But chimpanzees have invented a more creative method: catching insects and applying them directly to the open wound.

Scientists observed this behaviour in chimpanzees in the West African nation of Gabon, noticing that the apes not only use insects to treat their own wounds, but also those of their peers.

The research, published on Monday in the journal “Current Biology”, marks an important contribution to ongoing scientific debate about the ability of chimpanzees – and of animals in general – to selflessly help others.

“It’s like when you’re going to school and you read in your biology books about the amazing things animals can do,” Simone Pika, a biologist at the University of Osnabruck in Germany and a co-author of the study, told AFP.

“I think it could really be something like what will end up in those books.”

The project began in 2019, when an adult female chimpanzee named Suzee was observed inspecting a wound on the foot of her adolescent son.

Suzee then caught an insect out of the air, put it in her mouth, apparently squeezed it, and applied it to her son’s wound.

After extracting the insect from the wound, she applied it two more times.

The scene unfolded in Loango National Park on Gabon’s Atlantic coast, where researchers are studying a group of 45 central chimpanzees, an endangered species.

Over the following 15 months, scientists saw chimpanzees administer the same treatment on themselves at least 19 times. And on two other occasions, they observed injured chimpanzees being treated in the same way by one or several fellow apes.

The wounds, sometimes several centimetres wide, can come from conflicts between members of the same or an opposing group.

Far from protesting the treatment, the bruised chimpanzees were happy to be tended to.

“It takes a lot of trust to put an insect in an open wound,” said Pika. “They seem to understand that, ‘If you do this to me with this insect, then my wound gets better’. It’s amazing.”

Soothing properties?

Researchers have not been able to identify what bug was used on the wounds but believe it to be a flying insect, given the chimpanzees’ rapid movement to catch it.

Pika says the insect could contain anti-inflammatory substances that have a soothing effect.

Insects are known to have various medical properties, and researchers will need to conduct more work to detect and study the critter in question.

Birds, bears, elephants and other animals have already been observed self-medicating, for example by eating plants. But what is unique about chimpanzees is that they treat not just themselves but others.

Nevertheless, some scientists doubt the ability of animal species to exhibit prosocial behaviours such as selflessly caring for others, Pika said.

Still, in this case, the chimpanzees have nothing to gain – so why do they do it? In humans, prosocial behaviour is generally linked to empathy.

Perhaps the same feelings are at play in chimpanzees, Pika suggested.

“It is a hypothesis we must study,” she added.