Of course they smile!! Our Matti did everytime the kids came to visit. I didn't believe it at first, but then I started watching, and it was a definite smile.Matti had to be put down this fall, she was 17 , a Cairn terrrier, and the most loving dog I've ever kown. She never met a stranger, thought everyone came to see her, and everyone loved her. We've had many dogs over the years, but never one with the personality Matti had. We sure do miss her!