Thursday, October 9, 2014

A dog's nose and sense of smell

What's that smell?
A dog's sense of smell is nothing short of amazing. Dogs can find hidden objects, hidden people, and even detect cancer on a person's breath. But how good is it really?

Compared to a human, a dog's sense of smell is 10,000 to 100,000 times better. They have up to 300 million receptors in their noses, while a human has around six million. Proportionally speaking, the area of a dog's brain dedicated to analyzing smell is around 40 times larger than ours.

A dog's nose also works in a different way than ours. When a human inhales, we smell and breathe through the same airway. That is, the air we smell goes in and out with the air we breathe, because it is the air we breathe. A dog's nose is constructed to separate smelling and breathing. A portion of air takes a detour dedicated to smell, and the rest goes into the lungs.

When a human exhales, the spent air goes out the nose the same way new air comes in. When a dog exhales the spent air goes out through the slits in the sides of the nose, helping new odors to enter. This also lets them sniff continuously.

While a human can wriggle the nose, a dog can wriggle each nostril independently, and a dog can determine which nostril caught a scent. This is how they can located the source of smells.

On top of all this, dogs have an organ humans lack. It is called the vomeronasal organ and sits at the bottom of the nasal passage. It picks up pheromones, and has a part of the brain dedicated just to this purpose.

So, what does all this mean in terms a human brain can comprehend?

A dog could detect one teaspoon of sugar dumped into a million gallons of water, or detect one rotten apple in two million barrels.

~ Maria Sadowski ~


  1. Mom is amazed at what she has learned in the last 9 months of nose work and tracking. She knew we had good noses but to actually see what we can do blows her away, and it is only small potatoes! Now that we use our noses more for work and use parts that we didn't use before even our nose sounds have changed.

    1. I love your posts on the nose work. I'm so fascinated with dogs' senses - and cats' - you can really do amazing things!