74 Diet and culture at Sonso
and sat a couple of metres away feeding on leaves. The monkey vocalized but obviously
could not run away; this appeared to confuse Duane a little. After a while he went
[towards it] again and had a few stabs at it but then backed off and eventually left’
(S. O’Hara, pers. comm.). Possibly Duane considered the adult monkey to be too dan-
gerous even though it was caught in a trap. It is noticeable that most of the monkeys
caught by chimpanzees are juveniles which are less dangerous to catch and easier to kill.
We have seen chimpanzees engaging in stand-offs with black and white colobus
monkeys in which the chimpanzees have come off worst. The two species meet in the
canopy and the monkeys threaten the chimpanzees. On one occasion two adult male
colobus monkeys threatened and charged four adult male chimpanzees in a tree, with the
astonishing result that all four chimpanzees retreated and left the tree. This occurred
the day after a faecal sample we collected in the same place had yielded a number of
bones from a young monkey’s tail. We concluded that the chimpanzees might have eaten
a young colobus monkey and now the furious colobus adult males were retaliating and
keeping the chimpanzees away from their females and young.
The first record of meat-eating at Sonso was made on 13 August 1994.
At 7.30 a.m. field assistant Zephyr Kiwede found a group of males feeding on the bark of Ficus
exasperata, after which they moved towards another party of chimpanzees feeding on Cordia millennii
nearby. On the way, they made a lot of noise. Two adult males, Maani and Vernon, climbed up into a
tree, then a third adult male Duane approached on the ground, beating a tree buttress with his feet as
he arrived. He climbed up into the tree. Zephyr noticed that a blue monkey had been trapped up in the
tree by Maani and Vernon, and now Duane was climbing up towards it. As Duane got close to it, it
jumped into a neighbouring tree. Maani, Vernon and Duane gave chase but lost it. Maani and Vernon
gave up, but Duane continued the chase, moving on the ground. The monkey was moving up in the
trees and Duane climbed up towards it but it moved away and he climbed down again.
Soon afterwards, Zephyr saw a blue monkey — it was an adult male eating a young one (a case
of blue monkey infant killing, see Fairgrieve 1995b). Duane was watching carefully from the
ground. The blue monkey dropped some meat, a hind leg and part of the back and ribs, and then
left. The meat got stuck in some branches. Duane climbed up slowly and got the meat. He climbed
up further to where the blue monkey had been and then started eating the meat. Vernon and Maani
called from nearby and Duane replied. Then Vernon arrived and climbed up to join Duane. He
begged for some meat and was given some by Duane, he swallowed it immediately and begged
again, ate again and begged a third time but this time Duane hurriedly finished the meat and avoided
giving Vernon any more. Maani arrived too late to get any, Vernon and Duane were licking blood
from their hands. Then the three males climbed down, to find three more adult males, Bwoya,
Nkojo and Jambo, under the tree. They had arrived too late and missed the meat.This incident was unusual in that the chimpanzees did not catch the monkey, they ate
the meat of an infant already killed by an adult blue monkey. Whether the male blue
monkey dropped the meat by accident or as a sop to Duane we don’t know.
Just 8 days later we saw meat-eating again, on 21 August 1994. This time the
observers were two visiting students from the UK, Bob Smith and Jo Lee, later joined
by Zephyr Kiwede and Nick Newton-Fisher. They were attracted by the sound of
a chimpanzee screaming intermittently.