The long, narrow hands and feet of orangutans are well-suited for their life in the trees.
Orangutans, which means "person of the forest," are great apes, of the Hominidae family. There are two species orangutans: Pongo pygameus, found on the island of Borneo, and Pongo abelii, found on the island of Sumatra. Facts about these endangered primates can be classified according to physical appearance, habitat, behavior and the raising of their young.
Orangutan Appearance
Orangutans are the largest tree-living animals in the world, spending around 90 percent of their time in the branches. Of all the primates, orangutans feature one of the largest differences in the size of males and females. Adult males can weigh up to 300 lbs., while adult females weigh roughly half that. Males also reach heights of up to 5 feet, with arm spans as long as 8 feet. Unlike the other great apes, orangutans are covered by thick, reddish brown hair. The average lifespan of an orangutan is 30 to 40 years, though they can reach into their late 50s in zoos.
Orangutan Habitat
Once having roamed throughout Southeast Asia and Southern China, orangutans are now found only on the islands of Borneo and Sumatra. The Sumatrans have splintered into nine populations, all in Northern Sumatra, while the Borneans are more evenly distributed around the island. Both groups primarily inhabit peat swamp forests, tropical heath forests and mixed dipterocarp forests. They all live below 1,000 feet in elevation. Orangutans thrive in fruit-rich areas, preferring the fruit of the durian tree. In addition to fruits, they eat leaves, bark, flowers, honey, insects and vines. They sleep in the trees, constructing nests made of branches each night.
Orangutan Behavior
Unlike other great apes that live in troops, orangutans are semi-solitary, maintaining only a loose social structure. Mature males are the most reclusive, typically only socializing for short mating excursions. Females maintain long-duration relationships with their young but also typically avoid larger social interaction, except to mate. Adult males are intolerant of other males and interactions will lead to either aggression or avoidance. In the case of aggression, males will violently fight each other for up to several hours, especially in the presence of a female. These battles typically result in serious injury, including lost digits and eyes. Females rarely exhibit violent behavior.
Orangutan Young
Of all the world's mammals, orangutans are the slowest to mature and the slowest to reproduce. Females reach sexual maturity at around 12 years, but typically do not have their first offspring until they are 15 to 16 years old. Females typically give birth to a single baby. Males serve absolutely no role in the upbringing of young. These baby orangutans are completely dependent on the mother's care for the first two years. However, even after this, the close bond between mother and child continues. Mothers generally carry the young until they are five years old and continue breast-feeding until they are eight years of age. Young orangutans become independent around ten years of age, but females will commonly continue to visit their mothers until they are 15 to 16 years old.
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