Kloss’s gibbon is an arboreal species, spending most of its time in the canopy. They are active in the day (2) and get around by swinging from branch-to-branch, their long hands forming perfect hooks for grasping the branches (5). They live in groups, consisting of a breeding pair and their offspring, with social grooming helping to maintain bonds (5). These groups defend a territory, with loud bouts of singing serving to proclaim ownership (2). Neighboroughing males chorus before dawn and females after dawn with a 50 second great call (6). As young males and females reach sexual maturity they will leave the family group, with the aim of finding a mate and establishing a new group (5). These gibbons feed mainly on fruit, but will also take flowers and some invertebrates to supplement the diet (5).
Males and females form monogamous pairs. A single young is produced after a gestation period of seven to eight months. There is typically a gap of two to three years between each birth (2).