Aerodynamics of odours in a dog’s nose

What is highly sensitive to scent and can recognize the direction of the faintest odour? A dog’s nose!

Customs officers use dogs to find drugs in luggage. Police use canines to trail an escaped criminal. Emergency workers depend on man’s best friend after a natural disaster to find survivors trapped under rubble.

Dogs’ sensitive sniffing ability is due to the olfactory recess in their nasal cavity. It takes up about half the space inside its nose, sits just behind its eyes, and looks like a tangled mass of twisted airways.

Recently Brent Craven of Pennsylvania State University studied the aerodynamics of the air and odours flowing inside a dog’s nose.1

He and his colleagues put air-monitoring muzzles on seven breeds of dogs, including a Labrador and a Pomeranian, and filmed their sniffing (when tempted with spoons of peanut butter or tuna) on high speed video.

It turns out that dogs sniff at the same rate at which they pant—five sniffs per second. And the researchers were surprised to discover that dogs can sniff independently with each nostril. With each nostril pulling in a separate odour sample, Craven explained, the dog knows which direction a scent is coming from. The researchers also found that dogs retain the smell in their maze of scent receptors even after they have exhaled.

If you are looking for a highly sensitive, directional, rapid response, mobile, internally powered, rechargeable, odour detector, then why not use a sniffer dog?2  Its nose is another example of the superb design in living things—the organization of all the separate components into an integrated system that works with remarkable precision. Just as the sensitive nose of the humble dog can lead a tracker to his quarry, the amazing design in the living world can put us on the trail toward our remarkable Designer….

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