Do Dogs Smile?

Yesterday, after lots of scratches, pets and generally lolling about after the T8 signal was raised, I could have sworn Vicki was smiling at us. The corners of her usually downturned mouth lifted ever so slightly into what Greg and I interpreted as a smile.

When I was a kid we had a black Springer Spaniel mix named Kaiser. The name is unusual, given that Kaiser was female. This dog was also unusual because she smiled when we walked through the door, gave her treats or any other form of positive attention. She showed her teeth, wagged her tail and seemed generally delighted.

Is it possible that a dog can smile at being completely satisfied with life? I think so and once in a while Vicki's face shows it :c).