Injured orangutan uses plants to heal his own wound: NPR

When a wild orangutan in Indonesia suffered a painful wound on its cheek, it did something that surprised researchers: It chewed leaves of plants known to have healing and pain-relieving properties, rubbed the juice on the open wound, and then used the leaves as a poultice to cover your wound.

“This case represents the first known case of active treatment of wounds in a wild animal with a medicinal plant,” biologist Isabelle Laumer, first author of a paper about the revelation, told NPR.

She says she was “very excited” by the orangutan’s apparent innovation, which was documented in the Suaq Balimbing Research Site in Gunung Leuser National Park in northwest Sumatra, where about 150 orangutans live in a protected rainforest.

The orangutan is called Rakus. Laumer says he could have received the large wound in a fight with a rival male. A few days later, he was seen using a plant to treat his wound. The wound then healed, apparently without any infection.

Laumer and another researcher, Caroline Schuppli, led a team of cognitive and evolutionary biologists from the Max Planck Institute for Animal Behavior in Germany and Universitas Nasional in Indonesia.

What happened?

Rakus was discovered with the new wound on June 22, 2022. Three days later, he began eating the stem and leaves of a liana, a vine that researchers say the Suaq orangutan population rarely eats. From there, his behavior became increasingly intentional and specific.

Rakus spent 13 minutes eating the plant, and then spent seven minutes chewing the leaves and not swallowing them, but instead smeared the plant’s juices on his wound. When the flies began to land on his wound, Rakus covered it completely with leaves and ate the plant again.

Within five days, the wound had closed. And by July 19, about a month after the injury was likely sustained, “the wound appeared to have healed completely and only a slight scar remained,” the biologists said in their paper, published Thursday in Scientific Reports.

When Rakus was acting as his own nurse, he also appears to have been a good patient: the day after applying the leaves for the first time, the orangutan found the plant again and ate more leaves. He also rested much more than usual, which researchers said likely gave his body a better chance to heal.

What plant was used as medicine?

Its common name is Akar Kuning (Fibraurea tinctoria). It is a type of liana, a vine that climbs to the tops of trees to reach sunlight. The plant has analgesic, antipyretic and diuretic effects; In traditional medicine of the region, it is used to treat diseases ranging from dysentery and diabetes to malaria.

Analysis of the plant’s chemical compounds has found “the presence of furanoditerpenoids and protoberberine alkaloids, which are known to have antibacterial, anti-inflammatory, antifungal, antioxidant, and other biological activities relevant to wound healing,” according to the researchers’ article.

“It also contains jatrorrhizin (antidiabetic, antimicrobial, antiprotozoal, anticancer and hypolipidemic properties… and palmatine (anticancer, antioxidant, anti-inflammatory, antibacterial and antiviral properties),” the newspaper said.

So what does the plant taste like? We asked Laumer if she’d ever tried it herself.

“No, I haven’t,” he said. “Suaq orangutans rarely eat it (in only 0.3% of the approximately 390,000 feeding scans).”

Who is Rakus?

Rakus is a male Sumatran orangutan who is believed to have been born in the late 1980s, meaning he was around 32 years old when he was seen applying leaves to his wound. It was observed for the first time in the area in March 2009.

Their self-medication is extremely rare: researchers say that “in 21 years and 28,000 hours of observation,” observers at the research station have never seen orangutans using leaves to treat their wounds.

Rakus is not from the forest where he was seen tending to his wound.

“Male orangutans disperse from their natal area during or after puberty across long distances to establish a new territory in another area or move between the territories of others,” Schuppli said in a press release about the findings.

“Therefore, it is possible that the behavior is displayed by more individuals from its natal population outside the Suaq research area.”

Nearly two years after his injury, Rakus is thriving.

“He is now one of the dominant males in the research area,” Laumer told NPR.

What is “ointment behavior” and what does it mean?

Rakus’ seemingly innovative behavior suggests that “medical treatment of wounds may have arisen in a common ancestor shared by humans and orangutans,” according to the article.

Treating a wound with Fibraurea tinctoria It began as a lucky accident, the researchers say, noting that the plant has potent analgesic effects and adding that by applying a poultice, the orangutan’s main goal may have been to protect its wound from flies.

But since orangutans are believed to continue adding skills into adulthood through social learning, the article adds, it is possible that the treatment strategy “could also spread socially from one individual to another.”

Could Rakus share his medical knowledge with other orangutans? This enters into the social question of culture. In the past, Sumatran orangutans have demonstrated an ability to share innovative ideas, with popular behaviors extending to a natural boundary, such as a river.

The findings could lead to new insights into the evolution of self-care and medicine in primates.

Great apes, the closest relatives of humans, have been documented eating certain plants for therapeutic or antiparasitic benefits. The researchers also note that in Gabon chimpanzees have been seen applying small insects to wounds, although, they note, “the effectiveness of this behavior is still unknown.”

“The treatment of human wounds was most likely first mentioned in a medical manuscript dating back to 2200 BC, which included cleaning, plastering and dressing wounds with certain wound care substances” Schuppli stated in the press release.

Noting that both humans and African and Asian great apes take steps to treat a wound, he added: “There may be a common underlying mechanism for the recognition and application of substances with medical or functional properties to wounds.” and that our last common ancestor already displayed similar forms of ointment behavior.”