The golden monkey is the only other primate species found in the Volcanoes National Park. It got its name from the bright golden – orange colour of its trunk, outer thighs and base of the tail that contrasts sharply with the dark limbs, crown and tail end. It is a quite massive but alert monkey, with a thick and dense fur. The loud alarm calls can often be heard in the forest, even if the monkey themselves are hard sometimes to spot.
Golden monkeys live usually in family units of 10 to 15 individuals but can congregate to form much larger troops of several dozen animals. They are most active in the early and late hours of the day, feeding predominantly in the bamboo thickets, where most of these monkeys spend good part of the year.
The golden monkeys is a subspecies of the widespread Blue Monkey. It is endemic for the Albertine Rift region. It is somewhat larger than the other subspecies of this monkey and has a thicker fur, an adaptation to the harsh climate of the Virunga. The golden monkey is limited to the high altitude forests of the Lake Kivu region (Rwanda, DRC, and Uganda). It is globally considered as an endangered subspecies. In Rwanda, the golden monkey is restricted to the Virunga Forest, Gishwati forest (where a few groups are said to survive) and probably Nyungwe forest (with a small population in the bamboo area) the population of the Volcanoes National Park is probably the last viable one in the long term.
Two groups of the golden monkeys have been habituated to peaceful human visitors. The first habituated group lives on the slopes of Mt. Karisimbi and has around 90 individuals. The second troop of golden monkeys that went through the habituation process is even larger, with around 95, joining and splitting in different subgroups. It lives near the base of Mt. Sabyinyo. The total population of the golden monkey in Volcanoes National Park was estimated at about 4.835 individuals in 2007.