The orangutan, Pongo pygmaeus, is an ape that is found in the moist, coastal rainforests of Sumatra and Borneo which consists of Indonesia’s Kalimantan provinces, Malaysia’s Sabath and Sarawak, and the kingdom of Brunei Darussalam. Orangutans live in tropical rainforests and are arboreal primates meaning that they are tree dwelling.
Orangutans construct nests in the tree branches for the night in which they will curl up and sleep. These nests are made out of leaves and branches and they will sometimes use a leaf as a roof to protect themselves from the rain. Orangutans are omnivores, which means they eat a variety of meat and plants. They primarily eat fruit, leaves and small animals. However, 70% of a wild orangutan diet is fruit (Napier, 1988). The durian fruit is a juicy but smelly, cantaloupe-like substance that is among one of the orangutan’s favorites.
They also eat flowers, bark, nuts and small insects such as termites and butterfly larva (DeBoer, 1982). Adult orangutans are primarily solitary, except for mother-offspring pairs. However, weaned juveniles will sometimes flock in small groups. Orangutans are active during the day, or as (DeBoer, 1982) said diurnal. They live alone in large territories. This is probably due to their eating habits; they need a large area in order to get enough food and too many orangutans in one area might lead to starvation.
The only long-lasting orangutan social group is the mother and offspring, who live together for about 7 years. When mating, the male and female orangutans stay together for only a few days. Males are aggressive toward each other and often fight over females. They also will stake out areas in which they claim as their territory and fight other males if necessary (Galdikas, 1992).
The dominance hierarchy is the ranking system among the Primates. The hierarchy among orangutans is the Noayu, which is where there is a solitary male. There is marked sexual dimorphism among the orangutans. Females weigh only half as much as the males. Being lighter, females and juveniles often stay in the trees. Not only is there a noticeable difference in size, but males also possess quite a few different characteristics than female orangutans do.
For example, males have big cheek pads and facial hair that resembles a man’s moustache and beard. The numbers or orangutans have recently dropped tremendously owing to loss of habitat to deforestation and the killing of females for their young, to be sold as pets or zoo animals. Fewer than 30,000 individuals are believed to remain in the wild, and the species is listed as endangered (Galdkias, 1987)In relation to my observation, the orangutans acted very similar in captivity as if they were in the wild. The space was limited, but for what they had to work with, they displayed many of the behaviors they would have given they were in the wild. I noticed that the males remained solitary, as proven in my research.
In one instance, Kiko approached his sister and they groomed for a short amount of time, and Kiko went into a different section of the enclosure and remained by himself until the end of my observation. Junior, the dominating male, and father of Kiko, also stayed confined to himself. There was absolutely no interaction between Junior and the other orangutans. At one point of the observation, Junior showed a display of anger, sort of proving his dominance and went into the corner to set up a small, grounded nest. There were many displays shown throughout the thirty- minute time frame.
As stated above, Junior was angry because he was woken up by the commotion of the visitors, and began to throw the plastic barrel around. This might also relate to the social structure of a typical orangutan community. The males show aggression when their home feels threatened by another living thing and that would explain his irritation with the crowd. On more than one occasion, Bonnie, demonstrated a display of brachiating from branch to branch, and also up and down the gate against the glass. Orangutans are arboreal, meaning they are tree dwelling primates, so it is only natural instinctly and physically for them to brachiate throughout a tree-
