60 Diet and culture at Sonso
From the above it will be clear that Broussonetiais a new food for the Sonso chim-
panzees. If we didn’t know it was an exotic, and the time and place of its introduction,
we might conclude that it was an established item of diet of chimpanzees, something
they had evolved with and were by now genetically adapted to. The opposite is the case.
We approach the question of whythey like this new food in the next section.
The most frequently eaten fig species is Ficus sur. This is a smallish fig, rarely reaching
the size of a golf ball. It hangs in pedicles from the trunk and branches of the tree.
A fruiting F. surtree is a sight to behold. Pedicles, each holding from 20 to several
hundred figs, stick sideways out of the tree trunk and then droop down under the weight
of the fruit (Fig. 4.2). There are many thousands of figs on a single tree. They start life
green, then turn yellow and finally gain a reddish tinge before they drop. While the figs
(a)(b)Fig. 4.1: (a)Broussonetia papyriferafruit (arrowed) and leaves on stem (photo: V.R.). (b) Chimpanzee
feeding on B. papyriferaflowers (photo: V.R.).