Types of Dog Smiles

There’s more to a dog’s smile than meets the eye.
By Karen B. London PhD, March 2021
dog smiling with teeth

One of my favorite private consultations of all time involved a family who came to me, scared and sad, because they were worried about the way their beloved Golden Retriever was acting toward their two-month-old baby. Though the dog had been a total angel for more than four years, they were afraid they would have to rehome, or perhaps even euthanize, him: “He’s gotten aggressive and is showing his teeth to our daughter.”

I braced myself for an emotional session. In the work I do, it’s critically important for me be honest with my clients, particularly when a child’s safety is involved. Sometimes management and training are enough, but with a newborn—or really, children of any age—in the house, there can be no mistakes or management failures. A gate that isn’t latched or a door that isn’t shut can easily happen to anyone (especially to sleep-deprived new parents), but such lapses can have serious consequences.

When I met their dog during our appointment, I couldn’t reconcile my immediate impression of his docile nature with a dog who was threatening a baby. They described how he showed his teeth ever-so-briefly whenever they brought their daughter into the living room after a nap, when he first saw her each morning and when they came home with her after an absence. Because it was always in greeting and because their dog seemed about as threatening as the average butterfly, I suspected that he was smiling, but needed to know for sure. I couldn’t afford to be wrong; a baby’s safety depended on my understanding and assessment of the situation.

I had them step into the hallway with the baby for a few minutes, then return to my office. And that’s when I saw it: a lovely smile by a lovely dog. It was accompanied by a loose body, a gentle but enthusiastic tail-wag, a relaxed face, and what I can only describe as an adoring gaze.

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Thankfully, there was no need to be the bearer of bad news. Though these clients came to me about what they thought was an aggressive dog, I was able to tell them, honestly and joyfully, that he wasn’t aggressive at all, but rather, social, sweet and gentle.

In other words, their fears were misplaced. Even though the dog was regularly pulling his lips back and revealing his teeth, he wasn’t acting in an aggressive manner. (We did, of course, discuss some commonsense, standard, baby-related issues, including that all dogs and babies need supervision and can’t be left alone together.)

So, what was this dog doing? He was performing a behavior called smiling, which—as when humans do it—involves showing the teeth.

Two Types of Dog Smiles

What most of us call a dog smile is really a grin, a happy, open-mouthed face of a jolly dog. In this “happy grin” kind of smile, which can last for minutes, the lower jaw hangs open and the corners of the lips are pulled back in a relaxed way. Sometimes the tongue hangs out, or is at least visible inside the mouth. Though the bottom teeth often show, the top teeth aren’t likely to.

The second type, the one we’re discussing here, is a retraction of the lips that reveals the top and usually the bottom teeth as well. Because it resembles an aggressive expression that we call a “tooth display,” it can freak people out. However, this kind of smile has absolutely nothing to do with aggression. It is, in fact, quite a social expression.

These smiles are different from tooth displays or big grins. Both tooth displays and smiles reveal the upper teeth (and sometimes the lower teeth), but in contrast to tooth displays, smiles happen quickly and are subtle. The upward movement of the lips away from the teeth is often slight, and the retraction rarely lasts more than a second. The combination of minimal movement and speed makes it a challenge to capture them photographically. You have to be at exactly the right angle and height, which is difficult when a dog is moving around, often wagging not just the tail, but much of the body, as is so often the case when dogs smile.

Tooth displays, on the other hand, are usually performed by a dog who’s fairly stiff and still in both body and face. The showing of the teeth proceeds more slowly, and the expression can last for several seconds or more. Tooth displays are often an indication that a dog has been pushed past her comfort zone, perhaps by the approach or touch of another dog or a person, when she has a treasured object or is exhausted/in pain and wants to be left alone.

More on the Smile

Whenever a dog smiles in this fleeting, friendly and social way, I’m delighted. In my opinion, it reveals many positive qualities about that dog, and about the relationship between the dog and the recipient of the smile. Smiling dogs tend to be social, affiliative and loving.

That said, I’m not aware of any scientific studies that explore the meaning and context of such smiles. So, I base this opinion (and this discussion) on my own experience with smiling dogs, as well as discussions with other dog trainers and behaviorists over the years.

Smiles are often given while greeting people whom the dog adores, especially if the dog hasn’t seen the person for some time. The smiles seem to indicate that the dog is over the moon (to use a nontechnical term!) about the reunion, and about the opportunity to greet them.

I used to think that these smiles were a sign of a dog who was slightly conflicted during a greeting—nervous and excited, or perhaps interested but also cautious. However, I’m no longer convinced that’s true. Recently, I had an opportunity to observe this behavior at close range. Roxy, a Great Pyrenees/Poodle mix who stayed with us while her family was traveling, took turns sleeping with different family members. Each morning, she’d smile when greeting those whose room she had not slept in, or if one of us came home after a few hours out. Her biggest smiles, however, were on display when her family returned after an absence of more than a month. She was absolutely thrilled to see them.

I recently discussed what ethologists call smiles with Chelse Wagner, CBCC-KA CPDT-KA, of Dog’s Best Friend Training in Madison, Wisc. When I first started working as a dog trainer, I assisted in Chelse’s training classes, where I learned a lot from watching her work with dogs, and with people. As I was thinking about this topic, I contacted her to ask some questions about smiles (including the role of conflict and sociality) because I know no one better at reading dogs. She has several decades of experience working with dogs in shelters, as a trainer and as a canine behavior consultant.

Chelse pointed out that while dogs displaying a smile tend to have loose bodies, they will often hold their ears back and keep their body lower to the ground; this can make them seem ambivalent or conflicted rather than happy. Chelse has lived with two dogs who smiled this way; one was an exceptionally social Greyhound named Sage. As she described her, Sage’s smile was more likely to appear and more likely to be exaggerated the longer someone had been gone. The other, her senior mini Aussie, Charlie, smiled more when he was younger than he does now. He was especially likely to smile at Chelse’s husband, perhaps (as she suggests) because he was the first to be gone for extended periods.

It has been suggested that dogs who smile learn it from humans. The action of smiling is very common among primates, including humans, and it is highly possible that dogs are copying us. This implies that dogs who smile have good social skills, which fits with my experience. I cannot think of a dog I have seen smile who is not social. Nor can I think of any dogs I’ve seen smile who were prone to arousal or getting out of control in play, greetings or other social settings. That being said, I haven’t seen a ton of dogs who smile this way. But, given its fleeting nature, I’ve likely missed seeing it even when it was present.

If dogs learn to smile from people, it suggests that they have a strong connection to us and are capable of mimicking our behavior. It also accounts for the smile’s vaguely awkward and unnatural presentation. Dogs who smile remind me of small children who are asked to smile for a photo but don’t know how to offer a natural smile, one that reflects genuinely happy feelings.

A Good Result

The couple with the young baby and the smiling Golden Retriever were considering rehoming or even euthanizing their dog because they feared for the safety of their child. Imagine their joy—and mine!—when I was able to tell them that he was just smiling, and explain what that meant. He was a sweet, social dog, as they had always thought, and his toothy behavior was an ecstatic greeting rather than a threat.

Without knowing for certain what was in that dog’s heart, I could say with confidence that it appeared from his behavior as though he loved the baby. No wonder this consult stands out as one of my all-time favorites!

Photo from DogJoy / The Bark

Karen B. London, Ph.D. is a Certified Applied Animal Behaviorist and Certified Professional Dog Trainer who specializes in working with dogs with serious behavioral issues, including aggression. Karen writes the animal column for the Arizona Daily Sun and is an Adjunct Professor in the Department of Biological Sciences at Northern Arizona University. She is the author of six books about canine training and behavior, including her most recent, Treat Everyone Like a Dog: How a Dog Trainer’s World View Can Improve Your Life

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