Throwing itself from tree to tree over gaps of over nine metres, this tree-dwelling primate moves its forearms alternately to swing beneath the branches (3) (6). Despite exhibiting this brilliant form of locomotion, known as brachiation, the pileated gibbon is also able to move short distances by foot, and can also climb whilst moving slowly or feeding (5). The diet of the pileated gibbon consists primarily of fruits high in sugar, such as the fig (Ficus species), but it also supplements this sweet food with immature leaves, flowers and insects (5).
Pileated gibbons are active during the day, spending the nights and other periods of rest in tall trees (5). They live in small family groups which consist of a breeding pair and their offspring. Single offspring are born into the group every two to three years (5) (7), and leave the group around adolescence (5). Although these apes are monogamous, polygyny has been observed where the white-handed gibbon (Hylobates lar) occurs in the same area, with some groups containing females of both species (5).
Like all other gibbon species, pileated gibbons reinforce bonds between individuals in the group by social grooming, with one individual grooming another (5). Dominated by the female, the bond between breeding pairs is reinforced through ‘duets’. It is believed that these vocalizations are also necessary to establish and maintain the family groups’ territory (5), which they also defend with displays and threats (5) (6).