Yes, dogs can smile, but their "smile" is different from human smiles. Dogs often pull back their lips and may show their teeth in what is called a "submissive grin," which indicates they are relaxed, happy, or trying to communicate peaceful intentions. They have learned to mimic human smiles partly because they associate them with positive attention and rewards from people. Dogs tend to smile mostly for humans, not necessarily for other dogs, and this behavior helps strengthen their bond with humans. Additionally, some dogs smile as a peace offering or a way of showing submission. However, it is important to differentiate a friendly dog smile from other expressions like panting or aggressive teeth showing. In summary, dogs do smile as a social behavior mainly directed at humans, expressing happiness, submission, or friendliness.