Hair on the buttocks is a normal physiological phenomenon, is the human body development to a certain stage after the appearance of signs, some pathological reasons such as hirsutism can also cause hair on the buttocks. 1. Hair on the buttocks is a common physiological phenomenon, belonging to a kind of anal hair. Most people will have, and genetic factors have a certain relationship, such as the Mediterranean population in the phenomenon of long hair on the buttocks is more common. In addition, buttock hair tends to androgen levels, when entering puberty, with the rise in hormone 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 original disease will reduce the symptoms of excessive hair. If hair on the buttocks brings great mental stress, you can go to the hospital for treatment under the guidance of professional doctors.