Debunking Pet Myths: Can Dogs Smell Fear?

*The thoughts and opinions in each post on this blog are those solely of the attributed author and do not necessarily extend to all program collaborators or to Ethics in Animal Care itself.*

By Courtney Emken, Bart Emken CPDT-KA, and Jen Larson, KPA-CTP of DogBoys Dog Ranch


A dog’s sense of smell is unbelievably powerful. Dogs have around 300 million scent receptors in their nose, whereas humans only have 6 million. That’s FIFTY times more powerful than our sense of smell! Despite our olfactory inferiority in comparison to dogs, we can still detect 1 trillion scents. Now imagine what a dog can do!

So, can those high-octane snouts smell someone’s fear? Well, we put the myth to the test this week, and the answer we found is more complicated than you might imagine.

Why is the canine sense of smell so uniquely powerful?

Other than the scent receptors we mentioned earlier, dogs also have supplementary biological structures in their nose. These structures increase the power and scope of their sense of smell. This makes a dog’s nose their primary means of perceiving the world.

Think about it this way: humans have five senses, but we primarily rely on sight. Our eyes are incredibly advanced. They give us the most useful and the most information about the world. Now imagine what it would be like to see the world through your nose. This is the life of a dog.

Dogs also have a Jacobson’s Organ, this allows them to taste and smell simultaneously. There’s not really a way for humans to even imagine what this sensation would be like. Other animals with this structure, also known as the vomeronasal organ, include:

  • Snakes
  • Elephants
  • Cats
  • Horses
  • Salamanders
  • Turtles

The canine Jacobson’s Organ allows dogs to detect one another’s pheromones. If you see a dog licking the air, they’re trying to provide more info to this vital sense-apparatus.

What can a canine nose detect that a human nose can’t?

Quite a lot, as you may have guessed, but the specifics are astonishing. We still don’t quite know the limits of canine scent, but we do know what they’ve been trained to smell by humans, such as:

There’s even talk about dogs who can sniff out cancerous cells, though that’s still being debated. With all these examples, it’s easy to infer that dogs can smell our body chemicals and detect their changes.

What A Dog Senses When Someone Is Afraid

Dogs can tell when you’re afraid, but it’s not because they smell it on you. Well, it’s not just because they smell it on you. While it’s true that they can definitely smell the increased sweat that accompanies anxiety, that’s not the main communicator of fear.

Dogs communicate primarily with body language, and they’re experts at picking up yours. If you’re not paying attention to what your body is saying, then you could be sending anxiety signals like:

  • Short, shallow breath
  • Stiffened body posture/Freezing
  • Closed angles
  • Holding your breath
  • Side-eye or whale-eye

Unfortunately, these signals don’t just communicate fear to a dog, they can also be interpreted as signs of a threat. Dogs react to a person’s body language far more than their scent.

Being afraid, and whether the dog can smell it on you or not, is fairly irrelevant to how well a canine meeting goes down. If you pay attention and display non-threatening body language then a dog will have no reason to act defensively.

The most important thing to do is to send calming signals. These are the exact same signs that dogs show one another to relax and diffuse conflicts. Some examples of calming signals include:

  • Avoiding eye contact
  • Yawning
  • Sniffing
  • Scratching the belly
  • Pawing the ground
  • Licking the lips
  • Loose body posture

Even when performed by a human, these signals immediately reassure a dog that you’re not a threat and that you want to be friends. It’s how they talk to one another, and you can do it too.

So, it’s difficult to say that this myth is one hundred percent debunked. Dogs can certainly smell the physical changes in your body that occur during anxiety, but dogs don’t react to them as threatening signals. So let’s call it half-debunked.

If you have any questions, or just want to learn more about how to speak your dog’s own language, please contact us today. We’re fluent in dog, after all!


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