Orangutans have an enormous arm span. A male may stretch his arms some 7 feet (2 meters) from fingertip to fingertip—a reach considerably longer than his standing height of about 5 feet (1.5 meters). When orangutans do stand, their hands nearly touch the ground.

Orangutans' arms are well suited to their lifestyle because they spend much of their time (some 90 percent) in the trees of their tropical rain forest home. They even sleep aloft in nests of leafy branches. They use large leaves as umbrellas and shelters to protect themselves from the common rains.
These cerebral primates forage for food during daylight hours. Most of their diet consists of fruit and leaves gathered from rain forest trees. They also eat bark, insects and, on rare occasions, meat.

Orangutans are more solitary than other apes. Males are loners. As they move through the forest they make plenty of rumbling, howling calls to ensure that they stay out of each other's way. The "long call" can be heard 1.2 miles (2 kilometers) away.

Mothers and their young, however, share a strong bond. Infants will stay with their mothers for some six or seven years until they develop the skills to survive on their own. Female orangutans give birth only once every eight years—the longest time period of any animal. The animals are long-lived and have survived as long as 60 years in captivity.

Because orangutans live in only a few places, and because they are so dependent upon trees, they are particularly susceptible to logging in these areas. Unfortunately, deforestation and other human activities, such as hunting, have placed the orangutan in danger of extinction.