This will help you know more about the unknown yet not uncommon mental disorder.
Species Dysphoria is a disease in which the patient suffers from a severe feeling of discontent and has a notion that his physical body is of an incorrect species. It is like feeling that you are a cat, and lacking the absence of a tail, fur and paws. The person feels like he is a animal captured in a man's body. It is often mistaken as clinical lycanthropy, in which the person believes that he can shapeshift into another creature. The person does not deny that he is in a human form, but feels that he should not have been in a human form. Also see my work on http://princepetropia.blogspot.in/