In June 2022, a male Sumatran orangutan named Rakus suffered a facial injury below the right eye, apparently during a fight with another male orangutan at the Suaq Balimbing research center, a protected area of rainforest in Indonesia. What Rakus did three days later really caught the attention of scientists.
Its researchers described on thursday how Rakus seemed to heal his wound with a plant Known for its analgesic and healing properties thanks to its antibacterial, anti-inflammatory, antifungal and antioxidant properties.
How the orangutan was cured
According to primatologist and cognitive biologist Isabelle Laumerfrom the Max Planck Institute for Animal Behavior (Germany), the orangutan chewed the leaves of the plant to produce a liquid which Rakus repeatedly smeared on the wound and then applied the chewed plant material directly to the injury, much like medical plasters. Rakus too ate the plant, a perennial vine commonly called Akar Kuning -scientific name Fibraurea tinctoria-, added Laumer, lead author of the study published in the journal Scientific Reports. This plant is rarely eaten by orangutans in this area of peat swamp forests, home to about 150 critically endangered Sumatran orangutans.
“That we know, This is the first documented case of active wound treatment with a plant species with medicinal properties by a wild animal”, said the study’s lead author, Caroline Schuppli, evolutionary biologist at the institute.
Who is Rakus, the orangutan who cured himself with a medicinal plant
Rakus, believed to have been born in 1989, is a bridled male, with large cheek pads on both sides of the face, male secondary sexual characteristics. Rakus was one of the dominant males in the area. The researchers said the orangutan’s self-treatment of the wound did not seem coincidental.
“His behavior seemed intentional. He selectively treated the facial wound on his right bridle with the juice of the plant, and no other part of the body. The behavior was repeated several times, not only did he apply plant juice, but later also more solid plant material, until the wound was completely covered. The process took a considerable time“explains Laumer.
The wound never showed signs of infection and closed within five days, according to the researchers. “The observation suggests that the cognitive abilities necessary for this behavior – the active treatment of wounds with plants – may be as old as the last common ancestor of orangutans and humans,” Schuppli said.
“However, what exactly these cognitive abilities are remains to be investigated. Although this observation demonstrates that orangutans are capable of treating their wounds with plants, we do not know to what extent they understand the process.”
The relationship between humans and orangutans
The last common ancestor of orangutans and humans lived about 13 million years. Orangutans are one of the world’s great apes -the closest living relatives of humans- along with chimpanzees, bonobos and gorillas. Orangutans are the least related to humansbut they share approximately 97% of our DNA.
“It is possible that wound treatment with Fibraurea tinctoria arises through accidental individual innovation. It is possible that individuals accidentally touch their wounds while feeding on Fibraurea tinctoria and thus inadvertently apply the plant’s juice to their wounds,” Laumer said. “But it could also be,” Laumer added, “that Rakus learned this behavior from other orangutans from their area of birth”.
The medicinal plant that cured the orangutan
This plant, widely distributed in China, Indonesia, Malaysia, Thailand, Vietnam and other parts of Southeast Asia, It is used in traditional medicine to treat conditions such as malaria.
The life of orangutans
Orangutan means “forest person” in the Indonesian and Malay languages., and these apes are the largest arboreal mammal in the world. Orangutans, adapted to living in trees, lead a more solitary life than other great apes, sleeping and eating fruit in the treetops and swinging from branch to branch. “Orangutans have great cognitive abilities, especially in the area of physical cognition,” explains Schuppli.
“They are known to be excellent problem solvers. Wild orangutans acquire their skills through observational social learning, and these are passed down from generation to generation. “The population where this observation was made is known for its rich cultural repertoire, which includes the use of tools in different contexts.”
