DEAR DIDI: I am curious about how dogs find people that are lost or trapped in natural disasters. – Curious in Ripon
DEAR CURIOUS: Humans and all other mammals have five senses. Touch, hearing, sight, smell and taste. Neurophysiologically, humans are sight dominant. Thirty to 40 percent of our brain is devoted to sight, as compared to only eight percent for smell and just three percent for hearing. Dogs are completely the opposite of us. Canines are almost the complete opposites. Forty percent of their brain is dedicated to their sense of smell!
Dogs are able to separate smells directionally by which nostril the odor passed through. When they exhale the air exits through the side slits in their nostril to prevent interfering with fresh incoming air. They even have an olfactory organ at the bottom of their nasal passage that humans don’t have. It is called the Jacobson’s Organ and specifically processes pheromones which are the chemicals that are unique to each animal species and advertise sex-related details. Dogs are estimated to be able to smell 10,000 to 100,000 times better than a human. The variation is dependent on the length of the dog’s nose and therefore, the number of olfactory cells. Think of a Pug versus a German Shepherd. Yet, even the Pug can smell 10,000 times better than us! Humans have approximately three million scent cells in their noses. Dogs have up to 300 million cells.
Let’s look at some real world analogies to get some perspective on those numbers. They can detect one drop of blood in three Olympic sized swimming pools. Another trainer said a dog can find one rotten apple in among two million barrels! There are various true story documentations of a dog’s scent capabilities which are mind boggling. A drug sniffing K-9 was able to find a plastic container packed with 35 pounds of marijuana that had been submerged in gasoline in a gas tank. A cancer sniffing dog “insisted” on a melanoma in a spot on a patient’s skin that doctors had already pronounced cancer-free. A subsequent biopsy later confirmed the dog’s diagnosis!
When a Search and Rescue (SARS) dog is working on a scene they are processing all the scents around the scene. If a human is buried in earthquake rubble or an avalanche the dog is looking for any smells of a human. Human skin sloughs off approximately 30,000 to 40,000 cells every hour. People that are lost or trapped may have injuries providing other smells like blood, urine or infection.
Additionally, our hormones, which increase under stress and pain, can easily be tracked by a dog back to the source. As the smells enter their nostrils they are able to decide which way to turn by which nostril detected the smell first. How canines do detection work is a source of fascination for modern day scientists and lots of new studies are coming out monthly. We have even trained dogs to stay in MRI machines so we can watch their brains process during certain activities. We are even finding they have complicated emotions.
Dogs are truly our best friends in numerous ways.
Dierdra McElroy is a graduate of Texas A&M University and is an Animal Behaviorist specializing in canines. If you have questions or concerns about the pets in your house, you can get them answered through a future column of Didi’s Dogs. For a free consultation with Dierdra or to ask your dog behavior question, email www.CaliforniaCanineUnleashed.com.