Dogs live in a world that is far richer in scent than we can ever imagine. While we rely heavily on sight and sound, dogs use their noses to gather information about their surroundings, other animals, and even us.

One of the most fascinating parts of this hidden world is the use of pheromones. These are chemical signals that dogs release and detect, shaping much of their behaviour and social interaction. Although we cannot smell them in the way dogs do, pheromones are constantly at work in the background, influencing how dogs relate to one another and sometimes even how they respond to people.

Pheromones are not the same as ordinary smells. They are chemical messengers that carry specific information. Dogs produce them in a variety of ways, through glands in the skin, urine, faeces, saliva, and even from special glands around the ears and between the toes. When another dog encounters these signals, it is not simply smelling them but reading them as a form of communication. This is why dogs spend so much time sniffing each other and their environment. What looks to us like a quick sniff of a lamppost is, for a dog, the equivalent of reading a detailed noticeboard.

The way dogs detect pheromones is also remarkable. Alongside their powerful sense of smell, they have a special organ called the vomeronasal organ, or Jacobson’s organ, located between the nose and the roof of the mouth. This organ is finely tuned to pick up pheromones and send the information directly to the brain. When you see a dog pause, curl its lip slightly, and take in a deep sniff, it may be drawing pheromones into this organ for closer analysis. This behaviour is known as the Flehmen response and is common in many animals that rely on pheromonal communication.

So what exactly do pheromones tell dogs? They can reveal a wide range of information. A dog’s urine marking, for example, is not just about territory but also about identity. It can tell another dog the sex, age and even the health of the one who left the mark. Female dogs in season release pheromones that signal their readiness to mate, which is why male dogs can become so persistent when they detect them. Puppies are guided by pheromones too. A mother dog produces a special pheromone that reassures her litter and helps them feel safe. This same chemical has been copied in synthetic form and is now used in products designed to calm anxious dogs.

The emotional side of pheromones is particularly interesting. Dogs can release signals that reflect their stress or fear, and other dogs may pick up on this and react accordingly. This helps explain why tension can spread quickly in a group of dogs. On the other hand, calming pheromones can have the opposite effect, creating a sense of reassurance. Humans have learned to make use of this by developing sprays, collars and diffusers that mimic natural pheromones. These are often used to help dogs cope with fireworks, travel or being left alone. While results can vary, many owners find them a useful tool alongside training and reassurance.

What about us? Although we do not have the same vomeronasal organ function as dogs, there is evidence that pheromones may still affect us in subtle ways. We may not consciously detect them, but our bodies can sometimes respond. For example, some people notice that they feel calmer when they are close to their dog, and while much of this is down to the bond and routine of companionship, pheromones may play a small part too. It is a reminder that our relationship with dogs is not only emotional and behavioural but also chemical.

Understanding pheromones gives us a deeper appreciation of how dogs experience the world. It explains why sniffing is such an important activity and why it should never be rushed or dismissed as a nuisance. When a dog stops to investigate a scent, it is gathering information that is vital to its sense of place and security. Allowing time for this is part of respecting a dog’s natural needs. It also helps us see why some behaviours, such as marking or sniffing other dogs, are not random but rooted in a sophisticated system of communication.

Dog pheromones may be invisible, but they are powerful. They shape social interactions, influence emotions and even touch on the connection between dogs and humans. The next time you see your dog pause to sniff the air or investigate a patch of ground, remember that it is not just curiosity. It is part of a complex and fascinating language that has been guiding dogs for thousands of years.