Orangutans are widely known for their intelligence, having been documented using simple tools to forage for food. Now, in an incredible discovery of orangutan behavior, researchers have published an analysis of what they describe as the first time a wild animal has successfully treated a wound with a medicinal plant.
The observations were made in June 2022, by scientists studying the Sumatran orangutans that live in the rainforest reserve of Gunung Leuser National Park in Indonesia. A day after hearing orangutan calls that typically indicate aggression, the researchers discovered that a male orangutan named Rakus had a wound just below his right eye.
In the following days, the behavior of the 35-year-old orangutan astounded them. Rakus collected and ate stems and leaves from the climbing vine Fibraurea tinctoria (also known as akar kuning or yellow root). He also chewed some of the leaves without consuming them, essentially making a sappy poultice that he applied to the wound. This process was repeated, and the wound closed five days later. A month later, the orangutan was still free from infection.
Yellow root and other climbing vines are used in traditional medicine to treat conditions ranging from diabetes to malaria. Scientists have identified the chemical basis of yellow root's antibacterial, anti-inflammatory, and pain-relieving properties, which appear to have been recognized by Rakus, at least on some level. However, how he knew to apply the plant remains a mystery, as this behavior had never been observed in over two decades of studying orangutans at the national park.
Is there a doctor in this rainforest?
- Although Rakus’s behavior was unique in that he was using a known medicinal plant to treat an open external wound, previous observations have suggested that other animals may have some knowledge of self-medication.
- Orangutans in Borneo have been observed rubbing plants on their limbs, possibly to ease muscle soreness. Researchers have also noted instances of chimpanzees spreading chewed insects on wounds, though with uncertain results.
- Certain birds engage in “anting,” which involves rubbing ants on their bodies to remove parasites or mites.
- The first written documentation of people self-medicating their wounds appears in a manuscript from around 2,200 BC, though humanity’s first use of medicinal plants certainly predates this—perhaps even going as far back as our last common ancestor with orangutans millions of years ago.
