Research on ageing has entered an exciting phase, with evidence that long-standing theories did not satisfactorily explain ageing patterns found in nature. A major weakness of our current understanding of ageing is the lack of combination of demographic, evolutionary and functional approaches, especially in studies on wild populations. This proposal adopts an integrative multidisciplinary approach to investigate the ageing process in the wild, using data from replicated populations of Nothobranchius furzeri. This African fish from temporary pools has extremely short lifespan and rapid ageing, and has become a model taxon in ageing research. This enables to study a multitude of functional declines associated with the ageing, from histopathology through markers of oxidative stress to gene expression modification. Design of the project is based on our long-term experience with fieldwork in target region and substantial knowledge on the natural history of N. furzeri, and includes direct comparisons with actuarial and functional ageing in captive, wild-derived populations.