The chimp’s behavior was one of many instances observed over eight months that suggest chimpanzees could be using the forest as a natural drugstore. The study, published Thursday in the journal PLOS One, was carried out by a team led by Elodie Freymann of the University of Oxford and Fabien Schultz of Neubrandenburg University of Applied Sciences in Germany, which found that chimpanzees were consuming a variety of plants with medicinal effects but little other nutritional value, often when they had a health issue such as an injury or a parasite.
The findings offered strong support for “novel self-medicative behaviors in wild chimpanzees,” the researchers wrote, adding that further study of the animals’ behavior could “benefit our own species, potentially leading to the discovery of novel human medicines.”
The next area of investigation will be the “most interesting plant extracts” consumed by the chimpanzees, Schultz said in an email. There are “lots of ‘ifs,’” he said, but theoretically, “one day the knowledge of chimpanzees could save human lives.”
He was particularly interested in the potential application of the chimps’ go-to plants in addressing antibiotic-resistant bacteria and chronic inflammatory diseases — though he cautioned that there is a long road between this study and any possible drug breakthroughs.
The team observed two chimpanzee communities in the Budongo Forest for four months each. They tracked what the great apes ate and analyzed components of 13 plant species that seemed wholly unappetizing to a chimpanzee, such as bark and resin, to determine whether the materials had healing effects.
“Pharmacological results suggest that Budongo chimpanzees consume several species with potent medicinal properties,” the authors wrote.
Those struggling the most with parasites — something the scientists ascertained through testing their feces — had eaten plant material with the strongest antibacterial properties. An injured chimpanzee had eaten a fern with anti-inflammatory effects that was otherwise rarely consumed by the groups. All plant species, when tested in a laboratory, inhibited bacterial growth of E. coli, and some had been found in previous studies to have cancer-fighting or analgesic properties.
The authors noted that 11 of the 13 plant species had recorded uses in traditional medicine.
The researchers were surprised at the range of the ailments the chimps turned to plants for — and by the plants’ potency. “Maybe it shouldn’t have been as much of a surprise,” Freymann said in an email, “because the chimpanzees are incredibly smart and it makes perfect sense they would have figured out by now which plants can help them when ill or injured.”
She said the research showed it was “highly unlikely” the chimpanzees were eating the medicinal plants coincidentally as part of their diet. “In many of these cases, the ill or injured chimps sought out these resources when no other member of their group did,” she said.
The study adds to a body of research that suggests some animals may use plants or insects to self-medicate. Our closest cousins, the apes, have often played a starring role in this field, called zoopharmacognosy.
Last month, scientists published their observation in the journal Scientific Reports of an orangutan in Indonesia applying the juice and chewed-up leaves of a plant known for its medicinal effects to an injury on its face — which then healed without signs of infection. Two years ago, a different study of chimpanzees, in the Loango National Park in Gabon, said the animals had been seen repeatedly applying insects to wounds.
Isabelle Laumer, a primatologist and cognitive biologist at the Max Planck Institute of Animal Behavior in Germany who was the orangutan report’s lead author but was not involved in the PLOS One study, said in an interview that the new study has contributed “really important findings” that opened up avenues for further research.
“It’s always very fascinating to find out that our closest relatives are showing behaviors that we humans also show,” she said. “I think this study, again, points towards the similarities that we share.”
The authors of the PLOS One study called for strong conservation efforts to allow the continuation of such research, and to explore its potential benefits to humans in finding plants with medicinal properties. “It is imperative that we urgently prioritize the preservation of our wild forest pharmacies as well as our primate cousins who inhabit them,” they said.
