Orangutan Self-Medication: 7 Fascinating Facts How Wild Apes Use Plants
Wild orangutans have been observed applying chewed plant material to their bodies in ways that may help manage inflammation or treat wounds. In 2022, a wild Sumatran orangutan named Rakus applied the juice and pulp of a medicinal liana to a facial wound. Earlier research documented Bornean orangutans rubbing a foamy mixture of chewed leaves onto their arms and legs. These observations provide evidence of possible self-medication, although scientists are still investigating exactly how the behaviors work and how much they improve health.
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An illustrative depiction of an orangutan holding and chewing green leaves in a rainforest, inspired by documented plant-use behaviors in wild orangutans, including the application of chewed leaves to a facial wound by a Sumatran orangutan named Rakus. Created to accompany The Pader’s animal facts guide on orangutan self-medication. Illustration: The Pader. |
When an animal is injured, it cannot visit a doctor or buy medicine. Yet some wild animals interact with plants and other natural materials in ways that may help them cope with illness, parasites, or injury.
Orangutans offer a particularly fascinating example. Researchers have documented wild individuals chewing specific plants and applying the resulting material to their own bodies. One Sumatran orangutan even treated a facial wound with chewed leaves, creating a striking example of a behavior that resembles the use of a topical medicine.
Scientists call this type of behavior self-medication when the evidence suggests that an animal uses a biologically active substance to help manage a health problem. The distinction matters: researchers can directly observe what an animal does, but determining its precise purpose and medical effectiveness requires additional evidence.
SCIENCE HIGHLIGHT
A 2024 study documented a wild male Sumatran orangutan applying chewed leaves of Fibraurea tinctoria to a facial wound. The plant contains compounds with biological activities relevant to wound care, but the observation alone cannot prove which compounds affected the wound or how much the treatment contributed to healing.
6 Facts About Orangutan Self-Medication
1. A Wild Orangutan Applied Plant Material to a Facial Wound
The best-known case involved a male Sumatran orangutan researchers named Rakus. Scientists studying wild orangutans in the Suaq Balimbing research area of Indonesia noticed that he had a fresh wound on his face in June 2022.
Three days after the injury was first noticed, Rakus selected leaves from a climbing plant, chewed them, and repeatedly applied the resulting juice to the wound. He then covered the wound with the chewed plant material.
The behavior was documented by researchers studying the animals in the wild. It was not a treatment carried out by human caregivers.
The study, published in Scientific Reports in 2024, described this as the first systematically documented case of a wild animal actively treating a wound with a plant species known to contain biologically active substances.
2. The Plant Was Identified as Akar Kuning
The plant Rakus used is known locally as Akar Kuning and was identified as Fibraurea tinctoria, a climbing plant found in tropical forests of Southeast Asia.
Researchers selected this case for scientific attention because the plant is known in traditional medicine and contains compounds that have been studied for biological activity. Research on its chemical constituents has identified furanoditerpenoids and protoberberine alkaloids, groups of compounds associated in laboratory studies with activities such as anti-inflammatory and antimicrobial effects.
These properties make the behavior scientifically interesting, but they do not prove that the plant safely or effectively treats wounds in orangutans. The researchers observed a single case and did not experimentally test the treatment on the animal.
3. Rakus Repeatedly Applied the Chewed Leaves to the Wound
The sequence of actions was an important part of the observation. Rakus did not simply eat the plant as part of an ordinary meal. He chewed the leaves and applied the resulting material directly to the injured area.
The researchers interpreted this deliberate application as possible therapeutic topical behavior. The plant material was placed on the wound rather than swallowed for nutrition.
That distinction is important because animals can interact with potentially medicinal plants in several ways. Eating a plant, rubbing it into the fur, and placing it directly on an injury are different behaviors and may have different functions.
4. The Wound Later Closed, but the Observation Cannot Prove the Plant Caused Healing
Researchers continued observing Rakus after the treatment. The wound was closed by June 30, 2022, and was barely visible by August 25.
This timeline is consistent with the wound healing after the plant application, but it does not establish that the plant caused the healing or prevented infection. Wounds can heal naturally, and the study did not include a controlled comparison between treated and untreated wounds.
The scientifically responsible conclusion is that Rakus performed a striking form of wound treatment using a plant with biologically active compounds. Whether the behavior improved healing, reduced pain, prevented infection, or served several purposes remains a question for further research.
5. Bornean Orangutans Have Also Rubbed a Foamy Leaf Mixture Onto Their Limbs
The Rakus observation was not the first evidence suggesting that orangutans may use plants for health-related purposes.
A 2017 study documented Bornean orangutans (Pongo pygmaeus) chewing leaves of Dracaena cantleyi, producing a foamy mixture with their saliva, and rubbing it onto their upper arms or legs. The orangutans were not observed swallowing the leaves during this behavior.
Across the research period described in the paper, the behavior was rare. The researchers documented ten cases by September 2015 after long-term observation of orangutans in the Sabangau peat-swamp forest of Central Kalimantan, Indonesia.
The researchers investigated the plant's biological properties and found that extracts inhibited several inflammatory signaling markers in laboratory cell experiments. These findings supported the hypothesis that rubbing the plant mixture onto the body might help relieve muscle or joint discomfort.
However, the precise benefit to the orangutans was not directly measured. The behavior and the laboratory results together provide evidence consistent with self-medication, rather than definitive proof of a particular medical effect in the wild.
6. Scientists Are Studying How Animals May Discover Medicinal Uses of Plants
Orangutan self-medication raises a broader question: how do animals come to use particular plants in specific ways?
Researchers can investigate whether a behavior is repeated, whether an animal applies a plant to a particular body part, whether the plant contains biologically active compounds, and whether the behavior occurs in a context consistent with illness or injury.
Even with these clues, scientists must be careful about claims concerning intention. A purposeful-looking action does not automatically reveal exactly what an animal understands about the plant or its chemistry.
In Rakus's case, the targeted application of chewed leaves to a wound is strong behavioral evidence of active treatment. The chemical properties of the plant provide a plausible explanation for why the behavior might be useful. More observations and research are needed to determine how widespread this behavior is and whether orangutans learn it from other individuals or discover it independently.
In the 2017 study of Bornean orangutans, researchers recorded more than 20,000 hours of observations of 50 individuals over a decade. Even with that extensive observation period, the leaf-rubbing behavior was rare, highlighting how difficult unusual animal behaviors can be to document.
MYTH: Scientists have proved that orangutans understand plant chemistry exactly as humans do.
FACT: Researchers have documented specific plant-use behaviors and tested the biological activity of the plants involved. These findings support the possibility of self-medication, but they do not establish that orangutans understand the chemistry in the same way humans do.
Why Orangutan Self-Medication Matters
These observations offer a valuable window into the relationship between animal behavior and natural chemistry. Plants produce compounds that can affect living cells, and wild animals encounter those compounds through their food and environment. In some cases, an animal may use a plant in a way that appears to address a health problem.
The orangutan cases are particularly important because they involve external application: the animals placed plant material directly onto their bodies rather than merely eating it. The Rakus observation adds a documented example of a wild great ape applying a biologically active plant to an injury.
These discoveries do not mean that every unusual plant-eating behavior is medicinal, or that wild animals can be assumed to choose safe treatments. Instead, they show why careful long-term observation and laboratory analysis are both needed to understand animal self-medication.
Frequently Asked Questions
Did an orangutan really treat its own wound with a plant?
Yes. Researchers documented a wild male Sumatran orangutan named Rakus applying chewed leaves of Fibraurea tinctoria to a facial wound in 2022. The study describing the observation was published in 2024.
What plant did Rakus use?
He used Fibraurea tinctoria, a tropical climbing plant locally known as Akar Kuning. Its chemical constituents have been studied for biological activities that may be relevant to wound care.
Do orangutans use plants as medicine?
Researchers have documented behaviors consistent with self-medication, including applying plant material to a wound and rubbing a foamy leaf mixture onto the limbs. The medical benefits and full purpose of these behaviors require further investigation.
Did the plant definitely heal Rakus's wound?
The wound closed after the plant application, but the observation cannot prove that the plant caused the healing. Researchers did not experimentally compare the treatment with natural wound healing.
Is orangutan self-medication common?
The documented behaviors discussed here appear rare in the observed populations. The available cases do not establish how frequently orangutans use plants for self-medication across all wild populations.
The Takeaway
Orangutans have been observed using plants in ways that may help them manage physical discomfort or injury. The case of Rakus, the Sumatran orangutan who applied chewed leaves to a facial wound, provides particularly striking evidence of active plant-based wound treatment. Earlier research on Bornean orangutans documented a different behavior involving the application of a foamy leaf mixture to the limbs.
Both cases show how careful observation can reveal complex animal behaviors. They also demonstrate why scientific caution matters: the actions are documented, the plants contain biologically active compounds, and self-medication is a plausible explanation—but the exact benefits and mechanisms are still being investigated.
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Sources and Further Reading
- Laumer et al. (2024) — Active self-treatment of a facial wound with a biologically active plant by a male Sumatran orangutan. Scientific Reports.
- Morrogh-Bernard et al. (2017) — Self-medication by orang-utans (Pongo pygmaeus) using bioactive properties of Dracaena cantleyi. Scientific Reports.
- Full open-access text of the 2024 orangutan wound-treatment study. PubMed Central.
- Full open-access text of the 2017 Bornean orangutan leaf-rubbing study. PubMed Central.
Status: FACT-CHECKED
The article's central claims were checked against the original 2017 and 2024 studies published in Scientific Reports. It distinguishes the observed behaviors from proposed medical explanations, identifies the plants reported by the researchers, and avoids claiming that plant application definitively caused wound healing or that all orangutans use these methods.
The Pader presents wildlife and science information using credible sources and accessible language. Scientific information may be updated as new research emerges.