Scientists have observed a wild orangutan in Sumatra treating a large wound with a plant locally known to have medicinal properties, completely healing himself.

Rakus, the 35-year-old male orangutan who lives in the Gunung Leuser National Park on the island of Sumatra, Indonesia, had a red open wound just under his right eye. He then chewed the plant known as yellow root (or akar kuning) also used by people throughout Southeast Asia to treat malaria, diabetes and other conditions due it its anti-inflammatory properties, and applied it to his wound. Rakus also ingested a small amount, and five days after the wound was noticed, it had closed. Less than a month later it had healed without any signs of infection.

This event was noticed by scientists within the Suaq Balimbing research area of the park in 2022, but they did not make it public until a paper was published in the journal Scientific Reports on 2nd May 2024. Their paper is titled, “Active self-treatment of a facial wound with a biologically active plant by a male Sumatran orangutan.”

Although this is the first time this plant has been seen being used by an ape to heal a wound, self-medication in several non-human animals has already been reported. In 2017, scientists reported that six orangutans in Borneo rubbed the chewed-up leaves of a shrub with anti-inflammatory and analgesic properties onto their legs and arms. Simone Pika, an animal cognition scientist at Osnabrück University in Germany, observed a group of more than two dozen chimpanzees in Gabon applying chewed-up insects to their wounds. Other apes are known to occasionally eat rough leaves perhaps to help them expel parasites, Indian civets have been seen swallowing leaves to get rid of worms, and several birds have been seen engaged in a behaviour known as anting (rubbing themselves in ants, to help them treat parasites). 

Jordi Casamitjana
“Originally from Catalonia, but resident in the UK for several decades, Jordi is a vegan zoologist and author, who has been involved in different aspects of animal protection for many years. In addition to scientific research, he has worked mostly as an undercover investigator, animal welfare consultant, and animal protection campaigner. He has been an ethical vegan since 2002, and in 2020 he secured the legal protection of all ethical vegans in Great Britain from discrimination in a landmark employment tribunal case that was discussed all over the world. He is also the author of the book, ‘Ethical Vegan: a personal and political journey to change the world’.