The sexual dimorphism between females and males is quite small in body size. In contrast to other species of apes, pair bonding is displayed by gibbons and they tend to live in small family groups comprising of one monogamous pair of adults along with their offspring. They are diurnal, however, in contrary to great apes, gibbons don’t form nests and instead they lean on tree branches during night. Gibbons feed on ripe fruits but they also eat insects, birds and leaves. The most prominent aspect of gibbons is their singing conduct used for mate attraction as well as territorial defense, and their style of arborous locomotion termed as “brachiation”. However, on ground they walk on two feet (Hohmann, Robbins and Boesch, 2006).
Amongst the entire great apes genus, only Orangutans are found in Asia. Their average adult height is 1.5m while mean adult weight is 110 kg. However, the sexual dimorphism is quite significant in weight amongst males and females. The female adults have 1.25m average height and 45kg average weight. Orangutans are extensively solitary while strong social linkages exist exclusively amongst female orangutans and their offspring. Both female and male Orangutans either reside as individuals in a determined home territory or as transitory individuals, and within determined ranges there is only one dominant male that breeds primarily and safeguards the female population within his territorial dominion from coerced copulations. They are diurnal but spend most of their time on trees. They also exhibit “brachiation” and quadrupedal fist-walking. Every night a nest is being built on tree by Orangutans for sleeping. They mainly feed on leaves, bark and shoots and rarely on bird’s eggs, insects or small vertebrates (Stanford, Allen and Antón,