Whether you have a Beagle always on the hunt or a small pocket-sized pup that enjoys the breeze through an open window, you might be surprised to learn that dogs perceive the world primarily through their sense of smell, even more so than sight or hearing.

Their noses are marvels of nature, finely tuned to pick up scents and interpret the environment around them.

In this article, we’ll take a closer look at the astonishing world of a dog’s sense of smell.

A Nose With Astonishing Abilities

To truly grasp the canine sense of smell, let’s compare it to our own. Inside both human and dog noses are bony, scroll-shaped plates called turbinates.

These structures are where the air passes over as we breathe in and out. If we could peek inside, we’d find a spongy membrane that houses scent-detecting cells and tiny nerves that transmit information to the brain.

In humans, this scent-analyzing area is roughly the size of a postage stamp, whereas in dogs, it would be comparable to a sheet of computer paper when unfolded. That’s a massive difference!

Moreover, the part of a dog’s brain dedicated to interpreting smells is about 40 times larger than ours.

Experts estimate that an average dog can identify scents between 10,000 to 100,000 times better than humans. Some breeds are particularly notable for their olfactory prowess:

  • Dachshund: 125 million scent receptors
  • Fox Terrier: 147 million scent receptors
  • Beagle: 225 million scent receptors
  • Bloodhound: 300 million scent receptors

Just to put things in perspective, humans have a mere 5 million scent receptors

The Nose with Slits

Have you ever wondered about the slits on either side of your dog’s nostrils? Unlike humans, who breathe in and out through their nostrils, dogs have a unique system. When a dog exhales, the air passes through those slits.

allergy in french bulldog
Image credits: freepik/freepik.com

This allows them to essentially sniff continuously, and as the exhaled air swirls out, it can bring in new odors.

In Norway, a study at the University of Oslo found that a hunting dog, while searching for game, could sniff a continuous stream of air for up to 40 seconds, spanning at least 30 respiratory cycles.

Independent Nostrils

Try wiggling your nostrils independently—you’ll likely find it impossible. Dogs, on the other hand, can do just that.

These “individual nostrils” help dogs determine which nostril the scent arrives through, aiding them in pinpointing the source of a smell.

You’ve probably witnessed a dog zigzagging with its nose to the ground, following the direction of a particular scent through one nostril.

The Second Olfactory System

One crucial reason why a dog’s sense of smell surpasses ours is the presence of a special organ called the vomeronasal organ, also known as Jacobson’s organ.

This tiny but essential organ is located at the bottom of the nasal passage and is responsible for detecting pheromones released by different animal species.

The Jacobson organ relays information about sexual readiness and other sex-related details to the dog’s brain.

This is why dogs sniff each other’s behinds, as this area is rich in pheromones that convey information about health and sexual availability.

A Nose with Many Jobs

People have harnessed the power of a dog’s nose for various tasks that are beyond human capabilities:

Dogs in security
Image credits: bublikhaus/freepik.com
  • Airport security employs trained dogs to sniff out illegal substances or prohibited food products.
  • In the military, dogs are trained to detect bombs and landmines.
  • Search and rescue dogs use their keen sense of smell to locate individuals, whether alive or deceased, under collapsed buildings or in avalanches.
  • Trained canines help law enforcement track and apprehend fleeing suspects.
  • Therapy dogs can even detect drops in blood sugar levels in diabetic patients and, in some cases, identify certain types of cancer in humans.

A Nose with Its Own Unique Print

While a dog’s nose print doesn’t directly correlate with its smelling abilities, it’s fascinating to note that each dog has a unique nose print, just like human fingerprints.

Some kennel clubs even use nose prints as a way to identify dogs, which can be helpful in cases where a dog is lost or stolen, especially if it hasn’t been microchipped.

Taking Your Dog’s Nose Print

If you’re curious to capture your dog’s nose print, here’s a simple method:

You’ll need:

  • Food coloring (not ink or paint)
  • A pad of paper


  1. Wipe your dog’s nose with a towel to ensure it’s dry.
  2. Apply a small amount of food coloring to a paper towel and gently coat your pet’s nose with it.
  3. Hold a pad of paper to your dog’s nose, making sure the pad’s sides curve around to capture impressions from the sides of the nose.
  4. You may need to try a few times to get the right amount of food coloring and pressure to produce a clear print with all the details.


In conclusion, a dog’s nose is a truly remarkable sensory tool, and we may not fully appreciate the extent of its capabilities.

So, the next time you see your furry friend sniffing the air or following a scent trail, remember the incredible world of their sense of smell—one that we, as humans, can only marvel at.

You can explore further information on RSPCA or ASPCA related to your pet.

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Q1: How does a dog's sense of smell compare to a human's?

A dog's sense of smell is incredibly superior to a human's. While humans have about 5 million scent receptors, dogs have millions more, with some breeds having over 300 million scent receptors. This heightened sense of smell allows them to detect scents between 10,000 to 100,000 times better than us.

Q2: What are the slits on the sides of a dog's nostrils for?

The slits on the sides of a dog's nostrils enable them to breathe out through these openings, allowing for continuous sniffing. As the exhaled air swirls out, it can usher in new odors, aiding dogs in their scent detection.

Q3: Can dogs really detect specific scents through individual nostrils?

Yes, dogs can detect which nostril a scent arrives through, helping them locate the source of the smell. This ability to differentiate between the two nostrils contributes to their impressive tracking skills.

Q4: What is Jacobson's organ, and what does it do?

Jacobson's organ, also known as the vomeronasal organ, is a special organ located in a dog's nasal passage. It is responsible for detecting pheromones released by different animal species and relaying information about sexual readiness and other sex-related details to the dog's brain.

Q5: How are dogs' incredible smelling abilities used in various fields?

Dogs' extraordinary sense of smell has been harnessed for a wide range of tasks, including airport security for detecting illegal substances, military service for locating bombs and landmines, search and rescue operations for finding individuals under rubble or snow, and even in healthcare as therapy dogs that can detect changes in human health, such as drops in blood sugar levels or certain types of cancer.