Studying biological ageing in animal models can circumvent some of the confounds exhibited by studies of human ageing. Ageing research in non-human primates has provided invaluable insights into human lifespan and healthspan. Yet data on patterns of ageing from wild primates remain relatively scarce, centred around a few populations of catarrhine species. Here, we introduce the white-faced capuchin, a long-lived platyrrhine primate, as a promising new model system for ageing research. Like humans, capuchins are highly social, omnivorous generalists, whose healthspan and lifespan relative to body size exceed that of other non-human primate model species. We review recent insights from capuchin ageing biology and outline our expanding, integrative research programme that combines metrics of the social and physical environments with physical, physiological and molecular hallmarks of ageing across the natural life courses of multiple longitudinally tracked individuals. By increasing the taxonomic breadth of well-studied primate ageing models, we generate new insights, increase the comparative value of existing datasets to geroscience and work towards the collective goal of developing accurate, non-invasive and reliable biomarkers with high potential for standardization across field sites and species, enhancing the translatability of primate studies.This article is part of the discussion meeting issue `Understanding age and society using natural populations’.

Age-related changes in the capability to produce healthy young are common in humans and are increasingly well documented in nonhuman animals. However, differences among species in the nature of these age-related changes remain poorly understood. We compare patterns and consequences of age-related changes in female reproductive performance in seven primate populations that have been subjects of long-term continuous study for 29 to 57 y. Our analyses of parental age effects on fertility, offspring survival, and offspring development highlight some shared patterns of parental age effects that may be general across the order primates. At the same time, we also identify species-level differences that implicate behavioral and life-history patterns as drivers of the evolution of parental age effects.

Are differences in hypothalamic-pituitary-adrenal (HPA) axis activation across the adult life span linked to differences in survival? This question has been the subject of considerable debate. We analyze the link between survival and fecal glucocorticoid (GC) measures in a wild primate population, leveraging an unusually extensive longitudinal dataset of 14,173 GC measurements from 242 adult female baboons over 1634 female years. We document a powerful link between GCs and survival: Females with relatively high current GCs or high lifelong cumulative GCs face an elevated risk of death. A hypothetical female who maintained GCs in the top 90% for her age across adulthood would be expected to lose 5.4 years of life relative to a female who maintained GCs in the bottom 10% for her age. Hence, differences among individuals in HPA axis activity provide valuable prognostic information about disparities in life span. In wild female baboons, high fecal glucocorticoid concentrations measured repeatedly across adulthood predict shorter life spans. In wild female baboons, high fecal glucocorticoid concentrations measured repeatedly across adulthood predict shorter life spans.