We’ve all been there. That moment when you look at your dog and you see their face, their tongue sticking out, looking like they just heard a silly joke. You think, “Awwwww my dog’s smiling!” But are they really smiling the way we humans do? Are their smiles an expression of happiness like ours is?

Dogs tend to have a couple different types of “smiling” faces. According to PetPlace, in wolves (dogs’ ancestors), “smiling” is a sign of nervousness and submission. And this trait has been passed down to dogs.

“Dogs also are hard-wired to interpret the expression this way. To signal that he accepts his subordinate position, a subordinate dog retracts the corner of his lips, which pulls the mouth into that happy face we recognize as a smile,” the PetPlace article further explained.

If you see dogs “smiling” with all their teeth bared, that’s their warning signal that means, “Hey, back off.” However, dogs are known to be very sharp observers and learn patterns. So, when you reward your dog for “smiling” in the form of treats, belly rubs, or even just general excitement and happiness, they learn that every time they perform that submissive expression, they get rewarded for it.

Over time, your dog’s smiles may actually indicate genuine happiness or contentment, as in his mind, he’s created the association between smiling and getting rewarded for it.