In my post, What Happens at the Body Farm? I touched on cadaver dogs. Many of you wanted to learn more about these super sniffers, so let’s find out why a dog’s nose can detect odors and later, we’ll move onto how you can print your dog’s nose, and why.
It’s no secret that dogs have a far superior sense of smell than we do. Hence, why cadaver and drug dogs have become an integral part of law enforcement. In order to fully grasp dogs’ ability to track scents, we must first look at how this is possible.
Where we rely on our sight to interpret the world around us, dogs use their sense of smell. To really appreciate a dog’s olfactory ability, let’s first examine the structure of this amazing organ.
Structure of a Dog’s Nose
Inside any nose, ours included, are bony scroll-shaped plates called turbinates, over which air passes. A microscopic view reveals a thick, spongy membrane that contains scent-detecting cells and nerves that transport the information to the brain. Our scent-detecting area is about one square inch (about the size of a postage stamp). In dogs, if we were able to unfold the scent-detecting area to its full capacity, we’d find that it may be as large as 60 square inches (about the size of a sheet of printer paper).
Though the size of this surface varies with the length of the dog’s nose, even flat-nosed breeds can detect odors far better than we can. Additionally, a dog’s brain is also made for identifying scents. The part of the brain that’s devoted to analyzing smells is actually 10 times larger than ours, allowing dogs to better identify smells 10K-100K times more accurate.
“Let’s suppose they’re just 10,000 times better,” says James Walker, former director of the Sensory Research Institute at Florida State University. “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.”
To grasp dogs’ inherent power, below is a table from the Dummies Guide that shows the amount of scent-detecting cells.
Humans — 5 million
Dachshund — 125 million
Fox Terrier — 147 million
Beagle — 225 million
German Shepherd — 225 million
And the superstar scent trackers — Bloodhound with their 300 million scent-detecting cells. Bloodhounds have an added advantage. When they track, their floppy ears sweep the air toward their nose to amplify the scent.
Real Life Superheroes
Experts have reported incredible true stories about dogs’ amazing abilities. Information gathered from Nova.
- The black lab in Seattle who detected a floating orca scat from up to a mile away, across the choppy waters of Puget Sound.
- The drug-sniffing dog that found a plastic container filled with 35 pounds of marijuana submerged in gasoline within a gas tank.
- The cancer-sniffing dog who insisted a spot on a patient’s skin was melanoma after doctors had pronounced the area cancer-free. A subsequent biopsy confirmed melanoma in a fraction of the cells.
A Dog’s Nose
Our dogs’ noses have a pattern of ridges and dimples that, in combination with the outline of its nostril openings, make up a nose print — as unique as a fingerprint. There are companies that even register dogs’ nose prints in order to locate lost or stolen pets. This practice is especially popular among kennel clubs.
Dogs’ noses also function quite differently than ours. When we inhale, we smell and breathe through the same airways. When dogs inhale, a fold of tissue inside their nostril separates these two functions into different pathways.
Bioengineers at Pennsylvania State University are now working to reverse-engineer the canine nose to aid in the design of artificial noses that can detect odors as well as dogs.
In humans, the sense of smell is relegated to a small region on the roof of our nasal cavity, along the main airflow path. In other words, the air we smell releases as we exhale. In dogs, however, about 12% of the inspired air takes a detour into a recessed area in the back of the nose, dedicated to olfaction, while the remaining incoming air sweeps past that nook and down the larynx, into the lungs. Within the recessed area, the odor-infused air filters through turbinates, the scroll-shaped bony structures I mentioned earlier. Olfactory receptors within the tissue line the turbinates. These receptors recognize the odor molecules by their shape and send electrical signals to the brain for analysis.
We can’t wiggle our nostrils independently, but dogs can. This, along with each nostril’s aerodynamic reach, helps them determine which nostril an odor arrived in, aiding them in locating the odor’s source.
In addition, dogs have a second olfactory capability that we don’t have — an organ we don’t even possess. It’s called the vomeronasal organ, aka Jacobson’s organ. Located in the bottom of a dog’s nasal passage, this organ is solely used to detect pheromones. However, the pheromone molecules never mix with odor molecules or their analysis, because the organ has its own separate nerves that lead to a part of the brain devoted entirely to interpreting its signals.
Amazing, right? If any of you have ever had a dog in heat, this is why potential mates from thirty miles away littered your front lawn. And why, a wave of panic shot through your core when you envisioned them invading your house and mounting your precious baby.
Training Cadaver Dogs
Training a cadaver dog requires regular contact with human blood, decaying flesh, and bones. In the United States, dog handlers can legally obtain bodily components like human placenta and blood, but it isn’t always easy to find. Which is why trainers like Mary E. Cablk, a scientist at the Desert Research Institute in Nevada, often resort to using their own blood. Substitutes are available commercially, called ersatz odors — the most common is Sigma Pseudo Corpse Scent, which comes in three scents: recently dead, decomposed, and drowned.
However, the best way to train a cadaver dog is by using real scents at places like The Body Farm. Cablk had this to say about what type of dog is best to train: “You don’t want a really smart animal. Its curiosity might lead to distraction. Instead, look for a midsize dog that never tires of playing with a tennis ball or pull toy. Eventually, you will teach the dog to associate the smell of death with its toy by making the toy smell like death.”
“Your dog should be exposed to, and trained to find, all sorts of dead bodies — on varied terrain, day or night, rain or shine,” she said. “You have the whole gamut, from old dry bones to somebody who dropped dead from a stroke an hour before you showed up. Until proved otherwise, every area is a crime scene. Coach your dog to calmly sit or lie down when it locates a scent’s source. Digging, peeing, and frolicking can destroy evidence.”
How to Print Your Dog
Don’t let the smile fool you. My baby, Cascius, would NOT be happy if I tried this. Besides, he leaves enough prints on the glass doors to ID him a thousand times over.
But if you’d like to try to print your dog, here’s how:
Wipe your dog’s nose with a towel to dry the surface. Pour food coloring onto a paper towel and lightly coat your dog’s nose. Hold a pad of paper to his nose, but make sure to let the pad’s sides curve around the edges to pick up the full nose impression.
This may take a few tries to get the right amount of food coloring and pressure to produce a viable print. Food coloring is non-toxic and can easily be removed. I shouldn’t have to say this, but please don’t use ink or paint. Not only could you cause harm, but how would explain your dog having a blue or red nose?
Fascinating unrelated detail: Male dogs tend to use their left paw more, whereas females tend to use their right. And you know, I find this to be accurate. My dog is male and he’s definitely a lefty.