Discovery in the Wild
For the first time ever, scientists have observed an orangutan actively treating a facial wound using a medicinal plant. This behavior, published in the journal Nature Scientific Reports on May 2, 2023, is the first known instance of a wild animal using a plant with known healing properties to treat an injury.
Observation and Treatment
In 2022, researchers in Indonesia observed an adult male orangutan named Rakus in Gunung Leuser National Park with an open wound on its face. Three days later, they witnessed Rakus chewing leaves from a climbing vine known as Fibraurea tinctoria, a plant with known medicinal properties that has long been used in local folk medicine.
According to the study by Indonesian and German scientists, the orangutan "began chewing the leaf but did not ingest it, and used its fingers to transfer the plant sap from its mouth directly to the wound on its face."
When flies began to land on the wound, Rakus "patted the whole wound with the leaf mash and rubbed it until the red flesh was completely covered with green plant material."
Healing Process
The following day, Rakus was again seen consuming leaves from the vine, and within a week its wound began to heal, eventually closing without signs of infection.
The study describes this behavior as the "first systematically documented case of a wild animal actively treating a significant wound with a plant species known to contain bioactive compounds."
Intentional Treatment?
While the researchers cannot definitively conclude that Rakus's behavior was intentional, the repeated application of sap and leaves to the wound alone implies that it was attempting to treat its injury.
The researchers speculate that the orangutan may have discovered this treatment method accidentally, perhaps by chewing on the leaves and finding that the sap had a soothing effect when it came into contact with the wound.
Orangutans can learn skills from others in their group through observation, but the scientists noted that they had not witnessed similar wound-treating behavior during 21 years and 28,000 hours of observation in the Gunung Leuser area. However, Rakus had recently arrived in the area from another region, suggesting that it may have learned this treatment from a different community of orangutans.
Broader Implications
This new observation adds to the growing body of evidence suggesting that primates use plants for medicinal purposes, including ingesting leaves that contain antiparasitic properties. In another part of Indonesia, researchers have observed orangutans rubbing chewed leaves from a different plant species onto their skin, possibly to take advantage of its anti-inflammatory properties.
In 2022, scientists reported an instance of chimpanzees in Gabon that appeared to be applying insects to wounds.
Summary
For the first time, scientists have documented an orangutan actively using a known medicinal plant to treat a wound, suggesting that animals may have a greater understanding of plant-based remedies than previously believed. This discovery provides further insights into the complex cognitive abilities of our closest living relatives.