A Sumatran orangutan makes a medicine by chewing the leaves of a liana

This is the first “documented case of treatment of a wound with a species of plant containing active biological substances by a wild animal”, underline the authors of an article published in the journal “Scientific Reports”.

Self-medication in the middle of the tropical forest. A Sumatran orangutan healed himself with a bandage made from a medicinal plant, the magazine reports Scientific Reports, Thursday May 2, in a scientific article devoted to the question. This is the first time such behavior has been observed in a great ape in the wild.

Aged around thirty, Rakus is being followed with nearly 130 conspecifics, all in the wild, in an area of ​​the Indonesian Gunung Leuser National Park. Last June, scientists discovered that he was suffering from a nasty facial injury: flesh was exposed to the air, under his right eye and along his nostrils. According to Isabelle Laumer, primatologist at the German Max Planck Institute and main author of the study, there is little doubt: this injury had been “probably” received “during a fight with a neighborhood male.”

Three days later, Rakus began chewing leaves from a vine, locally called Akar Kuning (Fibraurea tinctoria). But instead of ingesting it, he brought his fingers coated with the juice of the plant to his raw wound. Before covering it entirely with liana pulp. Five days later, the wound was closed. Two weeks later, it left a barely visible scar. The “remedy” used is not miraculous, it is part of the traditional pharmacopoeia in the region, from China to South-East Asia.

Precursor orangutan or collective knowledge?

This vine and others similar “are used as traditional remedies for various ailments, such as malaria”, according to the cognitive biologist, cited by Max Planck. Thanks to antibacterial and anti-inflammatory properties, among others. Regardless, according to the study, this is the first “documented case of treatment of a wound with a plant species containing biologically active substances by a wild animal”.

The study believes that Rakus’ behavior, like that of its Borneo counterparts, was well intentional. Co-author of the study, Caroline Schuppli does not exclude a “individual innovation”, of accidental origin. Rakus could have unintentionally applied the juice of the plant to his wound, just after putting his fingers in his mouth. Further observations would be needed to be sure.

Several self-medication behaviors have already been observed in animals, particularly in primates. In the 1960s, the famous primatologist Jane Goodall first observed that chimpanzees absorbed leaves, the antiparasitic role of which was later revealed. A behavior observed since in bonobos and gorillas, with a selection by the animal of the plants ingested, the knowledge of which would be transmitted by females.