Zesta 155a case where the alpha male, Ntologi, of the M community at Mahale, was killed by the
other males of his community in a successful bid to remove him from power. Goodall
(1992) and Nishida et al. (1995) have described severe within-group attacks by males on
other males, the former case being on an alpha male, the latter, as in the present case, on
a young adult male.
This case, which was not lethal, nevertheless has some features in common with the
case of Zesta. The incident, involving the males of Mahale’s M group, was seen in 1991.
The victim was Jilba, a young adult male, who was attacked by five adult males, includ-
ing the alpha and beta males Kalunde and Shike, and by two adult females. Jilba was
attacked after he displayed near a group of males and females eating a recently captured
colobus monkey. The attack was fierce, including much biting, but lasted only one
minute before Jilba escaped. In explanation, Nishida et al. point out that Jilba had never
pant-grunted to the alpha male Kalunde and had a tense relationship with him. They
write:
The proximate cause of the aggression may have been as follows. Frustration regarding Jilba had
accumulated in many adult chimpanzees. On the day of the attack reported here, tensions were
amplified by the excitement of meat-eating. This excitement may have found an outlet in aggres-
sion towards Jilba, which was triggered by Kalunde’s violent chase. It is also possible that lower-
ranked males such as Bembe took advantage of the higher-ranked males’ aggression in order to
raise their own dominance status (Nishida et al. 1995: 210).As we shall see, this last point is relevant in the interpretation of the attack on Zesta.
A lethal intra-community attack was filmed in the Ngogo community at Kibale, in
which a large number of older males of this community severely injured a younger adult
male with much noise and screaming. This attack seems to have features in common
with the attack on Zesta at Budongo.
The start of the attack on Zesta was not seen, although the accompanying loud, high-
pitched screaming was heard by our students and staff at Sonso. They arrived at the
scene when Zesta was already badly injured. What happened is described here in as
much detail as is available, together with the best interpretation possible using our
knowledge of the individuals concerned and the social context both before and at the
time of the event.
Let me say at the outset that it was a complete and utter surprise to us all when it hap-
pened. Up to that time we had seen some cases of aggression between Sonso adult
males, based on competition, mainly over status, sometimes over oestrous females, but
injuries had been light or non-existent. We had seen the takeover of the community by
Duane, usurping the former alpha male Magosi with no more physical damage than a
bite to the finger. Later, when Duane was established, he occasionally safeguarded his
position with threats or even mild attacks. But he was tolerant: Magosi, whom he had
usurped for alpha status, was once again admitted to the caucus of dominant males and
was not ostracized. It seemed as if Duane and the rest of our adult males were well able
to control their aggressive tendencies.