Rakus, a Sumatran orangutan, chewed up a liana plant known for its medicinal properties and applied it to a nasty open wound on his face. This image was taken two days before he applied the paste.
Armas
With their bright eyes and prominent beards and mustaches, it’s easy to see how orangutans got their name; “orang” is Malay for person, while “hutan” means forest. Their similarity to humans doesn’t stop there. Researchers have observed a male orangutan treat a wound on his face with a plant that’s also used in human medicine.
It’s the first time any wild animal has been seen caring for a wound using a natural substance with known medicinal properties, researchers report May 2 in Scientific Reports.
On June 25, 2022, field biologist Ulil Azhari was observing a Sumatran orangutan (Pongo abelii) named Rakus in the Suaq Balimbing research area of Indonesia’s Gunung Leuser National Park. The area is home to about 150 of the apes, and researchers have been studying them since 1994. Azhari watched as Rakus chewed up a liana plant, locally known as Akar Kuning, and rubbed the resulting paste onto an open wound he suffered on his right cheek several days prior, likely from a fight with another male. After applying the past several times over about seven minutes, Rakus then smeared intact liana pulp over his injury, almost like a bandage.
Akar Kuning (Fibraurea tinctoria) is used by the local people in traditional medicine and has a long list of known medicinal properties, including being an antibacterial and anti-inflammatory treatment.
Isabelle Laumer, a cognitive biologist at the Max Planck Institute for Animal Behavior in Konstanz, Germany and member of the Suaq Project studying orangutans, read the notes from the observation and “was immediately getting very excited,” she says. “He only treated this wound and not any other body part. And this was done repeatedly.” Rakus’ intentionality, and the fact that his wound was closed just five days after the observation — and never became infected — convinced her that he was purposefully using the liana plant to treat his nasty gash.
“There’s a lot of literature about animals applying things to areas that hurt,” says Michael Huffman, a zoologist at Nagasaki University in Japan who has studied self-medication in primates for decades (SN: 11/3/90). “But this I think is the first published paper with details of both the chemical properties of the plant and the progress of the treatment itself.”
Laumer says she hopes the finding will help more people appreciate how similar orangutans are to humans and care more about protecting them. All three species of the apes are critically endangered. “It would be so sad if they would vanish from this world,” she says.
