E Other primate species of the Budongo Forest
This book is about the Sonso chimpanzees. It makes no attempt to describe the other primate species
living in the Budongo Forest, even in the range of the Sonso community. We have mentioned other
primate species in their role as prey of the Sonso chimpanzees. We have mentioned baboons as
crop-raiders, but mainly to compare them with chimpanzees and show how, in relation to traps, the fate
of chimpanzees is intimately bound up with that of baboons. In terms of dominance, chimpanzees
appear to be dominant over all the monkey species which generally move away when chimpanzees
appear in a tree where they have been feeding. Between the forest monkeys I do not know what the
dominance order is, but baboons with their larger size and aggressiveness are probably dominant over
the three forest monkey species.
Vervet monkeys (Cercopithecus aethiops) are not included here because they are not forest monkeys,
staying outside the forest all the time. They are fairly common around Budongo Forest and sometimes
raid farmers’ fields and household gardens.
In this appendix I shall do little more than outline the studies of prosimians and monkeys made so far,
almost all under the auspices of the BFP.
Prosimians: pottos and bushbabies
The commonest species of prosimian living in Budongo Forest is the potto (Periodicticus potto). This
species can be seen at night moving slowly in the canopy by shining a torch at it, when its large
eyes reflect the light with an orange glow. Nothing much appears to be known about the behaviour of this
nocturnal species in Budongo, though Ambrose (pers. comm.) observed a potto occupying a tree hole.
Surprisingly, efforts to find other species of prosimians e.g. galagospp. (bushbabies) which are
common in some other Ugandan forests such as Kibale and Kalinzu, have met with little success in the
Sonso area, and it seems that they are not at all common there. In 1970–71, Judy Harris did a survey of
prosimians in Uganda’s forests. In 1970 she observed four individuals in the Busingiro area of Budongo
Forest, and in 1971 she observed three individuals in the same area, each time using a method whereby
a colleague shone a 12 V spotlight out of a vehicle and looked for eye-shine. She concluded that there
were ‘very few [bushbabies] compared to other forests’ (pers. comm.).
In 2001, Lesley Ambrose recorded two unidentified galagos, one was heard along the Royal Mile in
the range of the Sonso chimpanzees and the other was identified by rapidly moving eye-shine on the
logging road that runs north from the Sonso sawmill (pers. comm.).
Monkeys
Four species of monkey live in the Budongo Forest: baboons, blue monkeys, redtail monkeys and black
and white colobus monkeys. All are relatively common; all four species would very likely be seen in a
one- or two-hour walk in the forest. The only comparative study to date of the three forest monkey
species, blues, redtails and colobus, together with chimpanzees, is that of Plumptre (in press), focusing
on dietary preferences and overlap, in logged and unlogged forest. He found that dietary overlap
was significantly higher than expected from random neutral models, indicating that for most com-
parisons, competition for food is unlikely to be important. All the monkey species occurred at higher
densities in logged than in unlogged forest. The two Cercopithecinespecies,C. mitisandC. ascanius,
preferred fleshy, ripe fruits over unripe ones. Interestingly,Colobus guereza, often assumed to be
Other primate species of the Budongo Forest 259