© CorbisChimpanzees and humans appear to be the most self-medicating animals.
An extensive look at what chimpanzees consume each day reveals that many of the plants they consume aren't for nutrition but are likely ingested for medicinal purpose.
The findings, published in the journal
Physiology & Behavior, indicate that the origins of medicine go way back, beyond the human species.
"We conclude that self-medication may have appeared in our ancestors in association with high social tolerance and lack of herbivorous gut specialization," lead author Shelly Masi and her colleagues write.
Masi, a researcher at the National Museum of Natural History in Paris, and her team recorded the items consumed by a community of over 40 wild chimpanzees at Kibale National Park, Uganda. They also documented the availability of the foods, as well as the social interactions between the chimps.
They also documented the same information for about a dozen wild western gorillas in Dzanga-Ndoki National Park, Central African Republic.
Unusual food consumption in chimpanzees, meaning foods not normally associated with nutritional needs, was twice as high as it was for gorillas. Gorillas turn out to have more specialized guts that are better capable of detoxyifying harmful compounds, making them have have less of a need to self-medicate than chimps and humans may need to.