Chimpanzees of Budongo Forest
Somewhere in the mahogany canopy of Budongo Forest, a chorus of pant-hoots rises and rolls out across the trees — a wild, escalating call that ends in screams and the deep thud of a chimpanzee drumming its feet against a buttress root. That sound belongs to one of our closest living relatives, and Budongo, on the southern edge of the Murchison Falls Conservation Area, holds one of the largest and most closely studied populations of them anywhere in Uganda.
This guide is a profile of the animals themselves — who Budongo’s chimpanzees are, how they are organised, what they eat, the tools and traditions they pass between one another, and the threats that shadow their forest. It is about the chimps first, and the trekking second.
Uganda’s Eastern Chimpanzee
The chimpanzees of Budongo are eastern chimpanzees, Pan troglodytes schweinfurthii, the subspecies found across Uganda and into the forests of the wider Albertine Rift. Uganda holds an estimated 5,000 of them, mostly in protected forests west of the Nile, and Budongo is one of the great strongholds.
Estimates put Budongo’s population at up to 800 individuals across the reserve’s 435 or so square kilometres, a number that researchers describe as unusually stable since long-term monitoring began in 1990. That stability, in a species listed as endangered on the IUCN Red List, is precisely what makes this forest so important. Budongo is not just a place to see chimpanzees — it is one of the places helping to keep them.
Adults are powerfully built, with black hair that greys with age, expressive faces, and a strength several times that of a person. They can live into their forties and fifties in the wild, forming lifelong relationships and, as decades of records show, remembering both allies and rivals across the years.
The Sonso and Waibira Communities
Much of what the world knows about these apes comes from two neighbouring communities followed daily by the Budongo Conservation Field Station. The Sonso community, a forest-edge group of around 70 individuals, has been studied since the early 1990s and is among the best-documented wild chimpanzee groups on Earth.
Its neighbour, the Waibira community, is larger — roughly 120 individuals — and hemmed in by other groups deeper in the forest. Habituation there only began in 2011, and the two communities differ in telling ways: Sonso has the more typical female-biased sex ratio, while Waibira carries an almost equal number of adult males and females, which sharpens the competition between its males.
Following them for decades has given researchers something rare in the wild — named individuals, known family trees, and life histories spanning generations. Every chimp in Sonso has a name and a story, from alpha males to the infants clinging to their mothers.
A Fission-Fusion Society
Chimpanzees do not move as one herd. They live in what biologists call a fission-fusion society: a community shares a home range and knows one another, but through the day it splits into small, shifting parties that forage, rest and travel apart, then merge again. One morning you might be beside your closest ally; by afternoon you are sharing a fig tree with a former rival.
Males stay in the community they are born into and form the political core, while females typically transfer between communities as they mature. Status among the males is real and contested. Studies of Sonso have shown a clear hierarchy, with the top rank at one point held by an alliance of two males who together displaced the previous alpha — coalitions, not brute size alone, decide who leads.
Holding it all together is a sophisticated vocal and gestural repertoire. The far-carrying pant-hoot lets scattered parties locate one another and coordinate reunions; subordinate chimps give soft “pant-grunts” of respect to those above them; and drumming on the great plank-like buttress roots sends a signal booming through the forest. Add hand gestures, facial expressions and grooming, and the result is a society run on relationships.
What Budongo’s Chimps Eat
Chimpanzees are ripe-fruit specialists, and figs are the foundation of life in Budongo — a good fruiting fig tree can draw a noisy crowd for days. But Budongo’s chimps are notably more leaf-eating than many populations studied elsewhere, leaning heavily on young leaves, especially those of Celtis mildbraedii, and turning to the seeds of the ironwood Cynometra alexandrii when the dry season thins the fruit.
They are omnivores, too. Both communities hunt, though in strikingly different ways. Sonso chimpanzees have a strong appetite for black-and-white colobus monkeys, which make up around three-quarters of their kills, and they hunt roughly once or twice a month. Waibira spreads its hunting across a wider menu, including duikers — small forest antelope that Sonso has never been recorded eating. These are learned, community-specific tastes, passed down rather than fixed by biology.
Tools, Culture and a Forest Pharmacy
Budongo’s chimpanzees are toolmakers with local traditions. Nearly all of them make leaf-sponges — chewing a wad of leaves into an absorbent ball to soak up drinking water from tree hollows. In 2011, researchers watched a new variant, moss-sponging, appear at a mineral-rich clay pit and spread through the community along lines of family and friendship, one chimp learning it from another. It is one of the clearest cases anywhere of a fresh cultural behaviour caught in the act of spreading.
Culture shows in smaller signals, too. The way individuals modify leaves in gestures — the flourish of “leaf-clipping” used in courtship, play and travel — differs between Sonso and Waibira like regional dialects. And Budongo has produced remarkable evidence of self-medication: chimps have been filmed applying chewed leaves to their own wounds, tending the injuries of others, and even carefully working to free companions from snares. Several of the plants they choose have known antibacterial and anti-inflammatory properties.
Threats and Conservation
The gravest daily danger is not disease or predators but wire. Snares, set for duiker and bushpig rather than for chimps, do not discriminate, and roughly a third of Budongo’s chimpanzees carry a snare injury — a missing finger, a crippled hand, a lost foot. Juveniles are especially vulnerable. The Budongo Conservation Field Station runs a snare-removal team that patrols the forest daily and lifts thousands of traps each year, many set by people the project has since employed as forest monitors.
Beyond snares, habitat loss squeezes the forest from its edges. As farmland presses in, chimps sometimes raid crops and human-wildlife conflict follows, while respiratory diseases passed from people remain a constant risk — one reason trekkers must keep their distance and never visit if unwell. Protecting the corridor between Budongo and neighbouring Bugoma Forest matters for keeping these populations genetically connected.
Frequently Asked Questions
- How many chimpanzees live in Budongo Forest?
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Estimates run up to around 800 individuals across the reserve, making it one of Uganda’s largest and most stable chimpanzee populations. Two communities, Sonso and Waibira, are habituated and studied in detail.
- What subspecies are Budongo’s chimpanzees?
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They are eastern chimpanzees, Pan troglodytes schweinfurthii, the subspecies found throughout Uganda and the Albertine Rift. The species is classed as endangered on the IUCN Red List.
- Do Budongo chimpanzees really hunt other animals?
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Yes. The Sonso community hunts black-and-white colobus monkeys around once or twice a month, while Waibira takes a broader range of prey including duikers. Hunting and meat-sharing are learned, community-specific behaviours.
- What is the biggest threat to them?
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Indiscriminate wire snares set for other animals are the greatest daily danger, and about a third of the population carries a snare injury. Habitat loss, crop conflict and human-borne disease add further pressure.
- Can I see these chimpanzees?
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Yes. Habituated chimpanzees can be tracked on guided treks from the Kaniyo Pabidi site within the Murchison Falls Conservation Area, giving visitors a genuine encounter with wild, well-studied apes.
Plan Your Safari
Meeting Budongo’s chimpanzees pairs naturally with the wider wonders of Murchison Falls, from Nile boat cruises to open-savannah game drives. Read our guides to chimpanzee trekking in Budongo, the best places to see primates in Budongo Forest and the black-and-white colobus the chimps hunt, then get in touch to build a tailored safari that puts this remarkable forest at its heart.