Orangutan Conservation

Classification and Distribution of Orangutan
Fossil evidence suggests that till 10,000 years ago, distribution of orangutan extended to across Java and mainland Asia (China, Vietnam, Laos, Cambodia and Thailand). The orangutan in Java Island may have become extinct in the 17th century. Today, populations are restricted to pockets of forest on the islands of Borneo and Sumatra. Before these two populations were classified as two subspecies but now they are divided into two species, Borneo Orangutan: Pongo pygmaeus and Sumatara Orangutan: Pongo abelii. The Borneo Orangutan is further categorized into three subspecies; P. p. pygmaeus (Sarawak & West Kalimantan), P. p. wurmbii (West & Central Kalimantan) and P. p. morio (East Kalimantan & Sabah).

The current population of orangutan in Sumatra Island is 6,500 and 54,000 in Borneo Island. A total of 60,500 orangutans live in the world. Sabah has 11,000 orangutans in 13 populations but 62% of them live outside of the protected areas (commercial forests). The number of orangutan living in Danum Valley Conservation Area is estimated at 500.

Ecology of Orangutan
The natural habitat of orangutan is limited areas of tropical rainforest, low land Dipterocarp forest and swamp forest at altitudes of less than 1000m. The orangutan has a slow and long life history. Duration of life is estimated over 50 years in the wild. The female matures sexually at about ten years old and male matures around 15 years old. The female has a baby every six or nine years. Therefore its reproductive speed is the slowest in mammals and this is one of the reasons the orangutan is in danger of extinction. A remarkable characteristic of the orangutan is that it is the largest arboreal mammal (Adult Female: 35 kg, Adult Male: 80 kg) living on earth.

The orangutan is a fruit-eating animal and loves fruits of wild durian, wild mangosteen, ficus and so on. However in the primary forest in Borneo where there are “long period of scarcity of fruits”, sometimes over several years, the orangutan then depends on young leaves and barks for food. They also feed ants and termites but they hardly eat vertebrates.

The orangutan stays on trees, sometimes over 30m above the ground, as there are fewer predators, especially in Borneo. They use leaves to make rainhats and branches as well as foliage too for roofs over the sleeping nests every night. The baby sleeps with the mother in the same nest while the young and the adults make their own nest and sleep alone.

Sociality of The Orangutan
The orangutans are generally passive but can be territorial and aggressive towards other orangutans. The adult male orangutan has a unique social and physical system named “Bimaturism”. There are two types of adult male, “Flanged Male” and “Unflanged Male”. The Flanged Male has a remarkable secondary sexual characteristics such as large body size (twice than adult female), cheek flanges and throat-pouch.

The Flanged Male is very aggressive towards the Flanged Male while it is tolerant towards the Unflanged Male. The Unflanged males will try to mate with any female and may succeed in forcibly copulating with her if she is also immature and not strong enough to fend him off. Mature females can easily fend off their immature suitors, preferring to mate with a flanged male.

Extinction and Conservation of Orangutan
The number of Orangutan decreased over 40% in the twentieth century due to habitat destruction and poaching. Previous logging activities and oil palm plantation had a great influence on the decrease of the orangutan. In the longer term, this loss of habitat may cause the population to decline further. When adult females are killed, the babies will be sold and the skull of the dead will be used to create as a souvenir that are sold illegally.

We need to cultivate the knowledge of people to be part of the world’s largest primate rescue and rehabilitation project and help save the orangutan from extinction. Rehabilitation programs from the government in Malaysian and other NGOs have contributed to conserve the orangutan.

Our sincere appreciation to Dr Noko Kuze and her team for the generous contribution on the research information and pictorial of the orangutan in Danum Valley Conservation Area for the purpose of the development of this webpage.

Research Project

Project Purpose

To clarify the ecology of the orangutan (P. p. morio) in their natural habitat (Lowland Dipterocarp Forest). Focus on adaptation to LOW and IRREGULAR fruit supply based on long-term research.

Ongoing Research Topics

- Activity patterns- Feeding ecology- Density of Orangutan - Ranging patterns - Locomotion and Positional behavior - Social system- Genetic studies of paternity, relatedness and genetic diversity- Cultural behaviors- Reproduction and Life history- Cognitive Ability- Physiology (Stress)- Health & Disease

Research Activity

Record following terms in 1-minute intervals by direct observation;- type of the behavior with posture and vocalization- height of the place staying - names of neighbor individuals (within 50m) if there are any neighbor - distance between nearest neighbor.
Record their travel path and home range by GPS.Collect samples of food and Identify them.

History of Research

1968-1990John Mackinnon (ref. MacKinnon J. 1974. Search of the Red Ape, Ballantine Books. London).1991-1994Nirofer Graffar2004 – On Going Tomoko KANAMORI 2005 – On Going Dr. Noko KUZE 2009 – On Going Saika YAMAZAKI 2011 – On GoingMr. Tomoyuki Tajima

Current Researchers

Tomoko KANAMORINationality:JapanSex: Female Position: Researcher (Doctor of Science) Affrication: Wildlife Research Center of Kyoto University, Japan Objective:Feeding Ecology and Social Behavior
Noko KUZENationality:JapanSex: Female Position: Research Fellow (Doctor of Science) Affrication: Japan Society for the Promotion of Science (JSPS), Wildlife Research Center of Kyoto University (http://www.wrc.kyoto-u.ac.jp/en/index.html), Japan Objective:Reproduction and Cognition
Saika YamazakiNationality:JapanSex: Female Position: Ph. D. student Affrication: Japan Society for the Promotion of Science (JSPS), United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Japan Objective:Social Behavior and Physiology
Tomoyuki TAJIMANationality:JapanSex: Male Position: Ph. D. student Affrication: Japan Society for the Promotion of Science (JSPS), Laboratory of Human Evolution Studies, Graduate School of Science, Kyoto University Objective:Social Behavior and Male’s Reproductive Success


Local collaborator:Dr. Henry Bernard (Institute for Tropical Biology and Conservation Universiti Malaysia Sabah)

Mr. Titol Peter Malim (Sabah Wildlife Department)

Contract grant sponsor:Japan Society for the Promotion of Science (JSPS)

JSPS-HOPE (Primate Origins of Human Evolution) Project

21st century COE programs, Graduate School of Science, Kyoto University

Global COE programs, Graduate School of Science, Kyoto University

Global Environment Research Fund

Special Thanks to: Dr. Marc Ancrenaz, Dr. Isabelle Lackman-Ancrenaz, Dr. Shiro Kohshima, Dr. Toshinori Tsubouchi, Dr. Goro Hanya, Dr. Waidi Sinun, Dr. Glen Reynolds, Ms. Salina Noor, Dr. Satoru Kuze, All staff of Borneo Rainforest Lodge, Sabah Wild life Department, Institute for Tropical Biology and Conservation Universiti Malaysia Sabah, Yayasan Sabah and Borneo Nature Tours SDN. BHD.

Ecological Study

General Information Region: Indonesia (Sumatra), Malaysia (Borneo) Total population:63,500 (7,500:Sumatra, 56,000:Borneo) Density of Danum Valley :1.04individuals/km2 / Population size:498 Density of Borneo rainforest Lodge :2.7individuals/km2

Classification of Orangutan

Taxonomy: Sumatra Borneo

Genus: Pongo Pongo

Species: abelii pygmaeus

Subspecies: P. p. pygmaeus, P. p. wurmbii, P. p. morio

Long life history: Life Span: over 50 years old (wild) Low reproductive speed:• Maturity: Male 15 years / Female 10 years
• Birth Interval: 6-9 years
• Gestation:8.6months (260days)
• First Birth: over 15 years old Largest arboreal mammal:Weight:Male: 80 kg / Female: 35 kg

Material and Method

Study Area: Borneo Rainforest Lodge(BRL)Borneo Rainforest Lodge(BRL)
- 2km2 around the tourist lodge
- Lowland Dipterocarpus Forest
- This area is reserved for research, education and tourism.
- N50°- Average temperature 28℃ The Content of Data:Research Period: July 2004 – Total Observation Time: 2801hr (on 1/Apr/2010)

Population in Borneo Rainforest Lodge

The Sex and Age Composition of Identified Individuals We suppose at least 17 (includes 5 babies )are Resident out of 29 individuals

Feeding & Food Item

Parentage of the feeding time of each food items Proportion of food items which orangutan especially eats Acknowledgement

When around Orangutans



The rules and guidelines of the Borneo Rainforest Lodge (BRL) are all in place for your own safety as well as the safety and well being of the conservation area and its residents. During your visit, kindly observe the guidelines set out below in order to ensure your experience here will be hassle free and something special to remember.

  • Do not step out of or leave the trail; these areas are off limits for your health and safety as well as the health and safety of the animals.
  • Do not approach, touch or feed any animals; physical contact with the orangutans can not only spread diseases from you to them, but also from them to you. The orangutan is very sensitive to diseases because of their genetic similarity humans and physical contact with other orangutans (they are semi-solitary animals).
  • Do not smoke in the forest; it increases the chance of fires, adds to the problem of littering and the smell can be disturbing to the animals. Cigarette butts are also agents for transmitting diseases.
  • If you are feeling ill, or you are carrying a contagious disease, volunteer to stay behind
  • If you feel the urge to cough or sneeze when you are near the animals (even if animals are on the tree) please turn your head away and cover your nose and mouth in order to minimize the spread of bacteria or viruses.
  • Flash photography is not permitted! The orangutan afraid and will avoid flash. Automatic flash is not effective in the forest. Please check your setting before going tracking.
  • Keep your voices down at all times. This will help you to locate the animals easily and allow you to observe the animals longer and nearer. Loud noise will deter the animals from appearing and or run away as you nearer approach them.
  • In the event the orangutan makes a call (sound) “Kiss-Squeak” and/or waves branches to you, it indicates that the orangutan is ANGRY (NOT greeting) or nervous seeing humans. Crouch down slowly, do not look the orangutans directly in the eyes and walk away slowly from the animal.
  • Do not stay UNDER the tree wherever the orangutan is around the same tree. Food particles and some branches may fall on you. These falling objects may be of danger to you.