In June 2022, a male Sumatran orangutan named Rakus 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. What Rakus did three days later really caught the attention of scientists.

Researchers on Thursday described observing how Rakus appeared to treat the wound using a plant known for its pain-relieving properties and for supporting wound healing due to its antibacterial, anti-inflammatory, anti-fungal and antioxidant qualities.

The orangutan chewed the plant's leaves to produce a liquid that Rakus repeatedly smeared on the wound and then applied the chewed-up plant material directly to the injury, much like a wound plaster administered by doctors, according to primatologist and cognitive biologist Isabelle Laumer of the Max Planck Institute of Animal Behavior in Germany.