Rangers have been recording footage of the gorillas they protect
The Democratic Republic of Congo's Virunga National Park and the surrounding Virunga volcanoes region are home to more than half of the world's population of mountain gorillas.
To ensure the long-term survival of this threatened species, teams of rangers monitor and patrol the park's Gorilla Sector.
Two of the rangers, Diddy and Innocent, have been keeping a weekly diary for the BBC News website that offers an insight into life on the frontline of conservation.
Here, they also share video footage that they have been recording over the past few months.
GETTING TO GRIPS WITH GORILLA TALK
Diddy, who has been a ranger for more than 16 years, gives an entertaining first lesson on gorilla communication.
MEET THE GORILLAS
Here is footage of some of the park's gorilla groups, known as "families", which are named after the dominant male or "silverback".
'MY FAVOURITE GORILLA'
Innocent, head of gorilla monitoring, is able to recognise every gorilla within the sector.
Each animal has a unique "nose print" that enables rangers to tell them apart.
Here, Innocent explains why the giant ape nicknamed "the bald gorilla" is his favourite.
THE JULY MASSACRE
In July 2007, the Virunga National Park grabbed headlines around the world for all the wrong reasons.
Several gorillas were shot dead by gunmen; an act described as "senseless and tragic" by conservationists.
Innocent recalls how he felt when he heard the news, and the aftermath of the "massacre".
(Some people may find this film upsetting)
PROFILE OF THE RANGERS
Head of gorilla monitoring in the Mikeno sector. He has worked in Virunga National Park for nine years. His father is a patrol post chief. His brother was also a high-level ranger, but was killed in the line of service in November 1996.
Head of tourism in the southern sector of Virunga National Park. He has been a ranger for 16 years and started working with the gorillas in the Mikeno sector in 1991. He was forced to flee from his work from 1997-2001 during the nation's civil war.