Injured in the face, a Sumatran orangutan treated itself with a bandage made from a medicinal plant, in the first observation of such behavior in a great ape in the wild, reported Thursday in the journal Scientific Reports.
Rakus, who is around 30 years old, was observed last June with a nasty wound on his face, exposing his flesh under his right eye along his nostrils. An injury received “probably during a fight with a neighborhood male“, according to Isabelle Laumer, primatologist at the German Max Planck Institute and first author of the study.
He makes his own ointment to treat a wound
The animal is being monitored with some 130 conspecifics, all in the wild, in an area of the Indonesian Gunung Leuser National Park.
Three days after his injury, Rakus began chewing leaves of 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 Southeast Asia. This vine and others similar “are used as traditional remedies for different ailments, such as malaria“, according to the cognitive biologist, cited by Max Planck. Thanks to antibacterial and anti-inflammatory properties, among others.
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“.
If confirmed by further observations, it would complete a growing list of self-medicating behaviors by animals, particularly in primates.
In the 1960s, the famous primatologist Jane Goodall first observed that chimpanzees were ingesting leaves, the anti-parasitic role of which was later revealed.
Coincidence or real use of medicinal plants?
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.
More recently, researchers observed Bornean orangutans, also in the wild, chewing the leaves of a medicinal plant before rubbing it only on their limbs. Coincidence? Dracenea cantleyi is typically used by indigenous populations to treat sore muscles and joint pain…
The study believes that Rakus' behavior, like that of its Borneo counterparts, was well intentional. With repeated and meticulous treatment of a very specific location, “which took a considerable amount of time“, according to Isabelle Laumer.
Co-author of the study, Dr. Caroline Schuppli does not rule out “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. As the plant has an analgesic effect, monkeys “may experience immediate relief, prompting them to repeat the procedure several times“, according to this head of the Cognitive Development and Evolution Group at Max Planck.
This behavior has not been observed locally until now, the researcher does not exclude that it is present in the area of origin of Rakus, young male orangutans leaving their native region after puberty.
The fact that, like humans, primates can actively treat an injury in this way suggests that “our last common ancestor already used similar forms of treatment using ointments“, according to Dr. Schuppli.