Fact or Fiction: Can Dogs Smell Cancer?

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It's no secret that dogs have incredibly sensitive noses. In fact, some scientists believe that dogs may have a sense of smell that's over 10,000 times as powerful as humans', according to PBS. That powerful sense of smell has enabled us to train and partner with dogs in finding missing persons, identifying drugs and explosives, and so much more. But can dogs smell cancer in humans?

There have long been stories about dogs' ability to notice cancer before even traditional cancer screenings. But is there truth to that rumor, or is it simply folklore? Can dogs detect cancer in humans? In this piece, we'll explore the science and behavior patterns behind cancer-sniffing dogs.

Can Dogs Really Detect Cancer in Humans?

As far back as 1989, according to Live Science, reports and stories of cancer-sniffing dogs have surfaced. In 2015, The Baltimore Sun reported that Heidi, a shepherd-lab mix, had sensed cancer in her owner's lungs. The Milwaukee Journal Sentinel described Sierra, a husky who detected and alerted her owner of ovarian cancer on three separate occasions. And in September, the American Kennel Club reviewed the book "Doctor Dogs," which shares stories of dogs detecting a host of diseases, including cancer.

According to Medical News Today, research indicates that, with training, dogs can detect a variety of cancers — even at early stages — in humans. "Like many other diseases, cancers leave specific traces, or odor signatures, in a person's body and bodily secretions. Cancer cells, or healthy cells affected by cancer, produce and release these odor signatures." With proper training, dogs have been able to smell cancer in humans' skin, breath, sweat and waste and to alert them.

Some dogs can detect cancer, but the aforementioned training component is key. The In Situ Foundation is nonprofit that's dedicated to just that: rescuing and training dogs to detect early stage cancer in humans. The foundation "uses high drive dogs, such as German shepherds, Australian shepherds, shepherd/lab mixes, beagles, Belgian Malinois, and most mixed breeds containing any of these combinations. Occasionally, we will test a dog who is not one of these breeds, who detects cancer with flying colors. The temperament and drive of the dog is what matters."

Siberian Husky sniffs human hand in medical office.

How Do Dogs Act When They Smell Cancer?

Stories of dogs' reactions to the smell of cancer vary. According to the Milwaukee Journal Sentinel, when Sierra the husky first detected ovarian cancer in her human, she exhibited intense curiosity — then ran off. "She put her nose on my lower belly and sniffed so intently that I thought I spilled something on my clothes. She did it a second and then a third time. After the third time, Sierra went and hid. I mean hid!"

The Baltimore Sun noted that Heidi "began burying her snout into her owner's chest and pawing at her anxiously" when she detected cancerous cells in her lungs.

These stories show that there isn't one single way dogs will react to the smell of cancer, as much of their reaction will be based on their individual temperaments and training. But the one thing dogs in all stories had in common was a distinct change in their normal behavior that indicated to their pet parents that something was off. If you notice a change in your dog's behavior, that doesn't necessarily mean there is anything to be concerned about; however, consistent patterns could be worth exploring. If a visit to the veterinarian shows that your pooch is healthy but their behavior continues, it may be worth scheduling a visit to your doctor as well.

Can dogs smell cancer? Believe it or not, science increasingly points to yes. And that's not so crazy — after all, dogs have long been known to be able to read humans in unparalleled ways. Their highly attuned senses alert them when we are sad or sick, and they often act as partners to help alert us to danger. It's just one more incredible demonstration of the powerful bond between humans and our four-legged best friends.

Contributor Bio

Erin Ollila

Erin Ollila

Erin Ollila is a pet enthusiast who believes in the power of words and how a message can inform—and even transform—its intended audience. Her writing can be found all over the internet and in print, and includes interviews, ghostwriting, blog posts, and creative nonfiction. Erin is a geek for SEO and all things social media. She graduated from Fairfield University with an M.F.A. in Creative Writing. Reach out to her on Twitter @ReinventingErin or learn more about her at http://erinollila.com.

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