Figure 2.

Age-related patterns of birth rates for female Amboseli baboons and for chimpanzees—filled triangles for baboons, open circles for chimpanzees. Baboon data are as in Figure 1. Chimpanzee data are from Ref. 22; note that data for ages 53–61 years in the chimpanzee plot are from a single female. Data are plotted on a scale of two chimpanzee years to one for baboons.