With an extension of the post-reproductive female life stage, they could enhance their inclusive fitness by giving kin assistance.
[2] He postulates that if women survive beyond an age at which they can reproduce and men continue spermatogenesis, then old males can benefit greatly if they can copulate with younger females.
[3] This serves to produce a more stable male hierarchy, where attainment of high social status and reproductive access is less reliant on physical strength.
Recruitment of help from kin and husbands may compensate by enabling females to reduce birth intervals by weaning offspring at an earlier age.
[14] Females that found their longevity extended, were constrained by the difficulties of increasing their follicular reserves and thus could enhance their inclusive fitness by giving kin assistance.