Wild orangutan observed treating wound with medicinal plant for first time

Scientists have, for the first time, observed an orangutan treating a wound with a plant known to have pain-relieving properties.

Biologists witnessed a wild male Sumatran orangutan (Pongo abelii) in Indonesia, chewing the leaves of a climbing plant known as Akar Kuning (Fibraurea tinctoria) and applying the juicy mixture to a wound on his right cheek.

The team said its findings, published in the journal Scientific Reports, could help shed light on how the knowledge of wound medications evolved in humans.

Rakus with a wound on his right cheek
Rakus with a wound on his right cheek (Suaq Project/PA)

It said this is the first time a wild animal has been observed using a plant with known medicinal properties to treat wounds.

The researchers said the existence of self-medication in great apes – the closest human relatives – suggest the behaviour could have arisen in a common ancestor shared by both.

Dr Caroline Schuppli, an evolutionary biologist at the Max Planck Institute of Animal Behaviour in Germany, said: “The treatment of human wounds was most likely first mentioned in a medical manuscript that dates back to 2200 BC, which included cleaning, plastering, and bandaging of wounds with certain wound care substances.

“As forms of active wound treatment are not just human, but can also be found in both African and Asian great apes, it is possible that there exists 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 behaviour.”

A team of biologists, which also included scientists from Universitas Nasional in Indonesia, observed the orangutan, named Rakus, selectively ripping off leaves and chewing on them, and then applying the resulting mixture precisely onto the wound.

Rakus had sustained the wound three days before his self medication was observed at the Suaq Balimbing research site in Indonesia – a protected rainforest area home to 150 critically endangered Sumatran orangutans.

He was seen smearing the chewed leaves onto the wound until it was fully covered – a process that lasted more than 30 minutes.

The researchers said there were no signs of wound infection in the following days.

The wound closed within five days and was fully healed within a month, they added.

The researchers said it is likely that Rakus was intentionally treating the wound with the medicinal plant as he did not apply it to other parts of the body.

Dr Isabelle Laumer, a primatologist and cognitive biologist at the Max Planck Institute of Animal Behaviour, said: “During daily observations of the orangutans, we noticed that a male named Rakus had sustained a facial wound, most likely during a fight with a neighbouring male.”

She said the Akar Kuning plant, which is found in tropical forests of Southeast Asia, is known for its pain relieving and anti-inflammatory effects and is often used in traditional medicine to treat diseases such as dysentery, diabetes and malaria.

Leaves of the Akar Kuning plant, which are between 15 to 17cm long (Suaq Project/PA)
Leaves of the Akar Kuning plant, which are between 15 to 17cm long (Suaq Project/PA)

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

She said Rakus was also observed resting more than usual while being wounded.

Dr Laumer said: “Sleep positively affects wound healing as growth hormone release, protein synthesis and cell division are increased during sleep.”

The researchers said there is also a possibility that Rakus may have found out about the healing properties of Akar Kuning by accident.

Dr Schuppli said: “Orangutans at the site rarely eat the plant.

“However, individuals may accidentally touch their wounds while feeding on this plant and thus unintentionally apply the plant’s juice to their wounds.

“As Fibraurea tinctoria has potent analgesic effects, individuals may feel an immediate pain release, causing them to repeat the behaviour several times.”