When Mathieu Shamavu posted a selfie on Facebook earlier this month, he called it "another day at the office."
And, indeed, it would be another day — for a full-time ranger whose "office" happens to be Virunga National Park in eastern Congo.
A UNESCO world heritage site, the sprawling and dizzyingly diverse park is home to a world-famous — and critically endangered — population of mountain gorillas.
Shamavu's job is to keep them safe. But sometimes, they see themselves more as colleagues.
Like when Shamavu struck a pose for that selfie — and the mountain gorillas in his company tried to be just as cool as their human friend.
Their pose may also suggest the gorillas, Ndakazi and Ndeze, are "learning to be human beings," Innocent Mburanumwe, Virunga National Park deputy director, told BBC News.
The female gorillas spent part of their lives at the Senkwekwe Center, a park facility dedicated to helping gorillas in tough times.
And this pair, orphaned by poachers at a young age, have certainly known their share of them. In fact, there are just 1,000 mountain gorillas left in the wild, about a third of them in Virunga National Park.
Established in 1925, Virunga was the first national park in Africa. Since then it hasn't wavered in its mission to protect gorillas, even as the region was embroiled violent conflict. Poachers still linger at the fringe of the park, looking for an opportunity to make more orphans, while enriching themselves.
But somewhere in a space that always seems at the edge of peril, about 600 park rangers have made a deep connection with their charges.
And sometimes, with one very viral selfie — flush with swagger and confidence — a couple of mountain gorillas show the world why it's so worth it.