Can Dogs Smell Fear in Humans?

You've probably heard that old expression about animals being able to smell your fear. It's an interesting idea and certainly encourages people to be brave, but is there any real truth to it? Can dogs actually tell when someone is afraid of them just based off smell?

In short, kind of, but not really. Dogs aren't able to smell the actual fear emotion, but they can definitely pick up on whether or not you're afraid of them. Dogs are unable to pick up what emotions smell like (they have great noses, but they're not THAT great), but they can pick up on the smells, movements, and body postures that might help them understand when a person is nervous, anxious, or afraid. 

For example, humans tend to sweat when they get nervous, and dogs are certainly able to pick up on that scent. Additionally, dogs are excellent at understanding and interpreting body language. So, odds are, if you're afraid of a dog, they are going to know it. Does that mean dogs can smell fear specifically? No. But there's more to it than just that!

To learn more about how dogs can sense fear, what signs of fear you give off that they might be able to sense, and signs your dog might be giving you to let you know that they know someone is afraid of them. 

While your dog can't directly smell fear itself, they can smell and sense the reactions your body is having that might clue them in to your anxiety or nervousness. If your dog notices that someone is afraid of them, nervous around them, or has anxiety, they might react in a few different ways. 

For example, some very sensitive dogs might calm down on the spot. They might change their demeanor from being super excited and happy-to-meet-you to a slower, gentler approach. Dogs are perceptive, and good-natured ones can typically alter their behavior when they can tell someone is afraid of them. 

This happens with children sometimes. Sensitive, smart breeds will often soften their approach and slowly or playfully introduce themselves to people who are afraid of them.

Other times, though, dogs can respond negatively to fear reactions. If a person is nervous, anxious, or afraid, that might translate poorly to a dog, and they might become anxious, afraid, or nervous as well. If this happens, it's possible that your dog might become skittish and anxious. It's also possible your dog might become aggressive and defensive, resulting in some unwarranted barking, nipping, or warning growls. 

As it turns out, the well-known phrase about dogs smelling your fear is rooted in something scientific. Typically, it's used as an expression to let someone know they need to act tough or brave lest the thing they fear realize how afraid they actually are. However, it's less of a myth and more of a misconception. 

When people are afraid, they sweat and when their adrenaline gets pumping, they give off a pretty particular odor. So, when someone says that a dog or another kind of animal can "smell your fear," what they really mean is, a dog or another kind of animal can "smell what your fear is making your body produce." 

Dogs can definitely smell your chemical changes and pick up on your body language if you're afraid of them, so, in a way, this weird misconception rings true.

Dogs can't literally smell the emotion fear, but they can smell when someone's body composition or odors change because of a certain way they're feeling. 

For example, when people are afraid or anxious, they often sweat - an odor that dogs can easily identify. We also give off a smell when our adrenaline pumps up that's packed full of hormones. We might not be able to pick up on this scent, but dogs, who can smell in parts per trillion, are able to smell the adrenaline scent without a problem. 

While they surely don't understand exactly what it means or why it's happening, they can definitely pick up on the change in smell and react to it. So, no, dogs can't literally smell the emotion of fear itself, but your sweat glands are certainly going to give them a hint at how you're feeling.

Dogs are sensitive to human fear. Not only can they smell how your body is reacting to them, they can sense your body language and your attitude, too. Some dogs will have sensitive responses to a human's nervousness naturally, but other times, dogs will have to be taught to tone down their excitement or to harness their anxiousness in response to someone's fear. 

The best way to train your dog to do this is with slow introductions to people paired with positive reinforcement. Make sure when you're introducing your dog to someone, they know not to jump up on them, rush them, or get too excited right off the bat. 

For this, they'll have to be very familiar with the command "no." Following this, make sure positive meetings and good behavior are enforced with lots of love, attention, and treats. Make sure your good dog knows that he or she has been a good dog - when that happens, they're far more likely to mimic that behavior in the future. Alternatively, make sure that your dog knows that negative reactions result in no treats and appropriate, safe reprecussions.