Orangs often live in small group of two to four animals, but adult males may be solitary. Orangs are arboreal, seldom leaving the trees, where they feed primarily on fruit but also on leaves, bark, and birds eggs. They build simple sleeping nests, or platforms, on which they spend the night.
Full maturity is attained at 10 to 12 years of age, sexual maturity is reached at about 8 years. Gestation lasts about 9 months. Humans are the orangs only significant enemy, and unless hunting and destruction of their forest are curtailed, orangs will soon become extinct.