At the time of these studies, DN was the alpha male but there was rivalry for the beta
position, held by VN. The gamma male, BK, had been challenging him for some months
(Arnold 2001). BK was an aggressive male, not involved in any alliances and he com-
peted with VN by threats and displacements. But he could not succeed because VN had
DN, the alpha male, as a very strong alliance partner (they had been alliance partners
since before DN took over from MG). DN did not tolerate challenges to VN from BK,
and BK had to back down each time because of the intervention of DN on VN’s side. In
the earlier part of 1999, BK started to settle down and ceased to actively challenge VN
(Arnold 2001). Then VN disappeared. He was last seen by our field assistants on 29 June
1999, after which he was never seen again.^56 This precipitated BK into the beta position
and the top four males in mid-1999 were: DN →BK→MA→JM. After them came four
other adult males who were less power-minded, and finally two adolescent males, AY and
ZF, who were becoming self-assertive but not yet serious contenders for male rank.
Dempsey focused on the beta male, BK, to see if he might try to usurp DN now that DN’s
alliance partner had disappeared. What happened was different. MA, the no. 3 male, asso-
ciated closely with DN, and proceeded to dominate BK. This seems to indicate a firmer
grasp of chimpanzee politics by MA than BK. Whereas BK was a rather aggressive male,
not good at forming alliances but inclined to go it alone, MA was more ‘laid back’, and in
fact over the 12 years we have known him he has always been a calm individual. At this
time, however, he did threaten BK, always supported by the smaller male ZF. For example:
On Sept 3 1999 at 12.30 p.m. MA and ZF arrived in an area containing BK, AY, KL and BB. On
arriving MA displayed and was joined by ZF. He displayed again at 12.33 directly below BK. At
12.35 MA shook branches and displayed again, forcing BK to climb higher up the tree. At 12.40
BK presented his backside to MA in a gesture of subordination. They then groomed one another,
alternately and mutually, for another 35 minutes (Dempsey 2000: 28).Over the course of September MA gained dominance over BK until there was no
doubt at all of his position as no. 2, with BK as no. 3. Indeed, in due course of time, MA
replaced VN as DN’s alliance partner.
Regarding ZF’s close partnership with MA, was this a case of MA ‘using’ ZF to
bolster his displays against BK? The evidence from the grooming relationship between
the two indicates that this was not the case: ZF groomed MA but MA was not observed
to groom ZF. From this it appears that ZF was the active partner in this alliance, and was
ingratiating himself with MA (‘sycophancy’ is the word used by Dempsey) while MA
was making no great effort to reciprocate or keep ZF on board. Instead, MA was groom-
ing his rival BK as well as dominating him — perhaps because, astute male that he
was, he understood that BK was aggressive and feared that without grooming he might
How to defeat an aggressive challenger 129(^56) We don’t know the reason for his disappearance. He may have been killed while crop-raiding, or perhaps
he died in a snare or trap, but his body was never found. At this time the Sonso community was receiving
incursions into its territory from the Waibira community to the north, and it is also possible that VN was killed
by the males of the Waibira community (of whom the Sonso community males seemed to be very afraid) but
evidence for this is lacking.