Time and again, it is a phenomenon how well dogs can smell. But what is the reason that their sense of smell works so excellently?

The dog owes its excellent sense of smell to the high number of olfactory cells in the nasal mucosa, a special breathing technique and the excellent processing of the information received in the brain. With up to 300 million olfactory cells, the dog‘s olfactory organ easily outperforms the human nose. The latter is equipped with just five million olfactory cells. The actual size and number of olfactory cells in dogs depends on the breed. Canines with long noses usually have a better sense of smell than their short-nosed fellows. When it comes to the olfactory mucosa, the dogs are also superior regarding the size of the surface area. It is about ten times larger than that of the human nose. This allows them to absorb and analyse significantly more scent molecules simultaneously. The ability to perceive the environment mainly through the nose makes the dog a macrosmat (Greek for “great nose”).

The technique makes the difference

In addition to the anatomical advantages, dogs also use a special olfactory technique that enables better differentiation of scent components. When a search and rescue dog begins to locate a victim, it inhales and exhales up to three hundred times per minute while sniffing intensively. This is an unimaginable feat for us humans, as a healthy adult can only manage a maximum of sixty breaths per minute, even with exertion. The swirling of the air enables the recognition of tiny amounts of scent molecules. To process the scent information, a message is passed on to the olfactory brain, which is particularly well developed in dogs. Every second, it evaluates whether the scent trace picked up is the one being sought. In a minute, up to fifteen thousand different odour images can be recorded. Humans manage less than four in the same time.

Dogs can smell stereo

Another special feature of the dog‘s nose is that both nostrils function separately, so dogs can smell two different odours at the same time (stereo), while humans only smell one odour (mono). This form of three-dimensional smelling enables the super noses to distinguish precisely whether a smell is coming from the left or the right, depending on which nostril the scent reaches first. This is also possible over greater distances.

No technology has yet become so perfected that it beats the fine nose of a search and rescue dog.

Markus Bock, Spokesperson for Deployment at IRO

Dog noses save human lives

To this day, the dog‘s nose cannot be substituted by any technical device. Under ideal search conditions, a well-trained search and rescue dog can detect scents at a distance of several hundred metres and can follow tracks in cities and towns over long distances, even after several hours or days. The use of search and rescue dogs is therefore the most efficient and reliable method of locating missing or buried persons.