An orangutan in Indonesia has been observed appearing to treat a wound with a medicinal tropical plant.

Scientists saw the Sumatran orangutan named Rakus pluck and chew up leaves of a medicinal plant used by people throughout Southeast Asia to treat pain and inflammation. The adult male then used his fingers to apply the plant juices to an injury on the right cheek. Afterwards, he pressed the chewed plant to cover the open wound, according to a study in Scientific Reports released on Thursday.

In June 2022, the male Sumatran orangutan named Rakus had sustained a facial wound below the right eye, apparently during a fight with another male orangutan at the Suaq Balimbing research site, a protected rainforest area in Indonesia. Researchers on Thursday described observing how Rakus appeared to treat the wound using the plant.

“This is the first time that we have observed a wild animal applying a quite potent medicinal plant directly to a wound,” said co-author Isabelle Laumer, a biologist at the Max Planck Institute of Animal Behaviour in Konstanz, Germany.

Photographs showed the animal’s wound closed within a month without any problems. Rakus, believed to have been born in 1989, is a flanged male, with large cheek pads on both sides of the face – secondary male sexual characteristics. He is one of the area’s dominant males.

Scientists have been observing orangutans in Indonesia’s Gunung Leuser National Park since 1994.