Abstract
In species with marked sexual dimorphism and where one sex undergoes stronger intrasexual competition, that sex is expected to age earlier or quicker. Here, we utilise a unique, longitudinal dataset of a semi-captive population of Asian elephants (Elephas maximus), a species with marked male-biased intrasexual competition, with males being larger and living shorter, and test the hypothesis that males show earlier and/or faster body mass ageing than females. We show sex-specific body mass ageing trajectories: adult males gained weight up to the age of 48 years old, followed by a decrease in body mass until natural death. In contrast, adult females gained body mass with age until a body mass decline in the last year of life. Our study shows that sex-specific life-histories shape ageing patterns, consistent with the predictions of the classical theory of ageing.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Main changes concern: - Figures: The main manuscript include only the GLMM trajectories, while GAMM trajectories are presented in Supp (SI7, Fig. S4). X-axis is now in age (years) to facilitate interpretation for the reader, but the original figure with delta age for x-axis is available in supp (SI5, Fig. S2). - Discussion: We more extensively discuss the results found in the light of previous results of actuarial and reproductive ageing found in this population (particularly the idea of mosaic ageing in females).
