EXTENDED POSTPREGNANCY ESTROUS CYCLES IN FEMALE LION-TAILED MACAQUES

Past studies of female primate reproduction have focused on regularly cycling females, and thus the reproductive characteristics of females in other reproductive states (e.g., pregnant or lactating) have rarely been investigated. In this study, data were collected on estrous swel lings and sexual and preceptive behavior in six female lion-tailed mac aques during recovery from lactational amenorrhea for the first three to five postpregnancy cycles. For these females, the length of the fir st lactational recovery swelling cycle averaged 81 days, nearly three times the length of cycles exhibited by nonparturient, isosexually hou sed females. Actual swelling durations were also nearly three times th e length of those seen in nonlactating females, and occupied a larger proportion of the cycle. For most females, cycle duration and sexual a nd preceptive behavior declined progressively over successive cycles. The alpha female in each group accounted for the majority of copulatio ns in the first three cycles, and this effect was pronounced in the fi rst cycle. Extended postpregnancy cycles in this species may be relate d to female reproductive competition and/or a tactic to attract extra- group males. (C) 1993 Wiley-Liss, Inc.