kloss's gibbon exclusively lives on the mentawai islands that lie to the west of sumatra. it is a diurnal inhabitant of the rain forest that hangs in the trees from its long arms and rarely comes to the ground. like all species of gibbons it lives together in pairs that stake out a territory from approximately 20 to 30 hectares of size. this area is defended vehemently against other gibbons. its diet consists mainly of fruits, occasionally also eating different plant parts, bird eggs, insects and small vertebrates.