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What happens if a dog smells your fear?

Can Dogs Smell Fear?

There is a long-established belief that dogs can smell your fear. It is very common to hear a dog owner tell their visitor not to panic as the dog bares its teeth. The idea is that, when you show fear to a dog, the dog can smell it and become afraid itself and thus see you as a threat. In recent years, many scientists have conducted independent research into this long-held belief with a focus primarily on dogs’ sense of smell.

For millennia, dogs have been employed in search and rescue missions. This is mainly because of their superlative sense of smell and their keen sense of perception. Trained dogs possess a heightened sense of smell which enables them to sniff out crime suspects, drugs, and bombs. In the same fashion, dogs’ sense of smell has found new applications in the field of medicine. Even detecting cancer, tuberculosis, and most recently malaria in humans.

Beyond all these, the powerful sense of smell of man’s canine friend goes deeper than picking up scents given off by physical objects only. Recent studies have shown that dogs can also smell some human emotions, including fear from the chemicals produced by the human body. To begin with, let’s examine the dynamics of dogs’ sense of smell.

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police dogs

The Olfactory Senses Of A Dog

A dog can easily identify the natural smell of its owner even when he is wearing very strong cologne. The armpits of a human for instance have a natural smell that comes from the secretions of the apocrine gland. Your friend may not be able to pick up this smell if you are clean and wearing cologne, but you can not fool your dog. It can smell you for who you are despite your deodorant. Ideally, dogs can pick up a smell from a distance of up to 15km. This is connected to the sizable amount of olfactory receptors present in their noses. This can range between 250 and 300 million depending on the dog breed. The Bloodhound species has the keenest sense of smell. The Basset hound, Belgian Malinois, Labrador retriever, and the herding breeds follow closely behind.

In addition to their numerous olfactory receptors, dogs have an anatomical feature that further enhances their sense of smell. Within the nasal cavity of a dog lies Jacobson’s organ, otherwise known as the vomeronasal organ. This special organ connects a dog’s nasal cavity to the roof of its mouth just behind the upper incisors.

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By function, the vomeronasal organ serves as a secondary olfactory system for chemical communications. The vomeronasal nerves are morphologically different from the nerves within the olfactory tissue in a dog’s nose. These atypical nerves lead directly to the dog’s brain and only respond to special odor signals. They are able to detect odors that are naturally undetectable by most animals. Comparatively, an average human has about six million olfactory receptors. The area of a dog’s brain that analyses smell in dogs is more than 40 times greater than in humans. Simply put, for every single olfactory receptor that a man has, a dog has up to 50.

This means that dogs have a sense of smell up to 1000 to 10000 times stronger than ours. Even more sensitive than the most advanced sound-picking instruments ever made by man.

shiba inu smelling

How A Dog’s Nose Functions

Scientific studies have shown that dogs’ noses function in a different design than our own due to anatomical differences. Respiration and olfaction in humans occur through the same airway. However, dogs have different passages for these two functions. A dog has a fold of tissue in its upper airway that enables it to separate the function of breathing from smelling.

When we breathe out air through our nose, we block out odors coming in because the odors and the exhaled air are passing through the same airway. On the other hand, the air exhaled by dogs takes a different route from the odor passage, the air goes out through the slit-like openings on the sides of their noses. In effect, dogs are able to sniff more than humans.

In addition, dogs can independently wiggle their nostrils. This means a dog can determine which nostril the odor arrived in and can easily locate the direction of the smell. This is what happens when we see a dog weaving forth and back in a particular location, having picked up a smell that caught its interest.

Dogs Can Smell Fear And Other Emotions In Humans.

You can fool your friends by masking your fear with a broad smile, but this charade is not going to work on a dog because of its incredible ability to smell fear. When we are unnerved by a situation, stress hormones become secreted into our bloodstream, particularly cortisol and adrenaline (epinephrine). The circulation of epinephrine through the body brings about some physiological changes such as an increase in heart rate, blood pressure, pulse, and sweating among others. A dog can easily perceive the smell of your sweat. It is not enough to conclude that a dog will sense your fear only because you are sweating.

Part of the physiological responses to fear also includes a fight and flight response. You will instinctively want to fight back or flee from the situation which may lead to reflexive movements that will give you away, no matter how subtle. Dogs are very intelligent animals. In addition to the smell of sweat and the other chemicals your body is releasing, a dog can detect your body language, and the defense mechanism you employ to conclude that you are indeed afraid. When a dog smells fear on you, its aggression becomes heightened and may end up attacking you.

dog smelling hand

The Research That Proved Dogs’ Ability To Smell Fear

Scientists have been fascinated by the widely held belief about dogs’ ability to smell fear. In January 2018, the Animal Cognition journal reported that a team of researchers led by Dr. Biagio D’Aniello, a neurobiologist at the University of Naples Federico II carried out an experiment to find out if dogs could detect some human emotions from the chemicals present in sweat. The sweat samples were taken from humans under emotional conditions of fear and elation.

The team obtained samples of armpit sweat from males—some samples were taken from men who had earlier been exposed to happy videos for the purpose of the experiment; Some other samples were taken from men exposed to scary videos. The third category was a control experiment in which no sweat was used at all. The sweat samples were then randomly presented to Golden Retriever and Labrador Retriever participants to smell.

The study was conducted in a calm environment. The dogs were made to stand in front of the humans from whom the sweat samples were obtained.

The Results Of The Experiment

Dogs exposed to sweat from someone who had seen scary videos (someone who was afraid) showed different behavior than the dogs exposed to sweat from a happy person (someone who had seen happy videos. It was observed that the dogs that were exposed to the sweat from startled men showed indications of stress and increased heartbeats.

To sum this up, it is indeed very true that dogs can detect emotion from the chemicals produced by the human body. You should note that a dog can truly see you for you, there’s no hiding your fear in front of a dog. It can smell the chemicals in your sweat and read the subtle display of anxiety.

Up Next…

Check out some of our other dog articles below.

  • Can Dogs See In The Dark – Find out if dogs can see as well as cats do in the dark.
  • Why Dogs Smell Butts – The real reason may surprise you.
  • Why Dogs Roll In Poop – Read on to know the real reason your dog rolls in stinky things!

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Do Dogs Smell Fear?

Do Dogs Smell Fear?

The topic of whether dogs can smell fear and differentiate emotions has been debated by many people for a long time. And if you want to find out what side is right, this article explains everything you need to know about.

Is It True That Dogs Smell Fear?

The study by D’Aniello et al. (2017) proved that dogs can smell fear through a person’s sweat and body odor. The moisture from a person when they’re afraid contains unique chemicals. It serves as a signal for dogs to identify human emotions such as fear.

Dog’s superior sense of smell also greatly contributes to their ability to pick up human emotions through odor. Their sense of smell is 10,000 to 100,000 times sharper than humans’.

Now, how can dogs detect fear through secreted sweat?

Chemosignals From Humans to Dogs

Dogs can detect fear and other human emotions through chemosignals. Chemosignals refer to chemical signals the human body releases that contain information like one’s emotional state (fear, happiness, anxiety, distress, and more). Sweat induces chemosignals.

Given that dogs possess an incredible sense of smell, these chemosignals help them detect specific human emotions. The study by D’Aniello et al. (2017) proved that dogs can detect human emotions via chemosignals.

Dog Breeds That Can Smell Human Emotions

According to the study by Svartberg (2006), Golden Retrievers and Labrador Retrievers have high rankings in behavioral traits related to socialization, curiosity, and fearlessness. Thus, they are often used as dog samples.

Here’s how both dog breeds are good at smelling human emotions:

Golden Retrievers

Golden Retrievers highly offer unconditional love for human companionship – and this is one of the reasons that make them easily identify different human emotions. When Golden Retrievers sense fear, they start to provide additional comfort and playfulness to reduce the negative emotions.

Additionally, Golden Retrievers are also very easy to train, and they are quick to catch up on tricks and specific commands which makes them one of the best service dogs to have.

Labrador Retrievers

Labrador Retrievers are one of the best therapy dogs because of their calm, obedient, and friendly personalities. Because of their nature, Labrador Retrievers are good when it comes to sensing human emotions, and they tend to reflect the emotions they sensed.

Like Golden Retrievers, this dog breed also provides comfort and seeks reassurance from their owners when they sense fear and sadness.

Can Dogs Sense the Difference Between Happiness and Fear?

Dogs can detect emotions via body odor, facial expressions, and body gestures. Aside from this, dogs can also sense the difference between human emotions like fear and happiness.

In the study by Siniscalchi et al. (2018), they state that dogs can differentiate emotionally positive sounds and negative sounds. The researchers also noted that dogs turning their heads to the left means they are using the right side of their brain, and turning to the left means they are using the right side of their brain.

Here are the highlights of their findings:

  • Dogs can identify positive and negative sounds using their ears.
  • It is harder for dogs to interpret emotions like disgust and surprise.
  • Dogs turn their heads to the left side for negative sounds (sadness and fear), and to the right for positive sounds (happiness).

The latter finding is important as previous studies confirmed that dogs process emotionally negative sounds using their right brain, and positive sounds with their left brains.

On the other hand, D’Aniello et al. (2017) also proved that dogs can differentiate emotions. The researchers conducted their study by collecting sweat samples from human volunteers after watching videos that were made to evoke fear and happiness.

Here are the highlights of their findings:

  • Significant behavioral changes among dogs were noticed after being exposed to sweat samples.
  • Dogs exposed to “fear odors” portrayed more stress signals compared to dogs who were given “neutral or happy odors.” They also had higher heart rates.
  • Dogs exposed to “neutral or happy odors” became more active and interactive with strangers.

Do Dogs Smell Fear: FAQs

Here are the answers to some of the most frequently asked questions:

What do dogs do when they smell fear?

When dogs smell fear, they lessen interactions with strangers, seek more reassurance, and comfort their owners. Dogs also tend to feel scared and anxious too; thus, mimicking the sensed emotion.

What other emotions can dogs sense?

Aside from fear, dogs can also sense emotions like happiness, sadness, and anger. Meanwhile, the study by Siniscalchi et al. (2018) shows that dogs have difficulties interpreting emotions like disgust and surprise.

Can dogs smell anxiety?

During anxiety attacks, the human body produces a hormone called cortisol (stress hormone). Since dogs can smell cortisol, dogs can also sense whether someone is feeling anxious. When dogs detect a high level of cortisol, they begin to act in a more comforting manner.

Can puppies smell fear?

Like adult dogs, puppies can also smell fear. Even though puppies are still small and young, their sense of smell is still incredible. Thus, they can also detect fear and other emotions through chemosignals.

Can dogs sense depression?

Dogs can also sense depression. When a person is depressed, their serotonin (the happy hormone) level drastically decreases, and since dogs can smell serotonin, they can detect if it’s rising or falling.

Based on various scientific studies, it is true that dogs can smell fear and other human emotions through chemosignals. Thus, it makes perfect sense when pet owners always claim that their pets know when they are feeling sad.

Aside from that, dogs can also sense and differentiate fear and happiness using their senses of smell, sight, and hearing.

Can Dogs Smell Fear

Time for Paws

It has long been thought that dogs can smell fear and that they adjust their behaviour accordingly. Now, a new study has proved that this is true, at least when it comes to Labradors and golden retrievers.

Italian Research

Researchers from Naples University created a unique experiment to test if dogs adapt their behaviour to how their owners are feeling. Dogs can readily detect airborne odours with their impressive sense of smell. As their ability to smell is so important to them, it should come as no surprise to learn that what dogs smell then influences their behaviour. To test the dogs’ reactions, researchers took sweat samples from men. Half of these had been taken from men who were watching a cheerful movie, in this case Jungle Book. The other half were taken from men who were watching the Shining which is a scary movie. 40 different dogs were then lead into a room containing their owner, a stranger and one of the sweat samples. The sweat samples had no effect on the humans in the room but the dogs were a different story. The dogs were able to detect the human emotional chemical symbols in the sweat. It became clear that the dogs were more likely to investigate the stranger in the room when the «happy» sweat was present.

Dogs and Their Owners

When a dog’s owner smells happy, the animal will feel relaxed with a new situation. When a dog smells the scent of fear, it becomes wary of a new person or situation and so will be less willing to explore strangers. The dogs studied in Italy didn’t become aggressive towards strangers when they smelled fear. It is not understood why this was the case and so more research into canine behaviour is required. Scientists are also keen to explore whether the ability to smell fear in humans evolved after dogs became domesticated or whether they have always possessed the ability to detect the emotions of other species. Few animals are as proficient as dogs at tuning in to the emotions of other species.

Labradors and Retrievers

The researchers at Naples University have been keen to point out that their study only featured two breeds of dog — Labradors and retrievers. These are breeds which are renowned for their sociable natures and low levels of aggression. It is possible that other breeds would display different reactions to the odours. However, anecdotal evidence would suggest that dogs in general are able to tune into their owners’ emotions and even those of strangers. Many dog owners will have experienced those strange moments when their otherwise friendly dog appears to be wary of a particular individual for no apparent reason. Dogs can smell fear but it is likely that they can also smell other emotions. They are often described as intuitive animals but perhaps their ability to make judgements about people isn’t confined to intuition. If they can smell fear, can dogs also smell aggression, depression and a variety of other human traits and emotions?Has your dog displayed inexplicable behaviour towards a person which has turned out to be insightful?

Feeling anxious at the thought of meeting your friends new dog?

Well, it turns out that the best way to handle it, particularly when it comes to avoiding any unnecessary nips, could be to switch off those nerves and adopt your most confident stance. A conducted by The University of Liverpool found that people who have heightened levels of anxiety are more likely to be bitten by dogs. This particular study was conducted on 694 people in 385 households in the UK. All participants were asked if they had ever been bitten by a dog and if they had, whether those bites needed treatment. Each person was asked if they knew the dog which had provided the bite. The study also enquired as to whether each participant was a dog owner themselves. One in four people stated that they had indeed been bitten by a dog before, and it transpired that men were almost twice as likely to have been the victims of these bites than women. The study also concluded that those who owned several dogs were more than three times as likely to have been bitten as those who didn’t call themselves dog owners. It was also acknowledged that over half of the participants had been bitten by a dog that they were not familiar with. Doctor Carri Westgarth, Research Fellow in Human-Animal Interactions at the University of Liverpool stated: Reporting being less emotionally stable was associated with an increased frequency of dog bites.  So it turns out that the behaviour of dogs could well be driven by the initial behaviour of the humans they interact with. Currently, there are 8. 5 million dogs living in the UK and statistics show that more than 6500 people require hospital treatment for dog bite injuries every year in England. The breed most likely to provide that bite? In a potentially surprising revelation, research from pet insurer Animal Friends have indicated that the humble family Labrador claims the top spot. And the image of the local postie being ravaged as they attempt to deliver your daily post? Well it transpire that this is still very much prevalent. According to research conducted by, roughly 14, 500 dog attacks took place on postmen and woman over the last five years, with over 2, 470 in 2017 alone. This research also found that out of these 2, 600 attacks, 36% occurred at the front door, with 35% of them happening in the front garden. Animal Psychologist, Doctor Roger Mugford, said the best thing for posties to do was befriend the dogs and keep them happy by always carrying a bag of treats. He also stated: Once a post man befriends a dog, they will be friends for life. To say that dogs can smell fear I am sure is very true. The way we move and the way we think is communicated to a dog. Caroline Kisko, secretary for animal welfare organisation The Kennel said that How dogs react to people is often determined by how people themselves react to dogs, so it is important that people recognise the best ways to interact with dogs and that owners always keep their pets under control and consider that not everyone may feel comfortable being around dogs or know how to interact with them. This is not to say that every dog bite is the result of a person with an anxious or nervous disposition as there are various reasons for dog attacks, and ones which result in a person being bitten. Kisko also pointed out that it is important to remember that any dog is capable of biting just as any dog is capable of being a well-adjusted member of society. It is therefore important that all dogs are properly trained and socialised from an early age to reduce the risk of bad behaviour, including biting. 

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