When a great ape in a zoo or in the wild suffers from a wound and needs treatment, whom does he seek for help? Fortunately, he can treat himself, according to a new study published in Nature’s prestigious, open-access journal Scientific Reports.
Researchers led by primatologist Dr. Isabelle Laumer of the Max Planck Research Group have been studying great apes and Goffin cockatoos at the University of Vienna, the Max Planck Institute in Leipzig, and the University of California at Los Angeles for the past decade
Laumer reported in her article under the title “Active self-treatment of a facial wound with a biologically active plant by a male Sumatran orangutan” that a wild male Sumatran orangutan (Pongo abelii) was seen applying chew leaves from Akar Kuning (Fibraurea tinctoria) – a climbing plant used in traditional medicine to treat wounds and conditions such as dysentery, diabetes, and malaria to a wound on his cheek.
First report of suspected wound treatment
She said that it was the first report of suspected wound treatment by a wild animal using a plant with known medicinal properties. Before this study, multiple wild primate species had been observed swallowing, chewing, or rubbing plants with medicinal properties but not applying them to recent wounds.
Although self-medication in non-human animals is often difficult to document systematically due to the difficulty of predicting its occurrence, there is widespread evidence of such behaviors as whole leaf swallowing, bitter pith chewing, and fur rubbing in African great apes, orangutans, white-handed gibbons, and several other species of monkeys in Africa, Central and South America, and Madagascar.
Laumer and colleagues observed the male orangutan — given the name Rakus by researchers – in June 2022 in the Suaq Balimbing research area in Indonesia’s Gunung Leuser National Park. Rakus chewed the plant’s stem and leaves and repeatedly applied the liquid this generated for seven minutes on a wound on his right cheek that he had suffered three days before. Rakus then smeared the chewed leaves onto the wound until it was fully covered and continued feeding on the plant for over 30 minutes.
The authors reported no signs of wound infection in the days following their observations, and the wound had closed within five days and was fully healed within one month.
As Rakus repeatedly applied plant material to his wound but no other body parts and the entire process took over half an hour, it is likely that he intentionally treated his facial wound with Akar Kuning. Previous research has identified antibacterial, anti-inflammatory, anti-fungal, and antioxidant properties in Akar Kuning, and the chewed leaves may have helped to reduce pain and inflammation caused by Rakus’s wound and supported wound healing.
The authors said they didn’t know whether this was the first time that Rakus treated one of his wounds or had previously learnt this behavior from other orangutans living in the place where he was born. As it appears that Rakus did intentionally treat his wound, this suggests that the behavior could have arisen in a common ancestor shared by humans and great apes.
The authors note that they have not observed other orangutans within the research area treating their wounds, however this could be due to the researchers rarely encountering injured individuals.
Previous analyses of plant chemical compounds show the presence of furanoditerpenoids and protoberberine alkaloids, which are known to have antibacterial, anti-inflammatory, anti-fungal, antioxidant, and other biological activities of relevance to wound healing. This possibly innovative behavior presents the first systematically documented case of active wound treatment with a plant species known to contain biologically active substances by a wild animal and provides new insights into the origins of human wound care.