- Human actions have led to the deaths of more than 100,000 Bornean orangutans since 1999, mainly for crop protection, bushmeat or the illegal wildlife trade.
- For the first time in 15 years, researchers surveyed residents of Kalimantan, the Indonesian section of Borneo, to find out why people kill the great apes and whether conservation projects help protect them.
- Researchers found that killings seriously threaten orangutan numbers, and that conservation projects have not yet helped.
Only about 100,000 Bornean orangutans (Pongo pygmaeus) remain, less than half of their original numbers. People are killing the iconic orange apes at rates that could lead to their extinction on the rainforest-clad island, despite the efforts of conservationists.
For the first time in over a decade, orangutan conservation researchers interviewed residents of villages in Kalimantan, the Indonesian section of Borneo. One-third of the villages reported that an orangutan had been killed in recent years, according to a recent study published in Conservation Science and Practice.
“Killing has occurred in recent times, and it’s likely still happening at a rate that could have considerable impacts on orangutan populations,” said Ph.D. candidate Emily Massingham of the University of Queensland in Australia, the study’s lead author.
The orangutans remaining on Borneo are threatened by the destruction of their tropical forest habitat and by individual killings, which have likely not decreased in the last 15 years, the researchers found. People sometimes kill orangutans to protect their crops, but also for illegal bushmeat or to capture infants for the illicit pet trade.
The brutal 2018 killing of an orangutan in Kalimantan, shot 130 times with an air rifle, made international news. It was one of about 1,700 reported crimes against Bornean orangutans from 2007 to 2019. The annual deaths of just 1% to 2% of adults can push the population into extinction, but past studies have found that up to 5% of orangutans in Kalimantan are killed each year.
To examine the scope of the problem, Massingham and her colleagues worked with Indonesian consultants to interview 431 people across 79 villages in Kalimantan. Some of the villages were located near orangutan or forest conservation projects, while others were not.
The team asked residents whether orangutans had been killed in their villages within the last five to 10 years. The researchers also asked what the villagers thought a man with a family would do when encountering a mother orangutan with a baby in the forest, or seeing an orangutan close to his crops.
Residents in more than one-third of the villages reported that an orangutan had been killed within the last decade. An alarming 11% reported a killing in their village within the last year.
About 40% of the people interviewed thought the imagined man would react illegally if he encountered an orangutan, such as killing it for bushmeat or selling its infant. Both the numbers of actual killings and attitudes toward orangutans were consistent whether or not a village had a conservation project nearby.
In the past two decades, conservation groups, the Indonesian government, private companies and communities have spent more than $1 billion to protect the great apes. However, the conservation projects alone are not enough, the new study suggests.
The killing of orangutans is a socially complex problem, Massingham told Mongabay. “We’re not saying that killing is a really common behavior,” she said. But, she noted, “there only needs to be a small amount of killing to have an impact, because orangutans are long-lived and slow breeding.”
This research clarifies declines in orangutans that researchers had not been able to explain through deforestation alone, said Maria Voigt, an independent consultant for Wildlife Impact, an NGO based in Portland, Oregon, in the U.S.
“We can see that orangutans are declining, we can see that forest is declining,” Voigt told Mongabay. “What we could also see was in that in a lot of the forested area, we have less orangutans over time. We couldn’t really explain that other than it’s likely killings.”
Future research should delve into what drives people to kill the animals, and should explore the effects of orangutan and forest conservation projects at local scales, Massingham maintains. To succeed, she concludes, conservation groups must work together and with people in local communities.
“It’s definitely about working with communities to understand what their needs and perspectives are, and understand what the drivers of killing are so that we can address them directly,” said Massingham.
Massingham, E., Meijaard, E., Ancrenaz, M., Mika, D., Sherman, J., Santika, T., … & Dean, A. J. (2023). Killing of orangutans in Kalimantan – Community perspectives on incidence and drivers. Conservation Science and Practice, vol. 5, issue 11, e13025. doi: 10.1111/csp2.13025
Madeline Reinsel is a graduate student in the Science Communication M.S Program at the University of California, Santa Cruz. Other Mongabay stories produced by UCSC students can be found here.