Startled Researchers Watch Wounded Orangutan Fashioning a Plant Poultice to Heal Himself

A research team in the Gunung Leuser National Park, Indonesia have been observing a Sumatran orangutan they call Rakus. In June 2022, Rakus was seen with a wound on his face, probably something he picked up fighting with other males.

The researchers then observed something never before seen in the wild, in orangutans or anything else: Rakus made a paste by chewing the leaves of a medicinal plant, then applied the poultice to his wound. Within a month his face had fully healed.

"He repeatedly applied the paste, and he later also applied more solid plant matter,” biologist Isabella Laumer tells BBC News. “The entire process lasted really a considerable amount of time – that's why we think that he intentionally applied it.” Laumer is lead author on an article documenting Rakus’s self-medication, published in Scientific Reports.

Rakus had been chewing the stem and leaves of Akar Kuning (Fibraurea tinctoria), a plant with  anti-inflammatory and anti-bacterial properties that is also used locally (by humans) to treat malaria and diabetes.

Great apes have been observed ingesting medicinal plants before, but Rakus is the first to be seen applying a plant to a wound. The researchers watching him don’t know how he learned folk medicine, but they will be closely watching other orangutans in the group to see if they’re sharing information.

“I think in the next few years we will discover even more behaviors and more abilities that are very human-like," Laumer says. “They are our closest relatives and this again points towards the similarities we share with them. We are more similar than we are different.”

Photo credit: Nature.com / Scientific Reports