Chimpanzees Show Forest Medicine Use By Self-Treating

Forest Pharmacy: Chimpanzees Reveal Advanced Medicinal Know-How

Wild chimpanzees in Uganda demonstrate sophisticated use of medicinal plants for treating injuries, not only on themselves but also on others. This remarkable behaviour, documented by University of Oxford scientists and local teams, offers profound insights into the origins of medicine and the complex cognitive abilities of our closest living relatives.

New research highlights the intriguing ways primates in Uganda, specifically chimpanzees, employ medicinal flora to address exposed sores and varied physical harms. Academics from the University of Oxford, collaborating with a regional crew within the Budongo Forest area, documented occurrences where the creatures utilized vegetation for rudimentary treatment, applying these remedies to their own injuries and, significantly, to the injuries of other chimpanzees. This investigation builds upon earlier findings that chimpanzees actively search for and ingest particular flora for their own healing. Furthermore, the researchers gathered many years of scholarly notes to assemble a record detailing the varied techniques chimpanzees employ for what they term 'woodland preliminary care'. This study underscores the depth of chimpanzee understanding of their natural environment.

Chimpanzees of Budongo Forest

The Budongo Forest Reserve, a sprawling expanse of tropical rainforest in western Uganda, serves as a critical habitat for an estimated 600-700 Eastern chimpanzees (Pan troglodytes schweinfurthii). It represents one of the largest and most ecologically significant forests in East Africa. The Budongo Conservation Field Station (BCFS), which people established in 1990, has been instrumental in the long-term study and conservation of these chimpanzees. Several chimpanzee communities reside within Budongo, with researchers primarily focusing on groups habituated to human presence, such as the Sonso and Waibira communities. This habituation allows for close observation of their natural behaviours without significant disturbance. The forest itself is a rich tapestry of biodiversity, providing not only sustenance but also a natural pharmacy for its inhabitants. Understanding the specific plants these animals select constitutes a key focus of ongoing research.

The collaborative research effort in Budongo involves international scientists and local Ugandan field staff. Dr Elodie Freymann from the University of Oxford's School of Anthropology & Museum Ethnography leads a significant part of this research. Her work, alongside colleagues and the dedicated team at BCFS, involves painstaking fieldwork, collecting behavioural clues and plant samples. This often means long hours tracking chimpanzees through dense forest terrain. The local team's expertise and continuous presence in the woodland are invaluable, contributing to both data collection and the protection of the chimpanzees. This partnership ensures a blend of cutting-edge scientific methods and deep local knowledge. The research underscores the importance of such collaborations in advancing our understanding of primate behaviour and ecology.

Image Credit - Freepik

A Deeper Look into Self-Medication Practices

This analysis, featured in the publication Frontiers in Ecology and Evolution, significantly contributes to an expanding collection of proof showing that various primates, such as chimpanzees, orangutans, plus gorillas, utilize organic remedies through several methods to preserve their well-being in their native environments. Elodie Freymann, the principal investigator, elaborated that chimpanzees exhibit an entire range of actions when they are unwell or harmed in their natural habitat, enabling them to care for themselves and uphold cleanliness. She further detailed that certain behaviors involve employing vegetation available in their surroundings. The primates, she noted, pat these plants onto their injuries or masticate the flora before administering the processed substance to an uncovered lesion. This methodical approach points to a functional understanding of plant properties.

Investigators examined video showing an extremely juvenile female primate grinding up vegetative matter and placing it onto a wound present on her maternal parent's physique. This instance of targeted treatment within a family unit is compelling. Expanding on this, records also show documentation of chimpanzees ministering to the sores of different creatures to whom they shared no familial connection.

Chimpanzees and Compassionate Care

Dr Freymann conveyed this finding's special significance, remarking that it bolsters the existing proof suggesting untamed chimpanzees possess the ability for compassionate understanding. Such behaviours challenge previous understandings of the limitations of non-human animal compassion. These acts of tending to others, especially non-kin, suggest complex social dynamics and a level of understanding that goes beyond simple instinct. The consistent presence of this behaviour in Budongo could indicate that medical care among chimpanzees is more widespread than previously realised.

The meticulous process of identifying which plants chimpanzees use for medicinal purposes involves both behavioural observation and pharmacological analysis. Researchers monitor unwell or harmed chimpanzees, noting any plants they consume that are not part of their typical diet. They then collect samples of these suspected medicinal plants for laboratory testing. For instance, a study that appeared in PLOS ONE detailed how scientists collected extracts from 13 species of trees and herbs. These extracts underwent testing for anti-inflammatory and antibiotic properties at Neubrandenburg University of Applied Sciences, with Dr Fabien Schultz leading the work. This rigorous scientific approach helps to confirm the medicinal effectiveness of the flora selected by the chimpanzees. The findings often reveal that these plants contain bioactive compounds.

The Forest's Medicine Cabinet Revealed

Pharmacological testing of plants selected by Budongo chimpanzees has yielded significant results. In one study, 88% of the tested plant extracts inhibited bacterial growth, while 33% demonstrated anti-inflammatory properties. Notably, dead wood from Alstonia boonei, a tree in the Dogbane family, exhibited the strongest antibacterial activity and also possessed anti-inflammatory qualities. This suggests chimpanzees might consume it to treat wounds. Interestingly, people in East African communities have traditionally used Alstonia boonei as a medicine for conditions like bacterial infections and gastro-intestinal problems.

Bark and resin from the East African mahogany tree (Khaya anthotheca) and leaves from a fern (Christella parasitica) showed potent anti-inflammatory effects. Researchers observed a male chimpanzee with an injured hand specifically seeking out and eating the fern's leaves, potentially to reduce pain and swelling. Another individual with a parasitic infection consumed bark of the cat-thorn tree (Scutia myrtina), a plant not previously recorded in their diet. Testing confirmed this bark had both anti-inflammatory and antimicrobial properties. These findings provide compelling evidence that chimpanzees intentionally seek specific plants for their medicinal effects.

Chimpanzee Wound Care

The methods of application are as fascinating as the plants themselves. Observers have witnessed chimpanzees licking wounds directly, which helps to remove debris and may introduce antimicrobial compounds present in saliva. They also lick their fingers before pressing them onto wounds. Leaf-dabbing is another common technique. Perhaps most sophisticated is the creation of a poultice, where they chew plant materials and apply the resulting paste directly to lesions. For example, one chimpanzee chewed Acalypha sp. leaves and pressed the pulp onto a cut; this plant has known antimicrobial properties. Another used Lasiodiscus pervillei foliage to clean away dirt and blood. A juvenile male named KO even mashed the stem bark of Argomuellera macrophylla and rubbed it into a leg wound. These behaviours often mirror traditional human medicinal practices in the region.

Image Credit - Freepik

Echoes of Empathy: Caring for Others

The observation of primates ministering to the sores of companions, particularly those they are not related to, offers a compelling glimpse into their social and emotional lives. Dr Freymann emphasised that such actions bolster the existing proof suggesting untamed chimpanzees possess an ability for compassionate understanding. Researchers documented seven instances of one chimpanzee helping another, termed prosocial care. In four of these cases, the caregiver and recipient were unrelated. For example, a male chimpanzee named ZG licked blood from a female's wound after an attack by other chimpanzees. In another remarkable incident from 2008, a male chimp freed an unrelated female from a hunter's snare, likely saving her life. These altruistic acts challenge the notion that such complex care is uniquely human.

This prosocial behaviour may extend from an ability to recognise suffering in others and a motivation to alleviate it. Dr Isabelle Laumer, a primatologist, noted that animals helping each other suggests an ability to identify others in need and then address those specific needs. The logbook at the Budongo field station, with testimonies extending to the 1990s decade, contains numerous anecdotal accounts of such helping behaviours. These include chimps aiding fellow chimpanzees in detaching traps from their appendages. The consistent documentation of these behaviours, both historically and in recent focused studies, suggests that providing care to others, even non-kin, might be more widespread among chimpanzees than previously understood. This could reflect strategies for building alliances or simply an inherent compassionate response.

A Legacy of Observation: The Budongo Logbooks

A portion of the many hundreds of penned accounts, meticulously recorded over decades, have significantly contributed to the current understanding of chimpanzee self-medication. Dr Freymann alongside her associates reviewed entries from an official journal kept at the research outpost within the woodland area, situated to the northwest of Kampala, the nation's capital. This collection of informal testimonies extends to the 1990s decade; regional on-site personnel, scientists, and guests contributed entries detailing any notable conduct they witnessed. These historical records provide a rich, long-term perspective that complements contemporary video footage and systematic studies.

Within that journal, narratives describe instances of foliage application to wounds and chimpanzees aiding fellow chimpanzees in detaching traps from their appendages. Beyond wound care, it documents certain unexpectedly person-like cleanliness practices: a particular entry recounts a chimpanzee employing foliage to clean its posterior following a bowel movement, a practice that likely helps prevent infections. Similarly, people have recorded chimps cleaning genitals with leaves after mating. These meticulous records, accumulated over many years, have been instrumental in building the record of 'woodland preliminary care' behaviours and highlighting the consistency and potential cultural transmission of these practices within chimpanzee communities.

Beyond Budongo: Medicinal Knowledge in Other Apes

It isn't solely chimpanzees among the non-human great apes that demonstrate an evident understanding of vegetation-derived remedies. Recent studies have illuminated similar behaviours in other great ape species, suggesting deep evolutionary roots for self-medication. A striking example involved a wild Sumatran orangutan named Rakus. Researchers observed Rakus mending an injury on its face, likely sustained in a fight, with a plant possessing known medicinal properties. He selectively ripped leaves from a liana called Akar Kuning (Fibraurea tinctoria), chewed them, and then repeatedly applied the juice to his wound before covering it with the chewed leaf pulp. People use this plant in traditional human medicine in Southeast Asia for its painkilling, anti-inflammatory, antibacterial, and anti-fungal properties. Rakus's wound healed successfully within a month, with no signs of infection. Researchers systematically documented this as the first case of active wound treatment with a biologically active plant by a wild animal.

Gorillas, too, exhibit behaviours indicative of self-medication. Scientists studying wild western lowland gorillas have observed them consuming tree bark and other plants outside their regular diet. Analysis of these items revealed rich antioxidant and antimicrobial compounds. Some plants showed antibacterial activity against multidrug-resistant strains of E. coli. Species such as the fromager tree (Ceiba pentandra), giant yellow mulberry (Myrianthus arboreus), African teak (Milicia excelsa), and fig trees (Ficus) are among those consumed and people also use them in traditional African medicine. These observations across different great ape species – including chimpanzees, orangutans, as well as gorillas – reinforce the idea that an inclination to find and apply organic remedies for well-being is a conduct with very old historical roots, quite possibly existing even before humankind.

Unlocking Nature's Pharmacy: Implications for Human Medicine

The examination of untamed ape conduct, particularly their use of medicinal plants, holds significant promise for the discovery of new human medicines. This field, known as zoopharmacognosy, investigates animal self-medication and the pharmacological properties of the natural remedies they employ. Scientists believe that by observing which flora chimpanzees and different apes select when they experience illness or sustain physical harm, we can identify vegetation with potent bioactive compounds. Dr Freymann pointed out that healing flora within the Budongo Central Forest Reserve might assist in creating important new pharmaceuticals, especially as challenges like antibiotic-resistant bacteria and chronic inflammatory diseases become more urgent globally. The targeted approach of observing primate choices can be more efficient than random screening of plants for medicinal properties.

Many plants identified through primate observation have already shown promising results in laboratory tests. For example, the strong antibacterial activity of Alstonia boonei, used by Budongo chimpanzees, aligns with its traditional use in treating bacterial infections. Similarly, bark and resin from the East African mahogany tree (Khaya anthotheca) inhibited pathogens like E. coli and E. faecium, which are increasingly resistant to existing treatments. The fern Christella parasitica, sought by an injured chimpanzee, demonstrated potent anti-inflammatory effects. This intersection of primate behaviour, traditional human medicine, and modern pharmacology creates a powerful pathway for drug discovery. Dr Michael Huffman, a renowned primatologist, suggests that observing self-medicating chimpanzees not only expands our knowledge of animal intelligence but can also directly help discover new medicinal compounds.

Image Credit - Freepik

The Intelligence of the Wild: A Lesson in Survival

The sophisticated medicinal practices observed in chimpanzees underscore their profound understanding of their environment and their remarkable intelligence. Dr Freymann communicated her thought that as our comprehension of chimpanzee actions and cognitive abilities expands, our realization deepens regarding the limited extent of human knowledge concerning the wider ecosystem. She conjectured that if she found herself suddenly placed within this woodland environment lacking sustenance or medical supplies, she questioned her own capacity for extended survival, particularly if she were to suffer an injury or fall ill. However, she added, chimpanzees flourish in this setting due to their understanding of how to unlock the area's hidden resources and procure every necessity for their existence from the immediate environment. This includes not just food and shelter, but also a complex array of natural medicines.

This intimate knowledge of the forest pharmacy is likely a combination of innate predispositions, individual learning through trial and error, and, crucially, social learning. Young chimpanzees, like the female observed treating her mother, likely learn by observing and imitating more experienced individuals. Dr Freymann suggested that these behaviours might even be part of a medicinal culture within chimpanzee communities. The intentional selection of specific plants, the varied application methods, and the extension of care to others all point to cognitive abilities that go far beyond simple instinct. It highlights a capacity for problem-solving, memory, and potentially even a rudimentary understanding of cause and effect in relation to health and healing. These behaviours challenge us to reconsider the breadth and depth of intelligence in the animal kingdom.

Conservation: Protecting Apes and their Ancient Wisdom

The continued existence of these remarkable medicinal behaviours, and the potential for future discoveries, hinges on the conservation of chimpanzees and their forest habitats. The Budongo woodland, akin to numerous tropical jungles, confronts perils from tree felling, land division, and human expansion. Traps, frequently placed by area inhabitants to capture duikers and wild boar for consumption, present a substantial risk to chimpanzees, often leading to grave physical harm or fatality, despite the primates not typically being the primary quarry. Estimates suggest that around 20% of chimpanzees in Budongo Forest and Kibale National Park have been maimed by snares. The Budongo Conservation Field Station (BCFS) plays a crucial role in mitigating these threats through daily patrols to detach traps, monitoring chimp health, and treating ensnared animals.

Protecting these "forest pharmacies" is not just about saving a species; it involves preserving a vast repository of medicinal knowledge. Dr Freymann stressed the urgent need to preserve these ecosystems for future generations. Conservation efforts must involve working with local communities to reduce dependence on forest resources, address human-wildlife conflict, and promote sustainable livelihoods. BCFS, for example, engages with communities bordering Budongo Forest, offering veterinary treatment for livestock to reduce hunting pressure and providing training in alternative skills like handcrafting. By safeguarding these environments, we ensure that chimpanzees can continue to practice their ancient medicinal traditions and that scientists have the opportunity to learn from them, potentially unlocking new treatments for human ailments for years to come.

Image Credit - Freepik

The Future of Zoopharmacognosy: Learning from Our Relatives

The field of zoopharmacognosy is rapidly expanding, driven by discoveries like those in Budongo Forest. Observing how our closest living relatives identify and utilise medicinal plants provides invaluable insights into the cognitive and social foundations of healthcare behaviours, potentially illuminating the evolutionary roots of human medicine. Researchers like Dr Fabien Schultz are now heading junior research groups focusing on ethnopharmacology and zoopharmacognosy, working with indigenous communities and observing self-medication in various animals, including chimpanzees, gorillas, and elephants. This interdisciplinary approach, combining primatology, botany, pharmacology, and anthropology, is crucial for understanding the full scope of animal self-medication.

Future research will likely focus on several key areas. Continued long-term observation of habituated primate groups is essential to document the full repertoire of medicinal behaviours and identify more plants for pharmacological analysis. Investigating the mechanisms of knowledge transmission – how these behaviours are learned and passed down through generations – will shed light on primate culture and social learning. Furthermore, exploring the gut microbiome of primates and how their plant choices might influence it could reveal new dimensions of health maintenance. As Dr Freymann alongside other experts have suggested, should researchers aim to utilize these extraordinary healing assets, the method of ethically and with due care watching and gaining knowledge from creatures is an exceptionally potent approach. The age-old understanding of the woodland, as demonstrated by chimpanzees, continues to offer valuable lessons.