Mandrill males are impressive chaps. The face, which is deeply grooved, is scarlet in the central area and blue on the sides. His hindquarters are hairless and vividly coloured: the area around the anus is scarlet, and the calluses are pink and violet. The genitals themselves are pink and red. Alpha males are bigger and more ornamented then subordinate males, and the females actively solicit matings from these show-offs. Females advertise their sexual receptiveness with a swollen perineum (near the reproductive region). Although mandrills may live in social groups of 200 or more individuals, each dominant male will have his own harem of five to 10 females and their young.