The orangutan was the first animal to heal a wound with a medicinal plant

This orangutan, who lives in the Suak Palimping Research Area in Indonesia's Gunung Leuser National Park, ate the sap of the climbing plant Agar Kuning (Fibrauria dictoria) and repeatedly applied it to the wound. A study published this Thursday in Scientific Reports.

Agar Kuning is a liana species known for its analgesic and antipyretic effects. In traditional medicine it is used to treat wounds and diseases such as diarrhoea, diabetes and malaria.

Ragus' behavior was observed and monitored in June 2022 by researchers from the Max Planck Institute for Animal Behavior (Germany) and Universitas Nacional (Indonesia).

“Rachus' behavior appeared to be deliberate,” said Isabelle Lamar, of the Max Planck Institute and one of the study's authors, as she selectively treated only the wound on her face with the plant's extract, and this was repeated several times.

This behavior suggests that medical treatment of wounds may have originated in a common ancestor shared by humans and orangutans, the Max Planck Institute highlighted in a report.

Prior to this study, wild animal species were observed to swallow, chew or rub medicinal plants, but not apply them to fresh wounds.

“During our daily observations of the orangutans, we noticed that a male Rakus had suffered a facial injury, possibly during a fight with another male,” explained Isabel Lamar.

Three days after the injury, Ragus Agar picked the leaves of Kuning, chewed them, and applied the resulting extract to the wound for precisely seven minutes.

Then, he applied the chewed leaves to the wound until it was completely covered and continued to feed the plant for over 30 minutes.

Chewed leaves helped reduce the pain and swelling of the wound and promoted its healing as it closed in five days and healed completely within a month.

As with all self-medication behaviors in non-human animals, the described case raises questions about the motives of these behaviors and how they arise.

“The treatment of wounds with Fibraria tinctoria in Chuak orangutans arises from unique findings,” highlighted Carolyn Shubley, lead author of the study.

Local orangutans rarely eat the plant. However, they may accidentally touch their wounds while feeding and thus accidentally apply the sap to the wounds. Because they have strong analgesic effects, they may experience an immediate release of pain, leading them to repeat the behavior many times, Schuppli suggested.

Because this behavior has not been previously observed, wound healing with Fibraurea tinctoria may be absent from the behavioral repertoire of the Chuak orangutan population, since, like all adult males in the region, Ragus was not born there and its origin is unknown.

“The behavior has been demonstrated by more individuals from their own populations outside the Chuak research area,” he pointed out.

This potentially novel behavior provides the first report of active wound healing with a biological agent in a great ape species and provides new insights into the existence of self-medication and the evolutionary origins of wound healing in close relatives of humans.