Sniffing

Dogs use sniffing to maximise the detection of odours. Sniffing consists of a series of rapid inhalations and expirations, normally 3 to 10, but possibly up to 30, during which the normal breathing mechanism is disrupted. Each nostril sniffs air from separate areas so that during sniffing there is a bilateral scent intake.

To maximise the efficiency during sniffing the dog needs each sniff intake to be unobstructed. Consequently, the expired air is passed out through the slits at the side of each nostril creating an air turbulence and allowing new odours to be inhaled directly into the centre of each nostril.

The alar fold

To enable this to happen, a structure just inside the nostrils called the alar fold (see above), opens allowing air to flow through the upper area of the nasal passages. When the dog exhales, the alar fold closes off the upper part and pushes air down and out through the lateral slits and the tiny wind currents created stir up even more scent particles. Watch for small puffs of dust rising up when the dog is sniffing close to the ground.

The importance of airflow during sniffing
During sniffing the inhaled air in the dog separates into two distinct pathways. The upper flow path, approximately 12% of each breath passes straight to the olfactory region, which is connected to the olfactory bulb portion of the brain. The rest of the air in the lower pathway, flows down the pharynx into the lung 4. 

The Dog’s Nose   Anatomy   The importance of mucus  

 Volatiles