A tremendous amount of the dog’s brain tissue is devoted to olfactory cells. (Some estimates allocate one-third of the dog’s brain to the chore of scenting.) All this adds up to a canine scenter that has thousands to millions of times the ability that we humans have.
A dog’s sense of smell is said to be a thousand times more sensitive than that of humans. In fact, a dog has more than 220 million olfactory receptors in its nose, while humans have only 5 million.
James Walker, former director of the Sensory Research Institute at Florida State University stated: “If you make the analogy to vision, what you and I can see at a third of a mile, a dog could see more than 3,000 miles away and still see as well.”
Put another way, dogs can detect some odors in parts per trillion. What does that mean in terms we might understand? Well, in her book Inside of a Dog, Alexandra Horowitz, a dog-cognition researcher at Barnard College, writes that while we might notice if our coffee has had a teaspoon of sugar added to it, a dog could detect a teaspoon of sugar in a million gallons of water, or two Olympic-sized pools worth.
The dog’s incredible sense of smell is being used to benefit mankind in ways we are still only beginning to imagine. Today’s working scent dogs are involved in search and rescue (some dogs can follow a trail that is more than a week old), finding cadavers (dogs have even detected drowned people in a depth of 80+ feet of water), detecting explosives, firearms, and drugs, and even scenting low blood sugar, seizures coming on and cancer in human patients. Work has been going on to use dogs to test the breath of humans to help diagnose internal diseases before they become evident with other methods.
Since smelling is hooked into the most primitive areas of an animal’s brain, there is reason to believe that smell is also linked to sensations created long before the animal was actually born.
We know, for example, that shortly after birth, Dam’s are able to pick out their own offspring by smell, and the puppies almost immediately learn the smell of their mother’s and where to find milk.
While at this time, it’s not easy to correlate long-lasting emotions to past events in dogs, I believe that this is surely something for us consider when we are dealing with a behavior or phobia problems that we can’t explain physically; It is very possible that their fears or “bad” behavior could be related to some household odor, personal product’s synthetic fragrance or even the smell of freshly cut grass that was associated with a bad experience in the dog’s past. I know in my own experience with working with dogs that have phobias to loud noises, I have been able to diffuse therapeutic grade essential oils while giving them their favorite treat and they learn to associate that particular aroma of the essential oil with good things – treats, tummy rubs, etc. so it only makes sense that they may be able to correlate traumatic past events with some scent as well. Something to think about, right?
Stay tuned for part IV of the Dog’s Nose Knows.