Mountain gorillas share 98% of their DNA with humans. Even a common cold could have dire consequences for the troop we are about to visit. With only around 800 left in the wild, these are some of the last remaining mountain gorillas in the world.
Mburanumwe spots a massive silverback chewing on a pile of bamboo and begins a series of gorilla-like grunts. "I just want him to know that we are friendly, that we aren't an enemy."
Mburanumwe knows gorillas. His father habituated the first troop here in 1987 and took him when he was just 11 to see gorillas for the first time. He says he was struck by how human they seemed.
Now he and his rangers dedicate their lives to protecting the critically endangered species. In Virunga, a park surrounded by one of the world's longest running and deadliest wars, where more than 140 rangers have been killed in the last decade, it's a place that continues to pay the ultimate price for conservation.
"Even when the war comes, we are here protecting these gorillas," says Mburanumwe. "We say we will die protecting these gorillas."
Gorilla executions spark change
He was here on July 22, 2007, when killers armed with automatic weapons hunted down the very troop we are visiting today.
"I was in charge of monitoring," Mburanumwe says. His rangers heard the shots and feared the worst. "When I heard they killed the whole family," he pauses, and even through the mask you can see Mburanumwe's emotion, "my heart breaks about the killing."
Four gorillas were targeted, executed at point blank range. Their lifeless bodies, including the troop's magnificent 500-pound silverback, were strapped to bamboo poles and carried down the mountain to be buried.
It is Virunga's gorillas that are perhaps the park's most prized residents -- not to mention its biggest draw for tourists to venture across the border from Rwanda. Africa's oldest park is also its most biologically diverse, with a varied landscape of active volcanoes, savannahs, mountains, lakes and forests. But tourism remains nearly non-existent as militant groups and criminal gangs continue to fund war by pillaging the park's resources.
The 2007 killings had a profound impact, says Mburanumwe. "They killed these gorillas just to discourage the rangers, so that we would leave the forest and then people could benefit from the rich soil."
But instead of discouraging his rangers, Mburanumwe says it emboldened them. The pictures were broadcast around the world. The Congolese authorities felt the pressure to make a change.
A Belgian prince to the rescue?
In 2008 the Wildlife Authority announced a new director of Virunga -- a Belgian prince named Emmanuel de Merode.
A lot has made about royal title, but the soft-spoken de Merode downplays it when we meet. "I'm not a member of the royal family," he says, before mumbling something about his family and a revolution in the 1800s.
A lot also has been made about his personal sacrifice. Just last year he was shot several times on the road between Virunga and Goma in what is widely believed to be an assassination attempt. The assailants have never been caught.
De Merode shrugs that off as well. "I was completely covered in blood," he says over the headset of the park's single engine Cessna as he gives us tour through the air.
"I got hit in the chest and the stomach. It went through my liver, through my diaphragm and lungs, and out the other side. It broke four ribs," he recalls, as if he was reading a grocery list before turning to the savannah below.
"Oh this is wonderful, this is a big herd of topi," he says, pointing to a group of antelope.
It's a combination of risk and charisma that's made him the darling of the conservation community -- a role he seems to accept grudgingly.
The notoriety of Virunga -- coupled with an Academy Award-nominated Netflix documentary that brought it to the world's attention -- has helped keep the park in the public eye, and kept donors at the table.
But given the chance, de Merode downplays it all, instead focusing his eyes on the park below.
He banks the plane to the left to get a better view of smoke rising from the forest. Charcoal points, he tells us. "You can see it all the way along, everywhere there is smoke. That's actually inside the park."
And then there's oil. "That's where the drilling was due to be," de Merode says, pointing to a pristine portion of Lake Edward's shoreline below.
Threats to Virunga are everywhere
The government has authorized UK oil giant SOCO to explore for oil in Virunga. Conservationists say the move is illegal, and there have been allegations of intimidation and violence towards local communities and towards de Merode and other park staff.
SOCO has denied the claims and in November abandoned the project, opting out of renewing its lease.
But the threats to the park are still everywhere. "We've lived through 20 years of civil war here and the underlying cause of that war is the illegal exploitation of natural resources," de Merode says.
And while his rangers are now trained by some of the best soldiers in the world, he knows guns alone will never win a battle for conservation inside a war zone. "We're in a race with all sorts of damaging industries. We can't stop this through law enforcement alone. We have to provide alternatives because the country has to develop."
Unless Virunga starts contributing to the economic development of the region, it has no reason to exist, de Merode says. That's where Matebe comes in.
Can hydroelectric plants fix "environmental injustice?"
The Matebe hydroelectric plant has to be one of the world's most picturesque construction sites. Workers are busy welding pipes that carry water from the mountains of Virunga and the home of its famous gorillas down an embankment and into a turbine hall that sits above an expansive savannah below.
When completed in December the plant will bring sustainable energy to the region for the first time.
"An acre of fertile agricultural land -- which is what the park could be -- would generate about $600 a year in net profit for a poor Congolese family," Merode says. "That represents about a billion dollars in lost revenue for essentially what are the poorest people on earth."
Matebe is one of eight plants being built. All are set to be online by 2025. De Merode says the $200 million project will address what he calls "environmental injustice."
If this clean, sustainable electricity will bring industry and jobs to the area, de Merode admits it could also bring more people and the threat of overpopulation on the park's boundaries.
But it's a risk he is willing to take.
"This whole question of the interdependency of the natural ecosystems and the economy is absolutely key to the survival of the park," he says.
"It's very simple -- if there are 100,000 people whose livelihoods rely on a healthy ecosystem in the park, they are going to want to protect that park."
If de Merode and his team succeed, they will solve what has always been conservation's greatest quandary in Africa: giving the local population real economic benefits from national parks.
"We are on the frontline in terms of trying to protect that last incredible piece of forest," he tells us. "And of course its role in terms of stabilizing climate, its role in terms of addressing climate change issues is fundamental."
Given the chance, de Merode says, Virunga's wildlife will recover from decades of plunder.
He points out an area of savannah below that has always been a traditional migration route. "This area is critical because the park suffered enormously during the war and all the wildlife that we flew over have been depleted. For them to be repopulated it has to come through this corridor."
On the mountain, the troop of gorillas once targeted has a new patriarch. A silverback named Bukima looks on, unimpressed as a two-year-old juvenile beats his chest before running behind his mother.
Innocent Mburanumwe has seen gorillas roaming the wild since he was a boy, but it still amazes him.
"It's wonderful, just wonderful," he says. But he knows amazement alone won't save Virunga's gorillas.
"It hasn't been enough, we need to do much better for people to see the importance of these gorillas," he says.
"They are the last gorillas we have in this world, so we have to protect them."