JAKARTA — Self-medicating in animals has been reported before, but scientists noted something particularly special when they observed a wild orangutan in Sumatra treating a wound on its face with a plant known to have healing properties.

It was June 22, 2022, when the research team in the Suaq Balimbing area of Indonesia’s Gunung Leuser National Park first noticed that the male Sumatran orangutan (Pongo abelii), which they named Rakus, had a fresh wound under his right eye and inside his mouth while vocalizing a long call. Three days later, the team observed Rakus start to selectively chew on the stem and leaves of the Fibraurea tinctoria liana, and then repeatedly apply the subsequent sap precisely onto the facial wound for several minutes. The orangutan eventually covered the wound with the chewed leaves, and by June 30, the wound was already closed and showed no sign of infection, the researchers reported in their recently published study in the journal Scientific Reports.

“This observation is the first time that a wild animal was observed actively treating his wound with a healing plant. So, that’s a very important finding,” study lead author Isabelle B. Laumer, a cognitive and evolutionary biologist at Germany’s Max Planck Institute of Animal Behavior, told Mongabay in an email interview.

Research has shown that some animals, especially primates and apes, engage in self-medicating behavior. However, despite these observations, there’s still limited evidence that orangutans frequently use plants for self-medication. Fibraurea tinctoria is an evergreen climbing plant found across much of Southeast Asia, including Indonesia, Malaysia, Thailand and Vietnam. It’s known for its pain-relieving, fever-reducing, antidote and diuretic properties. In traditional medicine, all parts of the plant — from leaves to stems, roots to bark — are commonly used to treat conditions like dysentery, diabetes and malaria.

Back in Sumatra, the researchers kept watching Rakus even after the orangutan stopped actively treating his wound on June 26. They saw that he spent more time resting than usual after getting hurt, but went back to normal once the wound had closed. By July 19, the researchers observed that Rakus’s wound seemed to have fully healed, with only a faint scar left.

The authors suggest that combining the known properties of the plant and orangutans’ intentional behavior supports the idea that making and using herbal ointments might be a form of self-medication to help reduce pain, prevent inflammation, and speed up wound healing.

Laumer said her team’s findings demonstrate that orangutans have the cognitive capacities necessary to come up with a behavior like wound treatment. She said the discovery could be seen as additional evidence of how similar orangutans are to humans.

“Our research cannot say anything about what these cognitive capacities are though. But many other studies show that orangutans are very smart,” Laumer said, also noting in the study that in some instances, humans have already adopted these practices, such as traditional healers in Indonesian Borneo learning from Bornean orangutans.

Many conservationists have welcomed the new study’s findings, including Farwiza Farhan, chair of the local NGO Forest, Nature and Environment Aceh Foundation (HAkA), which works on the conservation of Sumatra’s Leuser Ecosystem.

Farwiza, who wasn’t involved in the research but reviewed it at Mongabay’s request, said the study’s “amazing” findings provided further evidence that so much more knowledge of forest biodiversity and pharmaceutical potential remains unknown; that wildlife, forests, and humans are intertwined as many plant medicines that orangutans consume are similar to what humans use as medicinal plants; and that orangutans are more intelligent than humans give them credit for.

She said she hoped further research on orangutan behavior in their other habitats and landscapes would also happen as it would add more value to the protection of those forests beyond the value of their timber and land. The Suaq Balimbing research area spans 350 hectares (865 acres) of mainly peat swamp forest, and has since 1994 served as a site for noninvasive, almost exclusively observational research on orangutans.

“These findings are particularly relevant to conservation initiatives in Indonesia as we are racing against time, so many important keystone species in this country are heading toward extinction and we still can’t say we have full comprehension of what we’re losing,” Farwiza said.

Other studies have indicated that orangutan populations in Indonesia are on a steep decline toward extinction as their forest homes are razed at an industrial scale — even as the government claims the great apes are bouncing back.

Indonesia currently has no conservation strategy or action plan in place to guide national and subnational initiatives to save orangutans. In 2019, the country’s environment ministry issued the 10-year plan to that end, but subsequently revoked it supposedly to add forest protection measures. The plan still hasn’t been reissued.

Killing of orangutans is the leading driver of the population decline, often by agricultural workers who see them as fruit-eating pests or by poachers, followed by capture for the illegal pet trade, according to a 2022 study. Poaching and trade of all three orangutan species found in Indonesia is illegal, with violations theoretically punishable by a prison sentence of up to five years and fines of up to 100 million rupiah ($6,200).

Laumer said her team hasn’t had the chance yet to present its findings to Indonesian wildlife authorities, but is eager to do so. “We believe that these findings [will] help orangutan conservation because they contribute to raising awareness of this fascinating species,” she said.

Basten Gokkon is a senior staff writer for Indonesia at Mongabay. Find him on 𝕏 @bgokkon.

See related story:

Orangutan ‘beatboxing’ offers clues about human language, study says

Citations:

Laumer, I. B., Rahman, A., Rahmaeti, T., Azhari, U., Hermansyah, Atmoko, S. S. U., & Schuppli, C. (2024). Active self-treatment of a facial wound with a biologically active plant by a male Sumatran orangutan. Scientific Reports, 14(1). doi:10.1038/s41598-024-58988-7

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