Editor's note: This story contains graphic descriptions of violence that may be upsetting to some readers.



This story appears in the August 2020 issue of National Geographic magazine.

Life was already hard enough for Ntegeka Semata and her family, scratching out a subsistence on their little patch of garden land along a ridgeline in western Uganda. They could barely grow food for themselves, and now a group of desperate, bold, crop-raiding chimpanzees threatened their livelihood, maybe even their safety.

The chimps had been coming closer for a year or two, prowling all throughout Kyamajaka village, searching for food, ripping bananas from the trees, grabbing mangoes and papayas and whatever else tempted them. They had helped themselves to jackfruit from a tree near the Semata house. But on July 20, 2014, scary tribulations gave way to horror—a form of horror that has struck other Ugandan families as well. That was the day when a single big chimp, probably an adult male, snatched the Semata family’s toddler son, Mujuni, and killed him.

“A chimpanzee came in the garden as I was digging,” Ntegeka Semata recalled during an interview in early 2017. Her four young children were with her that day, as she combined mothering with hard fieldwork, but she turned her back to get them some drinking water. The chimp saw his chance, grabbed her two-year-old son by the hand, and ran.

View Images In July 2014, a large chimp snatched and killed a toddler named Mujuni Semata outside the family home in Kyamajaka village. Over time, the chimps returned to loom menacingly around the house, posing a threat to the other children. After the family fled to another village, the chimps continued harrying Kyamajaka—even glowering at their own reflections in the windows of the vacant Semata house.

The boy’s screaming brought other villagers, who helped the mother give chase. But the chimp was rough and strong, and the fatal damage occurred fast. “It broke off the arm, hurt him on the head, and opened the stomach and removed the kidneys,” Semata said. Then, stashing the child’s battered body under some grass, the chimp fled. Mujuni was rushed to a health center in a nearby town, Muhororo, but that little clinic couldn’t treat an eviscerated child, and he died en route to a regional hospital.

Things are still uneasy in Kyamajaka these days, for at least some people and some chimpanzees. Attacks by chimps on human infants have continued, totaling at least three fatalities and half a dozen injuries or narrow escapes in greater Muhororo since 2014. The main driver of the conflicts, it seems, is habitat loss for chimps throughout areas of western Uganda, forested lands outside of national parks and reserves, which have been converted to agriculture as the population has grown. The native forest that once covered these hillsides is now largely gone, much of it cut during recent decades for timber and firewood, and cleared to plant crops.

View Images Before surrendering their house, the Sematas built a simple bamboo fence for protection around their backyard kitchen. But the chimps still came near, taking papaya and jackfruit from trees close to the house, frighteningly present. So the family left.

Primate collision Having lost much of their forest habitat, chimps resort to raiding crops, sparking conflict. During the past two decades, chimp attacks on villagers’ children, killing or injuring them, have terrified communities. AFRICA AREA ENLARGED Chimpanzee range (Pan troglodytes) Built-up area Forested area Road National park (fully protected forest habitat) Central forest reserve (forest habitat with public access) Wildlife sanctuary Over the past 20 years, more than 20 attacks by chimps on humans were reported in the Western Region of Uganda. N 20 mi 20 km Murchison Falls National Park Budongo forest reserve Masindi Kasongoire DEM. REP. OF THE CONGO Hoima UGANDA Bugoma forest reserve Three children killed since 2014 Kibale Three children killed since 2014 Kagadi Fort Portal Semuliki N.P. Kibale National Park Rwenzori Mountains N.P. Kasese MATTHEW W. Chwastyk, NGM STAFF; scott elder SOURCES: RONAN DONOVAN; WDPA; Population density, FACEBOOK; ROADS © OPEnstreetmap Contributors, available under open database license Soroti Primate collision Murchison Falls National Park Having lost much of their forest habitat, chimps resort to raiding crops, sparking conflict. During the past two decades, chimp attacks on villagers’ children, killing or injuring them, have terrified communities. Masindi Port Budongo forest reserve Masindi DEM. REP. OF THE CONGO Nakasongola Kasongoire Kamuli Hoima AFRICA Chimpanzee range (Pan troglodytes) Kayunga Over the past 20 years, more than 20 attacks by chimps on humans were reported in the Western Region of Uganda. Bugoma forest reserve AREA ENLARGED Jinja Bombo Three children killed in the Muhororo area since 2014 Kampala Kagadi Kibale Mityana Muhororo Mubende Entebbe Semuliki N.P. Fort Portal Lake Victoria Built-up area Forested area Road National park (fully protected forest habitat) Forest reserve (forest habitat with public access) Wildlife sanctuary Kibale National Park N Masaka Rwenzori Mountains N.P. Kasese 20 mi 20 km MATTHEW W. Chwastyk, NGM STAFF; scott elder SOURCES: RONAN DONOVAN; WDPA; Population density, FACEBOOK; ROADS © OPEnstreetmap Contributors, available under open database license

Such demographic and landscape changes are happening fast throughout Kagadi District (which includes Kyamajaka), just east of Lake Albert and the Rwenzori Mountains, and in neighboring districts as well. The soil is volcanic and rich, well watered by seasonal rains, and suitable to support a burgeoning number of farming families that eke out a living on small private plots from staple crops such as corn and cassava, supplemented by domesticated fruits and a little income from cash crops: tobacco, coffee, sugarcane, and rice.

The Uganda Wildlife Authority (UWA) is acutely aware of the chimp problem, and though chimps outside protected areas (as well as within national parks and reserves) fall under the authority’s responsibility, private forests do not. “Unfortunately, it is hard for us—impossible for us—to prevent clearing of these areas,” UWA Executive Director Sam Mwandha said recently. “We can only plead; we can only educate and hope that people will appreciate them.”

View Images Ntegeka Semata comforts her two younger children, both born since their brother was killed. They left Kyamajaka for an inadequate new home: a rented room, safe from chimps but with no land to farm. More recently, they’ve acquired a farmable plot and started over.

But appreciating a forest for its long-term benefits, such as mitigating erosion and buffering temperature, can be difficult in the face of short-term pressures to grow crops for food. And with chimps in a forest patch, one moment of diverted attention by a mother as she gardens can result in a child being snatched. So the immediate need, Mwandha said, is to “create awareness” among people in such areas that their caution must be high, their vigilance continuous. That’s easier said than done, but the UWA recently assigned four permanent staff to this awareness campaign in western Uganda.

The chimps of Kyamajaka—maybe just a dozen or so in the village environs—nest nightly in the remnant woods at the bottom of a glen, where a small stream runs, or in the eucalyptus plantation nearby. By day, they emerge because their wild foods have largely disappeared, and they feed from the crop fields and fruit trees surrounding village homes. (Imagine, in your own life, stepping out to weed the tomatoes and encountering a hungry cougar.) They move stealthily throughout the village, mostly on the ground because there’s no forest canopy left to swing along, high and confident, as they would in deep forest. Despite the stealth, their pedestrian foraging sometimes brings them into close contact with people. They drink at the same stream where village women and children fetch water. When they stand, or walk upright, as they often do, they seem menacingly humanoid.

Chimpanzees, along with bonobos, are our closest living relatives. Their species, Pan troglodytes, is classified endangered by the International Union for Conservation of Nature. Their total population throughout Africa—at most 300,000, possibly far less—is smaller than the human population of Wichita, Kansas. As adults, they’re big, dangerous animals—a male might weigh 130 pounds and be half again as strong as a similar-size man. Chimps in productive forests live mostly on wild fruit, such as figs, but they will kill and eat a monkey or a small antelope when they can, tearing the body to pieces and sharing it excitedly. They relish meat. Because chimps tend to be wary of adult humans, especially men, their aggressive (and in some cases predatory) behavior toward people, when it occurs, falls mainly upon children. In some cases too, a chimp might pick up a small child out of sheer curiosity, as though grabbing a toy.

View Images Clearing of forest, both by small farmers and by giant sugarcane and tea enterprises, has shrunk chimp habitat to patches and strips, such as this stream forest in the Kinyara Sugar Works plantation, near a village called Kabango. According to one source, four children in Kabango have been attacked—and two killed—by chimps during the past decade.

Whatever the motive, it can be terrifying. For more than three years after the trauma of her son’s abduction, Ntegeka Semata and her husband, Omuhereza Semata, a farmer, continued to live in their house. They built a bamboo fence around their tiny backyard, enclosing the cooking shed in what they hoped would be a safe zone for the family. “I am scared all the time that other chimpanzees might come back,” Ntegeka said in that earlier interview.

View Images Chimps swipe corn, mangoes, papaya, and the favorite shown here, jackfruit, from villagers’ fields and trees. This female and her youngsters belong to a group of 22, marooned in a forest fragment along a stream corridor not far from Mparangasi. She carries an infant at her belly and a toddler on her back.

But the fence was flimsy, the chimps kept returning, and the Sematas felt under siege. Ntegeka couldn’t work in the garden. The children were sometimes too afraid to eat. Even their goat made piteous noises of fear. By the end of 2017, their house was vacant, with a broken window above the front door. The Sematas had fled and were living a marginalized existence in a rented room at a compound three miles away. They owned no farming land there. “I feel like we’ve been cast back into poverty,” she said.

Meanwhile the remaining windows of their old house reflected only the faces of chimpanzees, which visited regularly, glowering in, confused and provoked by the chimp images mirrored there, which seemed to be glowering out.

View Images Kyamajaka village has lost three children to chimp attacks during the past five years. Because fetching water from forest sources can be a dangerous chore, these kids from a Kyamajaka school walk to the spring in a group, with an adult, for the safety of numbers.

The death of Mujuni Semata was no isolated event. Police reports from the town of Muhororo (of which Kyamajaka is a satellite village, containing a few hundred families) describe two chimp-on-child attacks during 2017. On May 18, a toddler named Maculate Rukundo was seized in a cornfield while her mother worked the crop. The mother chased the chimps but then backed off, terrified, and ran to get help. A crowd of local people, soon joined by police, tracked the chimps to a patch of forest, where the little girl lay dead in a pool of blood and intestines, her gut torn open by chimp fingernails. Five weeks later, chimps (maybe the same group, but that’s hard to know) took a one-year-old boy from another garden plot, with his mother nearby, and again retreated to a patch of forest. A posse of local villagers pursued the chimps until they dropped the boy, who had a deep cut on his left leg but was alive. The police reported that in addition to this survivor with serious injuries, six young children had been killed in the area by chimps.

More recently, in mid-2018, a five-month-old girl was snatched from a veranda while her mother worked in the kitchen. The mother heard her child’s cries, raised a ruckus, and charged the chimps—and they fled. That baby was found alive, unconscious, in a nearby bush. After going to a well, a three-year-old girl was taken by a male chimp that scared away the child’s older friends and carried her off but dropped her, reportedly when he was challenged by an elderly man, a passerby, who raised the alarm. A 12-year-old boy in another satellite village was grabbed near a garden and suffered a deep arm wound as he struggled to get free.

From elsewhere in western Uganda come accounts of the same gruesome pattern, played out with variations: one child killed by a chimp on the sugarcane plantation at Kasongoire, in 2005; four chimpanzee attacks on children, with one fatality, near the Budongo Forest Reserve, farther north; eight attacks, back in the 1990s, seven of which were probably by a single rogue male chimp, on children from villages bordering Kibale National Park. Of those victims, three children were eviscerated, and some were partly eaten. That male, further demonized with the name Saddam, was hunted down and killed soon after his seventh child killing. He was an egregious anomaly. Most cases are more ambiguous, involving chimps that are reckless at one fateful moment, not repeated killers. This phenomenon is not confined to Uganda: It has happened elsewhere in chimp range across Africa, most notoriously at Gombe Stream National Park, famed primatologist Jane Goodall’s study site in Tanzania, where in 2002 an adult male chimp snatched and killed a human baby.

Chimpanzees in Uganda are protected by law, meaning that it’s illegal to hunt or kill one, regardless of whether it lives within a park or reserve (though permission has occasionally been granted to kill a rogue male such as Saddam). They’re further protected by tradition of the Bunyoro people, predominant in western Uganda, who tend to see chimps as different from other animals and, unlike some Congolese peoples across the border, don’t hunt them as food.

Despite law and custom, there have been killings of chimps too—retaliatory, defensive. The details will probably never be known. Late last year, an adult male chimp in the area was fatally speared. A young female was beaten to death there with sticks and stones. The carcass of another young chimp was reportedly found, decomposing, cause of death indeterminable but fingers cut off. Among communities of angry, powerless people who fear for their children, it’s not surprising. Chimpanzees aren’t the only desperate primates in western Uganda. All these painful ambiguities show up vividly at a place called Bulindi, where one group of chimpanzees and their fraught interactions with people are studied by a British biologist named Matt McLennan.

McLennan came to Uganda in 2006, as a doctoral student at Oxford Brookes University, in England, to study how chimpanzees adapt their behavior to living in a human-modified landscape. Why? Because he foresaw the challenges to come for chimpanzees everywhere. He knew that the Budongo Forest Reserve was good habitat containing about 600 chimps and that another forest reserve 50 miles to the southwest, Bugoma, harbored roughly the same number. Between those two refuges, Budongo and Bugoma, was a mixed landscape of small farms and large sugarcane plantations, with a growing human population and shrinking strips and patches of forest, which had once represented a connecting zone for the two reserve-protected populations and latterly sheltered small resident groups mostly isolated in remnant patches of habitat. A total of about 300 chimps lived within that middle zone, finding refuge in the forest patches, venturing out onto croplands for food. Some individual chimps—young females, for instance, escaping their fathers and brothers to find new mating possibilities—would move from one small group to another, or even from an isolated group into Budongo or Bugoma, providing some gene flow; but as the forest patches shrank and isolation increased, even that modest degree of intermixing became difficult.

Much of the land was private, loosely held by customary occupancy and inherited through the male line. After passage of the 1998 Land Act, which formalized traditional tenure in Uganda into deeded property, people felt greater security of ownership. That security, ironically, empowered them to harvest their forests and switch to crops. Survival amid such a landscape, for a single chimp or a group of them, was problematic.

View Images High in the canopy of good continuous forest, chimps can move safely through the trees from one source of wild fruit to another. This adult male, part of the Kanyawara group in Kibale National Park, which primatologist Richard Wrangham studied for 30 years, searches for ripe figs in the upper branches of a Ficus sur tree.

This tangle of circumstances drew Matt McLennan to Bulindi, a town on the road about halfway between Budongo and Bugoma, where he found a group of at least 25 chimps. With a local research collaborator named Tom Sabiiti, he began work, the first step being to persuade those animals to tolerate his and Sabiiti’s presence in the forest. He wasn’t trying to habituate them and make behavioral observations; instead he wanted to gather ecological data from indirect evidence such as fecal samples and nest surveys. Still, it was difficult. Unlike wild chimps in good, expansive habitat, which tend to be shy, these Bulindi chimps had a belligerent edge.

“We found out pretty quickly that they didn’t like people inside the forest,” McLennan told me. “Their strategy was to try to intimidate us. Which they did very effectively.” The big males especially: They hooted, drummed on the ground, thrashed vegetation. One day they chased McLennan 250 yards but left him unhurt when he fell. Eventually the chimps grew sufficiently inured to his and Sabiiti’s presence that they tolerated it without responding aggressively, and the pair gathered data for two years. At that time, McLennan recalled, a fair bit of forest still spanned the hillsides and shaded the stream valley draining through Bulindi, though clearance was under way, and the sound of chain saws rang out in the woods. Farming was mainly for subsistence, but cash crops (notably coffee and tobacco) had arrived. And the chimps were getting bolder. The first chimp attack on a child, within memory of local people, occurred in 2007. The following year, McLennan went back to England and wrote his dissertation. When he returned in 2012 to continue field research on the Bulindi chimps, things had changed.

Most of the forest was gone. Crop fields now spread widely across the hillsides above the small stream: corn, cassava, sweet potato, and other garden produce. There were fewer chimps in the local group and, among those still there, fewer adult males. Some of that decline may have been deaths from leghold traps, an illegal and sometimes lethal means of discouraging crop raiders such as chimps and baboons. The remaining chimps now seemed even bolder, at least around women and children, but their boldness was somewhat less aggressive. Their diet included more of the human crops. They had begun eating jackfruit, a new behavior since 2006, and local residents resented their jackfruit losses. McLennan decided that rather than bemoaning these changes, he would study how the chimps were adapting.

What he found is that the chimps at Bulindi are coping, at least for now. Their number is up slightly, from 19 in 2012 to 21 presently. Their condition is generally good: They’re robust and strong. Most adult females have infants. Genetic analysis of the chimps’ DNA, from fecal samples, suggests that their isolation hasn’t yet brought severe inbreeding—although, according to Maureen McCarthy at the Max Planck Institute for Evolutionary Anthropology, who led the genetic study, that could change with increasing isolation, decreasing female dispersal, and time.

But the Bulindi chimps do carry higher levels of stress-related hormones, at least during some times of year, than a population of chimps within the Budongo reserve, just 20 miles away. Does that mean their piratical way of life, staying so close to humans and raiding for their food, is inherently stressful? Maybe, although other complex variables also affect those hormone levels. It’s hard to know, at this point, whether the Bulindi chimps are thriving on human foods, suffering tension from their nearness to people—or both.

Among the people at Bulindi, attitudes toward the chimpanzees vary. One woman told me she wished they would stay in the forest. Her husband interjected: “The forest is over.” Another woman considered them a small nuisance for stealing her jackfruit and bananas, but at least they kept the baboons away. An amiable matriarch named Lillian Tinkasiimire, whose little red-brick house is graced with a mango tree in front, a fig tree behind, both of which attract chimpanzees, takes a steady view.

View Images Though chimps feed primarily on plants, they hunt animals when opportunity presents itself and relish the meat when they succeed. These females, in Kibale National Park, fight over the gutted carcass of a red colobus monkey after males of their group took the choice morsels: the brain and other organs.

“The chimps are very clever,” she told me. “If you don’t chase them, they will be your friend. If you chase them, you will see fire.” Tinkasiimire has preserved much of her forest. Her attitude is, let the chimps live there, let them be, let them visit.

McLennan hopes to encourage such tolerance and help make it less costly. He and his fiancée, Jackie Rohen—a writer trained in musical theater but now committed to the theater of conservation—have also created the Bulindi Chimpanzee and Community Project. It provides development assistance to families in the area and incentives to mitigate human-chimp conflict: payment of school fees in exchange for reforestation, for example, and starter plants for shade-grown coffee, fuel-efficient stoves that use less firewood, new borehole wells that allow women and children to avoid chimpanzees (as they gather at stream pools to drink) when fetching water. The best way to preserve peace between Bulindi’s people and its chimps, McLennan and Rohen recognize, is to help them stay apart.

At Kyamajaka and other villages near the town of Muhororo, three hours southwest of Bulindi, things are different. Matt McLennan doesn’t study these chimps, and no similar community project offers incentives to preserve forest or measures to defuse conflict. No one knows how many chimpanzees lurk or cower in the Muhororo forest remnants (maybe 20, maybe fewer?) or where their next unfortunate conflict with humans may occur. The Semata house stood vacant and solitary after the family’s departure, with chimps coming there frequently, more than a dozen individuals—as documented by photographer Ronan Donovan—to menace themselves in the reflective windows and kick their feet against the walls. What person would want to live in such a place?

Across the glen, half an hour’s walk down one garden hillside and up another, Donovan and I spoke with a man named Swaliki Kahwa, whose son Twesigeomu (known as Ali) was taken by a chimp a year earlier, before his second birthday—dragged away and fatally battered. Kahwa deferred to his elder brother, Sebowa Kesi Baguma, the village chairman, to tell us about it. Baguma, a grave but cordial man wearing a yellow T-shirt and green gum boots, produced a police report and showed us the postmortem photos, printed in shadowy but lurid magenta. The boy’s right arm had been nearly torn off; a gash on his right leg, near the groin, may have cut the femoral artery; some of his fingers were broken. According to the times listed on the report, little Ali took almost 12 hours to die.

View Images Ahumuza Kyarigonza, here riding safely as his mother sweeps the yard, was snatched from a garden area by chimps in 2017, and suffered a deep gash on his leg, but was rescued. Six children have been killed by chimps in this village, Kyamajaka, within recent memory. A police report on Ahumuza’s case states that young men have formed “vigilante groups” to kill chimps.

Baguma noted dryly that people of his village have been taught to consider chimpanzees “beneficial.” This is the message from one international conservation group with activists in the area and from others who imagine chimp-based ecotourism bringing visitors to the cornfields around Muhororo. “We don’t see any benefit,” said Baguma. “It’s killing our children.”

The national reserves, such as Budongo and others, with sizable chimpanzee populations, are a problem of one sort for the Uganda Wildlife Authority. Those areas are degraded by illegal woodcutting, cropping, and settlement, with which the agency, in partnership with the National Forestry Authority, deals firmly. Some illicit settlers are even evicted from the reserves. But for chimp-human conflict within communities such as Kyamajaka, garnished with scraps of private forest, UWA’s approach is gentler, as described by Executive Director Mwandha: creating “awareness” of the immediate dangers and potential benefits of chimpanzees amid villages, and patrolling to monitor chimpanzee presence.

Whether such awareness can change attitudes in the more traumatized communities, with children and chimps still in harm’s way, is an urgent question. Back across the glen, after listening to Baguma’s anger, Donovan and I encountered Norah Nakanwagi, the chairwoman of Kyamajaka, as she sat outside her house, resplendent in a black bandana and a floral blue outfit with puffy shoulders, the sort of formal dress known as gomesi in Uganda. She spoke in Runyoro, the Bunyoro language. It’s unsafe here for women and children, she said. She waved her hand at a cornfield. I can’t go there. We’ve had five children killed since 2007, she said. People tell us the chimps are beneficial. Yes, we should leave them alone, but it’s difficult to explain that to someone whose child is dead.

Then she switched to English: “Take them away. Not to kill them. But take them away.”

View Images Two months after the Sematas left their house, photographer Ronan Donovan set up nearby. He says that every day for a week, chimps—like this group approaching him through the trees—visited the house. Sometimes banging on the walls, they seemed enticed but agitated by their reflections in the windows, as if challenged by rival chimps living inside.

Why not move the chimps? Yes, people ask about that, McLennan told me. But move them where? There’s no vacant chimpanzee habitat anywhere in Uganda. And dropping them into occupied habitat would be murderously stupid, provoking chimpanzee war. Another dire option: Kill the chimps, fast and cleanly, to protect the people and put the chimps out of their misery. But are they in misery, with their high body fat and their healthy reproduction, fueled by pilfered mangoes and jackfruit?

No one is likely to advocate killing these chimps, dangerous though they may be, as official Uganda policy. Once adopted, where would that line end? Anyway, there’s a third option: trying to manage the situation somehow. Small projects, reforestation incentives, tactical mitigations, borehole wells, alternate sources of income, patience, sympathy. Creating greater awareness, as the Uganda Wildlife Authority suggests, of the immediate dangers and how to avert them, as well as the long-term possibilities, if any, of economic benefit from small-scale tourism. Incremental but tireless efforts to help chimps and humans observe an uneasy truce.

It’s a local problem that’s not just local. Uganda’s awful dilemma foretells the future of chimpanzees all across Africa. Less forest, more people, more desperation among the chimps, more conflict. What makes a village like Kyamajaka seem so pitiable, and a town like Bulindi seem so important, is that in those two places the future has arrived.