Time budgets of Waterbuck (Kobus ellipsiprymnus) of different age, sex and social status

Daytime budgets of waterbuck (Kobus ellipsiprymnus) of different age, sex, and social Status were measured at Lake Nakuru National Park, Kenya. Adult and subadult females spent more time feeding than adult and subadult males. Inside territories, females spent more time feeding than outside of territories. Time spent for agonistic behaviour was highest in young males. Satellite males spent less time for sexual behaviour than territory holders, but more time than bachelor males. Territory holders and satellite males spent the same amounts of time feeding - much more than bachelor males. Because the amount of forage ingested by ruminants is positively correlated with forage quality, this indicates that bachelor males were relegated to nutritionally inferior areas. Time budgets of males and females, site preferences of females, and faecal crude protein content of animals feeding at different sites (Tomlinson 1979) all suggest that territories are high quality feeding areas and that the social System of waterbuck is a resource defence polygyny. Sex differences in time spent feeding at the same site probably reflect a fundamental difference in the behavioural programming of males and females: females of polygynous species are more likely to be "energy maximisers" than males. Recent evidence points to differences in levels of sexual hormones as a proximate cause of sex differences not only of sexual and agonistic behaviour but also of maintenance behaviour.