Orangutans, it seems, possess a form of natural medicine cabinet. A new study published in Scientific Reports documents a male Sumatran orangutan named Rakus using a plant with known medicinal properties to treat a facial wound. This marks the first documented instance of an orangutan, or any animal, applying plant material directly to a wound as a topical salve.
Primate researcher Isabelle Laumer and her team made this remarkable observation at the Suaq Balimbing research site in Indonesia, a protected rainforest where they have studied wild Sumatran orangutans ( Pongo abelii) since 1994. In late June 2022, they noticed Rakus with a fresh wound on his right cheek pad (flange), likely from a recent fight with another male. Three days later, Rakus exhibited unprecedented behavior. He chewed and spit out parts of a nearby plant, creating a mixture that he then meticulously applied to his wound.
Snapshots of Rakus the orangutan before, during, and after his successful first aid treatment using Fibraurea tinctoria.Rakus applying the Fibraurea tinctoria plant mixture to his facial wound. (Photo: Laumer et al/Scientific Reports)
Rakus’s actions strongly suggest intentional medicinal application. He exclusively applied the plant pulp to his wound, spending approximately seven minutes ensuring complete coverage. He also consumed the plant the following day. The plant in question, Fibraurea tinctoria (also known as Akar Kuning), is traditionally used by local humans for medicinal purposes. Studies confirm its antibacterial, anti-inflammatory, and antifungal properties, among others. Remarkably, Rakus’s wound healed rapidly after the treatment, closing within five days and becoming barely visible by late August.
While other animals, including primates, have been observed self-medicating through ingesting plants with potential healing properties, Rakus’s behavior represents a novel discovery. A 2022 study documented chimpanzees applying crushed insects to their own wounds and those of others, but this is the first recorded case of an animal applying a medicinal plant topically to a fresh wound.
A close-up view of the wound healing process after the application of the Fibraurea tinctoria plant.Rakus’s wound healing rapidly after the application of the plant mixture. (Photo: Laumer et al/Scientific Reports)
How Rakus acquired this knowledge remains a mystery. Fibraurea tinctoria is rarely eaten by orangutans at Suaq, and the researchers have never witnessed similar behavior there despite decades of observation (though injuries are infrequent). Since adult male orangutans, like Rakus, often migrate from other areas, he may have learned this practice elsewhere. Alternatively, the behavior could be a result of accidental discovery and reinforcement.
Laumer suggests, “Individuals may accidentally touch their wounds while feeding on this plant and thus unintentionally apply the plant’s juice. As Fibraurea tinctoria has potent analgesic effects, individuals may feel an immediate pain release, causing them to repeat the behavior.”
A comparison of Rakus's appearance before and after the wound had completely healed.Rakus before the injury and after complete healing. (Photo: Laumer et al/Scientific Reports)
The research team will continue monitoring the Suaq orangutans to see if this behavior is repeated by others. This discovery highlights the complex cognitive abilities of orangutans and underscores our shared ancestry. Laumer emphasizes, “Observing wound treatment with a medicinal plant in our closest relatives again points towards the similarities we share. We are more similar than different.” She hopes this research will raise awareness of the critically endangered status of these remarkable primates.
