Hominidae: ape family
Great apeas are larger and more robust than their relatives the gibbons. An adult male gorilla can weigh as much as 595 lb (270 kg) while chimpanzees can weigh between 106 and 176 lb (48 and 80 kg).
All apes are able to walk on their hind legs, if briefly, although most - apart from humans - normally travel on all fours. Gorillas and chimpanzees are largely terrestrial, but the orangutan spends much of its time in the trees, where it swings from branch to branch with surprising agility. While gorillas are vegetarian animals, the chimpanzees and orangutans are more omnivorous in their eating habits.
Apes are generally gregarious and live in family-based groups which forage together during the day, and build sleeping nests at night. Male great apes are larger than females and may have other special characteristics.
The orangutan is unique among large primates because it is relatively solitary and lives in trees, whereas other large primates, such as humans, chimps, gorillas and baboons, live in social groups. The name orangutan means "forest people" in the malay language.
Female orangutans sometimes accompany each other while travelling and will eat together. Males, on the other hand, usually avoid one another. Orangutans travel less than 1 km (0.6 miles) per day through their home ranges, moving from branch to branch at a leisurely pace. These apes sleep in nests high in trees, made from leafy branches. Like the other great apes, orangutans are intelligent animals, and have often been observed using tools. For example, they use large leaves as umbrellas to keep the rain off, and smaller leaves as pads to protect their hands and feet when moving through thorny vegetation.
Old adult male orangutans can sometimes get very fat, and these have very round faces because of deposits of fat under their skin.
Distribution: sumatra and borneo.
Habitat: primary rainforests.
Food: mostly fruit, but also other vegetable matter, insects, small vertebrates and birds' eggs.
Size: 1.3 - 1.6 m (4.3 - 5.2 ft); 32 - 93 kg (70.5 - 205 lb).
Maturity: 12 - 15 years.
Breeding: single young born every 3 - 4 years.
Life span: up to 70 years.
Status: vulnerable, due to habitat loss.
The sumatran orangutan is now considered a separate species. Orangutans are the largest of all arboreal mammals and they rarely come down to the ground. They have a very slow reproductive rate. Although they are hunted, it is loss of habitat that represents the greatest threat to orangutans, combined with natural disasters such as forest fires that may sweep through their habitat. They feed on more than 400 different plants, with wild figs being a favourite.
Distribution: occurs only on the island of borneo, in rainforest up to altitudes of 800 m (2620 ft). Fossil evidence suggests their ancestors occurred on the southeast asian mainland, too.
Weight: 40 - 90 kg (88 - 198 lb); males are larger.
Length: 78 - 97 cm (31 - 38 in).
Maturity: 15 years for both sexes.
Gestation period: about 260 days; the youngster may be carried by its mother for 3 years.
Breeding: 1, rarely twins; weaning occurs at 3.5 - 4.5 years.
Diet: feeds mainly on fruit, but will also eat leaves and seeds.
Lifespan: up to 60 years.
Only males have the flattened area around the face, extending as a dewlap under the throat.
These are very long and may reach up to 2 m (6.6 ft). The hands are largely free of fur.
The coats of these great apes are shaggy and reddish.
On the move
Orangutans can use both their arms and legs together to grip on to branches alternately as they swing through the forest.