Chimpanzees apply 'medicine' to each other’s wounds, exhibiting empathy

Chimpanzees were spotted applying insects to their wounds, as well as the wounds of others, possibly to medicate their injuries. Recorded for the first time, the incident reflects a sign of altruististic behaviour similar to empathy in humans, according to a new study.

About 45 chimpanzees from Loango National Park in Gabon exhibited bouts of empathic behaviour, much like humans, said researchers of the Ozouga Chimpanzee Project.

Primatologist Tobias Deschner and cognitive biologist Simone Pika, studied the relationships and interactions between the chimps.

Simone said, "Self-medication - where individuals use plant parts or non-nutritional substances to combat pathogens or parasites - has been observed across multiple animal species including insects, reptiles, birds and mammals." 

"Chimpanzees eat insects but we did not know that they catch and use them to treat their wounds. Hence, they not only have an understanding of their food species (plants, insects, monkeys, birds, reptiles) but probably also about characteristics of other animal species that help to act against injuries."

The team recorded 76 cases of chimps using insects to heal wounds, from November 2019 to February 2021.

"An adult male, Littlegrey, had a deep open wound on his shin, and Carol, an adult female, who had been grooming him, suddenly reached out to catch an insect," Southern said in a statement. "What struck me most was that she handed it to Littlegrey, he applied it to his wound and subsequently Carol and two other adult chimpanzees also touched the wound and moved the insect on it."

Tending to others is prosocial, or positive behaviour - something that isn't often observed in animals, the researchers stated. 

"Prosocial behaviours have long posed a problem for evolutionary theory, because it was not immediately clear why organisms might help others in the face of selection operating in the interest of self," said the study.

"We do not know whether the observed behaviour involves empathy," Pika said.

It's possible that the insects have antiseptic or anti-inflammatory properties to soothe the pain of their injuries and promote healing. There is a long history of humans using insects for these same purposes dating back to 1,400 BC, the researchers said.

Next, the Ozouga researchers want to study the insects used by chimps to see if they have any pharmaceutical properties.