• Stephen Birchard

Dog's Sense of Smell: We knew it was good, but this is crazy!

Updated: Aug 28

Dogs have many redeeming qualities. For example, they are really good sniffers. They love to smell everything, especially us, and especially when we get home from work. We bring home a variety of new and interesting aromas on our clothing. They want to take inventory of those and make sure, by our familiar smell, that we actually are the people they were expecting to enter the house.

We've known about dog noses for some time, but recent research has shown that we underestimated this aspect of our furry friends. In her book, "Inside of a Dog", canine cognitive expert Dr. Alexandra Horowitiz describes the amazing sensitivity of a dog's nose based on results of multiple studies. For example, dogs can detect a teaspoon of sugar added to one million gallons of water; that's enough to fill 2 olympic sized pools! Their sense of smell is as detailed and discriminating as our sense of sight. Dogs' primary tool to investigate their world is not their eyes,or their ears, it's their nose.


The anatomy of the dog nose lends itself to their incredible sense of smell. The canine nose is filled with a labyrinth of egg shell thin bones, the turbinates, all of which are covered with sensitive mucosal linings and olfactory receptors. Included in this network are the vomernasal organs, the sensory tissues that detect pheromones, those hormone like substances that communicate sexual readiness from one animal to another. The part of the brain that receives the smell signals, the olfactory lobes, are gigantic compared to ours and they reside just behind these nasal turbinates. The trip from sensors to brain is very short.


You probably know that dogs can be trained to sniff out illegal drugs in luggage and bombs concealed in containers. But did you also know that dogs can detect cancer in humans? They can accurately detect cancer of the skin, breast, urinary bladder, and lung. In one study, dogs were given urine samples from normal people and those with cancer, and were trained to sit or lay down when they detected cancer. Out of 1,272 samples, they only missed on 14.


How does a dog know that you are mad? By your smell! Humans give off different aromas depending on their mood: afraid, stressed, or anxious, and dogs can sort them out with their nose. According to Dr. Horowitz, your dog knows when you've recently smoked a cigarette, had sex, or eaten a snack. When we move from room to room, we leave a trail of skin cells behind us that dogs can smell. This is how bloodhounds track escaped convicts, even days after they've left the vicinity.



We live in a smelly world, and dogs love it. The amount of information they obtain by sniffing their surroundings boggles the minds of animal experts. The next time you're walking your pup and she wants to stop every 20 feet to smell each vertical object, try to be patient. She's investigating her world using her best tool, her nose.

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