Gunung Leuser National Park, Indonesia - An orangutan in Indonesia has been spotted treating its own wound with a medicinal plant. This is the first time the behavior has ever been recorded in a wild animal.

Biologists from the Max Planck Institute of Animal Behavior in Germany and Universitas Nasional in Indonesia were observing a male Sumatran orangutan named Rakus who sustained a facial wound.

They saw Rakus eating, and then repeatedly applying sap from a climbing plant with anti-inflammatory and pain-relieving properties, which are commonly used in traditional medicine, to his wound. Biologists said he even covered the entire wound with the green plant mesh, and observed him at the Gunung Leuser National Park in Indonesia's Aceh province.

Isabelle Laumer from Max Planck Institute of Animal Behavior and an author of the study said Rakus probably sustained the facial wound during a fight with a neighboring male.

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"The behavior of Rakus appeared to be intentional as he selectively treated his facial wound on his right flange, and no other body parts, with the plant juice," Laumer said. "The behavior was also repeated several times, not only with the plant juice but also later with more solid plant material until the wound was fully covered. The entire process took a considerable amount of time."

The wound showed no signs of becoming infected, the scientists said.

The plant the orangutan used to heal is wound is known locally as Akar Kuning. It is used as a medicine by the Indonesians. It has antibacterial, anti-inflammatory, anti-fungal, antioxidant, and other healing properties, Laumer said.

Three days later, researchers spotted Rakus chewing the leaves of a vine called Fibraurea tinctoria, which is known for its medicinal properties and has long been used in local traditional medicine.

The orangutan "began chewing the leaves without swallowing them and using his fingers to apply the plant juice from his mouth directly onto his facial wound," said the study by the Indonesian and German scientists.

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The next day, Rakus was seen eating the vine's leaves again, and a week later his wound had closed up, subsequently healing without any sign of infection.

Primates have previously been seen eating plants or rubbing them on themselves in behavior scientists theorized was intended to ward off disease or discomfort. But the apparent treatment seen by researchers in Indonesia in 2022, and reported in the journal Nature Scientific Reports on Thursday, is the first time a wild animal has been seen applying medicinal plants to a wound.

Orangutans are known to learn skills from each other through observation, but the scientists said they had no record of similar behaviour in 21 years and 28,000 observation hours in the area.

The findings could offer insight into the evolutionary origins of wound medication, scientists said.