smelling dogs

The Sense of Smell in Dogs: How Well Can Dogs Smell?

Not without reason, dogs are used to detect drugs, people missing after a disaster and even sniff out diseases. Dogs owe their keen sense of smell to the large number of olfactory cells in the nasal mucosa, a special breathing technique and excellent processing of the information they receive in the brain. Did you know that dogs with this equipment can even smell your emotions?

Read on now and learn interesting facts about the sense of smell in dogs in our guide!

How well can a dog smell compared to humans?

Dogs smell much better than humans. The olfactory mucosa of a human measures about five square centimeters. Approximately five million olfactory cells are located here. In dogs, on the other hand, there are about 200 million olfactory cells in a mucosal area of 150 to 200 square centimeters. The actual size and number of olfactory cells in dogs depends on the breed. Four-legged dogs with long noses generally have a better sense of smell than their short-nosed counterparts.

Breathing technique: How does the dog use its sense of smell?

The many olfactory cells and the extensive olfactory mucosa are one reason why dogs perceive odors very intensively. During concentrated sniffing, they can also inhale up to three hundred times a minute to pick up as many scents as possible. These are analyzed by the brain in such a way that individual substances can be filtered out of countless molecules. In this way, it is possible to train dogs specifically to track or detect certain odors and use them professionally. In addition to the nose, they have another olfactory organ – the Jacobson organ.

What is the Jacobson organ?

The Jacobson organ assists the dog’s nose. It is located on the roof of the mouth and is connected to the nose through a small opening. Have you ever observed that a dog not only sniffs extensively at the urine of a fellow dog, but also licks it and then smacks it lightly? In this way, the scent molecules contained in the urine reach the Jacobson organ directly. The stimuli received in this way are also passed on to the brain and analyzed. The additional olfactory organ enables dogs to smell pheromones and moods. This tells them quite a lot about the conspecific, such as gender and whether it is a calmer or more aggressive contemporary. Male dogs can tell if female dogs are in heat and willing to mate.

How does the dog’s brain work?

Here again there is an essential difference to humans. Dogs and humans have an olfactory bulb, which is a component of the cerebrum. It processes the stimuli received via scents and transmits them. In dogs, the olfactory bulb takes up about ten percent of the brain. In humans, it is only one percent. Dogs therefore absorb considerably more scent molecules on the one hand and on the other hand the brain receives considerably more information about all the odors absorbed.

How differentiated can dogs smell?

Dogs’ ability to smell is made even more subtle by the fact that they can take in and differentiate odors from different directions at the same time. They can use their nostrils independently and therefore recognize what is in which direction. This is also possible over greater distances. The prerequisite for this is that the dog’s nose is not too short or even that the airways have atrophied due to breeding. A healthy, long dog’s nose, on the other hand, picks up an unimaginable number of odors all around it and can analyze and classify individual scent components.

Which dog has the best sense of smell?

While around 200 million olfactory cells already provide the best conditions for an excellent sense of smell, some breeds even surpass this. Among these are the following dog breeds with about 225 million olfactory cells:

German hunting dog breeds

Shepherd dogs


Labrador Retriever

The dog with the best sense of smell is the Bloodhound with about 300 million olfactory cells.

What can dogs smell?

Dogs assist in hunting by detecting killed game. They are able to sniff out the smallest amounts of drugs or traces of explosives. Trained search dogs pick up the specific scent of a person and can follow their trail even days later. In disaster management, they are used to find people under rubble, under a meter-high blanket of snow or buried by a landslide.

Can dogs “smell” moods, diseases and even DNA?

Anger, aggression, fear, sadness, happiness and joy are emotions that dogs can detect by smell, in addition to body language. This may be the reason why they occasionally avoid people or other animals. We as humans with a comparatively limited sense of smell can hardly imagine this.

However, it is not so far-fetched if you consider that dogs even recognize diseases or certain health conditions by smell: The animals are used, for example, to warn diabetics in time when their blood sugar drops or epileptics before a seizure. In a research series at the University of Leipzig, investigations were carried out with regard to the recognition of human DNA. It is not excluded that dogs can also smell it and filter it out of the surrounding scents.


If you want to keep your dog busy in a meaningful way, you can train “nose work” with him. In special courses of dog trainers or also about appropriate guidebooks you learn how to get your dog to follow the smell of a person or to find a hidden object. The object can be his favorite dog toy or a dog food treat.

What do dogs themselves use their sense of smell for?

The distinct sense of smell is used by dogs for orientation and communication. It helps them find food and mates, as well as detect danger.

The wolf, as the dog’s ancestor, can perceive its prey even if it is three kilometers away.

Over smells they find out whether a congener makes territorial claims, and communicate by means of scents own.

Via the emitted endogenous scents, the pheromones, they recognize the mood of other dogs and know, without seeing them, whether they are in a friendly or rather hostile mood. Also over the state of health they are informed thereby.

If two strange dogs meet, they circle each other after a short check and sniff each other, preferably in the anal area. Strangers are also sniffed extensively at first to find out who the dog is dealing with.
FAQ – Frequently asked questions about the sense of smell in dogs

What happens when dogs lose their sense of smell or it is disturbed?

When dogs can no longer smell anything, they are impaired. They no longer perceive their environment as intensively as they used to. The dog is considered a “nasal animal” or also a so-called macrosmatic. As described above, dogs use their sense of smell not only to recognize food. They also use it to detect prey and use their fine nose to identify sexual partners, friendly and hostile animals. When their sense of smell is missing, they are no longer as interested in their environment as they once were and can become apathetic.

Who has the better sense of smell dog or cat?

The dog has a better sense of smell than the cat. While the dog, as described above, has about 150 to 200 square centimeters of olfactory mucosa, the cat has only an area of 4 square centimeters of the so-called olfactory field. In the number of olfactory cells, the cat lies between dogs and humans.
Does cheese impair the sense of smell in dogs?

Among many dog owners, the rumor persists that cheese interferes with the sense of smell in dogs. This is not true. Cheese does not affect the animals’ sense of smell. However, you should only offer your four-legged friend a piece every now and then – if at all – because cheese does not belong on the dog’s diet.

Conclusion – Sense of Smell of Dogs

Dogs have an excellent sense of smell. One counts them to the “nose animals” or macrosmatics. Several factors are involved in the distinctive sense of smell. These include

Very large olfactory mucosa with, breed-specific, up to 300 million olfactory cells

High scent absorption due to very fast respiration

Odor absorption from different directions possible at the same time

Jacobson’s organ as an additional olfactory receptor

Olfactory bulb as olfactory area covers ten percent of the brain

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