The nose knows

The fact that dogs have super sniffers is no secret. Experts say a dog’s sense of smell is so much stronger than that of humans it's almost impossible for us to fully comprehend the distinction.

“One of the most remarkable features of the dog is its sense of smell,” David Taylor says in his book, You & Your Dog. “The dog’s sense of smell gives it all kinds of information and is about one million times more sensitive than our own. A dog also has 40 times the number of brain cells involved in scent recognition than the number in a human.”

Dogs can temporarily store air in a special nasal chamber even after they exhale, “so scent molecules accumulate there until there is a sufficient concentration available for the dog to identify an odor,” according to the web site dog.com. Dogs also have an organ in their nasal cavity known as Jacobson's organ, which allows dogs to “literally taste the air.”

But it’s one thing to know something intellectually, and quite another to see it in action for yourself.

The other day, while my wife Liz was at work, I took our chocolate lab, Aquinnah, for his mid-morning walk. The walk itself only covers about three blocks, but thanks to Aquinnah’s marathon stop-and-sniff sessions all along the route, it takes us about 15 to 20 minutes to make our rounds.

While we were out, Liz popped into the house to pick something up, but she had come and gone by the time Aquinnah and I returned home. Liz was not wearing perfume, and nothing was amiss when Aquinnah and I walked in. There were no signs of her visit. In fact, if Liz had not told me beforehand when she was going to stop at the house, I would have had no idea that she had done so.

But Aquinnah went into a frenzy as soon as we entered the house.

He usually obsesses over getting a drink of water and a biscuit right after a walk, so this was highly unusual behavior. To my eyes and nose, all was as it should be. But Aquinnah raced around the kitchen, the dining room and the living room with his schnoz held high in the air the whole time, sniffing excitedly, and with complete concentration.

As I watched him, three things became clear:

1) Aquinnah was not looking for information - his entire effort involved scent, and scent alone.
2) There was no doubt he knew someone had entered the house while we were out.
3) There also was no doubt he knew exactly who that someone was.

After all, the nose knows.