Evolution & Classification
Orangutans have a large, bulky body, a thick neck, very long, strong arms, short, bowed legs, and no tail. They are mostly covered with long, reddish-brown hair and grey-black skin. Sumatran and Tapanuli orangutans have more sparse and lighter-colored coats. The orangutan has a large head with a prominent mouth area. Though largely hairless, their faces can develop some hair in males, giving them a mustache.
Adult males have large cheek flaps, called flanges, to show their dominance to other males. The flanges are made mostly of fatty tissue and are supported by the face's musculature. Mature males' throat pouches allow them to make loud calls. The species display significant sexual dimorphism; females typically stand 3 ft 9 in tall and weigh around 82 lb, while flanged adult males stand 4 ft 6 in tall and weigh 165 lb. A male orangutan has an arm span of about 6.6 ft.
The hands of an orangutan are similar to human hands; they have four long fingers, but a dramatically shorter opposable thumb for strong branch gripping as they travel high in the trees. The joint and tendon arrangement in the orangutans' hands produces two adaptations that are significant for arboreal locomotion. The resting configuration of the fingers is curved, creating a suspensory hook grip. Additionally, with the thumb out of the way, the fingers and hands can grip securely around objects with a small diameter by resting the tops of the fingers against the inside of the palm, thus creating a double-locked grip.
Their feet have four long toes and an opposable big toe, allowing them to securely grasp things with both their hands and feet. Both their fingers and toes are curved, allowing them to get a better grip on branches. Since their hip joints have the same flexibility as their shoulder and arm joints, orangutans have less restriction in the movements of their legs than humans have.
Unlike gorillas and chimpanzees, orangutans are not true knuckle-walkers, but are instead fist-walkers. Knuckle-walkers use a more relaxed open hand with the middle segments of the fingers sweeping the ground while fist-walking happens with a more gripped fist so that the closest finger segments touch the ground.
In the Franchise
In the original Planet of the Apes film series the orangutans were the politicians, administrators, lawyers and priests of the ape society. They are the only known species of ape in the films that have orange hair instead of dark colors like black, brown and gray. The orangutans are peaceful and wise. Male orangutans have cheek pads, as seen in more recent orangutan characters like Nado and Maurice.
- Orangutans tend to be fewer than the other species of ape in the franchise, which may coincide with the real world statistics that orangutans are in the highest decline of the great apes conservation status with less than 70,000 left in the wild.
- In Conquest of the Planet of the Apes, Caesar stows away inside a cargo shipment of Bornean orangutans that came from Asia. His cover was blown when the humans realized that chimpanzees are not native to Asia, coinciding with the real fact.
- The orangutans were envied by other cast members of the original films because the hair covered their ears, thus removing the need for additional makeup.