Dogs are amazing at a lot of things. Their cuddling skills are unrivaled (sorry cats), some breeds catch balls better than most football players, and they make the best of friends. One of their other notable talents is their impressive sense of smell. Their snouts have been something humans have taken advantage of for centuries or longer, whether it be for finding food, avoiding danger or, in recent years, detecting medical conditions such as cancer.
For decades doctors have observed that dogs can detect certain diseases in humans by simply sniffing it out, but scientists still don’t understand how dogs are able to spot cancer or diabetes using only their noses. However, advancements over the last couple of years have brought researchers closer to solving this puzzle, which could lead to revolutionary treatment options for patients with cancer or diabetes.
Dogs can smell almost 10,000–100,000 times better than the average person. There are a variety of factors that make this difference so dramatic, from simple anatomical differences all the way to the gene expression of olfactory, or smell, receptor genes between humans and their furry pals.
Similar to wolves, the dog snout, with its generally long, narrow shape, was adapted for sniffing out food and intruders. This design allows for an increased surface area for methodically sniffing molecules within the air. Even the nostrils play a key role in this process, as pups will sniff with either their left or right side depending on the scent.
The dog brain is also specialized for maximizing on the nose’s potential. Olfaction is controlled in the brain through the limbic system, which also manages memories, behavior, and motivation. Unlike humans, where the size of limbic system is inversely related to the size of the isocortex, which controls higher-ordered function, these structures are similarly sized in dogs. Some scientists theorize that this is why dogs have a more refined sense of smell than we do. Dogs also have a more diverse and bigger catalogue of genes involved in smelling – they simply have a better sniffing toolkit.
A long-sniffing symbiosis
Humans quickly capitalized on our best friends’ eagerness to share their tools with us. People domesticated dogs tens of thousands of years ago. As early as the 1800s, and probably even earlier, dogs have been formally taking care of humans by assisting blind people and dramatically improving their quality of life. Not long after, the police began to take advantage of the ease of which dogs could be trained to help sniff out criminals; the earliest law enforcement dogs were assigned to the Jack the Ripper case in London in 1888.
The dog brain is specialized for maximizing on the nose’s potential
Dogs are now routinely utilized as integral members of military and police squads throughout the world. If you’ve ever seen working service dogs, you’ve probably noticed they are mostly German Shepherds, Labrador Retrievers, and Mallinois. While there is some debate over whether these breeds actually smell better than others, such as the short-nosed pug, it appears these dogs are routinely used based on longstanding beliefs about how easy it is to train them. That’s not to say your adorable terrier wouldn’t be a great service/law enforcement animal, but it might be easier to get a lab to be well behaved in public.
Sniffing out disease
Within the last 15 years, diabetes alert dogs have become, for some type I diabetics, a revolutionary advancement. It all started as initial observations from patients that their pet dogs would begin to act differently, such as become more vocal, or nudge them, when their blood sugar dropped. Once scientists began to study this phenomenon, it turned out that this was more than just coincidence.