It was a hushed moment among wildlife biologists: An orangutan in Indonesia, Rakus, was discovered to be treating an open cheek wound with chewed leaves from a medicinal plant also used by local human residents:

In addition to eating the leaves, Rakus chewed them without swallowing and used his fingers to smear the juice on his facial wound over seven minutes. Some flies settled on the wound, whereupon Rakus spread a poultice of leaf-mash on the wound. He ate the plant again the next day. Eight days after his injury, his wound was fully closed.

“It shows that orangutans and humans share knowledge. Since they live in the same habitat, I would say that’s quite obvious, but still intriguing to realize,” says Caroline Schuppli, a primatologist at the Max Planck Institute of Animal Behavior in Konstanz, Germany, and a co-author of the study.

Gayathri Vaidyanathan, “‘Orangutan, heal thyself’: First wild animal seen using medicinal plant,” Nature, May 7, 2024. The paper in Scientific Reports is open access.

After eight days of eating the creeper akar kuning (Fibraurea tinctoria), Rakus’s wound had closed up. In 21 years of observation, the primatologists had not seen another orangutan do this, so they suspect that Rakus, a newcomer to the area, had learned the behavior beforehand.

But why is the incident considered remarkable, given that, as is admitted in the article, many life forms self-medicate?

“It is the first study to scientifically demonstrate that an animal is using a plant with medicinal properties applicable to wounds, and putting those on the wounds and consistently treating over a period of time,” says Michael Huffman, who studies animal self-medication at the Institute for Tropical Medicine at Nagasaki University in Japan.

Vaidyanathan, “‘Orangutan, heal thyself’”

Okay, but how big a deal is that really?

There is a name for animals treating their own illnesses: zoopharmacognosy. A decade-old article by Joel Shurkin in the Proceedings of the National Academy of Sciences offered examples, including

•Baboons in Ethiopia eat the leaves of a plant to combat the flatworms that cause schistosomiasis.

•Fruit flies lay eggs in plants containing high ethanol levels when they detect parasitoid wasps, a way of protecting their offspring.

•Red and green macaws, along with many animals, eat clay to aid digestion and kill bacteria.

•Female woolly spider monkeys in Brazil add plants to their diet to increase or decrease their fertility.

•Pregnant lemurs in Madagascar nibble on tamarind and fig leaves and bark to aid in milk production, kill parasites, and increase the chances of a successful birth.

* Pregnant elephants in Kenya eat the leaves of some trees to induce delivery.

Shurkin J. News feature: Animals that self-medicate. Proc Natl Acad Sci U S A. 2014 Dec 9;111(49):17339-41. doi: 10.1073/pnas.1419966111. PMID: 25492915; PMCID: PMC4267359.

So insects, spiders, and birds do it as well as apes and monkeys. Smithsonian Magazine has featured sub-Saharan ants who carry wounded nestmates back to the colony and treat infected wounds with antimicrobials that they produce.

Back in 2018, an orangutan was reported to chew Dracaena cantleyi leaves into a soapy lather and then rub them on her body, perhaps as an anti-inflammatory for tired muscles. The paper is open access.

Many other examples are available, including the practice of some birds, like crows, of “anting”: They place ants on their bodies, perhaps to fight off microbes and fungi, using the ants’ chemical secretions like formic acid.

How did the orangutan learn to eat healing leaves?

Leaves are a part of the orangutan’s diet, says wildlife photographer Nicki Featherstone. The ape has been found to eat at least twenty-five varieties. Of course, that would likely mean sampling many more. Even if an orangutan did not eat a given leaf very often, he might know what it tasted like and how it affected him. Or else he might learn from observing what Mom did.

So, while Rakus’s story is fascinating, it isn’t really the event that science and other media seem to want to make it. The real reason for the intense interest is more likely the hope of raising the profile of endangered species protection and, less admirably, taking another bash at human exceptionality. For example,

CNN: “Researchers plan to closely observe any other wounded orangutans in the area to see if the behavior is repeated, said [Isabelle] Laumer, who added that the findings underline the commonalities between humans and orangutans. ‘We are more similar than different,’ she said. ‘We hope this study raises awareness on their critically endangered status in the wild.’” (Jack Guy, May 2, 2024)

NBC: “The researchers behind the study think that great apes’ ability to identify medicines and treat wounds could trace back to a shared ancestor with humans.” (Evan Bush, May 2, 2024) That’s a pretty far-flung speculation. Rakus’s self-medication is not evidence for common ancestry with humans, any more than birds’ “anting” or ants’ treatment of wounded comrades is. Similar behavior among disparate life forms is quite common. If the behavior is not derived directly from genetics, we cannot theorize about ancestry.

NPR asks an interesting question: “Might Rakus share his medical know-how with other orangutans? (Bill Chappell, May 3, 2024).

Fortunately, that’s a question researchers can answer via observation. It won’t be surprising if local orangutans imitate their new neighbor. But we shall see.