An orangutan from Indonesia was observed creating a medicinal paste and applying the paste on a facial wound to help it heal faster. The treatment was successful and hints at sophisticated self-medicating abilities.
This remarkable behavior is a clear case of active wound treatment with a plant species “known to contain biologically active substances by a wild animal,” researchers who documented the case say.
Self-medicating orangutan
It all started at the Suaq Balimbing research site in Indonesia. Rakus the orangutan had a pretty bad fight with a male rival. The fight left him with a nasty wound on his face. Three days after the injury, Rakus started picking and ripping the leaves of a liana called Fibraurea tinctoria.
The liana is known for its analgesic effects. It’s also sometimes used as an antipyretic (reduces fever) and diuretic. It also has some anti-inflammatory and antibacterial compounds. Rakus gathered the leaves and started chewing them. Rakus applied the resulting juice onto his face and lastly, covered his wound entirely in chewed leaves.
There’s no reason to believe this is anything other than self-medicating, researchers say.
“The behavior of Rakus appeared to be intentional as he selectively treated his facial wound on his right flange [cheek pad], and no other body parts, with the plant juice. The behavior was also repeated several times, not only with the plant juice but also later with more solid plant material until the wound was fully covered. The entire process took a considerable amount of time,” says lead author Isabelle Laumer.
“The present study may thus present the first report of active wound management with a biologically active substance in a great ape species and provides new insights into the existence of self-medication in our closest relatives and in the evolutionary origins of wound medication more broadly,” the study also reads.
The treatment worked. After just five days, the wound closed off and there was no infection. Furthermore, Rakus was also aware that he needed to get more rest.
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“Interestingly, Rakus also rested more than usual when being wounded. Sleep positively affects wound healing as growth hormone release, protein synthesis, and cell division are increased during sleep,” explains Laumer.
Just like humans used to do it
This behavior suggests once more that evolutionarily, orangutans are not that far behind humans. This is the first time we’ve noticed this behavior, but orangutans may have been self-medicating for a long time.
In fact, researchers say that this behavior is so similar to humans that it may have evolved in our common ancestor with orangutans.
“The treatment of human wounds was most likely first mentioned in a medical manuscript that dates back to 2200 BC, which included cleaning, plastering, and bandaging of wounds with certain wound care substances,” says Caroline Schuppli, senior author of the study.
“As forms of active wound treatment are not just human, but can also be found in both African and Asian great apes, it is possible that there exists a common underlying mechanism 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.”
Orangutans aren’t the only primates to do this. In the 1960s, primatologist Jane Goodall described the presence of whole leaves in the feces of chimps. By the 1990s, this was confirmed to be a behavior with a therapeutic and anti-parasitic function.
Since then, several types of self-medicating have been observed in nature.
Animals also self-medicate
Researchers usually classify self-medication into:
- Sick Behaviors: Exhibiting anorexia or other behaviors indicative of illness.
- Avoidance Behaviors: Avoiding things like feces, contaminated food, or water.
- Prophylactic Behaviors: Routine consumption of foods known for their preventive health benefits.
- Therapeutic Behaviors: Consuming small amounts of biologically active or toxic substances with little nutritional value to treat diseases or symptoms.
- Therapeutic Topical Application: Applying pharmacologically active plants topically to treat external health conditions or using such plants in nests as fumigants or insect repellents.
The latter is perhaps the most complex, and several animals have been observed doing it.
North American brown bears (Ursos arctos) make a paste of Osha roots (Ligusticum porteri) and saliva. They then rub their fur in this paste to repel insect bites and soothe existing bites. Navajo Indians are said to have learned to use this root medicinally from the bear. Bees also use resins as medication after a fungal infection and a chimpanzee in Gabon was spotted treating a wound with insects that contain medicinal compounds.
Rakus has now entered a very select group of creatures, but an important question remains: how did this behavior emerge? Is it that Rakus experimented with different plants and innovated it himself, or did he learn it from somewhere else?
“It is possible, that wound treatment with Fibraurea tinctoria by the orangutans at Suaq emerges through individual innovation,” says Schuppli. “Orangutans at the site rarely eat the plant. However, individuals may accidentally touch their wounds while feeding on this plant and thus unintentionally apply the plant’s juice to their wounds. As Fibraurea tinctoria has potent analgesic effects, individuals may feel an immediate pain release, causing them to repeat the behavior several times.”
At any rate, this hints that self-medicating in nature may be far more widespread and common than we thought. In the next few years, we’re likely to find more human-like treatments if we keep closely observing our primate relatives, concludes Laumer.
The study was published in Scientific Reports.
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