In this study troop of chacma baboons (Papio cynocephalus ursinus) at
Mkuzi Game Reserve, Zululand, South-Africa, it is suggested that risk
of predation and competition over safe spatial position had more impor
tance and effect on female behaviour than did competition for food. On
ly 6.4% of all agonistic events were over food patches and no signific
ant correlation was found between a female's dominance rank and propor
tion of time spent feeding, feeding bout length or diet composition. P
arameters of reproductive success, such as inter-birth intervals and i
nfant mortality were not correlated with female dominance rank. Female
mortality, however, was related to dominance rank and all of the five
females who disappeared during the study were low-ranking. Four of th
e five females disappeared after troop fission. There is circumstantia
l evidence supporting the suggestion that predation by leopards is the
main cause of mortality of females at Mkuzi. High levels of female ag
gression were recorded, with almost no occurrences of support coalitio
ns. Most of the aggression took place among similar ranking females, o
r was directed by the top ranking toward the lowest ranking females. M
ost of the female-to-female agonistic encounters were in a social cont
ext, and more than half were over a spatial position next to other adu
lt troop members. Aggression among females increased after troop fissi
on. It is suggested that the higher-ranking females may be better prot
ected from predation, through access to more central spatial positions
in the troop. Indeed, a positive correlation was found between a fema
le's dominance rank and the time spent next to other adult troop membe
rs. It may be that avoiding food competition by keeping larger distanc
es from others, while foraging, was translated in lower ranking female
s to a cost of higher predation risk.