Comparable Overall Copulation Rates Yet Rank‐Biased Access to Likely Fertile Females in Male Bonobos at Wamba

Objectives Female bonobos ( Pan paniscus ) resume sexual swellings in the early postpartum stage and exhibit prolonged sexual receptivity. Despite the simultaneous availability of receptive females, genetic evidence reveals a pronounced male reproductive skew in this species. We investigated how male bonobos allocate mating effort to females in the likely fertile window (LFW) versus non‐conceptive phases based on their dominance rank and dynamic party‐level competitive situations. Materials and Methods We conducted all‐day focal animal sampling on adult and adolescent bonobos in a free‐ranging group at Wamba. Female fertile windows were estimated using the end of the maximal swelling phase. Generalized linear mixed models were used to analyze rank‐related mating patterns. Results Overall copulation rates did not differ across male dominance ranks. However, higher‐ranking males secured a disproportionate share of copulations with LFW females. At the party level, higher‐ranking males preferentially copulated with LFW females when present, whereas lower‐ranking males were more likely to copulate with non‐LFW females as the number of LFW females increased. Discussion Our findings add evidence that the pronounced male reproductive skew in bonobos is driven by rank‐biased access to fertile females rather than total mating frequency. Subordinate males likely redirect mating effort toward receptive but non‐conceptive females rather than directly contesting with dominants over fertile females or forming consortships. This flexible shift in mating targets represents an alternative tactic that allows subordinates to marginally increase their participation in sperm competition despite high monopolization by dominants or to develop affiliative relationships with numerous females for future mating advantages.