National Park, Uganda (Clark Arcadi and Wrangham 1999). This attack took place on
14 December 1996 and was seen by the first author and field assistants, who were within
7 m of the events. The mother, MU, was a border-area resident from the northern part of
the range, who, like Mukwano at Sonso, was not totally committed to living in the
community but disappeared from time to time, returning later. Whether she mated with
males from other communities is not known.
On the day in question, MU and her infant MB were attacked by an adult male SY and
an adult female LP carrying a six-week-old infant, both more central members of the
Kanyawara community. The female initially attempted to intevene on the victim’s
behalf, chasing SY away and interposing herself as a kind of ‘peacemaker’ between SY
and MU. However, later LP joined in the attack after receiving aggression from SY.
Subsequently, MU was found without her infant which is presumed to have died as
a result of the attack.
The authors conclude: ‘Our interpretation of this is that LP and her young infant
risked serious attack from SY by not forming a coalition with him.’ In this case, there-
fore, it appears to have been coercion by the male that led LP to attack MU and the
infant MB. In the Gombe case of Passion and Pom the attack by the females was not
coerced. There appear to be many circumstances in which females attack infants; and
for males too there are a number of explanations for infanticide, including the killing of
infant males sired from outside the community, and the killing of infant males sired by
junior males inside the community. At least in the case of males there does seem to be a
regularity: the killing of males, potential rivals in the future. In the case of females (for
whom we have far fewer cases) the motivations seem to include fear of retribution, and
the desire for meat.
The role of females in cases of infanticide 153