Why Do Dogs Sniff?



There is no doubt that dogs love to sniff, they look forward to their walk and sniffing time. Sniffing and smelling is our dogs’ primary mechanism for processing new information and observing the environment. Part of what makes dogs so incredible is their heightened sense of smell and ability to remember and recall certain scents. You may have heard the expression that dogs ‘see with their noses.’  But these creature’s amazing nasal architecture actually reveals a whole world beyond what we can see. 

The Science of The Dog Sniff

In the following video by Alexandra Horowitz, teacher and researcher at Barnard College reveals how the dog’s nose can smell the past, the future and even things that can’t even be seen like cancer tumor.   Her research in dog cognition reveals a whole world beyond what we can see. 

 Like humans, dogs have five basic neurological senses: taste, touch, hearing, sight, and smell. Of these senses, smell takes the lead in the canine world. A dog’s ability to smell is far more advanced than ours. An average dog has a sense of smell that is about 100,000 times more sensitive than his owner’s partly because dog noses contain 150 million olfactory receptors while human noses only have 5 million. And dogs devote about 1/3 of their brain mass to the detection and identification of odors, while humans utilize a mere 5% for olfactory purposes.

Plus, dogs have an additional tool to enhance their sense of smell. A special organ called Jacobsen’s organ is located inside the nasal cavity and opens into the roof of the mouth behind the upper incisors. This amazing organ serves as a secondary olfactory system designed specifically for chemical communication. The nerves from Jacobsen’s organ lead directly to the brain and are different from the nerves in the olfactory tissue of the nose in that they do not respond to ordinary smells. In fact, these nerve cells respond to a range of substances that often have no odor at all. In other words, they work to detect “undetectable” odors.

Jacobsen’s organ communicates with the part of the brain that deals with mating. By identifying pheromones, it provides male and female dogs with the information they need to determine if a member of the opposite sex is available for breeding. In addition, this organ enhances the sense of smell that newborn puppies need to find their mother’s milk source. Jacobsen’s organ allows pups to identify their mother from other nursing dams. With a quick sniff, a pup placed between two nursing mothers will migrate to the one that gave birth to him!

The two separate parts of the dog’s odor detection system, the nose and Jacobsen’s organ, work together to provide delicate sensibilities that neither system could achieve alone. When the dog curls his lips and flares his nostrils, he opens up Jacobsen’s organ, increases the exposure of his nasal cavity to aromatic molecules and essentially becomes a remarkably efficient smelling machine.

Dogs have an advantage over people in that they use their keen sense of smell, along with a visual assessment, to provide vital information about a new canine acquaintance. Their acute olfactory senses enhance communication by utilizing amines and acids emitted by dogs as the basis for chemical communication. The chemical aromas identify gender and mood, and even communicate what a dog likes to eat. By simply smelling, a dog can determine if a new friend is male or female, happy or aggressive, healthy or ill. Dogs get a general idea about each other with a quick sniff, but get more detailed information by getting up close and personal.

Walking with Dogs

On walks, allow your dog plenty of sniffing time, to satisfy their needs. But concerns may rise when our pups consistently stop and go or sniff something for an extended period of time. Since sniffing is part of dogs life, the next best thing we can do is to be aware of what they’re sniffing and whether or not it’s safe.  If you want to move on, instead of pulling their leash give them a command such as “Let’s go” and reward them for obeying you.

Benefit of Dogs Sniffing

The benefits of sniffing on walks are endless. A dog smelling is like a human seeing… it’s just how we learn and observe the world. Sniffing gives dogs mental stimulation and serves very important functions. One pit-stop on a walk can tell a dog who peed there last, whether or not humans were there, or even if a squirrel stopped by for a minute. Dogs also get additional exercise and exploit more muscles when they stop and sniff. Think about it- they’re constantly stopping and going, running and walking at different speeds, turning around, jumping up or down, etc. The walk, plus the sniffing, will help tire out your dog and make the walk extremely beneficial and productive. Sniffing on a walk can also be used as a reward system. Your dog will learn that cooperation on the walk will result in quality sniffing time. This positive reinforcement is a great training method while also giving your dog freedom and necessary exposure, when you take your dog on a walk important to understand their needs. Dogs look forward to walks where they are free to smell everything and anything they want. Expecting your dog to not smell anything is basically like asking someone to not look out the window during a long drive… just not possible! Let your dog navigate the world and enjoy being outside. Leashed dogs during walks should have the freedom to use their noses while also having an owner that will compromise. 

My Suggestion: “Live in the Moment!”


On your next walk try to slow down, enjoy the nature and smell the roses with your dog, live in the moment. Last night during my walk with Christopher, I got to pay attention to the beauty of this flowering cabbage, while he was sniffing the area, I admired the beautiful leaves and different shades of cream and green on it.  I was so thankful he made me slow down otherwise, I would have passed by and never even notice the beauty of nature. 

Please share your walking experience with your pup.  Is your pup a sniffer? Have you noticed your pup sniff more when you go to a new area or in different seasons?  



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