Food preferences 61are still green, chimpanzees find them and cursorily eat a few fruits before passing on.
When they are yellow the feeding begins in earnest. On a tree they like, the figs rarely
get a chance to turn red.
They don’t always like these figs, however. I recall a F. surtree the chimpanzees
passed by regularly. At first the fruits were unripe and green and they ignored it. Later the
fruits turned a brownish colour and fell. I tested a fruit and found it to be dry. This was a
poor fruiting of the tree. Fig trees fruit sporadically, not seasonally, some fruitings being
heavy and luscious, others light and dry.
F. surfruits non-seasonally whereas B. papyriferahas two distinct fruiting seasons
coinciding with the two drier periods of the year (Fawcett 2000). However, chimpanzees
often feed on young leaves of B. papyriferaand these are available all the year round.
F. suris plentiful in the range of the Sonso chimpanzees and in most months there is a
fruiting tree to be found. So both species are reliable sources of food, and can properly
be described as keystone foods for this community.
There is no doubt that the Sonso chimpanzees like eating F. sur, but if a F. mucusotree
is fruiting heavily in their range they forget all about F. surand focus all their attention
onF. mucuso. The figs of F. mucusoare twice the size of F. sur, and can be extremely
juicy and succulent (even if full of sticky latex). Unfortunately for the chimpanzees,
there are far fewer F. mucusotrees than F. sur.
Fig. 4.2: Chimpanzees feeding on F. sur(photo: T. Mnason).