Gibbons (HYLOBATES CONCOLOR GABRIELLAE) (PONGIDAE). are inhabitants of dense evergreen tropical forests. They are arboreal and occasionally descend to the ground. They move primarily by brachiation when strong and long hands suspend and propel the body. They can leap from branch to branch for 8 meters or more.
Gibbon diet consists of fruit and leaves, sometimes of eggs, insects and small vertebrates. Before eating fruits gibbons often squeeze them among their fingers to test its ripeness.
Gibbons form small groups up to 6 animals: they are an adult pair and their offspring. The pairs of gibbons are rather constant. The new social bonds between a male and a female from other group are reinforced by mutual grooming.
Gibbons are strongly territorial, defending home range of each family. At dawn gibbons give their morning chorus. Their calls or songs are very loud and can last for 2 hours. These calls ensures accomplish group spacing and social bonds' reinforcing as well as defence of home ranges. After singing the family passes round it's range.