Two 3-year-old, female German shepherds were trained at the Italian Ministry of Defense’s Military Veterinary Center using positive reinforcement to recognize prostate cancer-specific volatile organic compounds.
The dogs analyzed more than 400 urine samples, and one dog detected prostate cancer with 100 accuracy, while the second had 98.6 percent accuracy.
However, prostate cancer isn’t the only type of cancer dogs have successfully sniffed out.
Man’s best friends have also proved their noses can detect breast, ovarian, colon, bladder, skin and lung cancer, typically by smelling breath samples.
Cancer causes the body to release certain organic compounds that dogs can smell but people cannot, and scientists hope that researching the phenomenon will help them one day develop an electronic nose that can detect cancer as dogs’ noses can.
With 220 million olfactory cells in their snouts — compared with a mere 50 million in a human nose — it’s estimated that a dog’s sense of smell is up to a million times better than ours.
In addition to scientific studies, there’s also anecdotal evidence that dogs can detect cancer.
Numerous dog owners tell stories of their pets persistently sniffing or nudging an area of their body that later turned out to harbor a tumor.
We all know how good are the noses of our dogs. Yet, I suspect, many do not know how truly good is that nose. The Science ABC site has a detailed account of Why Do Dogs Have Such A Great Sense of Smell?
Here’s part of that article:
Dog Nose vs. Human Nose
When we try to smell something, we inhale air with our nose and we use the same passage in our nose to exhale that air. Therefore, all the smell that we get when we are inhaling is lost when we exhale that air. However, a dog has two different air passages, one for breathing and another for smelling. This means that dogs are able to store the smell in their nose even while breathing out the air!
When dogs exhale, they send air out through the slits of their nose, but the manner in which this air is exhaled through their nose helps the dogs to draw in new odor molecules. This also helps dogs capture more smells when sniffing.
You must have noticed that dogs’ noses are always wet, but have you ever wondered why? The mucus on the dog’s nose helps it smell by capturing scent particles. A dog also has the ability to smell independently from each nostril, this helps the dog to understand from which direction the smell is coming.
The passage through which dogs smell the air contains highly specialized olfactory receptor cells, which are responsible for receiving smells. A dog contains about 225-300 million smell receptors, as compared to just 5 million of these receptors being present in a human nose.
Dog Brain vs. Human Brain
By now, we clearly know that dogs have a nose that can smell about 1,000-10,000 times better than a human, but how are dogs able to remember all the different smells that they have sensed throughout their life?
The answer lies in the difference between the brains of dogs and humans. A human brain has a larger visual cortex than dogs, whereas a dog’s brain has a much larger olfactory cortex than humans. The visual cortex is responsible for processing visual information, whereas the olfactory cortex is responsible for processing the sense of smell. A dog’s olfactory cortex is about 40 times larger than that of a human.
Working dogs are an amazing asset not only for people, but for wildlife, endangered species and even threatened habitats. Expanding on the skills dogs have for tracking down scents and guarding something important, we humans have enlisted their help in many ways for conservation.
Here are five ways dogs are contributing to environmental protection efforts.
Smell for scat
It’s amazing the amount of information that can be sussed out of an animal’s poop. We can determine diet, health, genetics — even whether or not an animal is pregnant. Scat is really important to biologists studying elusive, sensitive or endangered species. Putting dogs on the track is an ideal solution.
Take cheetahs, for example. Scientists in Africa are using dogs and their unparalleled sniffing power to find cheetah poop, all in an effort to get an accurate count on the endangered big cats. (Only 7,000 cheetahs are left in the African wild, according to estimates.) And it’s working. Two trained dogs found 27 scats in an area of 2,400 square kilometers in western Zambia, according to a study published in the Journal of Zoology. Humans, looking for cheetah tracks over the same area, found none.
Groups like Conservation Canines (a handler and dog from the program pictured above), Working Dogs for Conservation and Green Dogs Conservation specialize in this area. Conservation Canines rescues highly energetic, “last chance” dogs from shelters and trains them to track down the scat of dozens of species, from wolves to moose to owl. Even things that are nearly impossible for humans to find — the minuscule scat of endangered pocket mice or orca scat floating on the ocean surface — dogs can track down. They are able to make huge contributions to scientific studies, all without ever bothering the wildlife being studied.
Dogs are able to sniff out particular plant species, pointing ecologists to tiny patches of invasive mustard so that the plants can be removed before they take over an area.
Conversely, dogs can sniff out rare or endangered native plants so that the species can be protected. Rogue is one such dog. The Nature Conservancy writes, “The 4-year-old Belgian sheepdog is part of a Nature Conservancy collaborative project to test the efficacy of using dogs to sniff out the threatened Kincaid’s lupine. The plant is host to the endangered Fender’s blue butterfly, found only in Oregon’s Willamette Valley.”
Surveying for the plant species is difficult work for people. It can only be done when the plant is in bloom so people can visually identify it. However, dogs like Rogue can sniff out the plant even when not in bloom, which can potentially double the length of the field season.
“More refined regional mapping of Kincaid’s lupine could promote the butterfly’s recovery and delisting — and contribute to larger habitat goals and wildlife impacts.”
Track down poachers
The trade in rare or endangered wildlife is a lot tougher for traffickers thanks to wildlife detector dogs. Trained to smell anything from tiger parts to ivory to South American rosewood, dogs are used in shipping ports, airports, border crossings and other locations to sniff out smuggled products.
It doesn’t stop there. Trained dogs can lead rangers to armed poachers in the wild, tracking down the culprits over long hours through heat and rain. They can catch poachers in the act, rather than just the products.
“Canine sleuths aren’t limited to the plains of East Africa, either,” reports National Geographic. “In the Democratic Republic of the Congo, bloodhounds are assisting in the fight against poaching in forested Virunga National Park, where the world’s last remaining mountain gorillas live. In South Africa, Weimaraner and Malinois dogs are helping to find wounded animals and track poachers on foot through the reserves around Kruger National Park.”
Guard endangered species
Dogs are also useful in putting their protective nature to use for endangered species.
Livestock protection dogs are trained to keep predators like cheetahs, lions and leopards safe, which then reduces conflict between ranchers and big cats and minimizes the instances of snaring or retaliatory killing of big cats. Cheetah Conservation Fund has a successful livestock protection dog program, which places Anatolian shepherd and Kangal dogs with ranchers. That not only has significantly reduced the number of livestock killed by predators but is also improving the attitude of local people toward cheetahs.
Sometimes the dogs are put to work guarding the endangered species themselves. One such successful program uses Maremma shepherd dogs to protect colonies of little penguins from foxes.
Keep bears wild
Karelian bear dogs are trained to keep bears from becoming too comfortable around people. A program by Wind River Bear Institute named Partners-in-Life uses a technique called bear shepherding. This specialized breed of hunting dog is used to scare bears away, and are an important part of the “adverse conditioning” work that keeps bears from becoming habituated. The ultimate goal is to protect bears from becoming habituated, a problem that leads to their being relocated or euthanized.
“Our Wind River Bear Institute mission, with the effective training and use of Karelian Bear Dogs, is to reduce human-caused bear mortality and conflicts worldwide to ensure the continued survival of all species of bears for future generations,” states the program.
This list is only a handful of ways that dogs help us with environmental conservation every day. More and more, we are figuring out new ways to put their skills to work, and more and more the dogs are proving they’re ready for the task!
Editor’s note: This story was originally published in July 2016 and has been updated with more recent information.
Closing words from that Science ABC piece:
A dog does not care how you look or dress, but if he gets good vibes from your smell, then a dog will love you. The world is truly a better place because of these wonderful creatures that we are lucky enough to welcome into our lives.
Why not make the world smell a bit more beautiful for them?
Closing picture taken from the OregonLive website. A stunning picture of the “Fender’s blue butterfly, found only in Oregon’s Willamette Valley.”