Chimpanzees spotted apparently using insects to treat their wounds

A community of chimpanzees in Loango National Park in Gabon put insects onto their open wounds, seemingly as a form of first aid. While there has been evidence of animals using plants to self-medicate, these are the first known instances with insects.

In November 2019, Alessandra Mascaro, who works on the Ozouga Chimpanzee Project at Loango National Park, watched and filmed a female chimpanzee named Suzee nursing the injured foot of her son, Sia. Unexpectedly, she noticed Suzee take something from between her lips and apply it to the open wound. When analysing video footage of the exchange, Mascaro and her colleagues realised that Suzee had placed a winged insect on Sia’s wound.

“We had witnessed something really amazing,” says team member Simone Pika at Osnabrück University in Germany.

After the initial observation, the researchers continued to monitor Suzee and the roughly 45 other chimps in her community until February 2021. In total, they observed the behaviour in 22 chimps. In 19 cases, chimps would catch a small winged insect and press it between their lips, then rub it onto their own exposed wounds using their lips or fingers before removing the insect.

The researchers are unsure why the chimps do this. “What is intriguing me at the moment is, which insect species are they catching? And do they understand what they’re doing?” says Pika. It could be that the unknown insects have medicinal properties, say the researchers.

“You can find many amazing substances in insects which are antibiotic, antiviral, antibacterial, antifungal. They can have a soothing effect or help you to decrease the inflammation,” says Pika.

The team also suggests the insects could simply be a source of comfort. “Can you imagine when you were little and you fell, and the wound wasn’t really bad on your knees,” says Pika. “But then your mum put a little plaster on your knee and suddenly everything was better, right?”

These newfound behaviours in chimpanzees could help us understand the origins and evolution of self-medication, she says.

The team also saw evidence of chimps tending to others, as the remaining three cases involved an individual applying insects to another’s wounds.

There is still some debate whether animals beyond humans engage in this kind of prosocial behaviour, but these observations are a convincing example, says Pika.

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