The orangutan, Pongo pygmaeus, whose name derives from the Malay words for "man of the woods," has a high, arched forehead that gives it a distinctly humanlike visage. Long red hair distinguishes it from other apes, as does its habit of foraging for food individually, rather than in groups. Orangutans have been observed to eat more than 200 kinds of fruit. They live almost exclusively in the trees and are quite clumsy on the ground, where they move slowly on all fours. Orangutans are found only in lowland and tropical rain forest areas of northern Sumatra and lowland Borneo.
The orangutan spends most of its time in trees, using its long arms and hook-shaped hands and feet for grasping branches and vines. It seldom ventures to the ground, but when it does, it walks on all fours. Traveling through the treetops is difficult, so an orangutan only travels a few hundred meters each day. Each evening it builds a new treetop nest, often by bending down fronds of a betel tree. Older males, however, may travel and sleep on the ground.