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Cheryl Knott
Grantee: Cheryl Knott, Anthropologist
Borneo, Indonesia

Time spent by research team:
More than 50,000 hours over the past decade

Gunung Palung National Park, Borneo, Indonesia

Park's orangutan population:
About 2,500

Worldwide population:
15,000 to 24,000 in the wild

Dangers for orangutans: By some estimates more than 80 percent of all orangutan habitat has been destroyed. Since 1996 legal and illegal logging has consumed about five million acres (two million hectares) of forest each year.

Spreading awareness:
"Through our educational outreach programs and awareness campaigns around the park, we are drawing public attention to the orangutans' plight and helping to make a difference. It would be tragic to let these great apes slip away."


Learn More

Gunung Palung Orangutan Project
Visit Dr. Cheryl Knott's website featuring her orangutan research in Gunung Palung National Park, Borneo, Indonesia.

Balikpapan Orangutan Society–USA
Learn more about these red apes at this website, which includes education resources and things you can do to help protect orangutans.

Orangutans Online
This website contains frequent updates on topics related to orangutan conservation.

Global Forest Watchenglish/indonesia/
A World Resources Institute initiative, this network provides information on forests throughout the world, including Indonesia.


Felton, Annika M., and others. "Orangutan population density, forest structure and fruit availability in hand-logged and unlogged peat swamp forests in West Kalimantan, Indonesia." Publication forthcoming in Biological Conservation
(November 2003), 91-101.

Jepson, Paul, and others. "The End for Indonesia's Lowland Forests?" Science (May 4, 2001), 859-61.

Knott, Cheryl D. "Orangutan Behavior and Ecology." In The Nonhuman Primates, ed. P. Dolhinow and A. Fuentes. Mayfield Publishing Company, 1999.

Knott, Cheryl D. "Changes in orangutan diet, caloric intake and ketones in response to fluctuating fruit availability." International Journal of Primatology (1998), 1061-79.

Matthews, Emily, ed. The State of the Forest: Indonesia. Forest Watch Indonesia and Global Forest Watch, 2002. Available online at

Van Schaik, Carel P., and Cheryl D. Knott. "Geographic Variation in Tool Use on Neesia Fruits in Orangutans." American Journal of Physical Anthropology (April 2001), 331-42.

Van Schaik, Carel P., and others. "Orangutan Cultures and the Evolution of Material Culture." Science (January 3, 2003), 102-5.


Field Dispatch: Borneo

Photographs by Tim Laman

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This Week's Questions. Click on a question for a full response.


How much is known about infant mortality rates?


How did orangutans get their name?


Do orangutans have culture, and if so how?


How do orangutans respond to the researchers?


Are orangutans known to eat certain foods for self-medication?




Name:  Victoria  
Question 1:
How much is known about infant mortality rates? And what about those for dispersing juveniles? Do we know how good orangutans are at raising offspring that actually manage to contribute to the next generation, without the effects of logging, etc?
Infant mortality rates from natural causes appear to be extremely low in the wild. In fact, I know of no published accounts of an infant or juvenile death in the wild caused by nonhuman factors (although this must happen occasionally). Thus, if left alone, orangutans are extremely good at raising their offspring to adulthood. In light of their eight-year interbirth interval, this makes sense. Otherwise, such long birth spacing would not work.
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Name:  Ryan Jones  
Question 2:
Do orangutans have culture, and if so how?
Orangutans have been found to pass on traditions or behaviors to others in their population. Many of these behaviors are not explained by environmental differences, but are idiosyncratic. An example is the "kiss-squeaking" behavior I describe in my National
article. All orangutan populations seem to kiss-squeak when disturbed.  But at Gunung Palung they often do this by 'kissing' into a handful of leaves and throwing them down. This has been rarely observed at a few other places, but seems to be a regular
behavior only at Gunung Palung. This behavior or cultural tradition is thus passed on among members of our population. Studying the development and distribution of such cultural traditions in orangutans and other primates may help us understand how the
greatly elaborated use of culture in humans evolved.
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Name:  Sally G. Jones  
Question 3:
Are orangutans known to eat certain foods for self-medication, e.g., to treat themselves for parasites?
This is a good question, and we don't yet know for sure. But there is a Czech scientist, Ivona Foitova, who is studying this question at a number of sites in Borneo and Sumatra. I have also examined orangutan parasite load with collaborators Dr. Mark Skinner and Dr.
Alvin Gajadhar.
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Name:  Ann Wilkes  
Question 4:
How did orangutans get their name?
The word "orangutan" comes from the Indonesian and Malaysian words orang (person) and hutan (forest). So the word literally means "person of the forest."  Note that there is only one g in orangutan.  Many Americans pronounce the last syllable as "tang" although this isn't really the correct pronunciation. Also, it's best not to abbreviate orangutans to "orang" because in Indonesian and Malaysian this just means "person" and thus sounds a bit strange to a native speaker.
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Name:  Vicki  
Question 5:
How do orangutans respond to the researchers? Does a single person disturb them and what is the largest group that the orangutans will tolerate?
When orangutans are first encountered, they usually are upset by the presence of people and will vocalize at them, making a kiss-squeak sound for example, and sometimes dropping or throwing dead wood from the trees. At this stage we say they are "unhabituated." To study them, we need to habituate them by making them more and more
comfortable with our presence. So we stay with them as long as we can, keeping a good distance away, not looking directly at them, and letting them know we are not a threat.  Gradually they become accustomed to being followed by humans and are no longer disturbed. They usually only vocalize at us for a few days before becoming more
or less used to us. We also do not touch them or directly interact with them in any way.  We want them to behave as if we weren't there so that we can study their natural behavior.
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