Can Dogs Sense if Someone is Untrustworthy?

April 9, 2013

By Linda Cole

One reason people pick a specific dog breed is for home protection. Dogs bred as livestock guardians, like the German Shepherd or Anatolian Shepherd, have a natural instinct to protect their flock and family. Guardian dogs and breeds used as guard dogs tend to have a natural distrust of strangers. But being able to sense if someone is untrustworthy is something completely different. Do dogs have a sort of sixth sense about people?

My first dog was an American Eskimo named Jack. I took him with me pretty much everywhere I went and he was exposed to a lot of different people. Most of the time, Jack enjoyed being around other humans, but there were times he refused to allow someone to pet him, even though I saw nothing out of the ordinary from the people he pulled away from. However, his reaction to someone was something I noted because it was unusual behavior for him.

We know dogs can sense danger when it comes to certain health conditions. Trained medical dogs can smell changes in blood sugar levels. Dogs are trained to detect high blood pressure, a potential heart attack or an impending seizure, and they can smell different types of cancer. Even untrained dogs can pick up changes in our health. That has nothing to do with a sixth sense, but it does show how sensitive a dog’s sense of smell is. Scientific studies have shown that even humans can smell pheromones put out by other people which can give us signals about someone’s mood. If we can pick up someone’s pheromones, you know a dog has already processed that information.

Dogs are experts at reading the body language of other dogs and us. Canines living with cats learn to read their body language, too. They can look at our face and tell if we’re in a good or bad mood. Dogs are great at picking up subtle signs we don’t even know we’re showing. When a dog is around someone who’s nervous, excited or angry, they can smell and observe body language that could cause a dog to be apprehensive towards them. People with something to hide have a tendency to look away during conversations, and this isn’t missed by dogs. Of course, we can also pick up on obvious signs of nervousness.

Tone of voice is another way dogs decipher our moods, and it’s how they learn when we are giving them commands, praise or correcting them. Dogs have a good ear, and if you give a command in the form of a question instead of using a strong, firm voice, you’ll have a harder time trying to train your dog. We use our tone to communicate what we want. I have no doubt that inflections we miss in someone’s tone of voice may be something a dog can hear, and it could cause him to react with caution. When you consider a dog’s ability to read us in different ways, it’s possible they can sense something “not quite right” about someone.

It’s also possible that if you have a feeling about someone, your dog is picking up on the signals you’re putting out. Dogs know us pretty well, and if you are uncomfortable around someone, your dog is likely to react the same way. Some breeds, however, are naturally wary of strangers and may have a hard time getting close to someone they don’t know.

Researchers are learning to be careful when studying our canine friends to make sure dogs aren’t reacting to cues they put out. Chaser, the Border Collie dubbed the smartest dog in the world, was taught to recognize over 1,000 different objects, as well as the difference between a noun and a verb, and to understand short phrases. To make sure she was actually learning, the person testing her took great care to work in a controlled setting so Chaser wasn’t reacting to their subtle cues. Dogs are so good at picking up the smallest signals we don’t even realize we’re sending.

Most of the time, if you have a bad feeling about someone you don’t need your dog to reinforce that belief. Over the years, I’ve learned more about dogs, why they behave the way they do, how extraordinary their sense of smell is, and their expert ability to read our body language. There is no proof scientifically that a dog can pick up disingenuous intent from someone or that they even have a sixth sense, but Jack did teach me to think twice about someone he had doubts about. He was usually right. If your normally friendly dog has reservations about someone, it may be wise to pay attention to what he’s trying to tell you.

Top photo by carterse
Bottom photo by Les Chatfield

Read more articles by Linda Cole

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The personal opinions and/or use of trade, corporate or brand names, is for information and convenience only. Such use does not constitute an endorsement by CANIDAE® Pet Foods of any product or service. Opinions are those of the individual authors and not necessarily of CANIDAE® Pet Foods.

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  1. S Harris says:

    My dog reacts to pictures of criminals shown on the TV. It’s weird. He will growl and assume a position of protection. He has done this with pictures of Casey Anthony, Jodi Arias, and just a few moments ago he reacted to the picture of the terrorist involved in the Orlando Nightclub killings. I don’t know how he recognizes evil people.

  2. Ashley Rose says:

    Dogs aren’t always nice to nice people. I’ve always been a good person. But just because a dog barks at you, doesn’t mean you’re a bad person. I don’t know what to believe. When I was pregnant, dogs barked angrily at me. My son likes cats. When I stopped being pregnant, dogs were more kinder towards me, even kissing my feet, and licking my hands. So I don’t know why dogs were barking. My son is less than two years old, and he shares. That’s remarkable. You don’t see any children that age sharing. He’s advanced. He likes to try to do everything early. He’s a perfect angel. He’s the perfect son. I love him in every way. He’s my dear sweet angel. I miss him. I wish I could give him hugs right now.

  3. John says:

    Awesome post I feel like they do. My dog is usually really nice to everyone however my ex gf he was never very fond of needless to say she turned out to be the most toxic person ive ever met. Hes also barked insanely at one of my former friends everytime he would come over. ended up finding out he stole from me and pretty much just used me since he doesnt drive and i do and for other reasons.

  4. Loving Max says:

    Great post! Sadly though, I know how loving my son is with any animals but Max can be a bit stand offish with him one minute and then jump in his lap the next,,,it’s weird that my son and the kid across the street are the only 2 people he has EVER barked at (Max has barked maybe 6-7 times in my life with him) but both boys, gosh, they are now men really are 6’2-6’4″ and dark hair so I wonder if someone fitting that description was mean to Max before I got him? Weird.

  5. SlimDoggy says:

    Interesting post – I think dogs do have sense that pick up on things that we might not. They have pretty good intuition.

  6. Fuzzy Tales says:

    I don’t have a dog, but I absolutely would pay attention, if my normally friendly canine companion took a dislike to someone.

    On the flip side, I’m pretty darned non-aggressive and unassuming, prefer four-leggeds to two, but I’ve certainly been snapped at by the occasional dog, usually a small, ill-mannered one. Or maybe it’s been the cat fur I’m covered in on a daily basis that they’ve not liked. 🙂

    Still, I’d definitely pay attention to my non-human companion’s instincts!