The Amazing Secret Skill Your Dog Might Have

Photographed by Molly Cranna.
Dogs already have a well-deserved reputation for their excellent senses of smell. But their noses are actually so powerful that researchers have started to enlist dogs to help in detecting diseases.

To figure out how, we have to understand the way smell works. It turns out, researchers are still learning a lot about smell. In general, though, it's kind of like this: Receptors in our noses pick up chemicals in the air that our brains interpret as signifying a particular thing — e.g., roses, bananas, or NYC hot garbage. But dogs are able to interpret those signals with smaller amounts of the original chemical than humans require. That, combined with way more chemical receptors in their noses, leaves dogs with much more sensitive odor detection than humans.

Of course, some people do have more sensitive sniffers than others: For instance, researchers at the University of Edinburgh are currently working with Joy Milne, a 65-year-old woman who was able to smell her husband's Parkinson's. She described it as being a particularly odd "musky" stench.

Dogs are particularly interesting to doctors, though, because they can be trained to respond to those smells in certain ways, alerting their owners or medical staff that a patient is about to, say, hit dangerously low blood-sugar levels. So, here are three ways some very, very good doggies are helping out these days:


Disease-causing bacteria are getting better and better at protecting themselves against our strongest antibiotics. One superbug in particular, Clostridium difficile (C. diff) is a major problem for hospitals, where people are often already receiving a hefty dose of antibiotics. Catching C. diff early is a huge deal, because it can quickly become very serious and potentially life-threatening if left untreated.

That's where the dogs come in. The idea of using dogs to detect C. diff seems to have appeared first in the somewhat jokey (but still scientific) Christmas edition of the BMJ in 2012. This study followed the tireless work of Cliff, a 2-year-old beagle who has since retired from the job. But as of this week, there's a new addition to these ranks: A 2-year-old English springer spaniel named Angus who now works in Vancouver General Hospital.


In the case of diabetes, dogs aren't detecting whether or not someone has the disease, but rather when it's about to take a bad turn. In a study published last month in Diabetes Care, researchers learned that right before a sudden drop in blood sugar, diabetics exhale a chemical called isoprene.

It's not clear from this research why they exhale higher amounts of that chemical in particular, which is also normally found in our breath in smaller amounts. But this does suggest a method by which pups — such as Shirley, a labrador in England — can literally smell a hypoglycemic attack before it happens.


Dogs appear to have a knack for detecting several types of cancer, including lung, bladder, kidney, and prostate. A U.K. organization, Medical Detection Dogs, is currently investigating dogs' ability to sniff out breast cancer. The way dogs detect these cancers is still up for scientific debate, but the current thinking is that the development of malignant tumors causes the body to release smellable compounds in urine or breath.

Of course, most of this research is still anecdotal and (unfortunately) inconclusive. That means dogs — or technology based on their incredible abilities — aren't going to become primary diagnostic tools anytime soon. But it's clear that they can be still be useful in certain settings, even if it's just by making us feel a little bit better about the world knowing these cuties are out there.

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