A L'Hoest monkey, or Mountain monkey, (Cercopithecus l'hoesti) feeds at the edge of the Nyungwe Forest. The L'Hoest monkey is a medium-sized, omnivorous primate, which is the most terrestrial of the guenons found in Nyungwe. Although common in Nyungwe, it is considered a vulnerable species by the International Union of Nature and Natural Resources (IUCN).Covering 970 square kilometres, this Forest is one of the largest montane rain forests in Africa; it is also one of the oldest because it was largely unaffected by the last Ice Age. The diversity of life in Nyungwe is outstanding in an African context; no less than thirteen primate species live there including chimpanzees. Also, found there are more than 190 species of trees, over 100 different orchids and 275 species of birds with 24 endemic to the Central African Highlands.