dogs sense of smell

Your dog’s nose is an amazing tool that can sniff out even your “quietest” snack attack from three rooms away. A dog’s sense of smell stretches far beyond just the ability to sniff out your favorite meals and snacks. The way dogs use their nose is nearly the same way we use our eyes. While they still obviously use their eyesight, their nose can “see” more than 3,000 miles away, according to a recent article in Nova magazine.

It’s no wonder why our dogs always want the window rolled down on a beautiful drive. A dog’s sense of smell is 10,000 to 100,000 times more accurate than yours, according to James Walker, former director of the Sensory Research Institute at Florida State University.


Check out these 4 fun facts about your dog’s sense of smell if you’ve never given much thought to your dog’s snout.


1) Your Dog Thinks You Stink

Just kidding, but not really! In fact, no matter how clean you think you are, your dog can still smell you. It doesn’t matter what type of scented lotion, perfume, or cologne you put on; you have a unique smell that your dog can detect. In her book Inside of a Dog: What Dog’s See, Smell, and Know, the author Alexandra Horowitz explains the phenomenon of our “human stink.” Our skin is consistently producing and secreting oils and sweat that allow us to leave our signature scent on everything we touch. Even our breath has its unique brand of scent your pooch could pick up on.


2) Your Pet Can “See” With Their Nose

While dogs have great eyes and eyesight, their nose is the star organ. Dogs can be trained to smell as little as a pictogram, which is a trillionth of a gram. Every step you take, you unknowingly leave loads of skin flakes made up of skin cells behind. Humans shed about 50 million skin cells each minute. This biologically rich “snowstorm” that we shed helps dogs see us without actually seeing us.

3) Your Dog Can Tell Time with Their Nose

Have you ever noticed how your dog always seems to know that it’s dinner time? While keeping dogs on a schedule is part of it, their ability to literally smell “time is the most significant factor. A dog’s nose allows them to perceive the passage of time. Odors change throughout the day, including the odor of the air density around lunch, breakfast, or dinner time. Dogs know that strong odors indicate that something is “recent” or “coming.” This research on a dog’s ability to smell time is still extremely new and complex; however, it is a further indication of the unique and incredible technology that dogs innately carry and utilize.

4) Dogs Are Communicating When They Sniff Each Other

Sure, it’s a little gross when your dog sniffs a random dog’s “butt.” However, there’s some very important conversation happening. Your pets may not be discussing the weather as we might during small talk, yet they share important info like age, diet, and temperament. This curious exchange between your pets is an integral part of healthy socialization.


Sniff, Sniff, Hooray!

Sniffing is such an essential part of your pet’s happiness and health. Did you know that along with being able to smell you, your neighborhood pets, and when dinner time happens, your dog can also smell bacteria, insects, and certain medical conditions?

In recent years, organizations worldwide have looked to training dogs to detect medical conditions in humans. 

Dogs have for years been trained to sense and alert diabetic individuals to low blood sugar levels as well as imminent seizure activity in epileptic patients. Some dogs have been trained to seek out odors associated with several cancer types. 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. Depending on the type of disease process or cancer, dogs can detect these signatures in a person’s:

  • skin
  • breath
  • urine
  • feces
  • sweat

Dogs can detect these odor signatures and, with training, alert people to their presence. People refer to dogs that undergo training to detect certain diseases as medical detection dogs

Dogs have also shown to be able to help detect “bugs” of all kinds. Dogs are trained to seek out nasty “bed bug” infestations and detect harmful bacteria such as Clostridium difficile – an organism that causes many hospital-acquired infections – both in feces samples and hospital air.  

Dogs are now being trained to potentially sniff out COVID-19 in travelers as a form of a non-invasive screening.

Dogs and their keen sense of smell also play a vital role in police and forensic investigations as well in their ability to detect and locate specific people or substances of interest, ranging from illegal drugs to missing people to clandestine graves. Sophisticated detection equipment exists; however, this technology can often be expensive, have unsuitable portability, and may even be useless when searching vast areas. Fortunately for investigators, dogs and their fabulous noses are an ideal tool. 

Dogs, sometimes known as K9s or sniffer dogs by law enforcement professionals, have played an important role in legal investigations for decades, with their keen sense of smell being harnessed to aid investigations. The average human being has roughly five million sensitive cells within the nose to aid in scent detection. Having these vast numbers of cells appears to be substantial until compared to 200 million in the average dog’s nose. Further increasing the canine’s sense of smell is an organ in the roof of the mouth that is not present in humans. This organ essentially allows the dog to concentrate particular aromas, thus strengthening its ability to detect odors. Canines detect smells directly from the source or residual scents, odors that persist in an area after the source is no longer present.

Obviously, the air is full of a wide variety of different odors, many of which will be powerfully clear to the dog. Fortunately, they can distinguish between different odors, even if one smell overpowers another, and trace a specific scent to its source.


Drug Detection
drug sniffing dog

 The police commonly train canines to detect illicit substances to the extent that they are capable of locating even the tiniest trace of a drug. Such dogs are frequently trailed through train stations, airports, country borders, workplaces, and even schools to allow police to locate individuals carrying these illegal substances. The dog may be moved near pieces of luggage, near groups of people, or generally kept in the vicinity to react if he or she picks up on an odor of interest. An average stop and search conducted by officers may yield nothing, especially if the subject has hidden the drugs somewhere on his person. However, properly trained canines are usually able to detect the scent of illegal narcotics, regardless of where the suspect has concealed them.


Explosives Detection

Explosive sniffing dog

 Perhaps used more in recent years due to the increased focus on terrorism, canines have also been trained in the detection of explosive materials. The dogs are trained to detect the odors of specific substances such as Sulphur, nitroglycerin, and any other compound commonly used in the production of gunpowder and explosive devices. Such specially trained dogs may be used in airports to detect or at least deter terrorism, or in the homes of suspected bomb-makers to identify the presence of these substances on work surfaces and in storage areas. In these scenarios, it is vital that the canine is trained not to touch any substance or devices it locates, as many types of bombs can potentially explode if touched.


Arson Dogs

Like canines trained to detect explosives, arson dogs are instructed to detect the chemical traces of accelerants. During an arson investigation, one of the primary tasks is to determine what caused the fire and, if accelerants were used, establish where the accelerant was placed. 

Though the odor of most forms of accelerant is generally quite strong, a fire scene will often be engulfed by the smell of smoke and various burning materials. However, dogs can be trained to pick out the specific odors of flammable substances and locate the source. Even if the accelerant is found in numerous locations, the dog can be trained to pinpoint the area in which the accelerant concentration is at its highest.


Cadaver Dogs

 cadaver dog

 Also known as decomposition or victim recovery dogs, these specially trained canines are trained to follow the scent of decomposing flesh to locate the bodies of deceased human beings. Whether the corpse is on the surface, buried underground, or underwater, a dog’s nose is powerful enough to pick up the scent and trace it back to its source. Cadaver dogs can not only locate actual human remains, but also the location in which a corpse or body parts may have previously been stored by tracking down residual scents. Depending on the use of the cadaver dog, they will be trained to detect specific decomposition odors. For example, some may be trained to detect odors associated with the early stages of decomposition, whereas others may be required to locate older remains. Some dogs are specifically trained to sense dead bodies underwater, with the canine situated on a shoreline or boat. A newer concept is that of historical human remains detection dogs that are trained to locate historical or archaeological graves.

The term “man’s best friend” has been widely used when it comes to dogs. The loyalty of a dog toward its owner is something that cannot be questioned. The tables have now turned as humans have become more reliant on dogs and their fabulous noses than ever before – to help save lives and solve crimes. 

About Brook-Falls
Brook-Falls Veterinary Hospital and Exotic Care is dedicated to providing quality care to all companion pets and exotic animals. Brook-Falls is a Menomonee Falls, WI-based full-service veterinary hospital with an extensive range of comprehensive medical, dental, diagnostic, and surgical services to meet the varying needs of all patients. Brook-Falls Veterinary also offers informational and educational media and seminars for pet owners by way of blogs, digital TV series (Expert Veterinary Television), e-books, whitepapers, infographics, and more.
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