Hands are long, slender and prehensile with curved phalanges. The thumb is short and set close to the wrist. Feet are hook-like with a reduced big toe similar to hands. Fingers and toes show strongly curved nails. Behavior Brachiation in trees involves the use of all limbs, with the feet as effective as hands.
Movement is cautious in adults with no leaping or jumping.
They may make young trees sway dramatically in order to reach the next tree. On the ground orangutans walk quadrupedally with feet clenched and knuckle-walking . Bipedalism is only seen in captivity, walking with arms held upright for balance. Groups consist of an adult female with one or two young. Males may sometimes become nomadic and leave their native territory.