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Your Happy Pet: Your scent may be perfume to your dog

Original Publication Date: May 12, 2014
By C. Sue Furman, Ph.D.

Scientists estimate a dog's sense of smell is 10,000 to 100,000 times as acute as that of a human.

Theoretically, a dog can detect one rotten apple in 2 million barrels of apples.

So what does it mean when dogs greet by sniffing each other? For that matter, what does a whiff of a human tell a dog? What are they thinking?

Gregory Bern, a neuroscientist at Emory University, led a team of researchers who investigated the dog's sense of smell and found that to a dog the scent of a loved human may be like the scent of a familiar perfume to a human.

The researchers used functional Magnetic Resonance Imaging to determine the activity in the area of the dog's brain dedicated to smell. Twelve dogs of different breeds were trained to remain perfectly still but alert in the fMRI scanner. Each dog was exposed to five different scents. The scent samples came from the dog himself, an unfamiliar dog, a dog that lived in the same household, a human the dog had never met and a human that lived in the dog's household.

The fMRI scans showed that the area of the brain dedicated to detecting smells responded to each of the test scents.

This study tells us more about the part of the dog's brain that detects smell. It also, for the first time, indicates that a dog has a memory of smells that activate the brain, even when the person or dog associated with the smell is not physically present.

It is typical for your dog to greet you with bright eyes and a wagging tail when it sees you come in the door. This research shows that a dog remembers or thinks of its special human when only their scent is present.

The investigators expected dogs might be highly tuned to the smell of other dogs, but it seems that the strong reward response was reserved for their humans. This could be associated with food, play, a genetic predisposition to humans or something else. Determining just why dogs hold the memory of the smell of their human in high esteem remains to be answered by future investigation.

Have you ever come home to find that your dog had used your old shoe or shirt to cuddle in your absence? Perhaps it was just conjuring up thoughts of you through his sense of smell. This is another question to be answered by future research.

Gregory Bern's study does tell us that the scent of a loved human lingers in a dog's brain much like the scent of a loved one's perfume or aftershave lingers in the memory of a human. A whiff of your scent on a piece of clothing or furniture apparently keeps kind thoughts of you in your dog's memory when you are away.

Sue Furman, Ph.D, has published two books and a DVD on canine massage and teaches classes in pet massage, acupressure, first aid and CPR. See her schedule and submit questions at