Fig. 4From: Mixed messages: wild female bonobos show high variability in the timing of ovulation in relation to sexual swelling patternsComposite profiles of urinary E1 (open circles) and Pd (closed circles), derived from 26 ovulatory cycles from 9 females. Values are presented as mean ± SD and aligned to the day of ovulation (day 0), one day prior to the significant postovulatory rise in Pd, indicating the onset of the luteal phaseBack to article page