4. The Loose, Open “Doggy Smile”
While dogs do not grin in the exact same way humans do, a happy dog often holds their mouth slightly open with a relaxed jaw. Their tongue may loll gently over their lower teeth, and the corners of their mouth curve subtly upward.
Facial muscles remain smooth and relaxed rather than pulled back tight. This open-mouthed expression usually appears when your dog rests comfortably, finishes a fun walk, or receives affection from you.
