Every weekday morning at the In Situ Foundation in Chico, California, an eager pack of workers awaits their shift. One by one, they are led into a laboratory where their boss, a medical researcher named Dina Zaphiris, gives a simple directive: "Go find." With that, a shaggy staffer approaches a rack filled with human samples of blood, spit, and exhaled-breath condensate and begins to sniff, searching for the sample with a specific odor. Upon finding it, he sits down and points — with his nose. Mission accomplished: Our dogged worker has detected the organic compounds present in cancer.
Since co-founding In Situ, a canine medical-training center, in 2004, Zaphiris has trained more than 50 dogs to detect early-stage melanoma and upper thoracic, lung, breast, ovarian, bladder, and prostate cancers. The dogs' accuracy rate hovers at 98 percent. "In double-blinded trials, dogs blow away all the existing machinery and medical tests, which can generate false positives," Zaphiris says.
What makes Zaphiris' dogs — Stewie, Leo, Linus, Alfie, and Charlie — so effective? With 300 million olfactory receptors in each dog's nose, compared with a human's 5 million, they have the ability to smell things in parts per trillion (easily sniffing out, for example, 1cc of blood diluted in two Olympic-size swimming pools of water). "An MRI can show you a lump but not tell you whether it's cancerous," Zaphiris says. "What dogs' noses can do that machines cannot is be sensitive to the presence of cancer — and be specific that it is cancer."
We've long known that man's loyal companion can offer therapeutic benefits to trauma victims and soldiers with PTSD. Now we're discovering that trained dogs can work as effective diagnosticians, too, sniffing out early- and late-term cancers, Type 1 diabetes, and malaria. Increasingly, research also finds that just owning a companion dog can have positive health benefits. In fact, in the not-so-distant future, dogs may change the way we approach health care.
This appreciation of dogs is fairly new. It wasn't until the late 1970s that human-animal interaction began to emerge as a multi-disciplinary science. Before then, evidence of canine-related health benefits derived from dogs was merely warm-and-fuzzy anecdote. In 1980, Dr. Erika Friedmann, now a researcher at the University of Maryland School of Nursing, published a landmark study that found one-year survival rates of heart attack patients were significantly higher for pet owners, for a constellation of reasons including a calmative effect that lowers blood pressure, increased social support, and the cardiovascular benefits of dog walking. Then, in 1987, the National Institutes of Health went bolder, stating that "pet ownership is a variable in public health outcomes that, like food and exercise, cannot be ignored," says Dr. Alan Beck, director of the Center of the Human-Animal Bond at Purdue University.
In the three decades since then, the advantages dogs can provide have become clearer. In addition to aiding the blind, something service dogs have done for decades, they can now be trained to assist people who have mobility and balance impairments, or difficulty using their hands and arms, by opening doors, closing cabinets, and serving as balance supports. Showing a sensitivity to even the slightest human behavioral changes, trained dogs can sense when people with diabetes, epileptic seizures, and cardiac-related fainting spells are about to have an episode and warn them. Companion canines are also used as a calming agent for migraine sufferers and to help autism and dementia patients stay focused.
Even one of the least pleasant aspects of dog ownership — shedding — can positively impact the human microbiome. "The presence of dog dander in a home may activate the immune systems of young children, decreasing the likelihood of eczema, asthma, and respiratory allergies that may persist into adulthood," says Rebecca Johnson, director of the Research Center for Human-Animal Interaction at the University of Missouri College of Veterinary Medicine.
And we haven't even broached the benefits for the brain and nervous system. "There are real physiological responses that humans exhibit in the presence of and interaction with dogs," says Beck. Chief among them is a potent neurological response: a suppression of the stress hormone cortisol and a surge of endorphins (which decreases feelings of stress and pain), serotonin (which mitigates depression), prolactin (which induces feelings of nurture), and, most significantly, oxytocin (the "love" hormone released during social bonding, cuddling, and orgasm). Quality time with dogs also lowers blood pressure and heart rate and fosters a deeper sense of mindfulness. "Biophilia, our connection to nature and other living things, keeps us focused and in the moment, which is healthier than dwelling on the past or dreading the future," Beck says. "And pet ownership is a megadose of nature on demand."
The most dramatic results of canine health intervention tend to be seen in marginalized social segments — seniors, the incarcerated, juvenile delinquents, domestic violence survivors, and war vets. "Dogs allow people who suffer from dementia not to feel anxious, because dogs don't care what you forgot," says veterinarian David Haworth, who helped establish the Human Animal Bond Research Initiative Foundation, a nonprofit that's funded more than 300 canine-human health studies. "People with Alzheimer's and Parkinson's get great positive reinforcement from dogs when doing memory and physical rehabilitation exercises."
For anyone there's a clear-cut advantage to having a pup, according to gerontologist Dr. David J. Demko. "The physical and mental health benefits of owning a dog can add two years to the life of an owner," Demko estimates. For Haworth, who was recently named president of charities at PetSmart (where this story's author works), stats like these show that dogs' roles for the general public are unequivocal. "I think we should be giving doctors pads to write out prescriptions for pets."
That idea may not be so far-fetched. Lowering our heart rates and calming our nerves are substantial benefits on their own, but that's just a sliver of what trained canines may be able to do for us. In the future, dogs might roam our hospitals, public spaces, and offices.
"What I do was looked at as quackery by the medical industry 10 years ago," says Zaphiris of her cancer-detecting "biodogs" at In Situ. Today she collaborates with Duke University and trains dogs for the University of California, Davis, and the Paracelsus Klinik in Switzerland, the acclaimed European center for alternative medicine. "When the technique is approved by the FDA, I can screen 300 samples a day with a five-dog team," she says. With properly trained dogs and strict protocols, Zaphiris explains, cancer screening could become low-tech, or as easy as spitting into a cup and sending it out to be sniffed. And one day, she believes, "the work we are doing in scent detection will aid scientists to develop a Breathalyzer test for cancer."
That means anyone with a family history of cancer, smokers, people with certain pigmentation, or those who spend a lot of time in the sun could all have samples screened at a much younger age to improve treatments and prognoses, Haworth says. He doesn't think it will be so hard to get the public onboard. "Back in the 1890s, pathologists would taste urine for sweetness to determine diabetes, which is not so far from having dogs smell urine for cancer."
By using their incredible sense of smell, canines could even stop new diseases before they start. Dogs can be trained to inspect planes, vehicles, and luggage for meat or live animals that could transmit diseases to people. "You could crack down on poaching while also preventing horrible disease outbreaks — the next Ebola or HIV," says Dr. Brian Hare, the co-author of The Genius of Dogs.
Finally, dogs are also invaluable as test subjects: By studying how a sick pooch reacts to and fights off maladies, we can better develop solutions for humans. Compared with us, dogs age more rapidly and their diseases manifest faster, says Haworth; they also contract about 50 of the same diseases we do. "Under a microscope, B-cell lymphoma and bone cancer from a dog look almost identical to those in a human," he says. In other words, find out what cures a dog and you may be on your way to saving a human life. Older dogs have already been inducted into trials of a drug called Rapamycin, a fountain-of-youth pill shown to improve heart health, delay disease, and extend the life span of laboratory mice.
Though it may be hard to imagine dogs working as on-site technicians in hospitals and airports, or serving as personal cancer detectors in the home, their increased presence in health care settings is a testament to their steadfast bedside manner. "In every case where empathy is important, you will see dogs present more and more," Haworth predicts. "If I had to deliver a cancer diagnosis to someone, it would be really nice to have a pet sitting on his lap. Dogs aren't motivated by efficiency. They don't have to run off to their next patient. They're happy to hang out with you."
Some academics go a step further still. They argue that dogs are not only beneficial to human health but also an essential component of our very existence on this planet — that without human-canine kinship and the co-evolution of the two species, the world would not be what it is today. Dogs were the first domesticated animals, dating back at least 15,000 years, says Greger Larson, a biologist in the archaeology department at the University of Oxford. "Without dogs, you don't have other domesticated animals and plants. You don't have civilization." Dogs became essential workers, hunting game and protecting the agriculture and livestock that allowed the human race to flourish.
"Dogs evolved from a subpopulation of wolves that had a special temperament, not fearful or aggressive, that enabled them to get close to humans and their resources," says Hare. "Dogs changed genetically to become more like us psychologically. They evolved to pay attention to and care about you." A pet dog is a member of the family, and we see one almost as we do our own children. It's no wonder, Hare says, that dogs of all breeds have contributed more to our understanding of human psychology than any other species has.
That understanding goes both ways. Because they have cohabited with humans for so long, dogs know us better than any other animal. For example, Larson says, you'd never be able to train a cat to sense when someone was about to have an epileptic seizure or soothe a person with severe anxiety. Larson also believes that dogs have taught us about compassion. "I don't think anyone with a turtle thinks their turtle makes them a better person," he says.
Along with elevating our humanity, dogs have also helped us define masculinity, says psychologist Chris Blazina, a professor at New Mexico State University. "Many men exhibit 'normative male alexithymia,' which is the difficulty of dialing into your feelings and being able to express them," he adds. "Contemporary psychology says we are all hard-wired to make attachments throughout our lifetime, but these men feel they are an exception. The American ideal of masculinity — the cowboy, the sailor, Henry David Thoreau — is based on the idea of self-sufficiency, the sense of isolation being proof positive that you are a mature man." In the company of dogs, however, men let down their emotional walls, which allows them to form attachments without fear of judgment.
Through his research, Blazina, who recently co-edited Men and Their Dogs: A New Understanding of Man's Best Friend, has come to believe that dogs are covert therapists, able to process human emotion like we do. "Dogs exhibit something called the left gaze bias," he says. They look to the right side of our face, which is less able to hide the strong emotions that reveal themselves in micro-expressions (subtle versions of what poker players know as a "tell"). "They only do that with humans, not with other dogs or animals," Blazina says. "They are attuned to us, respond to our upsets, and soothe us."
Blazina speaks from personal experience, conveyed in his poignant memoir, When Man Meets Dog. Years ago he suffered from Ménière's disease, an inner-ear affliction that causes a loss of hearing and balance. "My dog, Sadie, would jump up on the bed and lie beside me when I had episodes," he recalls. "The vertigo was so strong that I would throw up until I passed out with my head in the toilet. I was unmarried then, and the thought that came to my mind was 'Who would take care of Sadie if I died?' That is one of the better parts of being a man: taking care of those we love and letting them take care of us. That relationship changed the quality of my life. Sadie's single-minded devotion was like no other connection I've had, and there is something incredibly uplifting about it."
The end result for all of us, Blazina says, is that dogs become a reprieve from the cultural burden of being the macho, stock characters we believe we have to be. "In the presence of a dog we love, we become more whole men."
David A. Keeps, the director of content at PetSmart, lives in Scottsdale, Arizona, with his two rescue dogs, Boing and Darla.