As it turns out, chimpanzees make pretty good doctors. For decades , scientists have been studying what chimpanzees do when they fall ill. This search has led to the identification of medicinal behaviour, which often involves the ingestion of plants with chemical or physical properties that can help the animal's recovery.
Author
- Elodie Freymann
Post-doc affiliate, University of Oxford
My team's recent study in the Budongo Forest of western Uganda found its chimpanzees show a range of healthcare behaviour - one of which, applying chewed botanical material to wounds, had never before been documented in chimpanzees.
Previous studies have shown that wild chimpanzees appear to treat their wounds and maintain sexual hygiene using medicinal plants found in their environment. What's more, they treat other group members, even ones who are unrelated to them.
In 2022, a study in Gabon, west Africa found that wild chimpanzees catch and apply insects to their wounds as well as the wounds of non-kin community members. A previous study had reported that chimpanzees in the Kibale Forest of Uganda occasionally dab the wounds of unrelated group members with leaves.
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Now our research , published in Frontiers in Ecology and Evolution, shows the chimpanzees of the Budongo Forest engaging in topical healthcare, both on themselves and others.
To figure out whether the Budongo chimpanzees practice first aid, we combed through more than three decades of hand-written observations from field staff and researchers who have worked in this forest, and searched video archives by Budongo primatologists. We also headed into the field to collect eight months of our own behavioural data. The aim: to accumulate all the cases we could find of external healthcare behaviour and see if a pattern emerged.
What we found surprised us. The Budongo chimpanzees appear to have quite a diverse behavioural toolkit for tending to their own wounds and maintaining hygiene in the wild. This behaviour ranges from simple actions like wound licking, to more complicated behaviour such as applying plant material to an injury.
In some cases, chimpanzees dabbed their open wounds with leaves. In rarer cases, they chewed up plant material (like leaves or stem bark) and applied it directly to the affected area with their mouths. Similar behaviour was shown in Sumatran orangutans in 2024.
But these chimpanzees don't limit their self-care to treating wounds. We recorded them freeing themselves from wire snares set by hunters, and cleaning their genitals with leaves after mating. In one notable case documented in the forest's logbook from 2009, a chimpanzee wiped herself with a leaf after defecating.
We also wanted to determine which plants the Budongo chimpanzees were selecting. We discovered that some of these plants, such as Alchornea floribunda and a species of Acalypha, have traditional medicinal uses and chemical properties related to wound-healing or infection prevention. Whether this is a coincidence, or an indicator that chimpanzees can identify medicinal plants helpful for wound care, is a question for future research.
Chimpanzee doctors
Buried in logbooks and video archives, we also found seven cases of chimpanzees providing healthcare for others in their community. Even more interesting, the demographics of the providers and receivers of this healthcare varied dramatically - occurring between both genetically related and unrelated chimpanzees.
Our study includes cases of chimpanzees licking each other's wounds and applying plant material to the wounds of injured group members. This kind of wound care, directed toward others, is considered "prosocial" as it offers no obvious or immediate benefit to the carer. In fact, this kind of direct interaction with the wounds of others can pose risks for the carer, exposing them to infectious pathogens or infections.
As far as we know, this is the first time prosocial wound care has been reported among chimpanzees in the Budongo forest reserve. We also noted cases in which chimpanzees helped free others from nylon snares, and one case in which a female wiped the genitals of a male in her group with leaves after mating.
Our findings add this site to the growing list of places where altruistic healthcare has been observed among non-kin, advancing our understanding of chimpanzees' capacity for compassion and empathy .
Survival of the kindest?
Chimpanzees are often painted as aggressive , Machiavellian and self-interested, especially in comparison to their peace-loving bonobo cousins. But it appears that these highly social animals have a softer side.
Chimpanzees are not the only animals who have been observed administering first aid to others. Recently, a US study found that mice help pull the tongues out of the mouths of unconscious cage companions, clearing their air passages. The carer mice were more likely to do this if they were familiar with the incapacitated mouse.
Even Matabele ants from sub-Saharan Africa will help treat nest mates' infected wounds with self-generated antibiotic secretions.
Non-human healthcare may take different forms, but it appears that animals throughout the animal kingdom can administer first aid to themselves and others. It may not be such a dog-eat-dog world after all.
Elodie Freymann does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
