TY - JOUR
T1 - Favorable ecological circumstances promote life expectancy in chimpanzees similar to that of human hunter-gatherers
AU - Wood, Brian M.
AU - Watts, David P.
AU - Mitani, John C.
AU - Langergraber, Kevin
N1 - Funding Information:
We thank The Uganda Wildlife Authority and the Uganda National Council for Science and Technology for permission to conduct research in Kibale National Park, and Makerere University for access to Ngogo and permission to use the facilities of the Makerere University Biological Field Station (MUBFS) there. We are grateful to John Kasenene and Gilbert Isibirye-Basuta for their support in our initial years of research and to Tom Struhsaker for establishing the Ngogo research station and for his continued support over the years. We thank the many researchers who have contributed to the Ngogo demography data base, notably Sylvia Amsler, Melanie Beurlein, Sholly Gunter, Bethany Hansen, Brent Pav, Kevin Potts, Racahna Reddy, Aaron Sandel, Lauren Sarringhaus, Hogan Sherrow, Marissa Sobelewski, Jacob Negrey and Monica Wakefield. Collection of those data, as with all of our work at Ngogo, would not have been possible without the invaluable assistance of Adolph Magoba, Godfrey Mbabazi, Lawrence Ngandizi, Alfred Tumusiime, and Ambrose Twineomujuni. We are indebted to Samuel Angedakin for his expert management of the Ngogo Chimpanzee Project and for facilitating our ongoing work, and especially to the late Jeremiah Lwanga for all the help he provided, over many years, as a researcher and Project Manager at Ngogo and as Director of MUBFS. We thank Martin Muller for providing demographic data from Kanyawara, and Anne Pusey for providing Gombe data. Jamie Jones provided valuable discussion of our methods and results. Three anonymous reviewers provided very helpful comments. Our research at Ngogo has been supported by NSF Awards SBR-9253590, BCS-0215622, and IOB-0516644, NIH grant R01AG049395, and by the Detroit Zoological Society, L.S.B. Leakey Foundation, the National Geographic Society, Primate Conservation Inc., the Wenner-Gren Foundation, the Institute of Human Origins, Arizona State University, Boston University, the University of Michigan, Yale University, and the Max Planck Society. We dedicate this paper to the memory of Jeremiah Lwanga.
Publisher Copyright:
© 2017 Elsevier Ltd
PY - 2017/4/1
Y1 - 2017/4/1
N2 - Demographic data on wild chimpanzees are crucial for understanding the evolution of chimpanzee and hominin life histories, but most data come from populations affected by disease outbreaks and anthropogenic disturbance. We present survivorship data from a relatively undisturbed and exceptionally large community of eastern chimpanzees (Pan troglodytes schweinfurthii) at Ngogo, Kibale National Park, Uganda. We monitored births, deaths, immigrations, and emigrations in the community between 1995 and 2016. Using known and estimated ages, we calculated survivorship curves for the whole community, for males and females separately, and for individuals ≤2 years old when identified. We used a novel method to address age estimation error by calculating stochastic survivorship curves. We compared Ngogo life expectancy, survivorship, and mortality rates to those from other chimpanzee communities and human hunter-gatherers. Life expectancy at birth for both sexes combined was 32.8 years, far exceeding estimates of chimpanzee life expectancy in other communities, and falling within the range of human hunter-gatherers (i.e., 27–37 years). Overall, the pattern of survivorship at Ngogo was more similar to that of human hunter-gatherers than to other chimpanzee communities. Maximum lifespan for the Ngogo chimpanzees, however, was similar to that reported at other chimpanzee research sites and was less than that of human-hunter gatherers. The absence of predation by large carnivores may contribute to some of the higher survivorship at Ngogo, but this cannot explain the much higher survivorship at Ngogo than at Kanyawara, another chimpanzee community in the same forest, which also lacks large carnivores. Higher survivorship at Ngogo appears to be an adaptive response to a food supply that is more abundant and varies less than that of Kanyawara. Future analyses of hominin life history evolution should take these results into account.
AB - Demographic data on wild chimpanzees are crucial for understanding the evolution of chimpanzee and hominin life histories, but most data come from populations affected by disease outbreaks and anthropogenic disturbance. We present survivorship data from a relatively undisturbed and exceptionally large community of eastern chimpanzees (Pan troglodytes schweinfurthii) at Ngogo, Kibale National Park, Uganda. We monitored births, deaths, immigrations, and emigrations in the community between 1995 and 2016. Using known and estimated ages, we calculated survivorship curves for the whole community, for males and females separately, and for individuals ≤2 years old when identified. We used a novel method to address age estimation error by calculating stochastic survivorship curves. We compared Ngogo life expectancy, survivorship, and mortality rates to those from other chimpanzee communities and human hunter-gatherers. Life expectancy at birth for both sexes combined was 32.8 years, far exceeding estimates of chimpanzee life expectancy in other communities, and falling within the range of human hunter-gatherers (i.e., 27–37 years). Overall, the pattern of survivorship at Ngogo was more similar to that of human hunter-gatherers than to other chimpanzee communities. Maximum lifespan for the Ngogo chimpanzees, however, was similar to that reported at other chimpanzee research sites and was less than that of human-hunter gatherers. The absence of predation by large carnivores may contribute to some of the higher survivorship at Ngogo, but this cannot explain the much higher survivorship at Ngogo than at Kanyawara, another chimpanzee community in the same forest, which also lacks large carnivores. Higher survivorship at Ngogo appears to be an adaptive response to a food supply that is more abundant and varies less than that of Kanyawara. Future analyses of hominin life history evolution should take these results into account.
KW - Chimpanzees
KW - Demography
KW - Hunter-gatherers
KW - Life-expectancy
KW - Mortality
KW - Ngogo
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U2 - 10.1016/j.jhevol.2017.01.003
DO - 10.1016/j.jhevol.2017.01.003
M3 - Article
C2 - 28366199
AN - SCOPUS:85015375060
SN - 0047-2484
VL - 105
SP - 41
EP - 56
JO - Journal of human evolution
JF - Journal of human evolution
ER -