Where, when, why: Human-orangutan conflict in Borneo

All too often, encounters prove fatal for dwindling orangutans.
Everyone’s problem: In Borneo, human-orangutan conflict occurs in both remote forested locations and more populated areas. Terry Sunderland/CIFOR

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BOGOR, Indonesia—A 90 kilogram full-grown male orangutan is sitting in your garden, eating mangoes stolen from your mango tree. You are unhappy about this. So how do you get rid of him?

According to conservation scientist Erik Meijaard, the best method is to find some friends, form into a line, and move forward waving your arms and shouting.

“Sometimes the big males are not very intimidated, in which case setting off firecrackers usually helps to persuade them to leave,” says the Center for International Forestry Research (CIFOR) consultant scientist.

Unfortunately these techniques are not common knowledge on the island of Borneo, home to more than 85 percent of the world’s remaining wild orangutans, where instances of human-orangutan conflict often end violently.

“In confrontation situations I hear that sometimes people can go beserk. In one story I heard villagers just set an entire tree on fire with an orangutan in it,” Meijaard says.

We found that human-orangutan conflict was most likely both in remote forested locations and in more populated areas of mixed land use and greater human activity

Nicola Abram

While many orangutans end up in rehabilitation centers with machete wounds, up to 1,250 a year are killed in these human-ape confrontations.

The same amount again are killed by hunters, and orangutan populations are at risk of decline or localized extinctions in Kalimantan, according to a recent study of which Meijaard was an author.


With a total island ape population currently estimated at between 50,000 and 60,000, this mortality rate cannot be sustained.

If Indonesia is to meet the orangutan action plan goal of stabilizing orangutan populations by 2017 then much work must be done to slow the death rate.

Seeking to inform conservation efforts the study has identified spatial patterns and drivers that underpin human-orangutan conflict.

Through the survey responses of 4839 villagers in Kalimantan, and partly in Sabah, Malaysian Borneo, the research documented the frequency and location of orangutan sightings and conflict.

Based on an analysis of this data, the researchers created a “spatial data framework”, identifying 39 key variables that could be important in determining conflict and killings — including distance to oil palm plantations and intact forest, among other factors.

“We found that human-orangutan conflict was most likely both in remote forested locations and in more populated areas of mixed land use and greater human activity,” says lead author of the study, Nicola Abram from the University of Queensland.

“One of the strongest indicators was road density, with greater conflict occurring at both ends of the spectrum — in very high or very low road density areas.”

The research is principally concerned with establishing patterns of correlation, but inevitably causality has been suggested by the data.

On the one hand, killings in areas of greater human activity are thought to result from inadvertent clashes with orangutans who have been displaced from their natural habitats, particularly by land conversion to oil palm or other agricultural purposes. But killings in more remote areas are thought to result from both conflict and hunting.

“So there’s a duality going on,” Abram says. “The oil palm issue and depletion of natural habitat is a major driver of killings, and that’s well documented. However the drivers behind hunting and killings in remote areas are less talked about.”

“We found that killings in predominantly Christian interior forest areas were often associated with consumption of the orangutan meat. Muslims are culturally forbidden from eating animals with digits, and killings in Muslim communities were more likely to result from conflict than hunting.”


Abram’s research is not principally concerned with examining the anthropological causes that underpin orangutan killings, but in a concurrent study conducted in Kalimantan, also coauthored by Abram and Meijaard, hunting for food was identified as a significant cause of orangutan killings — with 56 percent of survey respondents saying that the reason they had killed an orangutan was to eat it.

With a plurality of killing causes there inevitably must be different conservation strategies deployed to counter them, and the study makes a number of recommendations.

In areas where killings occur as a result of hunting for food or as “accidental bycatch”, the study says outreach programs should seek to educate and change attitudes towards hunting orangutans. Another issue flagged up is the lack of law enforcement, despite laws against killing orangutans.

With regard to human-orangutan conflict arising from competition over land and food, the study suggests other measures, including greater legal protections of habitat, effective management of legally mandated conservation areas within individual plantations, public awareness campaigns and, again, strengthened monitoring and law enforcement to protect against killings.

“For Muslim communities I’m considering reaching out to religious leaders to promote awareness of the fatwa on killing endangered species’. Local media campaigns could be very effective. But obviously a fatwa won’t be applicable among Christian communities, so your approach must be adaptable,” says Meijaard.

The oil palm issue and depletion of natural habitat is a major driver of killings, and that’s well documented. However the drivers behind hunting and killings in remote areas are less talked about

Nicola Abram

Although conservation solutions may have to depend upon their social context, Abram is confident that the spatial models she has developed to predict conflict will be applicable across different regions.

“The most important variables informing the models were land use, and land cover variables, as well as people’s perception of orangutan population levels, and these factors can translate easily into other landscapes, in both other parts of Kalimantan, and perhaps Sumatra,” she says.

“The predominant religious demographics are also a significant factor, but we can obtain this data for other regions too.”

“Drawing on these models there is potential to anticipate problems proactively and better inform landscape management.”

For further information about CIFOR’s research into orangutan conservation in Borneo please contact Erik Meijaard  at

CIFOR’s research on orangutans in Borneo is part of the CGIAR Research Program on Forests, Trees and Agroforestry

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