Do males know? Evidence-driven rainmaking of male bonobos to meet the fertile window of females

Do males know? Evidence-driven rainmaking of male bonobos to meet the fertile window of females. Heungjin Ryu, Chie Hashimoto, David A. Hill, Keiko Mouri, Keiko Shimizu, Takeshi Furuichi. bioRxiv, Mar 14 2022. https://doi.org/10.1101/2022.03.13.483391

Abstract : Female bonobos exhibit prolonged receptivity. One suggested function of the prolonged receptivity is to lower male mating competition. However, it is questionable whether easier access to receptive females can reduce male-male competition, given the exclusive nature of male reproductive success. We tested whether males could determine a fertile phase of females. We found that ovulation probability predicted male mating effort. High-ranking males copulated with the female with higher fertility, and male-male agonistic interactions increased when there were fertile females in the party. When there were multiple females with maximal swelling, males concentrated their mating effort on a female with an older infant whose maximal swelling started earlier, and they continued mating efforts until detumescence (rainmaking). These findings suggest that male bonobos distinguish between fertile and non- fertile phases of females and that having more receptive females in the party does not reduce male-male competition for fertile females. Teaser males use the rainmaker’s rule to meet the periovulatory phase of the female bonobo for better reproductive success.