Of course, a dog immediately recognizes its owner by their scent. Not only that: it also knows how they are feeling. Joy, fear, and stress emit certain scent signals that the dog perceives. An anxious postal worker can indeed provoke different reactions. Some dogs just bark at them because the stranger, who seems inferior due to their fear, needs to kindly exit their territory. More aggressive counterparts feel provoked by the foreign smell, and thus bite. Confident dogs, on the other hand, often react quite calmly.