Orangutan treats wound with medicinal plant, intrigues scientists

In a remarkable display of what appears to be self-medication, a male Sumatran orangutan named Rakus was observed treating a facial wound with a plant known for its therapeutic properties. The observation, made by scientists in June 2022 at the Suaq Balimbing research site in Indonesia, caught their attention and has shed light on the potential cognitive abilities of these great apes.

In June 2022, Rakus, a male Sumatran orangutan believed to be around 33 years old, sustained a facial wound below his right eye, apparently from a fight with another male. Three days later, researchers witnessed an extraordinary event. Rakus appeared to treat the wound using a plant known as Akar Kuning (Fibraurea tinctoria), an evergreen vine renowned for its pain-relieving, antibacterial, anti-inflammatory, anti-fungal, and antioxidant qualities.

According to primatologist and cognitive biologist Isabelle Laumer of the Max Planck Institute of Animal Behavior in Germany, the lead author of the study published in the journal Scientific Reports, Rakus chewed the plant's leaves to produce a liquid, which he repeatedly smeared on the wound. He then applied the chewed-up plant material directly to the injury, much like a wound plaster administered by doctors.

The researchers noted that Rakus's behavior appeared intentional and repeated. He selectively treated his facial wound on the right flange with the plant juice and no other body parts. The entire process took considerable time, with Rakus first applying the plant juice and later more solid plant material until the wound was fully covered.

Remarkably, the wound never showed signs of infection and closed within five days, suggesting the potential effectiveness of Rakus's self-treatment.

Senior author Caroline Schuppli, an evolutionary biologist at the Max Planck Institute of Animal Behavior, noted that this observation suggests the cognitive capacities needed for active wound treatment with plants may be as old as the last common ancestor of orangutans and humans, which lived around 13 million years ago.

While the researchers cannot determine the extent to which Rakus understood the process, the observation highlights the potential for sophisticated cognitive abilities in orangutans, one of the world's great apes and our closest living relatives, sharing approximately 97% of our DNA.

Akar Kuning is widely used in traditional medicine across Southeast Asia to treat conditions like malaria, underscoring the plant's therapeutic properties. The researchers suggest that Rakus's behavior could have emerged through accidental individual innovation or by observational social learning from other orangutans in his birth area, as these apes are known for their rich cultural repertoire, including tool use in different contexts.