The Nose Knows

The first thing your dog does when you walk in the door is sniff your legs. Dogs gather a lot of information from a quick sniff of their environment – both physical and emotional details. He smells where you've been and even how the experience affected you. Dogs sniff each other and each others' secretions constantly, monitoring various physiological and emotional changes on an ongoing basis.

Dogs live in a world of odors. Their sense of smell is their most refined sense; in fact, it is so refined a bloodhound can identify scales of skin shed by humans three days previously.

They can also detect drugs in hidden in body cavities, can sniff out rats, termites, bombs, missing persons, bodies drowned or buried in snow or rubble, and even the presence of melanoma cancer. Their noses are about as sensitive as our eyes.

The Facts:

The scrolled, scent membrane inside a dog's nose is about four times greater in area than the equivalent smell organ in humans. In the dog's nose, there are over 200 million scent receptors in the nasal folds compared to our 5 million.

Moisture on the nose helps to capture scent and transmit it onto odor-sensitive nasal membranes, which cover the nose's wafer-thin turbinate bones. These bones comprise of convoluted folds, ensuring that the tiniest amount of scent is captured within them.

Next time you take your dog for a walk, watch his/her nose at work.

Dog's Sense of Smell

Imagine if each detail of our visual world were matched by a corresponding smell.

What would that be like?


Say for instance, each petal on a rose may be distinct, having been visited by insects leaving pollen footprints from faraway flowers. What is to us just a single stem actually holds a record of who held it, and when. A burst of chemicals marks where a leaf was torn. The flesh of the petals, plump with moisture compared to that of the leaf, holds a different odor besides. The fold of a leaf has a smell; so does a dewdrop on a thorn. And time is in those details; while we can see one of the petals drying and browning, the dog can smell this process of decay and aging. Imagine smelling every minute visual detail. That might be the experience of a rose to a dog.

The nose is also the fastest route by which information can get to the brain. While visual or auditory data goes through an intermediate staging ground on the way to the cortex, the highest level of processing, the receptors in the nose connect directly to nerves in specialized olfactory "bulbs" (so shaped). The olfactory bulbs of the dog brain make up about and eighth of its mass: proportionally greater than the size of our central visual processing center, the occipital lobes, in our brains. But dogs' specially keen sense of smell may also be due to an additional way they perceive odors: through the vomeronasal organ.

The vomeronasal organ, first discovered in reptiles, is a specialized sac above the mouth or in the nose covered with more receptor sites for molecules. The dog's vomeronasal organ sits above the roof (hard palate) of the mouth, along the floor of the nose (nasal septum). Unlike in other animals, the receptor sites are covered in cilia, tiny hairs encouraging molecules along. The vomeronasal organ is probably why a dog's nose is wet.

A hearty sniff not only brings molecules into the dog's nasal cavity; little molecular bits also stick onto the moist exterior tissue of the nose. Once there, they can dissolve and travel to the vomeronasal organ through interior ducts. In this way, dogs double their methods of smelling the world.

Excerpt from chapter four, Inside a Dog by Alexandra Horowitz.

Cancer Sniffing Dogs - Part 2

Not only do dogs enrich the lives of their humans; they may also be trying to save our lives without us even realizing it! Dogs are detecting cancer; some are trained to do so, and others instinctively know something is not quite right.

Just because your dog is intently sniffing you does not mean you should run with alarm to your doctor. A dog's nose is 10,000 to 100,000 times more sensitive than that of a human. A dog also has a larger portion of brain and nervous system devoted to the olfactory sense. Thus, a dog's interpretation of his surroundings is greatly affected by the information obtained from his nose. Sniffing you is telling your dog where you've been, who you met, what you ate, how you're feeling, etc.

However, if your dog seems consistently and considerably concerned about your body - beyond sniffing you to learn about your day – you may want to consider taking it seriously. He may be telling you something. Dogs can even smell cancer on your breath, particularly breast and lung cancer.

So, what are dog's detecting when they smell cancer? They smell a metabolic waste that is excreted by cancer cells, but not normal cells. It seems that some dogs naturally find this chemical to be a concern, or, at the least, interesting. Dogs can detect these chemical traces in the range of parts per trillion, making them able to smell cancer even during the early stages!

Dogs are currently being trained to detect cancer, similarly to how a dog is trained to detect drugs or bombs. A treat-based reward system is used, along with samples from healthy and cancer patients. The dog is rewarded when he sniffs the cancer sample. Eventually the dog learns to alert to the cancer sample by lying down or sitting when he comes upon it. Cancer-detecting dogs are often trained and capable in a matter of a couple weeks.

Studies around the world are proving that dogs can be extremely accurate in smelling and identifying cancer. This could be a huge benefit in the early detection of cancer, possibly saving countless lives. Researchers hope to incorporate dogs and their talented noses (literally the best odor detectors known to man) into physical exams in doctor's offices, alerting doctors to possible cancer concerns.

Think of all the things our best friend does for us – provide therapy, guide the blind, protect and serve those in law enforcement and the military, search for our missing loved ones, alert us to bombs, guard our homes, detect our cancer... provide unconditional love. Such an incredible creature.

Cancer Sniffing Dogs - Part 1

When you consider that a dog's sense of smell is estimated to be 10,000 to 100,000 more sensitive than ours, it may not sound so surprising that dogs can smell cancer. Dog's natural scent abilities make them great candidates for detecting different scents, including cancer.

I found a great video that shows dogs in the UK that can sniff out and find cancer. This video is only a few minutes long but definitely worth your time.

I Smell Skunk!

I live in a wooded area and on my morning walks I have come across deer, herons, mallard ducks, and owls. As Ebony and I were walking this morning, I got this piercing smell. Quickly I called my dog to heel as I did NOT want her to meet the skunk.

As we came around the corner, I saw through the woods in a boggy area a multitude of skunk.......cabbage!

How can something so lovely smell soooooo badly?





At closer range the smell was awful! But look how pretty!