The orangutan in the wild applied a medicinal plant to heal its own injury, biologists say

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

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

She says she was “very excited” by the orangutan’s apparent innovation, which was documented at 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 may have picked up the large wound in a fight with a rival man. 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 spotted 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 Suaq’s 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, instead swallowing the plant’s juices into his wound. When the flies started landing on his wound, Rakus covered it completely with leaf material and went back to eating the plant.

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

If Rakus was his own nurse, he also appears to have been a good patient: The day after initially applying the leaves, the orangutan found the plant again and ate more leaves. He also rested much more than usual, which researchers say likely gave his body a better chance to heal.

Which plant was used as medicine?

Its common name is Akar Kuning (Fibraurea tinctoria). It is a type of liana, a vine that climbs into the tops of trees to reach the sun. The plant has analgesic, antipyretic and diuretic effects; in the 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 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. . paper

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

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

“No, I haven’t,” she said. “It is rarely eaten by Suaq orangutans (only 0.3% of all approximately 390,000 foraging scans).”

Who is Rakus?

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

Their self-treatment is extremely rare: The 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 over long distances to establish a new home territory in another area or move between each other’s territories,” Schuppli said in a statement press release on the findings.

“Therefore, it is possible that the behavior is shown by more individuals in their native population outside of the Suaq research area.”

Nearly two years after his injury, Rakus is thriving.

“He’s now one of the dominant men in the research area,” Laumer told NPR.

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

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

It is possible to treat a wound with Fibraurea tinctoria It started as a lucky accident, the researchers say, noting that the plant has powerful pain-relieving effects and adding that by applying a poultice, the orangutan’s main purpose may have been to protect his wound from flies.

But because orangutans are thought to continue to add skills into adulthood through social learning, the paper adds, it’s possible that the treatment strategy “may also spread socially from individual to individual.”

Could Rakus share his medical knowledge with other orangutans? This enters into the social question of culture. In the past, Sumatran orangutans have demonstrated a knack for sharing innovative ideas, with popular behaviors extending as far as 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, humans’ closest living relatives, have been documented to eat 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 efficiency of this behavior is still unknown.”

“Human wound treatment was probably first mentioned in a medical manuscript dating back to 2200 BC, which included cleaning, plastering and bandaging wounds with certain wound healing substances,” Schuppli said in the statement of press

Noting that taking action to treat a wound is seen in both humans and African and Asian great apes, he added, “it is possible that a common underlying mechanism exists for the recognition and application of substances with medical or functional properties to wounds. and that our last common ancestor already showed similar forms of ointment behavior.”

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