Prof. Ben Finkel delivers Anthro Department Talk on “The Challenges of Senescence for Wild Male Chimpanzees”
Longevity is a hallmark of human evolution. Yet little comparative work has investigated aging primates in the wild, and the uniqueness of our aging phenotype remains unclear. In our closest and particularly long-lived relative, chimpanzees, old males reproduce less and have lower dominance rank, but maintain certain aspects of body condition and continue to sire offspring. Identifying how senescence affects their performance will help clarify the role of aging in natural settings. To identify the challenges of senescence, I studied a long-lived cohort of 20 adult male chimpanzees at Ngogo in Kibale National Park, Uganda. I present evidence for foraging senescence; old chimpanzees ate more slowly and chewed less efficaciously. I also demonstrate that life-history tradeoffs may shift across adulthood. While neither energetic status nor testosterone declined with age, old males did move less, rested more frequently, and invested less in reproductive behaviors. These findings suggest that old male chimpanzees may strategically restrict activity in order to maintain reproductive condition, perhaps because they face greater foraging constraints. Such data inform our understanding of the mechanisms that undergird declines in fitness with age and may help illuminate how, like humans and other long-lived animals, chimpanzees adapt to age gracefully.
Ben Finkel is a biological anthropologist and primatologist with a focus on the evolution of senescence and life-history theory. His dissertation investigated the functional challenges of aging for wild chimpanzees at Ngogo in Uganda, where he has conducted field research since 2016. Ben‘s research interests also include foraging behavior, dental wear, food mechanical properties, the social function of testosterone, and conservation psychology with a focus on media portrayal of primates. He is also keenly interested in the analysis and display of quantitative information and works extensively in R.
