Very few people have ever seen a Cross River gorilla (Gorilla gorilla diehli), the rarest and most endangered of the world's four gorilla subspecies. Only about 250 to 300 of these animals exist in the world, and they have almost never been photographed in the wild.

Well, you're in for a treat. The Wildlife Conservation Society (WCS) this week released the first camera trap video footage of Cross River gorillas. The footage, shot in Cameroon's Kagwene Gorilla Sanctuary, shows eight different gorillas—representing about 3 percent of the entire species—casually walking through the forest. About halfway through the two-minute video, a male silverback charges toward the camera, beating his massive chest:

"Spectacular footage such as this, which we've never had before for Cross River gorillas, is absolutely vital to inspire local people, the governments of Nigeria and Cameroon, and the global community to care about and to save this unique subspecies," James Deutsch, executive director for WCS's Africa Program, said in a prepared release. "Continued research of this kind will help fine-tune management plans to protect this rarest of apes."

The video does contain a disturbing element if you look closely enough: one of the gorillas is missing a hand. The WCS theorizes that this could be an injury, now healed, caused by a snare left by hunters. Wildlife poaching used to be more prevalent in the region, but the sanctuary has been protected by antipoaching patrols since it was established in 2008. It is less than 20 square kilometers in size and is estimated to hold approximately 20 to 30 gorillas.

"Cross River gorillas occur in very low densities across their entire range, so the appearance of a possible snare injury is a reminder that continued law enforcement efforts are needed to prevent further injuries to gorillas in the sanctuary," said Liz Macfie, gorilla coordinator for WCS's Species Program.

Cross River gorillas only live in remote, mountainous regions along the Nigeria–Cameroon border, where they exist in extremely fragmented subpopulations spread out over 12,000 kilometers. The major threats to their survival are habitat loss and poaching. Most of the gorillas live outside of protected sites.

Previously in Extinction Countdown: Critically Endangered Cross River Gorillas May Have More Room to Grow

Video and still courtesy of the Wildlife Conservation Society