Many different things have the power to make us smile: A funny joke, our sunny day, an unexpected encounter with an old friend. When we smile, we know that it’s because we’re happy. But what about when dogs smile? What’s going on in their heads when their snouts stretch from ear to ear? Hypothetically, we’re thinking it’s some combination of treats, walks, cuddles, and belly rubs. Or maybe some dogs are just naturally happy, perfectly content to break out a smile for no reason at all. There’s no way to know for sure (unfortunately for all of us, dogs can’t talk and tell us what’s really going on) but at least we can enjoy their smiles on camera. See the most adorable doggy-grins in the photo below — oddly enough, the smile in #16 is totally relatable.