Glossary

Sense of smell

A dog's main sense, thousands of times more sensitive than ours by some estimates, with far more scent receptors and a dedicated airflow in the nose.

Also called: olfaction, dog nose, canine olfaction, dog's sense of smell, scenting ability

Smell is the sense dogs rely on most. A dog's nose has many more scent receptors than a person's, and estimates run from about 125 million to 300 million, compared with around 6 million in people. Much of the brain's processing is devoted to scent, and the exact advantage depends on the odor and the breed.

Dogs also sniff in a way that sorts air into one path for breathing and another for smelling, and exhaled air leaves through side slits so that new scent is drawn in with each sniff. A wet nose may also help catch odor molecules.

This lets dogs detect things people cannot, including drugs, explosives, missing people and some medical conditions. Scent is a source of information for a dog, not a skill it performs only on request, which is why sniff time on walks is valuable. Short-nosed breeds tend to have less nasal area but still smell far better than we do.

Last reviewed November 8, 2026

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Related terms

Vomeronasal organ A small scent-sensing organ in the roof of a dog's mouth and nose that detects chemical signals such as pheromones. Scent work Any activity in which a dog uses its nose to find a target odor, from backyard hide-and-seek games to trained detection jobs. Nosework A dog sport in which dogs search rooms, vehicles, outdoor areas and containers for a specific trained odor and alert their handlers. Enrichment Giving a dog chances to use its natural abilities, such as sniffing, chewing, foraging and problem solving, to improve its well-being.