Orangutan heals its own wound with leaves of medicinal plant

For the first time, it has been established that a wild animal heals its own wound by applying a concoction containing the leaves of a medicinal plant. The scoop was delivered by a Sumatran orangutan in Indonesia.

In June 2022, a research team saw that orangutan Rakus had a fairly large open wound just below his right eye in Gunung Leuser National Park in the tropical rainforest on the Indonesian island of Sumatra. According to researchers, the alpha male was injured during a fight with rival males. They deduced this from the loud screams of Rakus that they had heard a few days before they noticed the wound on the great ape.

Before and after. The open wound under the right eye of orangutan Rakus was clearly visible, but healed completely after a month. © AP

The scientists then observed Rakus chewing on the stem and leaves of a plant called akar kuning. This is an anti-inflammatory and disinfectant plant with an antibacterial effect. Locally, the plant is also used against malaria and diabetes. The orangutan applied the juice of the leaves to his injured cheek for seven minutes. Then he applied the chewed leaves to the wound so that it was completely covered. Then he continued to feast on the plant for another half hour. He repeated this procedure several times. And… the medicinal paste worked. After five days the wound was closed and there was no evidence of any infection. After a month, Rakus was completely healed.

According to the scientists, everything happened very consciously and Rakus therefore knew what he was doing. Orangutans rarely eat this plant and Rakus did the same thing over and over again. “He repeatedly applied the paste and later also a less liquid form of the plant,” said Isabella Laumer, lead author of the study, which was published in the journal Scientific Reports. “The whole process really took some time, so we think he did it deliberately.” In addition, Rakus also apparently rested much longer than usual, which leads researchers to believe that he was trying to regain strength after his injury.

It was already known that great apes use medicines to heal themselves. World-renowned biologist Jane Goodall noticed whole leaves in chimpanzee feces in the 1960s. Other scientists have also noted in the past that great apes ingested leaves with medicinal properties. But the fact that a wild animal itself applies a plant to a wound is a world first.

This was also possibly the very first time for Rakus itself, says Laumer. “Maybe he accidentally touched the wound with a finger that had the plant on it. Since the plant contains quite powerful analgesic compounds, he may have felt immediate pain relief, causing him to apply it again and again,” she says. Or: Rakus learned it from other orangutans in his group.

The scientists will now closely monitor the orangutans in the park to see if any other relatives of Rakus have this type of medical treatment. Laumer suspects that they will observe even more “human-like” behavior in these great apes in the coming years.