Did you know… dogs have up to 300 million olfactory receptors in their noses? Compared to only 6 million in our noses? When we inhale, we smell and breathe through the same airways. Dogs have a fold of tissue just inside their nostrils, so when they inhale, they can actually separate smelling and breathing. And when dogs exhale, the spent air exits through the slits in the sides of their noses, allowing dogs to sniff almost continuously.