Look up on any forest trail in Bwindi and sooner or later—usually sooner—you will see them. A flash of black and white high in the canopy, a long tail trailing like a pennant as a colobus monkey leaps between trees with an ease that seems to defy physics. Of all Bwindi’s primate residents, the black-and-white colobus is the most visually arresting—more conspicuous than the gorilla, more dramatic in movement than the smaller monkeys, and more immediately beautiful than almost any mammal the African forest produces. Understanding them deepens the forest experience significantly.
Which colobus species are in Bwindi?
Two colobus species inhabit Bwindi: the black-and-white colobus (Colobus guereza, also called the guereza or Abyssinian colobus) and the red colobus (Piliocolobus tephrosceles, the Ugandan red colobus). The black-and-white is the more commonly encountered—its bold pelage and tendency to feed in exposed canopy positions make it easy to spot even at distance. The Ugandan red colobus, with its rust-red back and grey-black limbs, is less conspicuous but still present throughout the forest. Both species are folivores—leaf-eaters—with digestive systems adapted to process leaves that would be toxic to most other primates. This dietary specialisation means colobus monkeys are found wherever Bwindi has mature forest with an accessible canopy, regardless of season, making them almost guaranteed sightings on any forest walk.
The remarkable digestive system
Colobus monkeys are named from the Greek kolobos, meaning “mutilated”—a reference to their reduced thumbs, which are vestigial in most colobus species. The thumb reduction is an adaptation for arm-swinging locomotion in the canopy; colobus monkeys brachiate (swing by their arms) more than most African primates, and reduced thumbs reduce snagging risk. More remarkable than their thumbs is their stomach: colobus monkeys have a multi-chambered, ruminant-like digestive system that contains symbiotic bacteria capable of fermenting the cellulose in mature leaves and neutralising the secondary plant compounds (tannins, alkaloids) that make those leaves indigestible or toxic to other animals. This fermentation system is physiologically expensive—it requires a large, heavy gut and relatively slow movement—but it gives colobus monkeys access to a food source that is available year-round and largely unexploited by the forest’s other primates.
Social structure and group dynamics
Black-and-white colobus monkeys live in small groups of five to fifteen individuals—one or two adult males, several adult females, and their offspring. Group cohesion is maintained through vocal communication: the dawn roaring of adult males is one of the characteristic sounds of Bwindi mornings, a deep, resonant call that carries across the forest and announces territorial presence to neighbouring groups. Within the group, females form the stable social core; males may move between groups over their lifetimes. Alloparenting—care of infants by females other than the mother—is common and pronounced: newborn colobus infants are born white (the adult pelage develops over weeks) and are passed between adult females as a form of social bonding. Watching a colobus infant move between “aunts” in the group, white against the dark canopy, is one of the more quietly affecting sights the forest offers.
Colobus as prey: the forest’s predation dynamics
Colobus monkeys are hunted by crowned hawk-eagles—the most powerful avian predator in Africa’s forests, capable of taking prey up to four times its own body weight. The crowned hawk-eagle (Stephanoaetus coronatus) is present in Bwindi and is an infrequent but documented predator of colobus. Chimpanzees also hunt colobus monkeys, particularly the red colobus, in organised group hunts that are among the most dramatic and disturbing behaviours documented in non-human primates. In Kibale Forest, chimpanzee hunts of red colobus have been studied intensively by researchers including John Mitani and David Watts; similar behaviour almost certainly occurs in Bwindi but is less well documented. The presence of predation pressure shapes colobus group behaviour—vigilance, alarm call systems, flight responses—in ways that are visible to an attentive forest observer even without witnessing an actual predation event.
How to find and photograph colobus
The best strategy for colobus photography in Bwindi is to slow down and look up. Colobus groups typically spend long periods resting in the upper canopy, particularly in the morning after a feeding bout. They are not secretive—their bold colouring and large size (adult males weigh 10–15 kilograms) mean they do not rely on concealment. Listen for the crash of a group moving through the canopy—a sound quite different from bird movement or wind. Look for the white cape and tail contrast against dark foliage, particularly in trees with an open canopy structure that allows light to illuminate their pelage. Once spotted, move slowly and quietly to a position where you can see clearly without disturbing the group. Colobus are generally tolerant of quiet human observers; abrupt movements or noise will cause them to move quickly into denser cover. A 100–400mm zoom is ideal for the distances typically involved.
Ecological role: colobus as forest recyclers
Colobus monkeys play a quiet but important ecological role in Bwindi’s forest through their digestive processing of leaves. A group of fifteen colobus consumes and processes enormous quantities of leaf material daily. Their dung, rich in partially digested leaf matter and gut bacteria, contributes to nutrient cycling in the forest soil. Their selective feeding—preferring young leaves of specific tree species—influences the growth patterns of those species in subtle ways. And their role as prey species—for both raptors and chimpanzees—connects them to the forest’s predation hierarchy. They are not keystone species in the dramatic sense that gorillas or figs are, but they are part of the complex web of interactions that make the forest function, and their absence would register in ways that current ecological modelling can measure but cannot fully predict.
A morning with the colobus
If your gorilla trek returns early, or if you have a free morning at the lodge, spend an hour simply sitting in the forest or at the forest edge and watching a colobus group. Begin before the gorilla trek pre-dawn if the lodge grounds abut the forest. The dawn calling of the males—that resonant, rolling roar—begins before the light is sufficient to see anything, and the silence after it is a different kind of silence from the pre-call quiet. As the light builds, movement begins in the canopy: the group wakes, shakes off the night’s dew, begins to move toward the first feeding trees of the day. Watch the juveniles chase each other through the branches while adults watch with the alert patience of parents who have seen this before. You have come to Bwindi for the gorillas. But the forest will give you colobus every morning without appointment or permit. Let it.
