Spend enough time on the social media platform of your choice as a dog person, and you’ll likely tap into the algorithm’s seemingly endless inventory of photos and videos of dogs “smiling.” Pit bulls curling the corners of their mouth in Grinch-like bliss when their person comes home. Open-mouthed Golden retrievers looking like their buddy just told them the best joke. A rescue pup who bears his teeth when he’s asked to “say cheese!”
These photos and videos are delightful, but they also raise questions: What are dogs actually communicating when they’re “smiling”? Do their smiles mean the same thing as human smiles? Humans and dogs have lived together to each other’s great mutual benefit for thousands of years, but there are still major miscommunications that occur between species (for example, we like hugging our dogs so much that we sometimes miss the signs that they’re uncomfortable). What’s at stake if we misinterpret what we think of as a “smile”?
It’s hard to say exactly what dogs are feeling when they curl the corner of their mouths up—i.e., what we humans might interpret as a smile—because research is limited on the subject. But behaviorists can extrapolate a lot from context clues and repeat behaviors.
“It’s not as well-studied as people think. So a lot of it is based on conventional wisdom or just general lore,” says Kate Anderson, veterinarian, board-certified behaviorist, and Assistant Clinical Professor at Cornell Duffield Institute for Animal Behavior. “Generally, the more relaxed [dogs] are in terms of how loose their body is, we think the more happy or the more relaxed with the situation they are.”
So when it comes to the mouth, a relaxed dog has a jaw that is slightly agape, teeth showing a little, and sides of the mouth turned up. We may not be able to conclusively label this look as a “smile” that is conveying “happiness,” at least in terms of what scientific research has concluded, but we can identify a calm dog, which is pretty close.
So what does the research say about smiles?
Though studies on specific facial features are limited, there is some research on the musculature of a dog’s face. What researchers have found is that domesticated dogs are able to move their mouths much quicker than wolves, and that a dog’s face is more similar to humans than to their canine ancestors when it comes to speed of expression.
The study’s authors, led by Professor Anna Burrows, Ph.D. at Duquesne University in Pittsburgh, point out that there could be a few reasons that humans selected (or dogs self-selected) the quick-moving facial structure over the slower, more wolf-like one: The ability to move their face quickly made it easier to communicate with humans and they were more adept at barking, rather than howling. Though the research is preliminary, it’s possible that the selective process favored dogs with faces that best resembled our range of facial expressions.
Even if dogs’ facial expressions might resemble our own, it does not mean that various canine and human expressions mean the same thing. In another oft-cited study headed by Cátia Caeiro and published in Scientific Reports, researchers sought to isolate various dog and human facial expressions and cataloged their appearance in relationship to different emotional stimuli. They found that, like us, dogs respond to contexts with different expressions and these expressions do reflect their emotion in the moment, but the expressions they produce are different from ours. The study’s authors wrote, “Most of the basic facial muscles are similar between humans and dogs, and share primary functions unrelated to facial expression. […] However, when it comes to emotional expression, dogs do not seem to make use of their muscles in the same way that humans do.” This can lead to “emotional misunderstanding” on the side of humans, who are naturally biased toward the meaning behind our own expressions and often untrained in recognizing dog body language.
Read the whole sentence, not just a word.
So how do we avoid this miscommunication? When interpreting what seems like a smile, know that the facial expression doesn’t stand alone, suggests Lore Huag, veterinarian and board-certified veterinary behaviorist. The mouth is a part of a whole and should be understood within its entire context.
“When you look at any particular signal—like what their eyes do or their ears or their lips or their tail—each of those is like a word, and then you have to put them together into a sentence,” she says.
For example, a submissive grin is one of the “smiles” in some dogs’ arsenals of facial expressions. In this expression, dogs pull both corners of the mouth up, and may bare some or all of their teeth. It can look strange and even aggressive, but in dog-speak, a submissive grin can sometimes be “an invitation to interact,” per Huag. It’s directed toward people—never other dogs or other animals (dogs learn to overcome an aversion to face-to-face interactions and eye contact with humans, Huag says, whereas they still avoid staring directly too long at other animals in order to appear less threatening). But no matter how the submissive grin actually presents, there are usually accompanying movements in the rest of the body, all of which help you read the full sentence.
Milo exhibiting his submissive grin.
“[The submissive grin] is friendly and it is ‘appeasing’ and usually their ears will go back a little bit, they’ll sometimes crouch or they’ll go into a stretch play bow when they do it,” Huag says. “They’re usually wagging in a low-ish sweeping, circular kind of wag. Sometimes they’ll curl their body a little bit. Typically they’re approaching.”
Here’s a live example from TikTok, and here’s one more.
It’s not so different from what people do, Huag points out. Imagine for a moment the smile you do when meeting a new acquaintance. It will look a little different than your dog’s version, but the goal is the same—that is, to say, “I’m friendly.”
The submissive grin is not always an invitation to interact, though. Dogs will submissively smile when they’re being scolded, possibly to elicit leniency from the scolder. So context always matters, as does interpretation. Huag recalls one of her previous dogs who did a lot of submissive smiling, and “over 50% of the people that saw her do that thought that she was growling at them aggressively.” This becomes a problem if humans interpret this appeasement smile as a threat, since they might punish the dog for the behavior. This kind of miscommunication can be confusing to a dog and can lead to behavioral issues.
Another type of “smile” that gets misinterpreted sometimes is panting. A dog panting can appear like a dog grinning—the edges of the mouth are turned up, the tongue is out, teeth are partially shown. In many situations, it stands to reason that dogs are happy when they’re panting since the look often accompanies exercise and play, but it can also indicate fear or anxiety (or, of course, simply being overheated). Again, to figure out whether your dog has a relaxed smile or an anxious pant, read the rest of the their language. Is the rest of their body, including ears and eyes, tense? What is their tail doing? Are they whining or making other noises?
The people-pleasing smile: Not just for humans
Dogs respond to their people’s positive reinforcement. So a dog who makes a smile-like expression and gets a positive reaction from their owner is more likely to repeat the expression in hopes of eliciting the same exciting response.
“There’s no scientific term for this [type of expression]. If you look at every textbook I own, there’s no smile, there’s no grin, there’s nothing describing this,” Anderson says. “I’ve seen this happen more than once, where the owner thinks it’s really cute and they inadvertently reinforce it, and so the dog does it all the time.”
See: the dog who can smile on command when their person says, “Say ‘cheese!’” It’s not technically a smile in the way we think of a smile—that is, a way to communicate a feeling of happiness, pleasure, excitement, or friendliness, but it certainly can be cute.
How do I know if my dog is smiling?
Not all dogs exhibit each of these types of “smiles.” When it comes to communicating with any animal, four-legged or two, it pays to pay attention.
“There’s always learning that happens with emotions, just like with people,” Anderson says. “You can describe human emotions from happy to sad. We all kind of have this innate way of telling a happy face from a sad face. But you can have friends that have a face that doesn’t look happy, but you know them well, and that’s their way of being funny or acting with people.”
Anderson believes that dogs have a rich emotional life, but we can’t always interpret it correctly. It’s always a great idea to learn your own dog’s language, to try and see things from their point of view to avoid any miscommunication. That way, when you see your dog’s version of a relaxed, happy “smile,” you can smile right back.
