FIDO FACTS

Dogs have up to 300 million olfactory cells and humans have six million cells—a colossal difference.

A dog could detect a drop of blood in a million gallons of water, or two Olympic-sized pools worth, like catching a whiff of one rotten apple in two million barrels.

The part of a dog's brain devoted to analyzing smells is, proportionally speaking, 40 times greater than ours.

When we inhale, we smell and breathe through the same airways within our nose. When dogs inhale, a fold of tissue just inside their nostril helps to separate these two functions, allowing them to smell more or less continually.

It’s all about which way the wind blows. When a dog breathes in he can tell which nostril an odour arrived in because each nostril's “aerodynamic reach” is so small. When a dog breathes out the expired air blows out the side slits in such a way as to augment the sampling of new odours. Follow that smell!