The Story of Orang Utans ( A Summary)

Thursday, November 24, 2011

The Story of Orang Utans ( A Summary)

Maybe for some people, the article I write this time is not so attractive than what I did before.  But in the proccess of writing it, I feel some different things that I meet from my previous note.  It because  this article reflect the love and admiration from my deepest heart. Yeah.... a love and devotion from a mother to her daughter. Where I try to answer the questions of interest and curiosity of  the life of orangutans and their ecosystem from a little girl aged seven years old who almost everyday asked me for this matter. She is only seven years old, but her heart has been touched by the love and passion to learn more about orangutans. As her mother, I can feel the enthusiasm  that reflect from her face everytime we make a discussion about this primates.

Frankly, I never know any information about this mammals further. But because of her, I strive hardly to find the answer to all questions that oftenly comes from her tiny mouth and for the enthusiasme that shine along her face. It finally encourage me to make this article from a summary of the various information I already noted and some discussion with a friend who involve to orangutans conservation works. May this article will help people who needs the same information.

Orangutan (also well-known as Mawas ) is a kind of great ape with long arms and reddish or brown fur, which live in tropical forests of Indonesia and Malaysia, especially on the islands of Borneo and Sumatra. The term "orangutan" is taken from the Malay language, which means human beings (orang) of forest. Including two species of orangutans, Sumatran orangutan (Pongo abelii) and the orangutans of Borneo (Borneo) (Pongo pygmaeus). What is unique is an orangutan has a close kinship to humans at the level of the kingdom Animalia, where orang-utans have a level of 96.4% DNA similarity. Because of its similarity with human being orang utans found as intelligent mammals , that they have been known to use found objects as tools; for example, they use leaves as umbrellas to keep the rain from getting them wet. They also use leaves as cups to help them drink water. 

The Eye of Baby Orangutan

Usually the Orangutan mother teaches the babies how to get food, how to get a drink, and a variety of tree species in different seasons. Due to this  action, we can see that orangutans have a complex map of the forest areas of their brains, so they are not spent energy losses when searching for food. The children can also find different kinds of trees and plants that are eatable and how to handle food, which is protected by a shell and sharp spikes

Orangutans are omnivores (they eat both plants and animals) but are mostly herbivorous (plants comprise most of their diet). They eat fruit (their favorite food), leaves, seeds, tree bark, plant bulbs, tender plant shoots, and flowers. They also eat insects and small animals (like birds and small mammals). 

Orangutans are shy, solitary animals that are active during the day (they are 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 orangutan stay together for only a few days.

Each evening, orangutans construct a "nest" in the tree branches for the night in which they will curl up and sleep. These nests are made out of leaves and branches. Nests are shared by a mother and her nursing offspring. Sometimes, the orangutan will use a leaf as a "roof" to protect itself from the rain. Orangutans often nap in the afternoon after a morning spent obtaining food.

Way of Life

Male orangutans are capable of very long, loud calls (called "long calls") that carry through forests for up to 0.6 mile (1 km). The "long call" is made up of a series of sounds followed by a bellow. These calls help the male claim his territory, call to females, and keep out intruding male orangutans. Males have a large throat sac that lets them make these loud calls. It usually move by swinging from one branch to another; this is called brachiating. Orangutans can also walk using their legs (but rarely do). Orangutans do not swim.

Orangutans live about 50 years in captivity; their life span in the wild is only 30-45 years (like most animals, they live longer in captivity). Orangutans are mature and capable of reproducing beginning when they are 7 to 10 years old. Females are pregnant for 8.5 to 9 months and give birth to a single baby. Young orangutans are weaned from their mothers at about 6-7 years of age. The animal that poses the biggest threat to the orangutan is man (who uses its habitat and sells young orangutans as pets). 

Orangutans belong to the:
  • Kingdom Animalia (all animals)
  • Phylum Chordata
  • Subphylum Vertebrata (animals with backbones)
  • Class Mammalia (warm-blooded animals with fur and mammary glands)
  • Order Primates (which includes 11 families, which include lemurs, monkeys, marmosets, lesser apes, great apes, and humans)
  • Family Pongidae (the great apes, including gorillas, chimpanzees, bonobos, and orangutans)
  • Genus Pongo (gorillas and orangutans)
  • Species pygmaeus
    • Subspecies  P. p. pygmaeus (with a round face and dark red hair; found in Borneo)
    • Subspecies P. p. abelii (with a narrow face and paler hair; found in Sumatra)

Phisycal Characteristics

Orangutans have a large, bulky body, a thick neck, very long, strong arms, short, bowed legs, and no tail. Orangutans are about 2/3 the size of the gorila. They are mostly covered with long reddish-brown hair. The orangutan has a large head with a prominent mouth area. Adult males have large cheek flaps (which get larger as the ape ages). Orangutan hands are very much like ours; they have four long fingers plus an opposable thumb. Their feet have four long toes plus an opposable big toe. Orangutans can grasp things with both their hands and their feet. The largest males have an arm span of about 7.5 feet (2.3 m). 

Social Life
Orangutans live a more solitary lifestyle than the other great apes. Most social bonds occur between adult females and their dependent and weaned offspring. Adult males and independent adolescents of both sexes tend to live alone. The society of the orangutan is made up of resident and transient individuals of both sexes. Resident females live with their offspring in defined home ranges that overlap with those of other adult females, who may be their relatives like mothers and sisters. One to several resident female home ranges are encompassed within the home range of a resident male, who is their primary breeder. Transient males and females range broadly. They usually travel alone, but as sub-adults they may travel in small groups. However this behavior does not extend to adulthood. 

The social structure of the orangutan can be best described as solitary but social. As the ranges of males and females overlap, they commonly encounter each other while traveling and feeding and brief social interactions may occur. Interactions between adult females range from friendly, to avoidance to antagonistic. Resident males may have overlapping ranges and interactions between them tend to be hostile.

Mom & the babbies

During dispersal, females tend to settle in home ranges that overlap with their mothers. However, they do not interact with them any more than the other females and they do not seem to form social bonds. Males disperse much farther from their mothers and enter into a transient phase. This phase lasts until a male can challenge and displace a dominant, resident male from his home range. 

There are dominance hierarchies between adult males that regularly encounter each other with the most dominant males being the largest and having the best body conditions.  Adult males dominate sub-adult males. Both resident and transient orangutans aggregate on large fruiting trees to feed. The fruits tend to be abundant, so competition is low and individuals may benefit from social contacts. Orangutans will also form travelling groups in which members coordinate travel between food sources for a few days at a time. These groups tend to be made of only a few individuals. They also tend to be mating consortships, each made of an adult male and female traveling and mating.

Reproducting and Parenting
Male orangutans exhibit arrested development. They mature at around 15 years of age by which they have fully descended testicles and can reproduce. However they do not develop the cheek pads, pronounced throat pouches, long fur or long-calls of more mature males until they gain a home range, which occurs when they are between 15 and 20 years old. These sub-adult males are known as unflanged males in contrast to the more developed flanged males. The transformation from unflanged to flanged can occur very quickly. Unflanged and flanged males have two different mating strategies. Flanged males use long calls to advertise their location which attract estrous females.  Unflanged males wander widely in search of estrous females and upon finding one, will force copulation on her. Both strategies are successful, however females prefer to mate with flanged males and will seek them out for protection from unflanged males.  Resident males may form consortships with females that can last days, weeks or months after copulation.
Female orangutans experience their first ovulatory cycle between 5.8 and 11.1 years. These occur earlier in larger females with more body fat than in thinner females.  Like other great apes, female orangutans have a period of adolescent infertility which may last for 1–4 years.  Female orangutans also have a 22-30 day menstrual cycle. Gestation lasts for nine months with females giving birth to their first offspring between 14 and 15 years old. Female orangutans have the longest interbirth intervals of the great apes, having eight years between births.
Male orangutans play almost no role in raising the young. Females are the primary caregivers for the young and are also instruments of socialization for them. A female often has more than one offspring with her, usually an adolescent and an infant, and the older of them can also help in socializing their younger sibling. Infant orangutans are completely dependent on their mothers for the first two years of their lives. The mother will carry the infant during traveling, as well as feed it and sleep with it in the same night nest.  The infant doesn’t even break physical contact with its mother for the first four months and is carried on her belly. The amount of physical contact soon wanes in the following months.  When an orangutan reaches the age of two, its climbing skills are more developed and will hold the hand of another orangutan while moving through the canopy, a behavior known as "buddy travel". Orangutans are juveniles from about two to five years of age and start to exploratory trips from their mothers. Juveniles are usually weaned at about four years of age. Adolescent orangutans seek peers and play and travel with peer groups while still having contact with their mothers. Infanticide has not been recorded in the two orangutan species like it has in other primate species. Paternity uncertainty, the range patterns of female dispersals and the fact that the ovulation of females depends on food availability may make infanticide by males ineffective.


Current population estimated at less than 30,000 people spread across two distribution area (Sumatra and Kalimantan). It is estimated that the number of wild orangutang in the forests of Sumatra contained only around 6500-7500. In  Borneo was recorded  about 12000-13000 species. The reduction in the last of 10 years about 30%-50% . When the State remains, after 10-20 years into the future orangutans will extinct. In addition to the threat comes also from the activities of animals hunting, either to be sold as pets or meat.

Orang Utans' Contribution to Ecosystem

To get a baby of orangutan, then had to kill its mother, and if the baby survived falling from a tree, then the baby was taken by the hunters. If the decline in the orangutan population will pose new problems for the balance of the ecosystem that is the declining number of biodiversity . It because orang utans is very helpful in spreading the seeds of plants that maintain the balance of the forest through which it distributes seeds.
Orangutans are species for conservation. Orangutans play an important role for forest regeneration through the fruits and seeds they eat. The loss of orangutans reflects the loss of hundreds of species of plants and animals in the rainforest ecosystem .

Organisations, Rescue and Rehabilitation Center

Some organisations are working for the rescue, rehabilitation and reintroduction of orangutans. One of them is  The Borneo Orangutan Survival (BOS) Foundation  founded by Dr Willie Smits in 1991 and dedicated to the conservation of the endangered Bornean Orangutan and its habitat through the involvement of local people. It is audited by a multinational auditor company  and operates under the formal agreement with the Indonesian Ministry of Forest to conserve and rehabilitate orangutans. BOS manages orangutan rescue, rehabilitation and re-introduction programmes in East and Central Kalimantan. With almost 1000 orangutans in its care and employing between six hundred and a thousand people at a hundred site  BOS is the biggest primate conservation NGO worldwide.
BOS already built some rehabilitation and rescue center for orangutans,  they are  Wanariset that begans as tropical forest research station near Balikpapan in the Indonesian Province of East Borneo and Nyaru Menteng located in Palangkaraya, Central Borneo founded by Lone Drøscher Nielsen.  In Nyaru Menteng the sanctuary was designed to hold up to 100 orphaned orangutans while they go through rehabilitation. In addition to quarantine cages, medical clinic, and nursery, the sanctuary had a large area of forest in which orangutans could learn the skills needed to live in the wild.  Nyaru Menteng quickly became the largest primate rescue project in the world, with nearly 700 orphaned and displaced orangutans in its care at the present. Many of these orangutans are only weeks old when they arrive, and all of them are psychologically traumatized. The sanctuary not only saves the mostly orphaned baby orangutans from the local farmers and illegal pet-traders, but has developed a process for their gradual re-introduction to the remaining Borneo rainforest.

At the end of this summary, I could feel that same spirit which is transmitted by my  little girl. How delightful knowing something new.  I very well understand to have smart kids with the high sense of  conscience must begin with good support by the parents. From her I learn many things including orangutan itself. Thank you dear, for teaching me many things in life especially for the spirit and the huge emphaty that  grows in you in your very young age. May the positive atmosphere you have inside will support you to achieve success in the future.


With so much love I dedicate this article  to my children to support them more knowledge about the life of orang utan. And to all activist who concern about urangutans conservation. So much thankful to a friend, Kisar Odom who support me with complete information about orangutan and its conservation. Terima kasih sudah membantu untuk menyempurnakan kasih sayang seorang ibu kepada putrinya.

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