Great apes of the world

Great apes are so called because of their size, but these magnificent animals are equally ‘great’ in a metaphorical sense.

The orang-utan Pongo pygmaeus, confined to the islands of Borneo and Sumatra, is Asia’s only surviving great ape. Mainly solitary and arboreal, it is the largest tree-dwelling primate. Large males can weigh 90 kilos (200 pounds) or more. Orang-utans are sparsely covered in long hair, which darkens with age and ranges in colour from bright orange to dark brown.

African great apes - chimpanzees and gorillas - are covered with short, coarse, black hair. Although they are accomplished climbers, they are equally at home on the ground. They usually move around on all fours, but will walk short distances on two legs.

Chimpanzees are mainly found in tropical rainforest, though some frequent savannah woodland. They usually live in loose groups of thirty or more individuals and are extremely vocal communicators. Adult chimpanzees stand about 1.2 metres (four feet) tall and weigh around 45 kilos (100 pounds). The bonobo, or pygmy chimpanzee Pan paniscus, is slightly smaller and more upright than the “common” chimpanzee (Pan troglodytes). Less comfortable on the ground, it is the most arboreal of Africa’s great apes and is confined to the left bank of the Congo River in the swampy forests of the Democratic Republic of Congo.

The gorilla is the largest of the great apes. An adult male can weigh over 180 kilos (400 pounds). When mature, males develop a silver-grey saddle, hence the name ‘silverback’. Adult females weigh about 90 kilos (200 pounds). Lowland gorillas occur in Angola, Cameroon, Central African Republic, the Democratic Republic of Congo (DRC), Equatorial Guinea, Gabon, Nigeria and the Republic of Congo.

The western lowland gorilla Gorilla gorilla has an estimated population of 10,000. Although it is the most widespread gorilla, numbers are decreasing rapidly. Its population is currently threatened not only by deforestation and the bushmeat trade, but also by potentially devastating outbreaks of the Ebola virus. It lives in flexible social groupings and, in that respect, more closely resembles chimpanzees than other gorillas. It also has a broader diet and consumes a larger proportion of fruit. As with all apes, logging and the bushmeat trade have taken a heavy toll and led to severe fragmentation of the population. The eastern lowland gorilla (Gorilla beringei graueri), found only in eastern DRC, is less well known. Its population is thought not to exceed 7,000. By virtue of its location, it is highly vulnerable and has been severely affected by both war and illegal mining.

Mountain gorillas (Gorilla beringei beringei) are generally larger than their lowland counterparts. They are confined to two small, protected patches of afromontane forest in Uganda’s Bwindi Impenetrable National Park and the Virunga Volcano Region where Rwanda, Uganda and DRC meet. Along with the Cross River subspecies of the western lowland gorilla (Gorilla gorilla diehli), the mountain gorilla is one of the two most endangered apes in the world.

See IUCN Red Data Book for more information on the status of great apes.