One dog listened to the sound of its partner whining, a sign of stress, or an unfamiliar dog whining. (pettao.com)
Additionally, most dogs whine when greeting people because they're excited, and in an extremely aroused state, they may not have control over their behavior. (aspca.org)
Just think of dogs whining at the vet's office, when there are thunder storms or when left along during the day. (pethelpful.com)