Lassie can do much more with her nose than balancing a cookie and tracking the scent of your neighbor's cat. An abundance of remarkable stories seem to suggest that dogs use their noses for navigation. Some theories, meanwhile, suggest dogs may also use different tactics.
Blessed with 300 million olfactory receptors and a sense of smell 40 times greater than a human's, it's no surprise dogs rely so much on their powerful sniffers. To make a fair comparison, just as you can detect a teaspoon of sugar in a cup of coffee, your dog can detect a teaspoon of sugar in a million gallons of water, explains Alexandra Horowitz in her book "Inside of a Dog."
As if Lassie's nose wasn't impressive enough, the tasks she manages to achieve using her olfactory skills are truly astounding. Dogs have been known for being capable of detecting drugs, explosives and even missing people buried under several feet of snow. In a similar way, Lassie can put her nose to work when navigating unfamiliar terrain by following scent trails that she remembers from her jaunt away from home.
A dog may rely on a mental spatial map to navigate her way home. This theory assumes that dogs draw their own mental maps of their environment using memories of familiar odors and visual landmarks as references. It's as if they have a built-in GPS and know precisely where they are in space and time, explains animal behaviorist Nicholas Dodman. This theory doesn't fully explain how some dogs are capable of finding their way home from far away using routes they never used before.
When information from the senses is unavailable and familiar landmarks are lacking, dogs may utilize more sophisticated methods to find their way home. Biologist Rupert Sheldrake suggests that a dog's brain works as a storehouse of memories and associations that defeats space and time. After conducting several field experiments using a navigationally gifted dog, Sheldrake came to the conclusion that a sense of home must exert some sort of draw that causes a dog to search until he finds his way.
Sometimes, bonds between dog and owner are so strong that a lost dog's desire to being reunited with his owner may cause the dog to operate in ways that go beyond logical explanations. You may call it a psychic connection or a sixth sense, parapsychologist Joseph B. Rhine of Duke University prefers to call it PSI trailing. While he conducted many experiments that validate PSI trailing as a possible explanation for a pet's homing instinct over great distances, so far, PSI trailing still remains a mystery.
Combo of Methods
While a dog's nose may definitely play a role in finding his way home, a dog's homing instinct remains a mystery to scientists. Most likely, Lassie returns home by engaging in a combination of tactics that help her succeed. Dogs may basically do all they can in order to be reunited with their masters, including using their powerful sniffers, relying on familiar landmarks and perhaps using a sixth sense unknown to science. One fact is sure, though, when Lassie wants to go home, she can do the unexplainable.
- Nova Science Now: Dogs' Dazzling Sense of Smell
- Power of the Dog: Things Your Dog Can Do That You Can't; Les Krantz
- Web MD: Pets' Amazing Abilities
- Dog Sense: How the New Science of Dog Behavior Can Make You a Better Friend; John Bradshaw
- Dogs That Know When Their Owners Are Coming Home, Fully Updated and Revised; Rupert Sheldrak
Adrienne Farricelli has been writing for magazines, books and online publications since 2005. She specializes in canine topics, previously working for the American Animal Hospital Association and receiving certification from the Certification Council for Professional Dog Trainers. Her articles have appeared in "USA Today," "The APDT Chronicle of the Dog" and "Every Dog Magazine." She also contributed a chapter in the book " Puppy Socialization - An Insider's Guide to Dog Behavioral Fitness" by Caryl Wolff.