With regard to the post below, if any of you are members of alternative rock bands then I think 'Phineas Gage was not an asshole' would be a great name for a song.
And now for something completely different.....
When a dog sniffs, he uses a different route of airflow than for normal breathing. A structure just inside the nostrils called the alar fold, opens allowing air to flow through the upper area of the nasal passages. A bony pocket traps odor molecules and they are dissolved in the mucous covered scent receptors where signals of this chemical change travel from the receptor along the olfactory nerve to the olfactory bulb at the end of each nasal passage.
When the dog exhales, the alar fold closes off the upper part and pushes air down and out through the slits on the side of the nose, which stirs up even more scent particles.
Odor molecules emanate from the source in a cone shape. Depending on environmental factors, odor molecules will be denser at the source and thinner as they disperse into the air. Scent detection dogs will scan this scent cone as they trail the source, often making a ‘whuffing’ sound.
From the Cadaver Dog Handbook by Andrew J. Rebmann, Marcella H. Sorg, Edward David
(Scooter can make 'woofing' sounds but I don't think that's what they are talking about.....)