TERMINATION OF REPRODUCTION IN NONHUMAN AND HUMAN FEMALE PRIMATES

We examined demographic records from 13 captive primate species and a human population to determine age-related changes in female reproduction. In most species age-specific fertility declined and interbirth intervals increased with age. Using an operational definition of termination of reproduction based on individual variance in interbirth intervals, a proportion of females in most nonhuman species had terminated reproduction before death. Compared to other primates, a greater proportion of chimpanzees and human females ceased reproduction, and humans, in particular were reproductively inactive for relatively longer than would be expected from their body weight. These empirical data quantify the extent of reproductive termination and thereby extend hitherto anecdotal accounts of this phenomenon in primates.