Along with other gibbons, the Siamangs are the top trapeze artists of the animal world. They leap with confidence across formidable gaps between branches, launching themselves 30-50 feet, using their hands as hooks. This mode of locomotion is called brachiation. While their arms are used for travel, their feet are used to carry objects. When walking, Siamangs will hold their arms above their heads for balance.
Siamangs live in family groups lead by a dominant male.
They are protective of one another and sociable among themselves, huddling together in groups of two or three when they sleep. The call of the Siamang excels that of other gibbons because of the animal's sound-amplifying throat sac. The female emits a series of barks alternated with booms resonated in the vocal pouch, which she blows up like a balloon. It is quite a display of territory and power and can be heard for a considerable distance. Siamangs eat fruit, leaves, insects, nuts, small animals, birds and bird's eggs.