Licks, smells and puppy dog tails

Today, I let him win.

That's because I have fresh appreciation for his sniffing behavior, after reading a new book, Being a Dog: Following the Dog Into a World of Smell by Alexandra Horowitz, a professor of cognitive science who runs the Dog Cognition Lab at Barnard College.

In it, she explains the elegant engineering of the dog's olfactory system and how familiar canine behaviors -- licking, sneezing, tail-wagging -- have associations with smell.

On a recent afternoon at Riverside Park in Manhattan, I met Horowitz and Finn, her affable black 9-year-old mixed breed. There she -- and he -- shared some sniffing insights that have since made my walks with Chico more intriguing and fun.

Dogs sniff, humans sniff, what's the difference?

"There are many ways to sniff, and the human method is not the best," Horowitz said. Sniff researchers (yes, you read that correctly) have found we have about 6 million olfactory receptors; dogs have 300 million. Humans sniff once per second-and-a-half; dogs, five to 10 times a second.

"They even exhale better than we do," Horowitz continued, describing a sort of doggy yoga breath. Dogs exhale through the side slits of their nostrils, so they keep a continuous flow of inhaled air in their snout for smelling. "This gives them a continuous olfactory view of the world."

Why do dogs love to lick stinky toes?

Licking is related to smell, Horowitz said. Dogs and many other animals have a second smell system called the vomeronasal organ (VNO) above the roof of their mouth and below the septum dividing the sides of the nose.

Sniffs pick up airborne odors, but the sensitive VNO can detect the smell of molecules that have been absorbed in tissue. One way is through licking.

Why do dogs love to roll around in things that smell repulsive?

One theory is that their sense of smell is really a complex motor system related to the brain. And so, Horowitz said, when Finn alights upon a rotting squirrel corpse in the park, the smell that fires up the olfactory lobe in his brain also travels to the motor cortex and tells him to lean his whole body into the found object of desire.

Is wagging related to smell, too?

Yes. Many of a dog's identifying smells are in the anal glands. Those sacs transmit how a dog is feeling -- anxious? playful? -- and the essence of who the dog is. To greet one another, said Horowitz, as Finn demonstrated obligingly, hailing a goldendoodle named Polly, "dogs wag, basically dispensing their personal odors from their rumps."

Can companion dogs smell as well as working dogs?

While working dogs are encouraged to use their smelling ability and rewarded for it, Horowitz said, pets are discouraged from doing so. "They're taught that it's impolite to smell a rump because it's impolite for people to do it. We put those kind of mores on our dogs."

As a result, they sniff less and rely more on visual cues.

Horowitz writes about how she took Finn to remedial "nosework" classes. She soon saw that he found huge delight in finding objects by scent.

How can pet dogs exercise their sense of smell?

"Take a smell walk with them," Horowitz said. "Let them lead the way and smell and linger. Let them sniff each other. There's a pleasure for owners in letting a dog be a dog, to acknowledge their dogness. They put up with a lot of our humanness."

How can humans exercise our own sense of smell?

In the book, Horowitz writes about her experiments in recharging her olfactory system. Her advice for us is comparatively simple.

"Take a cue from the dog," she said. "Put your nose in things and take dedicated sniffs. Name the smells. I enjoy smells more now... They tell me about the world. That's as close as I get to being doglike."

ActiveStyle on 10/24/2016