Reproductive aging patterns in primates reveal that humans are distinct

Women rarely give birth after approximately 45 years of age, and they experience the cessation of reproductive cycles – menopause – at approximately 50 years of age, after a fertility decline lasting almost two decades. Such reproductive senescence in mid-lifespan is an evolutionary puzzle of enduring interest because it should be inherently disadvantageous. Further, comparative data on reproductive senescence from other primates, or indeed other mammals, remains relatively rare. Here we carried out the first detailed comparative study of reproductive senescence in seven species of nonhuman primates in natural populations, using long-term, individual-based data, and compared them to a population of humans experiencing natural fertility and mortality. In four of seven primate species we found that reproductive senescence occurred prior to death only in a small minority of individuals. In three primate species we found evidence of reproductive senescence that accelerated throughout adulth...