Orangutans are diurnal, spend a majority of their time awake during the day.  A large portion of their daylight hours, much like the Gorilla, is spent searching for and consuming food. At night Orangutans build nests with branches and leaves for sleeping.  This is typically a new nest nightly as the Orangutan is rarely ever in the same location each evening. These nests are built at tremendous heights to protect the Orangutan from nightly predators.

diurnal adj.

1: (biology) belonging to or active during the day; "diurnal
animals are active during the day"; "diurnal flowers
are open during the day and closed at night" [ant: {nocturnal}]
2: having a daily cycle or occurring every day; "diurnal
rhythms"; "diurnal rotation of the heavens"; "the diurnal
slumber of bats"

     The Orangutan, unlike other Primates, is a solitary animal, preferring to spend much of their time in small groups rather than complex social structures.  Mature male Orangutans appear to be totally intolerant of each other. The meeting of two mature males results in either aggression or avoidance. Adult male participation in social groups is normally limited to sexual consort ship with adult and adolescent females. Adult females however may be seen with young, with other adult females and with adolescents. This interaction among females is common both with and outside their own families.  As with Chimpanzees and Gorillas, the relationship between mother and young lasts for long periods of time.  During this "mother" phase, the time spent with non-related orangutans is relatively short.   Sub adult males usually associate with adult females. Adolescent females travel together when age differences are minimal. This semi-solitary social system probably evolved as a result of food distribution (food sources are scattered rather than concentrated) and a lack of predators.

consort ship \Con"sort*ship\ (k[o^]n"s[^o]rt*sh[i^]p), n.

1. The condition of a consort; fellowship; partnership.

      Although mostly arboreal, males will occasionally come to the ground to move between stands of trees. While females stay near their mothers home range, males emigrate long distances. This helps to minimize inbreeding in the species.