Lifespan, longevity, and ageing
Maximum longevity: 59.4 years (captivity) Observations: Physiological observations indicate that chimpanzees develop age-related changes typical of humans at considerably earlier ages, and geriatric chimpanzees were originally defined as animals with 34 years of age and older (http://www.chimpanzoo.org/). Even in captivity, young adult chimpanzees have considerably higher mortality rates than humans (Hill et al. 2001). Therefore, while it is not known whether the pace of ageing is different between chimpanzees and humans, the onset of ageing appears to occur at earlier ages in chimpanzees. The MRDT and IMR were estimated based on mortality rates obtained from field sites (de Magalhaes 2006).+p Determining the maximum longevity of chimpanzees is problematic due to the many anecdotal reports. "Cheeta", a male chimpanzee who participated in some Tarzan movies, has been reported to be 75 years of age and still alive, though these claims have not been verified and might well be overestimated (http://cheetathechimp.org/). One wild-born female called "Little Mama" was estimated to be over 70 years of age at Lion Country Safari in Florida (http://www.lioncountrysafari.com/). Another specimen, called "Gregoire", reportedly died at the age of 66 in Congo after living most of his life in Brazzaville Zoo. In spite of these claims, chimpanzees in captivity have not been confirmed to live for more than 60 years (Richard Weigl 2005). Therefore, although the issue is controversial, the established maximum longevity of chimpanzees remains the 59.4 years that a female called "Gamma" was when she died in 1992 at Yerkes Regional Primate Research Center in Atlanta (Hakeem et al. 1996). Similarly, the maximum longevity in the wild belongs to one 55 year-old female, though there are unverified reports suggesting a longer lifespan (Hill et al. 2001).