Chimpanzees Utilize Healing Plants for Wound Care

New research has revealed that wild chimpanzees are capable of self-medicating their wounds with plants, assisting injured companions, and freeing others from traps set by human hunters.

This behavior, documented in a study published in the journal Frontiers of Evolution and Ecology on Wednesday, offers new insights into the evolutionary roots of human medicine.

Over approximately eight months, the study combined video footage and photographs with historical data, revealing that chimpanzees engage in actions like biting plants, applying leaves to wounds as makeshift bandages, and grooming wounds of fellow animals. Observers noted a chimpanzee pressing a leaf against its wound for treatment.

The findings contribute to ongoing discussions about whether altruistic behaviors are exclusive to humans, as they show that even chimpanzees without familial ties can exhibit care toward one another.

“Humans often pride themselves on being unique in their capacity for empathy and altruism,” says Elodie Freyman, a postdoctoral researcher at Oxford University and the study’s lead author. “These animals demonstrate that they can identify others in need and respond appropriately.”

Chimpanzees and bonobos, the closest genetic relatives to humans, bolster the argument that healthcare concepts may have existed millions of years prior to the emergence of Homo sapiens.

“Our shared ancestors likely exhibited these caring behaviors,” Freyman stated.

An increasing number of studies indicates that various animal species can self-medicate with differing levels of sophistication. For instance, elephants have been observed to consume specific leaves for medicinal purposes, hinting that animals might be addressing health issues like digestion.

As research on animal medicinal behaviors expands, experts believe it provides crucial insights into our own evolutionary past.

“Evidence of healthcare behaviors exists among our ancestors, dating back to pre-Neanderthals, but the evolutionary pathways of such explorative behaviors remain unclear,” remarked Alessandra Mascaro, a primate researcher and doctoral candidate at the University of Osnabrueck in Germany. “We are only beginning to uncover these complexities.”

In 2022, Mascaro published findings illustrating that Gabonian chimpanzees applied insects to their own wounds and anticipates that further observations will clarify how these behaviors evolved.

Studying chimpanzee self-medication poses challenges due to the rarity of such behaviors.

Freyman dedicated two months to researching chimpanzees in Budongo Forest, Uganda, where observing these animals can be both physically taxing and demanding.

“Some days involve sitting at the base of a tree for hours, while others might have you stuck in a muddy hole while trying to observe them. The day’s tasks depend heavily on the group’s activities.

During her fieldwork, Freyman noted numerous instances of care behaviors among chimpanzees. She also discovered historical observational records from previous studies that revealed behaviors not documented until now, indicating a pattern of medicinal practices dating back to the 1990s.

“Collating these observations paints a remarkable picture of chimpanzee care,” she remarked.

From her findings and historical records, Freyman documented 41 instances of chimpanzee wound care, including four cases involving unrelated individuals.

“These results suggest that prosocial behaviors among nonkin may be more widespread than previously recognized,” noted Isabel Laumer, a cognitive biologist at the Max Planck Institute for Animal Behavior in Germany, who was not part of this study. “Further research is essential.”

Mascaro, who has studied chimpanzee healthcare behaviors in Gabon, acknowledged that the new findings from Uganda show similar medicinal behaviors across different populations of chimpanzees.

“Prior to this, we had limited knowledge about chimpanzees in that part of Africa,” Mascaro stated.

The phenomenon of self-medication has also been observed in other primates. Last year, Laumer documented that Indonesian orangutans apply leaves to facial wounds as a remedy for injuries sustained during conflicts. The plants they utilize often possess pain-relieving properties recognized by humans.

This body of research broadly indicates that primates are capable of identifying and utilizing plants with medicinal qualities.

“Chimpanzees consider forests not only as a food source but also as a repository for medicinal resources,” Freyman emphasized, underscoring the importance of preserving forest ecosystems.

She suggested that humans may have learned about medicinal plants from these primates, and that pharmaceutical companies could benefit from studying animal behavior to discover valuable medical compounds in the future.

“If you wish to refine the knowledge of these remarkable medicinal resources, observing and learning from animals is an effective, ethical, and responsible approach,” Freyman concluded.