In a first recording, male Sumatran orangutan ‘Rakus’ reported using medicinal plants to heal his wound

A male orangutan, on the Indonesian island of Sumatra, has been captured on video by German and Indonesian scientists using a medicinal plant to treat a wound on his face.

The person – named ‘Rakus’ – lives in Suaq Balimbing, a protected rainforest area that is home to around 150 critically endangered Sumatran orangutans.

Cognitive and evolutionary biologists from the Max Planck Institute of Animal Behavior (MPI-AB) in Konstanz, Germany and Universitas Nasional, Indonesia conducted a study. It was directed by Caroline Schuppli and Isabelle Laumer.

“During daily observations of the orangutans, we noticed that a male named Rakus had suffered a facial wound, most likely during a fight with a neighbor,” said Isabelle Laumer, first author of the study, in a statement from MPI-AB.

“Three days after the injury, Rakus selectively tore off the leaves of a common-named vine Akar Kuning (Fibraurea tinctoria), chewed it and then applied the resulting juice precisely to the facial wound repeatedly for several minutes. As a final step, he completely covered the wound with the chewed leaves,” the statement said.

According to Laumer, the plant that Rakus uses as a poultice is found in the tropical forests of Southeast Asia. It and other related plants are known for their analgesic and antipyretic effects. In fact, they are used by locals in traditional medicine to treat various diseases such as malaria.

“Analyses of plant chemical compounds show the presence of furanoditerpenoids and protoberberine alkaloids, which are known to have antibacterial, anti-inflammatory, antifungal, antioxidant and other biological activities relevant to wound healing,” said Laumer.

Five days after Rakus nursed himself, his wound healed. Not only that, he also rested more than usual when he was injured. “Sleep has a positive influence on wound healing because growth hormone release, protein synthesis and cell division increase during sleep,” says Laumer.

Self-medication in non-humans

It’s not that self-medication hasn’t been observed before in non-human species. “The closest apes to humans are known to ingest specific plants to treat parasitic infections and rub plant material on their skin to treat sore muscles. Recently, a chimpanzee group in Gabon was observed applying insects to wounds,” the MPI-AB noted.

However, the treatment of a wound with a biologically active substance has not been documented so far.

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According to Laumer, Rakus’ behavior in this case appeared to be intentional. This is because he selectively treated his facial wound with the plant juice.

“The behavior was also repeated several times, not only with the plant sap but later also with firmer plant material until the wound was completely covered. The entire process took a significant amount of time,” said Laumer.

“Since the behavior has not been observed before, it may be that wound treatment is involved Fibraurea tinctoria is so far absent from the behavioral repertoire of the Suaq orangutan population,” the statement said.

According to Schuppli, Rakus’ place of origin is unknown, as male orangutans usually leave their native range after reaching puberty and establish new habitats.

Orangutans (‘Man of the Forest’ in Malay) are one of the extant species of great apes. The others are the common chimpanzee, gorilla and the gracile chimpanzee or bonobo.

The flame-colored orangutans are found on the islands of Sumatra in Indonesia and Borneo, which is divided between Malaysia, Indonesia and Brunei.

There are taxonomically three species of orangutans: the Sumatran, the Bornean and the Tapanuli.

Rakus’ behavior shows that medical wound treatment may have originated in a common ancestor shared by humans and orangutans, the scientists hypothesized.

The earliest record of people cleaning, plastering, and bandaging wounds with certain wound-care substances is found in a medical manuscript dating from 2200 BCE.

“This potentially innovative behavior (by Rakus) presents the first report of active wound treatment with a biologically active substance in a great ape species and provides new insights into the existence of self-medication in our closest relatives and into the evolutionary origins of wound medicine. broader,” says Schuppli.

She added: “Given that forms of active wound treatment are not only human, but also occur in both African and Asian great apes, it is possible that there is a common underlying mechanism for the recognition and application of substances with medical or functional properties. to wounds and that our last common ancestor already showed similar forms of ointment behavior.”

Active self-treatment of a facial wound with a biologically active plant by a male Sumatran orangutan was published in Scientific reports on May 2, 2024.