A Sumatran orangutan named Lacus was seen using a plant to treat facial wounds that may have been sustained during battle.
An Indonesian orangutan was observed treating its wounds with medicinal tropical plants. This is the latest example of how some animals are trying to alleviate their illnesses with treatments found in the wild.
Scientists witnessed a Sumatran orangutan named Lacus plucking and chewing the leaves of a medicinal plant used by people across Southeast Asia to treat pain and inflammation. The adult man then used his fingers to apply plant juice to the wound on his right cheek. He then applied chewed plants to cover the open wound like a bandage, according to the study published Thursday in Scientific Reports.
Previous studies have documented several species of great apes searching for medicine to cure themselves in the forest, but scientists have never seen animals treat themselves in this way. I had never observed it.
“This is the first time that we have observed a wild animal applying a highly potent medicinal plant directly to a wound,” said co-author Isabel Romer, a biologist at the Max Planck Institute for Animal Behavior in Konstanz, Germany.
The observations took place in Gunung Leuser National Park on the Indonesian island of Sumatra, where researchers discovered Lacus injured in June 2022. Researchers believe Lacus may have been injured while fighting a rival male orangutan.
The researchers then observed Lacus chewing the leaves of the plant, which has the scientific name Fibraurea tinctoria, without swallowing them, and using his fingers to apply the plant’s sap directly through his mouth.
The plant, known as Akal Kuning in Indonesia, is rarely eaten by orangutans in the peat swamp forest, home to about 150 endangered Sumatran orangutans.
Photos showed that the animal’s wound closed without any problems within a month.
Lacus is believed to have been born in 1989 and is a flanged male with large cheek pads on each side of his face, a secondary male sexual characteristic. He is one of the leading men of this region.
“Probably self-medicating.”
Scientists have been observing orangutans in Indonesia’s Gunung Leuser National Park since 1994.
“This is a single observation,” said Emory University biologist Jacobus de Rode, who was not involved in the study. “But often we learn about new behaviors starting with one observation of him.
De Rode noted that the orangutans applied the plants only to the wound and not to other parts of their bodies, adding: “It’s most likely self-medicating.”
Study co-author Caroline Spree of Max Planck said Lacus may have learned this technique from other orangutans who live outside the park and away from researchers’ daily monitoring.
Scientists have previously documented that other primates use plants therapeutically.
Orangutans on the island of Borneo, which straddles Brunei, Indonesia and Malaysia, are known to rub their bodies with the juices of medicinal plants, perhaps to relieve pain or ward off parasites.
Chimpanzees have been observed chewing bitter-tasting plant shoots in several locations to soothe their stomachs. Gorillas, chimpanzees, and bonobos swallow certain rough leaves to get rid of stomach parasites.
“If this behavior exists in our closest living relatives, what does it tell us about how medicine first evolved?” Nonprofit Diane Master Gorilla Foundation Tara Stoinski, president and chief scientific officer of , said she had no role in the research.