Chimpanzees may use insects as medicine to treat wounds, study finds

Simone Pika says she was "pretty amazed" the first time she saw a chimpanzee pluck an insect from the air and apply it to her son's wound.

The biologist was observing 2019 footage of chimpanzees at the Loango national park in Gabon, Africa, when she saw the female chimp Suzee inspecting a cut on her adolescent son's foot.

The mother looked around, grabbed a flying insect, stuck it between her lips, then dabbed it on the wound, almost like a human mother applying a Band-Aid to a child's scraped knee.

"We looked at this video clip and then we were like, is it true what we are seeing here? What is she doing?" Pika, an animal cognition expert from the University of Osnabrück in Germany, told As It Happens guest host Peter Armstrong.

Since then, Pika and her colleagues observed 76 chimpanzees with wounds over a period of 15 months. In 25 per cent of the cases, the chimps were seen catching insects and applying them to the injuries.

The findings have been published in the journal Current Biology.

In some cases, Pika said, the chimpanzees applied the insects to each other's wounds, like Suzee and her son. 

"There seems to be this special degree of trust between the animals doing it," she said. "They just keep still in a way they know something good will happen to them."

In other cases, she said, the chimps used the insects on their own wounds, in what the study's authors say may be a form of self-medication. 

But in each instance, the steps are the same: Pluck a flying bug from the air, immobilize it by squeezing it between their lips, then rub it on the cut. 

Earlier studies have shown that chimpanzees and great apes use plants as herbal medicine. But Pika says scientists have never before seen them use insects in this way.

"This has never been observed, and it's also resulting in so much attention," she said. "When this is happening, all the other chimps in the party, they are coming. They want to look at it and they are totally interested. And so we think they have to learn it, and it also could be a cultural behaviour in chimpanzees."

Next step: Find out what's in the bugs

The scientists don't know what kind of insect, or insects, the chimps are using. 

Their next step, Pika said, is to work with their insect expert colleagues to collect samples of the insects' remains and identify them. Then they can determine whether they have any medicinal benefits.

She says there are several bugs in the area known to have antibacterial or anti-inflammatory properties.

"Or maybe they just have a soothing, like a painkilling, function," she said. 

Ammie Kalan, a primatologist at the University of Victoria, called the study "rare and incredible." 

"These findings support the growing body of evidence for empathy in our closest living relatives and provide a unique opportunity to investigate the knowledge of nonhuman animals about the medicinal properties of other organisms in their environment, as well as how such knowledge might be learned and passed down across generations," she told As It Happens in an email.

"The implications of such research is therefore challenging our definition of what it means to be human and minimizing the differences between us and nonhuman animals."

She says she's made similar observations in her own field work of chimpanzees tending to each other's wounds.

"I've observed one individual licking the cut of another for example, but the use of another organism here is fascinating," she said. "I am only eager to find out what this insect is and what its potential medicinal properties are"

Written by Sheena Goodyear. Interview with Simone Pika produced by Niza Lyapa Nondo.