All positions of a dog’s ears should be gauged relative to the way the dog normally carries his ears when he is relaxed. Dogs with severely cropped or very long ears will be harder to read.
Ears erect or slightly forward: “What is that?” This is a sign of attention in response to a sound or when studying a new situation. Accompanied by a slightly tilted head and a relaxed or slightly open mouth, the meaning changes to “This is really interesting” or “I do not understand that” and is associated with observation of an event. However, when accompanied with bared teeth and wrinkled nose, it is an offensive threat by a confident dog.
Ears pulled back flat against the head: “I am scared” or “I am protecting myself against a possible attack.” This is usually associated with a challenge of some sort.
Ears pulled slightly back: On a prick-eared dog such as a German Shepherd, the ears take on a slightly splayed, sideways spread in this position. It means “I do not like this” and “I am ready to fight or run.” This is the look of suspicion and may show both aggression and ambivalence.