THE MENSTRUAL-CYCLE OF THE SPIDER MONKEY (ATELES-GEOFFROYI)

The ovarian cycles of four adult female spider monkeys (Ateles geoffro yi) were followed daily throughout 30 days by means of vaginal swabs a nd blood samplings. Cytological analyses of the vaginal swabs and radi oimmunoassay determination of the daily levels of estradiol-17 beta (E -2) and progesterone (P-4) wer done in order to classify the kind of o varian cycle of this species. Our results show that Ateles geoffroyi f emales display menstrual cycles of about 24 days on average. By compar ison with the well-known menstrual cycles of women, apes, and Old Worl d monkeys, the four distinctive cytological phases (bleeding, follicul ar, periovulatory, and luteal) could be recognized; mid-cycle E-2 peak s followed by mid-luteal increases of the same hormone were present in all four females. P-4 levels were higher after the E-2 peak, although both hormones were present throughout the cycles. Also, age-dependent features, hormone profiles, and changes in menstrual phases lengths w ere detected. (C) 1998 Wiley-Liss, Inc.