Select Page

For about three months each year, University of Wisconsin Oshkosh anthropology professor Stephanie Spehar spends  her time deep within the jungles of Borneo, studying the local primates and helping conserve the Wehea, one of the oldest rainforests in the world.

Spehar’s most recent findings could change the way wild orangutans are studied in the future.

Located in Indonesia, Borneo claims the title of Asia’s largest island, and its Wehea forest is home to several rare and endangered species. An indigenous population called the Wehea Dayak protect and manage its 38,000 hectares, which provide habitat for perhaps its most elusive creature–the Bornean orangutan.

Normally, tracking and studying orangutans is a difficult task. They must be followed through dense jungle, a territory that’s much easier to navigate if you have the ability swing through the trees. Determining the population of orangutans using current methods is also somewhat taxing and unreliable–one of the most popular ways is to physically count the frequency of ground nests.

In an effort to find an easier and more accurate way to measure the population of the orangutans in the Wehea, Spehar performed an experiment along with a team of students, locals and research assistants. The experiment compared some of the old methods of population estimation with one that uses motion detecting camera traps.

“People have been using camera trapping to study and monitor populations of large cats, but nobody had applied the techniques to studying great apes,” Spehar said. “That was essentially what we did in this study. Orangutans are currently endangered, so one of the things we have to do to prevent their extinction is to monitor their current population.”

Spehar said she and her team were initially doubtful of the effectiveness of their camera traps because of the orangutans’ arboreal tendencies.

“We were kind of skeptical at first because camera traps are typically set pretty close to the ground,” Spehar said. “The thing about orangutans is that they spend a lot of time in the trees.”

Despite their doubts, the camera traps captured countless images of orangutans roaming the forest floor. After meticulously sifting through them, the team was even able to identify individual orangutans, something that Spehar said is essential for estimating population size.

“The two methods give us somewhat different results, but the most important thing that I think came out of it was that camera trapping is potentially a more precise method of counting orangutans,” Spehar said.

Spehar’s results are somewhat of a revelation in primatology. Previous studies indicated that Orangutans only traveled on the ground for short distances–mainly larger males.

“What we found is that we captured orangutans on the ground as often as we captured other primates that are known to be primarily terrestrial,” Spehar said. “So this tells us that orangutans at Wahea are moving on the ground a lot. They also found that males and females travel on the ground with equal frequency.”

Spehar’s findings illustrate how technology may shape future study of Orangutans and other primates, and she said will continue to travel to Borneo for further research.

“The Wehea is a really special place and these trips are really only possible because I work collaboratively with the Wehea people, students, assistants and many others,” Spehar said.

Read more: