Abstract:
Understanding individual behavioural differences, or ‘personalities’, within animal populations has been acknowledged to play an important ecological and evolutionary role with implications for aspects such as population persistence, demography, adaptive potential, community dynamics and disease dynamics. Little work has contributed to understanding the drivers of personality in a social ungulate. I used a social bovid, the African buffalo (Syncerus caffer), as a model species to assess personality and its role in health in a wild population of this social species. My objective in this thesis is three-fold; (1) to identify consistent versus plastic behaviours and examine the drivers of average personality and the changes in personality over time, (2) investigate the role that consistent personalities play in infection and overall health in buffalo and (3) determine the effects of maternal personality on calf behaviour, survival, growth and health.
I quantified five behavioural traits in a herd of ~65 buffalo in the Kruger National Park, South Africa, through repeated observations of the same individuals during seven 3-day periods over the course of two years: social rank, boldness, curiosity, tenacity, and leadership. Rank and curiosity were highly consistent over time and boldness and leadership, although measured via distinct experiments, captured the same behavioural variation. I show that rank and curiosity impact infection status and health status (as defined by principal component axes), in that highly ranked animals have fewer infections and are healthier but more curious individuals have more infections. I also present evidence that the health, in terms of condition, of calves of higher-ranking mothers may benefit due to their mother’s preferential access to food resources granted because of their position in the social hierarchy. Calves of more curious mothers, although more likely to be exposed to tick borne parasites while following their mother’s exploratory forays, may benefit going forward as increased exposure at a young age may result in increased immunity in adulthood.
Overall, this body of work reveals the importance of understanding individual personality differences and shows that these differences are measurable but challenging to assess in a large, wild ungulate. Additionally, this work elucidates the role of unique personalities on infection status and health in individuals, but also maternal effects of personality on calves, thereby highlighting the importance of including behavioural assessment in future disease research.
