Why Poison Is a Growing Threat to Africa’s Wildlife

Deadly chemicals are now a weapon of choice for those who see lions, elephants, and other wild animals as threats to livestock and property.

This story appears in the August 2018 issue of National Geographic magazine.
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A young male lion was one of three members of Kenya’s famous Marsh Pride to die in 2015 after eating a cow carcass that Maasai herders had laced with carbosulfan, an insecticide. The lions had killed several cows.
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A traditional way to kill animals with poison is to tip arrows—like these made by Maasai at a market in Olpusi Moru, on Kenya’s border with Tanzania—with a lethal substance from the bark of the Acocanthera tree.

Two male lions had been killing cattle and goats for weeks. The Maasai herdsmen in Kenya’s Osewan region had seen enough.

Solve the problem by Christmas, the Maasai told the Kenya Wildlife Service in late December last year, or we’ll solve it for you. “We know how to kill lions,” one young Maasai warrior said in Swahili during a heated community meeting, and he didn’t mean only the spears that he and his fellow Maasai carry. He also meant poison, now a weapon of choice for herders who see lions as threats to their livelihood rather than the national symbols the wildlife service tries to protect.

Kenneth Ole Nashuu, a senior warden with KWS, as people call the wildlife service, decided that the best solution was to relocate the lions from Osewan, north of Amboseli National Park, where they’d come in contact with grazing livestock, to a neighboring national park, Tsavo West. But first they had to be tranquilized.

On Christmas Eve night Ole Nashuu and other rangers were joined by Luke Maamai, from the conservation group Lion Guardians. They climbed into a Land Cruiser, drove to a clearing in the bush, and parked. Under a big, bright moon, with lights off, they waited for the rogue predators—young brothers—to appear.

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Conservationists hold a sickened gray heron and birds that died after aerial spraying of the pesticide fenthion in the Bunyala rice-growing area. Villagers collect and eat the birds, even though they’re poisoned.

Maamai, who’s Maasai, placed a speaker on the roof of the vehicle and broadcast into the darkness the recorded bleating of a dying buffalo calf, a sound lions can’t resist. After just 15 minutes a large animal stepped from the shadows on the right. Ole Nashuu switched on his headlights. It was a lioness, one of two sisters that partnered with but weren’t related to the brothers. The lioness, about 10 yards in front of the vehicle, moved cautiously toward a small tree Maamai had baited with goat innards. Ole Nashuu signaled to a veterinarian who was sitting in a second Land Cruiser, his rifle loaded with a tranquilizer dart.

After directing his men to shimmy the passed-out lioness into a cage, Ole Nashuu congratulated the group on a successful mission. The removal of the female, he said, would disrupt the pride and stop the brothers from preying on the community’s livestock—a curious claim, it seemed, because the young male lions, the primary mischief-makers, were still out there.

Later that night my guide, Simon Thomsett, a leading expert on raptors in Kenya, and I were trying to sleep in his Land Cruiser when we heard growling and grunting—first at a distance, then closer. It was the two male lions, presumably searching for the female. The team darted and captured one of the brothers, but the other escaped. The captured male and female eventually were released in Tsavo West. Previous experience suggests they probably haven’t survived: Lions dumped without acclimation into another pride’s territory are treated as intruders and often experience a torturous death.

“We want to give them a second chance,” says Francis Gakuya, head of veterinary services at KWS, which is responsible for the welfare of all wildlife in Kenya. But many lion experts believe that in such situations, it would have been more humane to kill the troublesome lions on the spot.

Meanwhile, contrary to the warden’s theory about disrupted prides, the remaining male continued to prey on livestock. This time herdsmen—possibly not local—didn’t seek outside help. They poisoned the male and the other female by lacing a goat or cow carcass with chemicals that killed the lions after they fed on the dead animal. By the time KWS heard about it and sent a veterinarian to investigate, the lions’ bodies had rotted.

The vet also found the remains of vultures and a hyena, probably only a fraction of the animals that had died after feeding on the contaminated livestock carcass—the extended “crime scene” that’s common in wildlife poisonings. Unfortunately the vet didn’t take samples for testing, even though certain poisons can stay in a body for a long time. So the only people who know what substance killed the lions are those least likely to talk about it.

How Pesticide Misuse Is Killing Africa's Wildlife This animated explainer shows how pesticides are destroying the continent’s ecosystem.

In Kenya and across Africa, poison is used to kill small creatures for food (the impact on human health is unclear), poach elephants and rhinos for their tusks and horns, and acquire animal parts for traditional medicine. Another vexing use of poison results from encounters between people and wild animals—when a lion or hyena kills livestock, for example, or an elephant destroys property—and it usually involves a pesticide, because pesticides are cheap, readily available, and deadly.

“Poisoning is a big problem,” Gakuya acknowledges. And judging from the Osewan episode, it’s a problem that continues to elude solution. Retaliatory poisoning can happen anywhere anytime, but the evidence of it is often anecdotal and almost always incomplete. Even so, nearly everyone monitoring Kenya’s wildlife—biologists, KWS staff, and conservation groups—agrees that poisoning is likely to increase because human-wildlife conflicts are increasing.

Kenya’s protected areas are under siege, including all the premier reserves and parks in the south: Masai Mara, Amboseli, Tsavo West, and Tsavo East. Rapid development—from highways, railroads, power plants, and power lines to heavy industry, high-tech centers, and growing cities—is encroaching. Kenya’s population, already overwhelming local resources, is expected to nearly double to more than 80 million by 2050, and open country is being converted into farms, blocking animal movements.

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Until recently Maasai drove tens of thousands of cattle into the Masai Mara National Reserve. Cattle incursions fluctuate in response to subdivision of neighboring lands, population growth, local politics, and drought.

As a result, lands adjacent to parks—the large, collectively owned tracts known as group ranches, as well as other community lands—are becoming inhospitable to wildlife. For elephants and other large animals that need those areas for migration between parks, for seasonal dispersal to find food and water, and for giving birth, the onslaught is catastrophic.

Kenya has arrived at a crossroads. “We’re no longer preserving our nation as a haven for wildlife,” Thomsett says, referring to Kenya’s accelerating economic growth. “We’re trying to become the Dubai of Africa.” That may seem extreme, but it’s hard to argue with the facts.

The lion is Kenya’s signature wild animal, but fewer than 2,000 remain in the entire country, down from an estimated 20,000 five decades ago, and the species has vanished from about 90 percent of its original range. Some experts predict that within another 20 years, lions will be reduced to zoo-like numbers, living under zoo-like conditions. Every deliberate poisoning brings Kenya one step closer to what the African-wildlife photographer Peter Beard famously called “the end of the game.”

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Incursions of livestock into Masai Mara have become so disruptive that the reserve is in effect shrinking. “Part of the Mara will survive, but not what’s here now,” says the Mara Conservancy’s Brian Heath.

People around the world have long used poisons to hunt game and kill enemies. In East Africa the Acocanthera tree contains a compound that even in small doses can arrest the heart of a large mammal and has been popular for centuries. More recently the use of strychnine for “pest” control was so routine that none other than George Adamson, the celebrated conservationist known fondly in Kenya as Baba ya Simba (Father of Lions in Swahili), used it to dispatch hyenas he deemed a nuisance.

But the most fateful change, the mixed blessing that still plagues much of Africa and countries elsewhere, including the United States, was the development of synthetic poisons—insecticides and herbicides—for agriculture. Beginning in the 1980s, when the human population started to explode across Africa and competition for space and food increased sharply, landowners and pastoralists found that pesticides could also be employed to kill predators (lions, leopards, wild dogs, jackals), scavengers (hyenas, vultures), and crop raiders (elephants, certain birds). At some point people also started using the deadly compounds to poach ducks and other waterfowl and then sell them as food.

A national movement to address poisoning began when Nature Kenya, East Africa’s oldest natural history organization, learned that farmers were using pesticides to kill lions in the north. Darcy Ogada, who was on Nature Kenya’s Bird Committee, volunteered to design and oversee surveys to gauge the extent of the problem. She enlisted an aspiring ornithologist named Martin Odino to conduct the surveys.

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These Maasai drive cattle and sheep from their village into Masai Mara reserve, reducing forage for wildlife hunted by lions and hyenas. The predators kill livestock, and herders retaliate by poisoning carcasses.

One place they focused on was the Bunyala rice fields, in western Kenya, along Lake Victoria. According to unofficial reports, people there were killing birds with the pesticide Furadan 5G, a purple granular substance made by a U.S. company, Philadelphia-based FMC. Furadan 5G contains the compound carbofuran, a neurotoxin so poisonous that it had been banned or severely restricted in Canada, the European Union, Australia, and China and had been prohibited for use on food crops in the U.S. Yet Kenya had allowed the substance to be imported via the Juanco Group, a distributor in Nairobi.

During his first visit to the Bunyala region, Odino found that most agro-vets—small agricultural-supply stores in rural areas—sold Furadan 5G to anyone. He confirmed that poachers were applying Furadan to rice to kill ducks and to snails to kill African openbill storks that feed on them. Animals were dying by the thousands. Poachers sold the birds to local residents, who believed that contaminated bush meat, if properly prepared, could be rendered harmless, or almost so. Men eating soup containing poisoned bird parts told Odino that their knees felt weak afterward, a symptom consistent with a compound that can disrupt brain-cell activity. But no studies have been conducted.

Ogada took the findings to Paula Kahumbu, CEO of WildlifeDirect and one of the most influential conservationists in Kenya, who had been hearing about similar incidents elsewhere in the country. Kahumbu assembled a task force to address the problem. The inaugural meeting, held in April 2008, was “pivotal,” Ogada says. “For the first time a whole group of conservationists were talking about the issue in the same room.” Still, Kahumbu knew it would be difficult to persuade the government to ban a chemical that Kenya’s booming agricultural industry had become dependent on. “They don’t have a cheaper and equally effective alternative,” she says.

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Inside Masai Mara, herders inspect the injuries a cow suffered during a lion attack. Young Maasai men once had to kill a lion to earn their stripes and become a warrior.

The poisoning problem received worldwide attention in early 2009, when a U.S. television newsmagazine, CBS’s 60 Minutes, aired a report about Furadan 5G killing lions in Kenya and highlighted Furadan’s availability. Citing “30-plus poisonings” in the Amboseli region and “another 35 or 40” in pastoral lands (not conservation ranches) in Laikipia, northwest of Mount Kenya, carnivore biologist Laurence Frank told correspondent Bob Simon, “That’s gotta be just the tiny tip of the iceberg.”

The exposure embarrassed FMC, which pulled Furadan 5G from the market in Kenya and set up a buyback program. The strategy was effective, to a point: Since about 2010, agro-vet shops haven’t sold Furadan 5G. But carbofuran is still very much available. Occasionally Furadan enters the country from elsewhere in Africa. And now counterfeit Furadan is in circulation, as are other carbofuran-based products from China and India. Meanwhile another FMC pesticide, a pink substance called Marshal, has shown up on carcasses meant to lure predators. Marshal contains carbosulfan, which breaks down into carbofuran in low, yet still toxic, concentrations. Despite the efforts of Kahumbu, Odino, Ogada, and others, Kenya’s government has not outlawed carbofuran. President Uhuru Kenyatta has prioritized food security, and the nation’s population growth makes a ban doubtful. More food means more intensive farming, with more herbicides and insecticides, according to Kahumbu. “Banning any pesticide is quite unlikely,” she says.

As for FMC, Cori Anne Natoli, a company spokeswoman, wrote in an email that “this is the first that we have heard of any misuse of Marshal insecticide,” adding that the company is investigating and claims no responsibility for any availability in Kenya of Furadan.

Perhaps the most glaring reminder that Kenya continued to be a pesticide free-for-all after the Furadan recall was a poisoning incident nearly three years ago involving the Marsh Pride, the immensely popular lions that were featured on the BBC series Big Cat Diary. In early December 2015, the pride, which breeds in the Musiara Marsh, near the northwestern boundary of Masai Mara, killed several cattle. In response, herders spiked a carcass with poison. One lioness died, and a second, severely weakened, was mauled to death by hyenas. Shortly afterward a debilitated male was trampled by buffalo and had to be euthanized by a KWS vet. A postmortem revealed traces of carbosulfan as well as old spear wounds—battle scars from herders’ previous attempts at retaliation.

The edges of all protected areas have become more dangerous for wildlife, but nowhere is the threat to large, highly mobile animals more obvious than in the eastern part of the Mara region. Outside the reserve, ranch livestock herds have been expanding and open land shrinking, prompting Maasai pastoralists to drive more and more cattle into the reserve to graze, especially during the dry season or times of drought.

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A hyena waits to make its move on a dying Marsh Pride lion. The night before, a herd of buffalo repeatedly attacked the young lion, too disabled by pesticide poisoning to escape.

At the height of the incursions, thousands of cattle amble illegally into lion habitat. The lions develop a taste for witless, slow-moving prey, taking victims on both sides of the boundary. In a country where guns are difficult to acquire legally, the herders turn to the weapons at hand: poison or spears. “At night it’s mayhem,” Thomsett says, evoking a part of the wildlife experience tourists don’t see.

Recognizing that ending the mayhem, or at least containing it, will rely on the cooperation of local people, nongovernmental organizations have tested a new approach—community-based conservation—to try to reduce retaliatory poisonings, poaching, and other kinds of violence toward Kenya’s wildlife.

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Villagers in Empopogi, east of Masai Mara, treat an injured goat with brightly colored antiseptic spray. The night before, hyenas killed more than a hundred goats and sheep, ripping open their bellies.

The most notable of the organizations use similar strategies. They include patrolling for homemade wire snares—a cheap and effective method for disabling zebras and similar animals for bush meat—compensating livestock owners for lost cattle and goats (with government and private money), and providing sturdier bomas, the often flimsy stick-and-branch corrals where animals are kept at night. Since 2010 the Anne Kent Taylor Fund has fortified nearly 800 bomas in the Mara region, and in almost every case livestock predation has decreased, which means the main motive for retaliatory and protective poisoning was eliminated.

One of the groups’ most promising strategies has been to hire area residents as rangers, conflict mediators, and conservationists. “Wildlife management is people management,” says Richard Bonham, co-founder of Big Life and its Africa director of operations, referring to the problem of human-wildlife conflict around Amboseli.

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A Big Life officer reports to headquarters after a hyena killed sheep on collectively owned tracts called group ranches east of Amboseli National Park. Big Life compensates herders who have lost animals to predators.

It would be easy to hold the Kenya Wildlife Service primarily responsible for the failure to stop wildlife poisoning, and some people do. The agency’s ambitious vision—“to save the last great species and places on Earth for humanity”—seems to exceed its capacity.

Everywhere I traveled, I heard accounts of incompetence: samples from poisoned animals not taken, samples lost, samples misidentified, samples not being tested, and results never coming back from the lab. There also were complaints about improper treatment of injured but recoverable animals that led to needless deaths, poorly executed crime-scene investigations, and a lack of consistent, comprehensive data on which to base policies and procedures.

But KWS is at the mercy of larger forces, and chief among them is inadequate funding, says Brian Heath, head of the Mara Conservancy, which manages the Mara Triangle—the western and most ecologically robust section of Masai Mara. “At the national level, conservation is not a high priority,” he says. Heath, also a former KWS trustee, points out that the government gives considerably more money to the tourism board than to KWS, even though the tourism industry, the second largest sector of Kenya’s economy, would collapse without the great species and places KWS is charged with protecting.

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Poachers in the Bunyala rice fields poisoned an African openbill stork by feeding it snails containing the pesticide carbofuran. They use incapacitated storks as decoys to attract others, which are sold as bush meat.

The country’s national parks are understaffed, and many staff members are undertrained. Veterinarians often are overworked because they’re required by law to treat every human-inflicted injury to wildlife, even minor snare wounds, which can delay them from responding to a poisoning incident with multiple animal deaths. “It’s very frustrating,” says KWS’s Francis Gakuya. Everywhere basic resources are insufficient, from too few vehicles to not enough fuel.

Another overlooked piece of the national puzzle is the role of police and judges. Mara Conservancy rangers caught two of the suspects in the Marsh Pride poisoning. But their Maasai neighbors raised bail, and the men were released. That was the end of it—no follow-up, no trial, no one held responsible. Prosecutions for poisoning wildlife in Kenya have increased recently, but most offenders go unpunished. “The most important thing to do is to start arresting people,” says ornithologist Odino, echoing the lament of everyone who believes the gravity of animal-poisoning crimes is still not appreciated.

And so the poisonings continue. Carbofuran remains popular, but anything handy and lethal will do. Some 40 vultures died in a single incident in Masai Mara this year, almost certainly the collateral damage of retaliation against lions. Traditional concoctions are still used, especially among elephant poachers in Tsavo East, where at least half the elephants killed are felled by poisoned arrows—possibly as many as 15 last year. It’s easy to smuggle strychnine from Tanzania on a motorbike, and any employee of a flower farm can divert a new insecticide to the local black market. Even cement has been used to poison wildlife, a perverse irony in a country booming with construction. Near Nairobi I saw a billboard advertising Simba Cement, which is made in Kenya. The sign depicted the face of a male lion over which the following words were superimposed: “King of the Concrete Jungle.” If nothing else, the species will survive as a symbol.

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Ornithologist Martin Odino (at right) and a helper burn African mourning doves poisoned by pesticide in the Bunyala rice fields. Incinerating the doves prevents more deaths of birds and scavengers that would feed on the carcasses. Vulture populations in Kenya have crashed because of wildlife poisonings.

One day the anti-poaching patrol of the Anne Kent Taylor Fund escorted me on a behind-the-scenes safari into Nyakweri Forest, atop the Siria Escarpment, outside Masai Mara. Patrol leader Elias Kamande, a young Kenyan conservationist, showed me a wooded area that until recently had been an elephant nursery.

“Two hundred females giving birth at one time,” Kamande said. Today the refuge is being decimated by charcoal producers. Where months before had stood large, leafy hardwood trees was now a clear-cut area the size of four football fields—one of hundreds such treeless scars scattered throughout the remaining patches of escarpment forest. The lucrative but illicit charcoal industry is a by-product of land subdivision. Maasai here and outside other protected areas have been dividing up group ranches, with every male age 18 or older receiving a share—essentially privatizing the land while transitioning to sedentary life.

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A Maasai girl bounces on the carcass of a 52-year-old female elephant near Amboseli National Park, which is hemmed by farms. Rangers suspect the elephant was poisoned for raiding grain stores and removed her tusks.

“Five years from now,” Kamande said, referring to the Nyakweri Forest, “all this will be gone.” What will replace it? Settlements, herds, crops, and fences, lots of fences. That’s likely to lead to the elimination of animals—elephants, lions, giraffes, hyenas, buffalo—that have moved freely between the Mara Triangle and the escarpment, both of which are part of the larger Mara ecosystem.

Kenya still has time to save crucial dispersal areas and migration corridors. Doing so hinges in large part on areas called conservancies that are managed to make it attractive, by providing local people with income from tourist lodges, as well as other incentives, for landowners outside protected areas to set aside habitat for wildlife. When conservancies are established—from the regions of Masai Mara and Amboseli to the Tsavos—poisoning tends to decrease, at least in the short term. “It’s still an experiment,” Heath says, noting that drought, population growth, or government policy could undo everything.

Around Amboseli, Big Life recently started another experiment on neighboring group ranches: purchasing conservation easements, which are agreements not to put up fences, construct new buildings, or otherwise disrupt wildlife habitat.

What will happen if the easements and conservancies fail?

“The park is dead,” Big Life’s Bonham says.

During certain times of the year, almost all of Amboseli’s roughly 200 lions, like the two rogue brothers near Osewan, live outside the protected area, in the greater Amboseli ecosystem. As long as big animals such as lions and elephants have safe access to the overall ecosystem, which at two million acres is more than 10 times as large as the park, they’ll likely remain resilient. Both populations have crashed before, in the case of lions mostly because of retaliatory spearings by Maasai. But they’d never have rebounded to today’s numbers (about 1,600 elephants) if they’d been confined to the “island” known as Amboseli National Park. Managing the livestock ranches for the benefit of wildlife as well as agriculture would keep alive the possibility of lions and elephants surviving in Kenya.

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In Masai Mara, villagers, along with rangers, community leaders, veterinarians, and NGO staff, participate in a three-day poison-response workshop under the auspices of the Endangered Wildlife Trust. They learn how to conduct forensic examinations, using dead animals like this goat, and revive wildlife sickened by poison.

Either way people are adept at living without things once deemed indispensable, a phenomenon Peter Beard described in terms of elephants. The animal’s “ability to destroy its habitat while adapting with great cunning to that destruction,” he wrote, is also a trait of Homo sapiens.

Kenyans and visitors to Kenya are growing accustomed to seeing fewer and fewer lions—so few now that each lion has its own name, like a domestic pet, and an online fan club. It’s not hard to imagine a time when pesticides are no longer a concern: no wildlife, no conflict. Or as Simon Thomsett says, “There will be nothing left to poison. Game over.”

Edwin Dobb’s previous stories include “ Alaska’s Choice,” about a controversial mine, in the December 2010 issue. Charlie Hamilton James covers conservation issues in Africa and the Amazon. This is his seventh story for the magazine.