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Home > Dogs > Can Dogs Smell Cancer in Other Dogs? How Do They Do It?

Can Dogs Smell Cancer in Other Dogs? How Do They Do It?

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Dogs’ wild ancestors used their keen sense of smell to avoid predators and hunt prey. Today’s pet dogs inherited those instincts and incredible noses. You’ve probably heard of working dogs who can detect blood sugar changes in people with diabetes. A growing area of research is using dogs’ sense of smell to detect cancer.

Dogs can smell cancer in humans, so it’s entirely possible they could also smell the disease in other dogs. Learn more about how dogs’ noses work and an organization that trains dogs to detect early-stage cancer in humans.


How Can Dogs Smell Cancer?

jack russel terrier and pug dog sniffing each other outside
Image By: Yekatseryna Netuk, Shutterstock

Dogs can smell many things that we can’t, thanks to the unique anatomy of their noses. A dog’s nose has 300 million olfactory receptors. As a point of reference, we only have around 6 million. And unlike us, dogs can breathe in and out simultaneously. Dogs also can smell separately with each nostril, similar to how we can see differently with both eyes.

In Situ Foundation, a non-profit organization based in California, trains dogs to detect early-stage cancer in human samples. In Situ rescued several of their working dogs from shelters. Teams of five or more dogs work with trainers to learn how to detect cancer in doctor-collected samples. In Situ’s cancer-detecting dogs have been used in clinical trials with organizations like UC Davis and Duke University.

Some breeds have a better sense of smell and are more trainable than others. In Situ’s cancer-detecting dogs have included German shepherds, an Australian shepherd, and a Labradoodle.

In recent years, the North Carolina State University College of Veterinary Medicine studied whether dogs can detect canine cancer. This research is evolving and, so far, has been based on a limited number of samples.

Signs of Cancer in Dogs

Senior mixed breed dog resting at home
Image By: Larissa Chilanti, Shutterstock

If you notice that another dog continually sniffs your dog, don’t automatically assume it’s cancer. Dogs sniff other dogs for lots of reasons. But combined with other signs, it could warrant a call to your vet, who can assess your dog’s overall health.

Canine cancer is common and frequently affects senior dogs. Over 50% of dogs 10 years or older will develop cancer. The most common forms of cancer in dogs are skin cancer, bone cancer, and lymphoma. As your dog ages, ask your vet if they recommend any cancer screenings.

It’s vital for dog owners to take note of unusual signs or behavior. Dogs with cancer may have palpable or visible lumps, sores that don’t heal properly, changes in appetite, pain, weight loss, lethargy, and difficulty breathing. These signs aren’t specific to cancer and overlap with other illnesses. The sooner a vet diagnoses any medical condition, the more options you may have for treatment.



Dogs can smell cancer in humans and most likely can smell the disease in other dogs, the latter of which is an emerging area of research. However, as the studies continue, the roles dogs play in detecting disease are likely to increase. Call your vet if you have any questions or concerns about your pet’s health.

Featured Image Credit: Meesiri, Shutterstock

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