Longevity and mortality of captive chimpanzees in Japan from 1921 to 2018

Abstract

Utilizing the Great Ape Information Network (GAIN), an open-access nationwide database containing the detailed life history information of all apes who have lived or currently reside in Japan, we present a robust chimpanzee life table by single year of age and sex including 821 individuals spanning nearly a century, current through March 11, 2019. While the demographic composition and status of captive chimpanzees in Japan has been previously reported, longevity and mortality statistics have not. We show that female and male survivorship do not differ significantly, and that a live-born chimpanzee in Japan can expect to live 28.3 years (females 26.3, males 30.3). Life expectancy increases to 34.6 years (females 33.4, males 35.7) for individuals who reach one year of age, and to 40.4 years (females 39.2, males 41.5) for those who survive to adulthood. The oldest chimpanzee in Japan, a wild-born male, lived an estimated 68 years. One in six infants are stillborn, and nearly 80% of all infants born alive survive beyond their first birthday. Finally, we report that a seasonal death pattern exists and chimpanzees in Japan are more likely to decease in the winter months (Dec–Feb) than in any other season.