In a scientifically documented event, a wild Sumatran orangutan was observed methodically treating a facial wound with a specific plant. This observation provides significant insight for scientists studying animal intelligence and the origins of natural medicine. The discovery illuminates the sophisticated cognitive abilities present in great apes.
The Case of Rakus the Orangutan
In Indonesia’s Gunung Leuser National Park, researchers documented an adult male Sumatran orangutan named Rakus. In June 2022, Rakus was observed with a significant open wound on his right cheek, likely from a territorial dispute with another male.
A few days after sustaining the injury, Rakus was seen selectively seeking out a specific liana, a type of climbing vine. He began to pluck its leaves, chewing them without swallowing to create a green paste. Using his fingers, Rakus then carefully applied the juice from this pulp directly onto his facial wound.
After applying the liquid, Rakus took the remaining solid leaf matter and completely covered the injury, creating a makeshift bandage. Researchers monitored Rakus over the following weeks and noted that the wound healed successfully without signs of infection, closing within a month.
The Akar Kuning Plant’s Medicinal Power
The plant Rakus chose for his treatment is known locally as Akar Kuning (Fibraurea tinctoria). This vine is rarely consumed by the orangutans in the research area, suggesting his actions were highly selective. Akar Kuning is also a well-known component of traditional human medicine across Southeast Asia, used to treat pain and inflammation.
Scientific analysis of Fibraurea tinctoria confirms its use as a healing agent. The plant is rich in bioactive compounds, including alkaloids with antibacterial, anti-inflammatory, anti-fungal, and antioxidant properties. These compounds are directly relevant to wound healing, as they can prevent infection and reduce swelling.
The presence of these chemical properties demonstrates that the orangutan’s choice was not random. The application of the plant likely provided a pain-relieving effect while protecting the open wound from bacterial contamination.
Animal Self-Medication (Zoopharmacognosy)
This behavior is part of a field known as zoopharmacognosy, which studies how animals use natural substances for self-medication. Scientists have recorded other animals engaging in such behaviors, like chimpanzees swallowing rough leaves to purge their intestines of parasites.
Other primates also use plants for health. Bornean orangutans have been seen rubbing their bodies with plant juices to alleviate muscle soreness or deter parasites. Similarly, some monkeys rub plants with antiviral properties into their fur.
The case of Rakus stands apart from these observations. While many examples involve ingesting a substance or rubbing it on fur, this was the first documented instance of an animal applying a medicinal plant directly to an open wound. This represents a more complex form of medical treatment than previously witnessed.
What This Teaches Us About Orangutan Intelligence
The deliberate, multi-step process of creating a paste and applying it as a poultice suggests a sophisticated level of understanding and planning. Rakus’s behavior appeared intentional, as he selectively treated only the wound and no other part of his body.
A central question for researchers is whether this was an act of individual innovation or a learned behavior. Since this treatment had never been documented at the research site, it is possible Rakus discovered the method on his own. It is also plausible he learned it in his youth, as he was born outside the study area.
Regardless of its origin, the event underscores the capacity for complex problem-solving in non-human primates. This act of self-medication may shed light on the evolutionary origins of human wound care. The observation highlights the potential for new medical insights hidden within the natural world.