Mortality rates among wild chimpanzees

In order to compare evolved human and chimpanzees' life histories we presen t a synthetic life table for free-living chimpanzees, derived from data col lected in five study populations (Gombe, Tai, Kibale, Mahale, Bossou). The combined data from all populations represent 3711 chimpanzee years at risk and 278 deaths. Males show higher mortality than females and data suggest s ome inter-site variation in mortality. Despite this variation, however, wil d chimpanzees generally have a life expectancy at birth of less than 15 yea rs and mean adult lifespan (after sexual maturity) is only about 15 years. This is considerably lower survival than that reported for chimpanzees in z oos Or captive breeding colonies, or that measured among modern human hunte r-gatherers. The low mortality rate of human foragers relative to chimpanze es in the early adult years may partially explain why humans have evolved t o senesce later than chimpanzees, and have a longer juvenile period. (C) 20 01 Academic Press.