An orangutan has extremely long arms, compared with its legs and upper body. Its arms reach to its ankles when it is standing upright. It has long, curved fingers and toes that help it grasp branches, and its shoulder joints and hip joints are remarkably flexible.

Orangutans can walk on the ground, but they rarely do so. When they do, they walk on all four limbs, slowly and cautiously, and they usually only walk as far as the distance from one tree to the next. They travel much more gracefully when swinging from branch to branch in the trees.

Because they live so dangerously high in the trees, a mother orangutan must be careful with her offspring. At first, an infant simply holds on as tight as it can to its mother. Soon, however, the mother encourages her young to climb. She usually stays within arms’ reach until the young orangutan builds its strength.