Man buttocks long hair, medical refers to anal hair, belong to the normal physiological phenomenon, is the human body development to a certain stage after the emergence of signs, some pathological reasons such as hirsutism will also cause buttocks long hair. 1. Anal hair is a normal physiological phenomenon, most people will have, and genetic factors have a certain relationship, usually gathered in the family. Anal hair is the human body development to a certain stage after the appearance of signs, often with the level of androgen, when entering puberty, with the rise in androgen levels, there will be an increase in body hair and other physical characteristics. 2. Some pathological causes such as hirsutism will stimulate the body to produce excessive androgens, which will lead to excessive hair on the buttocks, and active treatment of the primary disease will reduce the symptoms of hirsutism. If there are no abnormal symptoms of hairiness, no special treatment is usually needed. If excessive hair affects your normal life, you can go to the hospital for treatment under the guidance of a professional doctor.