Is medicine the property of man? If the image of a chimpanzee in a white coat looks straight out of the Planet of the Apes, the fact remains that the great apes may have something to teach us about medicine.
Sabrina Krief, primatologist at the internationally-renowned French Natural History Museum and veterinary scientist, has studied the feeding behaviour of these great apes for almost 20 years.
In the heart of the Congolese and Ugandan forests, sick chimpanzees work as pharmacists; they carefully select the plants they use to clean their wounds, regulate their digestion, and relieve their ailments. An individual infested with parasites moves away from the group to chew on Albizia bark, a tree that is not part of the usual diet. Shortly after, his faeces no longer show signs of the parasite. Chimpanzees are not content to heal themselves; they also prevent diseases. Sometimes they chew the very bitter leaves of Trichilia rubescens, despite the lack of nutritional value; the leaves contain molecules that can protect them from malaria.
Medicinal plants can be toxic when consumed in large quantities, and chimpanzees need to control the amount ingested according to their needs, their physical condition and the properties of the plant. In more than one third of the cases, the plants they select are similar to those used by humans in traditional medicine.
These examples illustrate the ability of chimpanzees to choose plants or parts of plants that help maintain or improve their health, and to avoid those that could worsen or degrade their condition. These conclusions were able to be formulated thanks to drawing on several different experts. Veterinary faecal analyzes coupled with behavioral observations provide valuable insights into the health status of animals. Combining these data with biomass data and botanical, biological and chemical analyses of the plants selected by the primates, the research team showed the ability of self-medication in apes.
What is the origin of this capacity? Is the knowledge acquired by transmission between generations or individuals of the same group? Is it the result of mimicry or individual trial-and-error learning? What is the innate part of this ability? In an attempt to answer these questions, Sabrina Krief and her team conducted comparative studies of several species of African great apes, both in the wild and in captivity. The consumption of medicinal plants was shown even in the case of orphaned chimpanzees raised by humans and released in the wild. This confirms the existence of individual trial-and-error but also the importance of social transmission in the choice of substances with biological activities in chimpanzees.
This ability of chimpanzees to adapt their diet to their state of health is a great discovery in terms of animal behaviour; it also proves to be a source of hope in terms of human health. To date, humans have only explored about 10% of plants for both their chemical and biological properties. The observation of the medicinal choices of chimpanzees makes it possible to discover plants with interesting active principles more quickly, which could be used to create new remedies. It is also important that these same men do not destroy the tropical forests, treasures of biodiversity and habitat of chimpanzees, now threatened with extinction in the near future!
Director of Sebitoli Chimpanzee Project : http://www.sabrina-jm-krief.com/