Smithsonian magazine reports:

In June 2022, a team of researchers observed a behavior never before witnessed in the animal world: A Sumatran orangutan named Rakus self-treated an injury using a medicinal plant.

At Gunung Leuser National Park, a rainforest reserve on the western Indonesian island of Sumatra, scientists heard from the treetops a series of “long calls,” a behavior that usually preempts assertions of male dominance or aggression. The next day, they saw Rakus with an open wound on his right cheek, just below his eye.

Days later, the team watched Rakus get to work—picking and chewing the stems and leaves of Akar Kuning (Fibraurea tinctoria), or yellow root. The plant is a climbing vine native to the region that local people use for its medicinal qualities to treat conditions such as diabetes, dysentery and malaria.

While hardly a staple of the orangutan diet—the team noted that yellow root is eaten only 0.3 percent of the time—Rakus consumed it anyway. He also chewed it, without swallowing, then spread its juices and poultice on his wound, where some flies had begun gathering. Rakus came back to the plant and ate it the next day, and soon, his wound was fully healed. This week, an analysis of the orangutan’s behavior was published in the journal Scientific Reports.

“[This] is the first observation of a wild animal actually treating his wound precisely with a medical plant,” Isabelle Laumer, a primatologist at the Max Planck Institute of Animal Behavior in Germany and the lead author of the study, tells National Geographic’s Daryl Austin.

It took five days after treatment for the wound to close, and scientists saw no signs of infection after one month. Research on yellow root’s chemistry has shown the plant to have “antibacterial, anti-inflammatory, anti-fungal, antioxidant, pain-killing and anticarcinogenic properties,” the Guardian’s Nicola Davis reports. [Continue reading…]