Why Do Dogs Smile?

Posted by Joey DiFrancesco on September 30, 2022

Few things are cuter than a smiling dog. When your pup is panting, jaw slightly ajar, looking up into your eyes with their baleful expression, and smiling, you’re in heaven!

You might see the smile as validation that your doggo really loves you and has a great time around you. While that sentiment is probably very true, it might not be the case that your dog is “smiling” at you in the way you want them to.

Sure, they're sort of "smiling" how humans smile, but what does the expression mean for dogs? Do dogs smile when they're happy?

Let’s get down to the bottom of it so you can finally know whether or not your dog is truly grinning at you.

A Breakdown of Dog Smiling

There’s no doubt that it looks like our dogs are smiling at us, and it’s also true that their ‘smiles’ make us incredibly happy. When your dog smiles at you, what do you do?

You bend over, pet the living heck out of them, and praise them for being such a good girl or boy. We kind of react the same way when humans smile at us.

What Smiles Mean to Humans

Someone smiles your way, and, depending on the situation, you generally like them more than you would if they shot you a blank expression. It’s instinctual for us to see smiles as friendly expressions, and this probably dates back to our days as less-evolved primates.

For example, when chimpanzees and other monkeys bare their teeth, it’s almost always a sign of friendliness or submission. This is an indication of the individual’s non-threatening intentions, and that acknowledgement makes the recipient feel at ease.

It’s like a gesture saying “i’m not going to attack you, relax!”

That gesture has evolved, and smiling is now an incredibly complex thing. People have unique smiles, and there are shades of different smiles that express nuanced meanings according to the recipient, the situation, the cultural context, and much more.

In all cases, though, smiling involves baring one’s teeth.
(This all ties into the dog’s smile, don’t worry).

Dogs & Humans Over Time

Canines have associated with humans for more than 30,000 years, with the exact date of domestication being up for debate. The Paleolithic dog of the Late Pleistocene existed roughly 30,000 years ago and was closely connected to hunter-gatherer human camps.

Some people think these were the first domesticated dogs. Others think that the Late Pleistocene Wolf was the predecessor of the dog, splitting into two subgenera of domesticated dogs and modern wolves.

These ancient canines would have been social animals, biologically equipped to engage with people on some level. The process of living and working in packs, for example, would have given them the nuts and bolts of social interaction. Still, ancient wolves wouldn’t have been the friendly companions we know today, and odds are that they wouldn’t have smiled back at us (unless they were puppies, which we’ll get to next).

So, how do we get from growling wolves to smiling dogs? A combination of domestication and evolution.

Why Dogs Evolved to Smile Through Domestication

Domestication is the gradual process of breeding animals to fit into the daily lives of humans. In some cases, an animal simply needs to be born and raised in the presence of humans to be truly 'domesticated.'

In most cases, though, a wild animal will not be safe to keep as a pet, no matter how cute it was as a baby. Over thousands of years, though, selective breeding allows us to end up with a population of animals that are fit to live and work as pets.

Just look at the full spectrum of domesticated dogs and compare them to their original ancestor, the wolf. We hand-pick certain traits and pass them down the line through breeding, and we end up with domesticated animals that enrich our lives in countless ways.

Neoteny

There’s something called ‘neoteny’ in domestication. Neoteny occurs when an adult individual retains the characteristics they naturally had during childhood. In nature, these juvenile characteristics fall by the wayside.

Think of the cuteness of babies. The adorable qualities of babies slowly fade as they're better able to care for themselves. Some theories suggest that cuteness is an evolutionary tactic to draw adults toward small, helpless babies in order to care for them.

As the baby becomes more capable, the level of cuteness declines. When those traits remain into adulthood and get passed down, that is called neoteny.

Through the process of domestication (and general evolution in some cases), those traits get selected for and become normal in the future population of the species. Further, the environmental factors that demand certain mature traits are removed when an animal becomes domesticated, so there’s no selective pressure that prevents childlike qualities from going away.

This goes for mental and physical characteristics alike.

Passing Down Puppy Qualities

In the case of dogs, many of the characteristics that wolf puppies have are those that are advantageous for pet dogs to have.

Playfulness, sociability toward non-canines, the appearance of smiling, floppy ears, puffy coats, and even the inclination to alert a master that prey is captured rather than killing the prey themselves; these are some neotenized traits that exist in dogs today.

Different dogs were bred out at different rates, so the level of neoteny is unique in the case of each breed. Some breeds actually hunt to kill or perform duties that their adult wolf ancestors would have been naturally skilled at, so those breeds (like huskies and malamutes) aren’t as neotenized as most other breeds.

On a fundamental level, juvenile animal behavior is much more malleable and submissive than adult animal behavior. It’s advantageous to have a dog that listens to you and doesn’t attack, for example.

It also turns out that many of those juvenile traits are cute or enjoyable to humans.

Intentional and Non-Intentional Evolution

Through the process of domestication, dogs evolved to survive and thrive in different environments. They did well in this respect, too, because they entered our lives and never left.

Research into mirrored genes between dogs and humans suggests that we co-evolved together over the past 30,000 years. Our effect on dogs has altered their genes and vice versa.

Selective breeding occurred and still occurs to produce dogs with specific traits. If a dog is an excellent sheep herder, for example, that dog will be bred and its offspring will likely be capable sheep herders as well.

The dogs without desirable traits might not be allowed to have offspring. This removes undesirable traits from the gene pool in favor of more useful or enjoyable traits.

Girl sitting on a hill with two smiling corgies

In that process, there were likely some things that we didn’t change consciously. For example, we might have been more inclined to keep the dog that looks like it's smiling at us than we would be to keep the dog that doesn’t.

Someone might find a dog smiling to be funny and keep that animal around. They might also feel comfortable with a particular dog's body posture or become happy when they think the dog is happy, seeing as smiling is a sign of happiness in humans.

While there might not have been a utilitarian need for dogs to smile back at us, we might have simply preferred those dogs to the others. It’s very similar to the way we might feel about people who smile at us versus those who don’t.

These subtle canine characteristics are genetic in most cases, so the favorable traits that endear us to dogs would have been passed down and honed over generations.

Don't believe us? Look at your dog in the face and ask yourself how you feel. Does it sort of feel like your pup is genetically modified to be the most lovable version of themselves? That's because they are.

Reinforcement of The Behavior

So, dogs probably retained the ability to smile through the process of neotenization and selective breeding. Still, their smiling doesn’t necessarily mean they’re happy.

But it doesn’t mean they’re unhappy, either. Happiness and smiling in dogs might just sort of be uncorrelated. In other words, the smile probably doesn’t reflect a specific emotion for dogs.

That said, we tend to reward them when they smile. That means they’ll keep doing it because they love the amazing praise they get when they do. In that sense, your dog might happily smile in anticipation of pets or treats. Dogs learn to do things you like mostly because they enjoy the rewards they get when they repeat those behaviors.

Also, there’s a very good chance that you have a few parallel genes tucked away somewhere that compel you to love your dog.

We evolved together, and that kind of long-term relationship only occurs across species when it’s mutually beneficial. That means our love for dogs improved our chances of survival. Their love for us also improved their rate of survival.

That’s some deeply true love for you to think about the next time your pup smiles at you.

So, Is Your Dog Smiling For Real?

The short answer is no. But should you be sad that your dog isn't smiling at you the way you thought they were? No!

Your dog smiles because they know you love it. You love it because you and your ancestors have loved dogs for (possibly) 30,000 years. The simple fact is that their smile makes you happy, and that makes them happy.

What’s the difference between that and a ‘genuine’ smile? In effect, nothing.

Aggressive vs Friendly Gestures

Aggressive dog snarling versus a small happy dog smiling

It might be difficult to distinguish between submissive smiling and an aggressive baring of the teeth.

You know your dog, but it can be tricky to tell the difference in other dogs. In these situations, it’s important to look at the dog’s body language, check the body posture and assess how the dog might be feeling.

In many cases, a dog bares its teeth at you to let you know not to approach. Don’t approach a dog if you’re unsure about the gesture it’s giving you.

If the dog is giving a warning, it’s baring his teeth as if to say “look at these, I will use them if I have to. Stay away.” You may also notice pointed ears and a firm, flexed posture. The dog’s tail might also be pointed and they’ll likely make vocalizations like growling and snarling.

You’ll typically see more than one of the symptoms above in combination if the dog is aggressive.

If the dog is offering up a submissive grin or a little reward-seeking smile, they’ll look relaxed. Again, if you’re ever unsure, it’s best to stay away from the animal in question.