Importance of older males: influence of age structure on social dynamics between males in an elephant bull area.

This thesis explores male sociality in African savannah elephants (Loxodonta africana), focusing on the influence of age structure on social dynamics between males in a male dominated area. There is much to learn regarding the nature of relationships in non-reproductive all-male groupings and the benefits afforded to males in associating with each other. Moreover, in long-lived species, all-male groupings provide an opportunity for individuals of vastly different age and experience to interact, and there may be different benefits afforded to males of different age in associating with one another. I conducted focal animal sampling of male elephants aggregating at hotspots of social activity, and a camera trap survey of elephant movements and behaviours on elephant pathways in Makgadikgadi Pans National Park, Botswana. I found differences in grouping and performance of several behaviours with male age. Adolescents were more likely to travel in all-male groups, and mature bulls were more likely to travel alone, suggesting association with other males is more beneficial for younger males. Adolescents performed greeting behaviours at greater rates than adults, and such behaviours may facilitate further beneficial interactions between males. Adolescents also directed more aggressive and fear-related behaviours to non-elephant targets when alone, compared to when with other males. Adolescents may therefore perceive themselves to be at greater risk when socially isolated, and grouping with other males may reduce predation risks, and improve adolescents’ ability to safely navigate unknown, risky environments. Males’ olfactory responses to pathways and experimentally placed urine deposits, however, did not vary with age, suggesting remote monitoring of same-sex conspecifics is equally important across the life course. Urine from adult males was more likely to evoke heightened responses than urine of adolescent males, suggesting males may be able to discern the age of same-sex conspecifics from their remote deposits. Such remote assessment of potential affiliates, threats or competitors sharing the environment is likely beneficial for males living in highly fission-fusion societies. I also found evidence for important social roles of older males in all-male groupings. Older males were more likely to lead their group movements, suggesting they may guide younger, less experienced males in locating critical resources. Male elephants were less likely to direct aggression to non-elephant targets when more males from the oldest age cohort were present. Older males may be particularly effective assessors of environmental risk, and elephants may perform less aggressive behaviours to non-elephant targets when more older males are present due to reductions in anxiety. Alternatively, older males may police other males’ aggression behaviours. The African elephant is of conservation concern and a species involved in several unresolved human-wildlife conflicts. Throughout this thesis I therefore also relate findings to potential management and conservation implications