Scientists believe that most animals show emotions through facial expressions, just like humans—which means maybe your dog can smile. How did they come to this conclusion? The same way all scientists come to all conclusions: By torturing mice.
Have you ever been convinced that your dog was smiling at you? When you were not on mushrooms? You may have been right! A new study shows that animals use the same muscles to express emotion. Face-type muscles:
"A mouse's pain face is exactly the same as the human pain face, at least with respect to those features that they have in common (tightening of the eyes, bulging of the nose and bulging of the cheeks)," and humans and mice use the same muscles to create those signals, Mogil said. Mice also have two expressions that are "mouse-specific" (movement of the whiskers and ears,) he added.
Because we all have common ancestors, it's likely that all animals share similar "pain faces." And if they share "pain faces," they share "happy faces," too! The thing is, dogs might not be able to be happy. Not because of the economy or anything, just because they are dogs, and they don't feel human emotions.
Scientific Conclusion: Your dog can smile, if your dog knows how to be happy, which he probably doesn't, because he lives with you.