Humanity is the only species I know of that will purposely hurt themselves. People that do it usually do not have the tools to deal with a problem in their life, and they were left emotionally scarred. It happens to more people then you think, and it is very counter productive. People try to match the emotional pain with physical pain, and it just leaves you still in the shape that you are in, but now the pain is showing physically. If you are cutting yourself, or any other form of self abuse, you need to go talk to a friend, Counselor (They legally cannot share info with other people, or any other trusted adults.