Monkeys, Apes and Humans Gibbon Species Hylobates spp.
Gibbons are the smallest apes, weighing approx.
Siamangs are about twice as large, weighing approx. Gibbons and Siamangs are brachiators in middle canopy rainforest. Siamangs are sympatric with other Gibbons, utilizing different feeding patterns. Home ranges are about 40 hectares. Groups travel about 1 km per day, although there is considerable variation.