Red apes of the forest: Orangutans live in tropical and swamp forests on the Southeast Asian islands of Borneo and Sumatra. These shaggy red apes are the largest arboreal mammal and the only great ape found in Asia.
The other great apes—gorillas, chimpanzees, and bonobos—are all native to Africa. Its stocky body has a flexible pelvis, a thick neck, and bowed legs. The orangutan's arms are longer than its legs, reaching nearly to its ankles when the ape stands up. Like other apes, orangutans don't have a tail. Orangutans spend most of their life in the trees, swinging confidently from branch to branch.
Their long fingers and toes can easily grasp branches and vines. With arms longer than their body and long, strong fingers and prehensile feet, life in the trees works well for them. In fact, orangutans look a bit awkward on the ground, using their arms as we might use a pair of crutches or lifting those arms high above their head when they walk.
Adult male orangutans are much larger than adult females. Sumatran orangutan: Lives on Sumatra. The hair is longer and lighter-colored than that of Bornean orangutans. Bornean orangutan: Lives on Borneo. Adult males have much larger flanges and a large throat pouch. The hair is shinier, and the females rarely have any beard at all.
Bornean orangutans are more heavy-set than Sumatran orangutans. Tapanuli orangutan: The southernmost population of orangutans on Sumatra. This species, described in , differs from both of the other two species in subtle—but consistent—ways: it has a slightly smaller skull, a shallower face, and various skull, jaw, and tooth measurements that differ.
