A dog’s nose is an incredible scent detector. This ability has been used to train bomb-sniffing dogs, narcotics and contraband sniffers as well as tracking hounds.
But even the best electronic scent-detection devices — which use the dog’s nose as their gold standard — have never been able to quite live up to their canine competition.
But new research — which took a plastic dog nose and strapped it to a bomb sniffing device — might change that.
What makes a dog’s nose special?
Dogs have almost 300 million smell receptors in their noses, compared to the meagre six million us humans have: their sense of smell is more than 40 times better than ours. But those smell receptors are just part of the puzzle.
Matthew Staymates, lead author on a new paper published Thursday, figured that the canine sniffing skill also has something to do with the anatomy of a dog’s nose.
A former roommate of his had done his PhD in dog nose anatomy and actually had a computer model of a dog’s nose and entire head. So Staymates used a 3D printer, printed out a dog’s nose, and attached it to an electronic detector.
“Sure enough, a week or two later, I had a fully functioning, anatomically correct dog’s nose that sniffs like a real dog.”
From that, he worked with something called a schlieren imager to watch air go in and out of a nose when the dog is snuffling around the ground. Here’s what that looks like:
He found that dogs are even better at detecting than we thought — and it has little to do with the amount of brain space dedicated to scent or even the number of sensing cells they have. The key is the anatomy of how the air flows in and out.
It all comes down to the nostrils
When a dog exhales, a turbulent air jet comes out of each nostril — just like us humans.
But the way dogs and their noses are positioned on the ground means those exhaled jets are directed (or “vectored”) down towards their rear.
It’s a bit complicated, but fluid dynamics says that vectoring air backward also causes air to be pulled forward. This means the air in front of the dog is pulled into his nose as he exhales.
“He’s kind of reaching out and pulling a new plug of fresh air from ahead of himself,” said Staymates. “He inhales it then immediately and he analyzes it with a pretty amazing chemical detector. And he does this about five times a second.”
The benefit of that anatomy? Dogs can sniff a larger environment and also know the direction of where the scent is coming from.
Here’s a video of Staymates explaining the concept:
Making detectors more like dog noses
The shape and function of a dog’s nose is already being used to improve electronic scent detectors.
Staymates and team have created prototypes that are being affixed to commercially available bomb and narcotic detectors that work in the same way as a dog’s nose.
And the upgraded sensors, the “doggyfied” ones, work a lot better — up to 18 times better.
It’s amazing how dogs evolved this incredible scent detector — and all it took was 3D printing, optical imaging and a fantastically clever idea to finally figure it out.
Article source: http://www.cbc.ca/news/technology/artificial-dog-noses-are-being-used-to-improve-drug-and-bomb-detectors-1.3876192?cmp=rss