Dog Pain VS Happiness of a Dog

Pain and happiness of a dog: Animals are able to share with us some expressive aspects of their emotional manifestations. We suppose that when a dog wags his tail that it means he is happy, and if he shows his teeth we believe he is mad. It's that simple, but the truth is that we know very little about an animals true feelings. It is difficult to measure the mechanisms of pain and pleasure in a dog because they do not communicate verbally, but through studies we have been able to see if the sensations they feel are enjoyable or not. Reception of physical touch is one of the ways that lets a dog feel a certain pain. When a dog has a wound or cut he moans and cries because of the effect of the impact that has caused an unexpected pain. It is possible also that the dog won't cry about pain but he will let it be seen in his facial expressions allowing us to see that he is suffering. When a dog is suffering emotionally he shows it as well in his face, and he will sit or stand in positions that are obvious that he is anxious. He may cry or moan as well.  Discovering the value of different motivations helps us to understand the mechanism that determines certain behaviors of the dog. The data that is obtained with the already formed stimulus that are made up of a number of diverse elements that work together, is very important. It is said that every living being acts under the influence of natural stimulus that continually gives into influences that correspond to their own characteristics besides those they receive through the things that condition them. But why should we deny the possibility of the mental process of a dog if we have not yet been able to read their minds?