How Strong Is a Dog’s Sense of Smell? 7 Mind-Blowing Facts About Your Dog’s Olfactory System.

How Strong Is a Dog’s Sense of Smell? 7 Mind-Blowing Facts About Your Dog’s Olfactory System.

Are you tired of your dog taking detours during their walk and sniffing every little thing that they find? You may be pretty aware of your dog having a good sense of smell but we assure you don’t know half of what goes around in your dog’s nose. You have no idea how awesome your dog’s sense of smell is.

So, How Strong Is a Dog’s Sense of Smell?

 Very strong. A dog’s sense of smell overpowers ours by 10,000 to 100,000 times. The canine olfactory system has been known and studied for a long time and the results are extraordinary.

Here are 7 mind-blowing facts about your dog’s olfactory system.

1. Dogs Have 300 million Olfactory Nerves

A human nose has 6 million olfactory receptors. Now compare that to a dog’s nose which has 300 million olfactory receptors. James Walker, former director of the Sensory Research Institute at Florida State University who did a rigorous study in the olfactory system of dogs, says, “Let’s suppose they’re just 10,000 times better. If you make the analogy to vision, what you and I can see at a third of a mile, a dog could see more than 3,000 miles away and still see as well.”

Alexandra Horowitz, a dog-cognition researcher at Barnard College, explains the strength of a dog’s olfactory nerves in her book “Inside of a Dog: What Dogs See, Smell and Know”. While humans may only detect a teaspoon of sugar added to our coffee, our dogs can smell sugar added in a million gallons of water.

In addition to the fact that dogs have hundreds of millions more olfactory nerves, the part of a dog’s brain that detects smell is also 40 times bigger than that of humans. This is why a dog’s sense of smell is up to 100,000 times better than ours.

2. Dogs Have a Secondary Olfactory System

Apart from the super-strong primary olfactory system, dogs also have a secondary olfactory system, thanks to an organ that humans don’t have – the vomeronasal organ. Also known as Jacobson’s organ, this is located just above the roof of the mouth at the bottom of a dog’s nasal path. This C-shaped organ detects pheromones, the chemicals secreted by animals that can signal mating and heat cycle.

3. Dogs Have an Incredible Sense of Tracking

You will be surprised to know all the wonders dogs can do with their nose. One of the most remarkable things is tracking. Deborah Wells and Peter Hepper of the Animal Behaviour Centre at Queen’s University, Belfast, in Northern Ireland, stated in their study that dogs can correctly determine what trail a person has walked on from just five steps. Dogs can catch the odor from the very first step and based on the smell, can eventually track the whole trail.

Scientists are still amazed as to how dogs take tracking to such an extreme, like finding a totally unfamiliar missing person. James Walker exclaims, “It is a really big issue as to how in the heck dogs are doing it, that is, how they are tracking a so-called gradient.”

4. You STINK To Your Dog!

How many times have you complained that your dog smells bad? Well, let me tell you, you don’t smell so good to your dog either. In fact, you stink to your dog!

Every human has a unique smell, very much like fingerprints. Our dogs recognize us completely through our smell. Alexandra Horowitz, in her book Inside of a Dog: What Dogs See, Smell, and Know writes a brilliant description of a dog’s sense of smell:

“…dogs find it incredibly easy to distinguish us by scent alone. Trained dogs can tell identical twins apart by scent. And our aroma remains even when we’ve left, hence the “magical” powers of tracking dogs. These skilled sniffers see us in the cloud of molecules we leave behind.”

5. You Can’t Hide Anything from Your Dog

A dog’s sense of smell is so strong that they can smell anxiety, fear, and sadness in you. The changes of adrenaline in the human body when we feel things are invisible and therefore impossible to detect by a human’s nose. However, a dog can do it perfectly.

You might be able to fool your family and friends with a fake smile, but not your furry companion!

6. A Dog’s Nose Functions Differently from A Human Nose

Humans inhale, exhale, and smell through the same olfactory tract. The air we smell goes in and out together with our respiration. However, when dogs inhale, a fold of tissue inside their nasal pathway separates into two different paths, one for smell and one for respiration. Brent Craven, a bioengineer at Pennsylvania State University, found out that about 12% of the air that a dog inhales detours into the back of their nose, an area that is responsible for olfaction.

We exhale through our nose, also exhaling all the incoming odors. Dogs exhale only 88% of the air, that too in such a manner that automatically forces new odors into the nose. This means that dogs are continuously smelling all the time.

7. Real-Life Stories

Here are some incredible true stories about dogs and their astonishing sense of smell.

  • A drug-sniffing dog successfully located a packet of 35 pounds of marijuana immersed in gasoline inside a gas tank.
  • There is a black stray dog called Tucker in Washington that was able to smell a floating orca from miles away in an inlet of the North-Pacific ocean.
  • A domestic dog was able to sniff cancer in a spot of the patient’s skin that was already marked cancer-free by the doctors. A biopsy was done after the dog-sniffing became consistent and melanoma was found in a tiny fraction of cells.
  • A study was carried out in 2006 with five dogs that were trained to detect cancer. The result showed that after they were trained, there was accuracy of 88% in detecting breast cancer and 99% in detecting lung cancer, that too in all four stages of this disease.

Top 5 Dog Breeds with The Strongest Sense of Smell

  1. Bloodhounds
  2. Basset Hounds
  3. Beagles
  4. German Shepherds
  5. German Shorthaired Pointers

How Important Is Sniffing to Dogs?

Sniffing is very important to dogs. Humans primarily use the sense of vision to connect to the world. Dogs depend on the sense of both vision and smell. To their minds, five minutes of sniffing is like five minutes of physical exercise. It’s not just their nose that is working, it is their brain too. Sniffing can help to release unutilized energy and make them feel calm and safe.

Dogs and Their Wet Noses

It is believed that a dog’s nose works even better when it’s wet. Is it true? Yes. Absolutely. When the outer part of the nose is damp and the nasal canal is mucus covered, the scent particles are efficiently captured. As a matter of fact, if dogs find their nose dry, they will lick their nose to make them wet.

How Can You Encourage Your Dog to Sniff and Smell?

Here are some ways you can be ‘nose-aware’ about your pooch’s smelling instinct:

  1. When you are taking your dog out on a walk, you can use a long leash and let them take their time sniffing along the way.
  2. You can give your dog a full five minutes to explore and sniff around especially if it’s a new place for them. This way, your dog will be acquainted with the environment and will feel safe and calm.
  3. Even if you’re taking your dog out on the same regular lane, they will always find something new to sniff. So, don’t be irritated at your dog and drag them away if they take time sniffing the same things every day.
  4. You can encourage sniffing by including it as a part of their daily play. Hideaway whatever toy they love the most and let them sniff and find it.
  5. Just appreciate what a wonderful creature your dog is and how amazing their nose is.


Dogs have a very strong sense of smell. They smell up to 100,000 times better than humans and do wonders with their noses. Sniffing also keeps them happy and mentally stimulated. They discover the world through their sense of smell.

Now that you know how strong is your dog’s sense of smell, explore more articles related to the canine sense of smell here. 

How strong is your dog’s sense of smell? Do they come running as soon as they take a whiff of their favorite food? We would love to hear from you. Please share with our community by leaving a comment below!

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