Rakus

Rakus is a wild male Sumatran orangutan (Pongo abelii) living in the Suaq Balimbing rainforest of north-western Sumatra, Indonesia. He gained international attention in 2024 after being observed self-treating a facial wound with the juice of a medicinal plant, an act widely regarded as the first documented case of deliberate self-medication in a wild great ape using a plant with known healing properties. This rare behaviour provided remarkable insight into the cognitive and behavioural sophistication of orangutans and their capacity for innovation in the wild.

Background

Rakus has been monitored as part of a long-term orangutan observation project in the Suaq Balimbing research area, one of the richest habitats for studying wild orangutan behaviour. He was first identified in the late 2000s as a young, unflanged male (a developmental stage before full maturity). Over time, he developed the large cheek pads, throat sac, and dominant status characteristic of a flanged male orangutan. Researchers distinguished him by unique facial features, including light markings beneath his eyes.
Sumatran orangutans are critically endangered, with their population threatened by habitat loss, logging, and agricultural expansion. Long-term monitoring of individuals like Rakus has been crucial for understanding their social structure, foraging behaviour, and adaptive intelligence.

Observation of the Self-Medication Event

In June 2022, Rakus was observed with a noticeable open wound below his right eye, likely sustained during a territorial fight with another male. Over the next few days, observers witnessed a sequence of highly unusual behaviour:

• Rakus deliberately plucked leaves from a woody climbing plant known locally for its medicinal qualities, identified as Fibraurea tinctoria.
• He chewed the leaves into a pulp without swallowing them and repeatedly applied the sap to his wound.
• He then used additional leaf fragments to cover the wound, possibly acting as a protective dressing.
• After the treatment, Rakus rested for long periods, which may have aided recovery.

Within a few weeks, the wound healed completely without infection or complications, leaving only a faint scar. The entire process appeared deliberate, careful, and purposeful—suggesting an understanding of the plant’s beneficial properties.

The Medicinal Plant: Fibraurea tinctoria

The plant used by Rakus, Fibraurea tinctoria, is a climbing vine found in Southeast Asian forests. It is known in traditional human medicine for its anti-inflammatory, antibacterial, and pain-relieving properties. The plant contains protoberberine alkaloids, chemical compounds that inhibit microbial growth and reduce inflammation.
The fact that Rakus selected this particular species—rarely eaten by orangutans—indicates that his choice was intentional and behaviourally specific, aimed at healing rather than feeding.

Scientific and Behavioural Significance

Rakus’s behaviour represents a major discovery in primate ethology. It provides the first recorded instance of a wild great ape applying a plant-based substance directly to a wound, a form of topical self-medication previously observed only in humans and some other mammals like elephants and certain bird species.
This event demonstrates:

• Cognitive awareness: Rakus appeared to recognise his injury and actively sought a means to treat it.
• Behavioural innovation: He displayed a novel behaviour not previously seen in his population.
• Knowledge of plant properties: His use of a medicinal plant suggests an understanding, possibly learned or intuitive, of its healing effects.

Such behaviour adds to the growing body of evidence that great apes possess advanced problem-solving abilities and can use elements of their natural environment for therapeutic purposes.

Broader Ecological and Evolutionary Implications

The observation of Rakus has several implications for understanding both orangutan intelligence and the evolution of healing behaviour in primates:

• It supports the idea that self-medication is an ancient evolutionary trait, predating human medical knowledge.
• It suggests that orangutans, despite their solitary lifestyle, possess individual learning capacities and environmental awareness similar to other highly intelligent primates.
• It highlights how environmental knowledge—especially of medicinal plants—can evolve through experience or observation within a species.

Orangutans and Cognitive Complexity

Sumatran orangutans are known for their advanced cognitive abilities. They use tools, build elaborate nests, plan routes, and exhibit social learning. Rakus’s action adds another dimension to this intelligence—health awareness and self-care. The incident suggests that orangutans may have a degree of self-recognition and understanding of cause-and-effect relationships, allowing them to respond to bodily injuries proactively.

Conservation Context

The Suaq Balimbing rainforest, part of the Leuser Ecosystem, is one of the last strongholds of Sumatran orangutans. Such behavioural discoveries underline the importance of protecting these habitats, not only for species survival but also for advancing scientific understanding of primate evolution and behaviour.
Deforestation, palm oil expansion, and illegal logging threaten both the orangutans and the ecosystems that sustain them. Rakus’s case demonstrates how much remains to be learned from wild populations when they are allowed to live undisturbed in their natural environment.

Research Significance

The long-term observation of Rakus was made possible by continuous behavioural monitoring programmes. These studies rely on systematic recording of daily activity patterns, plant usage, and social interactions. Without such long-term field presence, rare behavioural innovations like Rakus’s self-treatment would go unnoticed.
His case also raises new research questions:

• Was the use of the medicinal plant learned through trial and error, observation, or instinct?
• Do other orangutans in the population exhibit similar self-medicating behaviour?
• Can such knowledge spread culturally through imitation or social learning?

The answers to these questions may redefine scientific understanding of primate health behaviour and cognition.

Symbolic and Cultural Impact

Rakus has become a symbol of the deep connections between animals, health, and the natural world. His actions blur the boundary between instinct and intelligence, reminding humanity of its evolutionary continuity with other great apes.
The discovery also challenges long-held assumptions about the uniqueness of human medicine, suggesting that the roots of self-care and healing may lie deep within primate ancestry.