Although it may attract your attention, I actually know more than one smiling dogIf it sounds weird but it is. In this case I will refer to the dalmatians.
This is one of the races The most beautiful that we can find, they are strong, active, muscular dogs that have the peculiarity of having five more pairs of facial muscles than other breeds. Its character is affectionate and outgoing, but it is a pet that needs a lot of care.
But as I mentioned at the beginning, this is not the only case in which we see the dogs smile. Many experts consider that dogs smile as part of a conditioned reflex or as a submissive behavior. The truth is that apparently dogs do not smile for the same reasons that we do.
In some cases what appears to us to be a smile is a sign of nervousness or submission in the presence of another dog. In these cases what happens is that the corners of the lips are retracted causing the mouth to produce a face that appears to be smiling, this we identify as a smile.
Self-confident alpha dogs rarely smile as they consider themselves our equals and don't need to prove their difference.
The dog that raises its lips to show its fangs is sending a signal for you to stay away from him.
Another case is when a dog smiles without showing its teeth, in these cases it may happen that the owners are moved by this attitude and give it a reward, so the dog will notice that by making this gesture it is rewarded and will do it repeatedly times.
In these cases, it can be considered that your dog's smile can be something genuine, associating the expression with which he is happy.