Ah, smell.. or olfaction as it’s often known. Olfaction is a dog’s primary sense. They trust their sense of smell over every other sense. However, not all dogs have equal abilities when it comes down to the sense of smell.
To break it down, a dogs nose is designed for superior smell. The nasal plane (end of nose containing nostrils) is kept moist to dissolve and release scent particles. The nostrils are comma shaped to swirl the scent throughout the nose. This helps dogs to smell in detail. For example, if you let your dog smell a plate of ketchup, he not only smells the ketchup, but also every.. single.. ingredient with in the ketchup.
The inner nose is compiled with olfactory receptor cells to process scents. Dogs with longer muzzles have more olfactory receptor cells than dogs with short muzzles. In example, humans only have 5 million olfactory receptor cells, where as a German Shepherd Dog has 220 million! A dachshund has 125 million, and a fox terrier has 147 million. So different dogs have different scenting abilities, but they all out rank us humans. Another reason dogs smell so well is that at the end of each of these olfactory receptor cells, there are cilia. The cilia are tiny hairs coated in mucous and help to trap scents with in the nose. Humans have about 6 to 8 cilia at the end of each olfactory cell, but dogs have 100 to 150. Each of the olfactory receptor cells connect to nerves that lead to the olfactory lobe in the brain. In a dogs brain, this lobe is the size of a large walnut, where as in a human it is the size of a pea.
One other thing that makes a dogs sense of smell so incredible, is that they can actually smell under water! Thanks to the vomeronasal organ, or more commonly refered to as the Jacobs organ. It runs along the bottom of the nose, just behind the teeth, and is directly connected to the olfactory lobe via 608 nerve bundles. In the skull, there are two small holes in the roof of the mouth, in a live dog they are not visible, that they can somehow pull a scent through with out inhaling. They use this organ to draw in smells while diving in water to smell what they are looking for.
Dogs tend to associate many memories with their sense of smell. Because this is their primary sense, they trust it with their lives. In a previous entery, I explained how a dog sees. They are considered near sighted, so if you’ve ever thrown a treat on the ground close to a puppy and it’s taken him awhile to find it, it’s because he is not trusting his eyesight, even if he might see it. He is trusting his nose to find it.
It is very important to take care of your dogs teeth because any kind of infection or problem with his teeth can effect his olfaction, similar to when we get a headache and it effects our eyesight. So if your dog developes a behavior problem, have him checked by a vet to see that his senses are all in order. Imagine how you’d act if your primary sense wasn’t working correctly.