Ear shapes vary from breed to breed, but in general, happy dogs wear their ears in a relaxed fashion, says Mullen. One ear may be cocked up, or both may be loose and floppy. If a dog’s ears are pinned back, it could be a sign of fear or aggression, says Dr. Rachel Barrack of New York City’s Animal Acupuncture. Ears pricked forward often indicate that a dog is interested in something that is going on around them.
Happy dogs sometimes appear to smile, says Dr. Georgette Wilson, DVM, the director of scientific and regulatory affairs and resident veterinarian at Hartz. The mouth is open, and while some teeth may be visible, the animal is not baring them or curling back its lips in an aggressive manner, she says. Open mouth panting should not be confused with smiling, as this could be a sign the dog is stressed or overheated, says Barrack.