Study Finds Dogs Can Smell When Humans Are Stressed

Animals

| LAST UPDATE 10/12/2022

By Amie Alfaro
Dog Senses Smell Eyesight
Zak Kendal via Getty Images

Man's best friend can do everything - from taking walks to playing fetch and now being able to smell if their owner is stressed. According to a recently published study, dogs are able to smell if humans are stressed or calm by the difference in odor. Here's what to know.

The research that was published in the journal PLOS ONE expanded upon the knowledge that dogs can determine if humans are happy or fearful based on their sense of smell. This study took it one step further. The researchers used a sample group of 36 participants to test their theory that dogs can smell changes within the human body, even something as specific as being stressed. The researchers collected breath and sweat samples from the participants, then those samples were given to the dogs, along with two blanks. The dogs had to identify which sample was the stressed sample. Out of the 20 dogs who were tested, 4 passed to the next phase. During the second round, the dogs were presented with the same stressed sample they had sniffed earlier, along with a sample from the same individual collected before the task began and a blank.

Dogs Spaniel Sense Smell
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The researchers documented that the dogs chose the correct sample in 93.8% of the trials. Dogs have a slight advantage over humans when it comes to using their noses. They have 220 million olfactory receptors, whereas humans only have 50 million. Other completed studies showed evidence that a dog's sense of smell is connected to its sense of sight. Additionally, the sense of smell can differ within dogs. Hunting dogs, such as spaniels, terriers, and lurchers, would use their noses more regularly and therefore have a stronger sense of smell than other dogs. These studies' findings help better understand the relationship between humans and dogs. They also have significant implications for understanding Emotional Support Animals and how service dogs operate and can continue to help humans.

These findings will continue to help researchers learn more about the relationship between humans and dogs. Stay tuned as more is discovered.

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