smell objects.

They smell molecules.

Their olfactory system is highly specialised for detecting volatile organic compounds (VOCs)—tiny molecules continuously released by people, animals, plants, food, and even the ground itself.

When your dog approaches someone, they can detect substances such as acetone, isoprene, various aldehydes, volatile fatty acids, and many other compounds present on the skin and in human breath. The unique combination of these molecules creates what is essentially a chemical fingerprint for every individual.

When your dog sniffs another dog's urine, they are not simply identifying "the smell of pee." They are analysing an extraordinarily complex mixture of volatile organic compounds, amines, fatty acids, and molecules originating from different bodily secretions. It is this unique chemical blend that tells them who passed by.

Where we perceive an odour, dogs perceive information. Their nose is not simply a more powerful version of ours. It is a highly specialised system designed to detect the molecules that, over millions of years of evolution, have proven most valuable for finding food, communicating with other animals, navigating their environment, and ultimately surviving.

Now imagine this: "Tomorrow morning, you wake up with a superpower."

As you pass someone on the street, you instantly know whether they've been to the beach that morning, whether they live with a cat, whether they've just finished cooking, whether they've been out for a run, or whether they walked down this very street a few hours earlier.

Every bench, every rock, and every footpath contains an entire world of information that has always been there, hidden from you. Would you really hurry past without stopping? Or would you spend much of your time exploring this fascinating new universe?

Most likely, you would do exactly what your dog does.

You would use that superpower constantly.

Because it would be impossible to ignore it.

There is another important difference between us that we rarely stop to consider. We wake up and check our phones. We read the news. We listen to the radio. We watch television. We talk to neighbours and friends. Information reaches us constantly.

Without even leaving home, we can find out what is happening in our neighbourhood—or on the other side of the world.

Dogs have none of that.

The only way they can stay up to date is by going outside and gathering information directly from their environment. Every scent carries information. While we catch up on the news, dogs catch up on the world.

Every walk is their daily update.

Cala Fornells, Calvià.

If you live in Calvià, try giving your dog that extra time in places such as Puig de sa Morisca Archaeological Park, with more than eight kilometres of trails winding through pine forests, Mediterranean scrubland, and breathtaking views over the bay. Or explore the path that runs through the pine woods of Cala Fornells to the secluded coves of Cala San and Cala Rafax, where the forest meets the sea.

For you, it will be a beautiful walk. For your dog, it will be an opportunity to discover the world through their nose.

In a way, when a dog stops to sniff, they're reading the neighbourhood newspaper. The only difference is that this newspaper is written in scents.

And they're not just "reading" the present.

Scents change over time. They disperse, age, interact with other compounds, and are carried by the wind. Dogs can use these changes to follow scent trails and distinguish a recent scent from an older one. Although science cannot yet confirm that dogs know exactly how much time has passed since someone was there, we do know that they perceive how scents evolve over time.

We see a snapshot of a moment. They perceive part of its history.

We look at a clock to tell the time. They lift their noses.

There is another fascinating aspect of the canine sense of smell that researchers are still exploring. We measure time with clocks, calendars, and schedules. For dogs, however, the passage of time may be linked, at least in part, to the way scents change.

Researcher Alexandra Horowitz has suggested that dogs may use changes in the intensity and composition of scents as a way of orienting themselves throughout the day. When you leave home, for example, your scent doesn't disappear all at once. It gradually fades and changes in composition. Your dog may learn that when your scent reaches a certain level, it usually means you're about to return home.

The same may apply to many other scents in the environment. As the day progresses, the people passing by change, the activity of other animals changes, temperature and humidity fluctuate, and even the way scent molecules disperse through the air is constantly shifting.

For an animal whose primary source of information is smell, all of these changes could form a kind of "chemical clock" far richer than anything we are capable of perceiving. We still don't know exactly how dogs experience the passage of time. But we do know that, for them, the world is not a still photograph. It is a landscape that is constantly changing with every new molecule that reaches their nose.

Perhaps the best demonstration of the extraordinary power of a dog's nose is found not during a walk, but when working alongside humans.

Detection dogs help locate missing people, find survivors trapped beneath earthquake rubble, identify explosives such as TNT, RDX, and PETN, detect illegal drugs, and assist in locating human remains—even in bodies of water—by identifying the volatile compounds that rise to the surface.

There are also dogs trained to detect changes in human body odour associated with certain medical conditions, including some types of cancer and episodes of hypoglycaemia.

More than three centuries ago, the scientist Robert Boyle described how a Bloodhound was able to follow a person's scent trail for approximately eleven kilometres across heavily travelled roads before finding them hiding on the upper floor of a house. Today, stories like this continue to amaze us, but we no longer attribute them to magic. Instead, we recognise them as the remarkable capabilities of one of the most sophisticated olfactory systems evolution has ever produced.

The next time your dog stops in front of what seems like nothing more than a patch of grass, perhaps it's worth putting your phone back in your pocket and waiting a few extra seconds. You may only see grass. Your dog is exploring an entire universe.

And the more we understand that universe, the easier it becomes to realise that a walk is about much more than simply walking.

For a dog, every walk is an opportunity to update everything they know about the world.

“When you let me stop and sniff, you're not just taking me for a walk. You're allowing me to use the superpower I was born with to discover my world.”