Rachel Hogan sat on the floor chomping on a banana leaf while Nkan Daniel, a baby gorilla, watched. She waited for signs that he might mimic her behavior. Sure enough, seconds later the ape grabbed some leaves of his own and began to nosh.

It was 2001, and Hogan was in Cameroon on a three-month stint volunteering with Ape Action Africa, a nonprofit primate rescue organization. Meeting Nkan Daniel (Nkan means gorilla in a local dialect) changed her life, she says. Hogan stayed on in Cameroon and in 2010 became the director of Ape Action Africa.

The baby gorilla, just two weeks old, had been found by the Cameroonian government in the home of a woman seeking to sell him as a pet for about $30. Poachers had killed his mother and other relatives for the trade in “bush meat.” Across Africa, and especially in Cameroon and surrounding Congo Basin countries, demand for the meat of wild animals—apes and monkeys but also bats, porcupines, and a host of other species—has been surging.

When Nkan Daniel arrived at Ape Action Africa’s sanctuary in Mefou National Park, a 45-minute drive from Yaounde, Cameroon’s capital, someone handed him to Hogan. “I put him on my front as a female gorilla would, and that’s where he just latched on,” she says.

From that point on, he rarely let go. Hogan, terrified and unprepared, began to play the role of gorilla mother. She taught him how to eat and tended to him when he whimpered. When she slept, he snoozed on her chest. When she dressed and showered, he still clutched on tight. “I learned to do everything one-handed,” she chuckles. “In those days it was all about him.”

These days, though, Hogan focuses on all the animals in the 2,500-acre sanctuary: 213 monkeys, 111 chimps, and 23 gorillas, some recovered in the forest, others saved from the pet trade. All became orphans at a young age after poachers killed their adult family members for meat.

View Images These monkeys are for sale at the weekly market in the village of Nendumbia in the Democratic Republic of Congo. Some view the meat as a status symbol. Photograph by Pete Muller, Nat Geo Image Collection

Villagers have long trapped or shot forest animals for sustenance. But the scale of hunting is far greater today and has been increasing, facilitated by road building in the forest for logging and mining operations and fueled by growing demand in urban markets, where comparatively well-off customers consider wild-sourced protein both a delicacy and a status symbol. A smaller international market for exotic meat thrives in Europe and the United States.

The trade in bush meat, much of it illegal, has spawned spin-off businesses: Leftover primate skulls, for example, are shipped to the U.S., where they’re prized as trophies, and to China, where they’re used in folk medicine. And motherless primates too small to provide much meat can earn traders a profit in the pet market.

Conservation experts estimate that up to six million tons of bush meat are taken from the Congo Basin each year. In Cameroon, says Denis Mahonghol, a forest and trade officer with TRAFFIC, the organization that monitors the global wildlife trade, “the problem is increasing year after year.”

Primates—especially vulnerable to hunting because unlike some of the smaller animals, they reproduce slowly—have borne the brunt of the trade. For example, poaching is one of the greatest threats to critically endangered eastern and western gorillas, both found in the Congo Basin. As primate numbers fall, ecosystem health suffers: The animals feed on forest fruits, dispersing seeds in their feces as they move around.

Many African countries, including Cameroon, outlaw the hunting of species at risk of extinction such as great apes and pangolins, and a U.N. treaty prohibits cross-border sales of these animals and their parts. Moreover, the U.S., England, and other countries ban the import of exotic meats because of their potential to spread disease: Ebola and HIV-AIDS have both been linked to bush-meat consumption.

Hogan says that educational campaigns and a crackdown by law enforcement in Cameroon have helped spread awareness of the problem, pushing the illicit business underground. “Even your average Joe knows it’s illegal,” she says.

But Mahonghol, who’s been working to combat the bush-meat crisis since 2008, says widespread corruption has stymied real progress: “The laws and regulations are in place, but to implement them in the field is a big problem.” In exchange for payment, some law enforcement officers will look the other way or issue hunting permits, he says.

For some hunters and traders the prospect of big profits makes it worth risking arrest. On Bioko Island, off the coast of Equatorial Guinea, where 77 percent of the population lives on less than $750 a year, according to the Center for Global Development, hunters can earn $2,000 a year selling wild meat. (Read more about hunting for bush meat on Bioko Island).

Safe from hunters in the sanctuary, Nkan Daniel—now a silverback, a dominant adult male—heads a troop of 10 other gorillas, all of whom will spend the rest of their lives there. Though he’s emerged as a leader among his family group, Nkan Daniel hasn't lost affection for the woman who reared him. “He thinks I'm his mother of 16 years,” Hogan says. “He's the love of my life.”

Still, she also regrets that they had to be brought together at all. “I would have happily not met Nkan Daniel, the same as I wouldn’t have met any of these animals because they’re not meant to be here with us,” she says. “They’re meant to be in the forest.”