A selfie of a park ranger and two standing gorillas in Africa has gone viral. The photo shows two park rangers with a pair of orphaned mountain gorillas in Virunga National Park in the Democratic Republic of Congo.

Ranger Mathieu Shamavu, who is part of an anti-poaching unit, took the picture with the endangered apes, who appeared to be posing and casually standing upright. The park posted the image on its Facebook page with the caption "Another day in the office" on Thursday, and it immediately drew massive attention — mostly because users couldn't believe it. The park, however, addressed those concerns on Instagram.

"YES, it's real! Those gorilla gals are always acting cheeky so this was the perfect shot of their true personalities! Also, it's no surprise to see these girls on their two feet either—most primates are comfortable walking upright (bipedalism) for short bursts of time."

Get Breaking News Delivered to Your Inbox

In an interview with BBC News, the park's deputy director, Innocent Mburanumwe, said the gorillas had learned to imitate their caretakers, who have looked after them since they were less than 4 months old. According to Mburanumwe, they see the park rangers as their parents because the gorillas' mothers were both killed in 2007.

"I was very surprised to see it... so it's very funny. It's very curious to see how a gorilla can imitate a human and stand up," he said.

The park noted the viral photo was taken under "exceptional circumstances," adding, "It is never permitted to approach a gorilla in the wild."

According to the park's website, around one-third of the world's endangered mountain gorillas reside in Virunga National Park, which stretches across the eastern part of the country.