Dogs Can Indeed Smell Fear--Here’s How They React

Fagjun | Published 2017-10-29 18:33

Dogs are capable of smelling fear on humans, and when they do, they get scared, too.

Dogs get scared when we're scared.



According to a new study, dog owners who say that their furry four-legged friends can tell how they feel may actually be onto something. The statement, however, that dogs can smell fear is both true and misleading. For one thing, fear--the emotion itself--doesn’t actually have a scent. However, feeling afraid induces an animal to release pheromones, which then release a scent.


Animals produce pheromones through bodily fluids, like sweat and urine. However, we don’t really smell these chemicals the same way we smell usual scents. This is because they register through our accessory olfactory system and not through the main one.


So if dogs can smell fear, how do they react? Researchers say that fear, once dogs smell it, is actually contagious.

The Smell of Fear and Happiness

Our fear affects our dogs in significant ways.



We already know that dogs can pick up on emotional cues based on what they can see and hear. What we weren’t sure of, however, was whether or not dogs can pick up on these cues through their noses.


Researchers then took sweat samples from male volunteers to test how dogs react to the “scent” of fear. The samples were taken from the volunteers as they watched The Jungle Book and The Shining. These movies were meant to elicit happiness and fear, respectively. After the samples were collected, the researchers placed each one of 40 dogs in a room with their owner, a stranger, and one of the sweat samples.


The findings showed that the samples produced by fear didn’t affect humans. However, they had a noticeably significant effect on the dogs. “The dogs were not only able to detect human emotional chemosignals, but they also affected their behaviour,” said Professor Biagio D'Aniello, one of the researchers.


When the samples produced by happiness were the ones that were in the room with the dogs, the dogs were more likely approach the stranger they were with. However, when the dogs were in the room with the fearful smell, they showed signs of stress and were more likely to seek assurance from their owner. They also had a quicker heartbeat and were more wary of the stranger in the room with them.

Dog-Human Interactions

The study included retrievers, a breed known for being more friendly than aggressive.



These findings show how attuned to human emotions dogs are. Not only can they pick up on visual and auditory emotional cues, but it turns out that they can also indeed smell our emotions, including fear. It’s not clear if this is an inherent ability in dogs, or if it was a byproduct of domestication.


According to D’Aniello, the dogs’ reaction to the smell of fear was also interesting. The smell induced a wary response instead of an aggressive or attack response. Then again, the dogs in the experiment were labrador and golden retrievers. These dogs are known for being low in aggressiveness, so it’s possible that other breeds may have different reactions.


This study is likely to be an important addition to a body of research regarding the ways dogs gather sensory information on humans.

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