Abstract: | During 6 years of monitoring breeding groups of lion-tailed macaques, it was discovered that females regularly emitted a non-copulatory vocalization during the follicular portion of the menstrual cycle. In the majority of cases females focused visually on a particular male when calling. Two-thirds of all calls were directed at males living outside the group. The responses of targeted males were consistent with the evidence from its temporal pattern that calling is a behavior used by females to draw attention to their willingness to receive copulations. Given that lion-tails are highly arboreal, it is postulated that in the wild state females use calls to attract the attention of males under conditions of limited visibility. As an unambiguous indicator of receptivity, this vocalization may facilitate the reproductive management of captive populations. |