Chimps Observed Applying Insects to Open Wounds in 'Surprising Behavior'

Chimpanzees have been observed applying insects to open wounds in a new "surprising behavior," scientists have said.

A research team from Osnabrück University, Germany, has observed this behavior in a community of about 45 chimpanzees living in the Loango National Park in Gabon, Africa, since 2019. Researchers found they regularly use insects to treat their own external wounds, as well as to treat others.

Self-medication has been observed in many species before. For example, chimpanzees have been known to swallow and chew leaves that contain chemical properties to kill parasites.

However, they have never been seen treating external wounds before, or using insects to self-medicate.

Loango National Park is home to the Ozouga Chimpanzee Project, led by primatologist Tobias Deschner and cognitive biologist professor Simone Pika.

The behavior was first observed by a volunteer on the project, Alessandra Mascaro, who watched as a female chimpanzee applied an insect to her son's injured foot. A week later, PhD student Lara Southern observed an adult male, Freddy, doing the same thing.

The chimps would reach out and catch an insect then apply it to an open wound.

Over the next year, researchers began to watch and film all individuals with injuries and gradually built up a record of 22 instances. Footage of the behavior was released by the team and their findings are published in the journal Current Biology.

Pika said that to observe individuals not only treat their own wounds, but also the wounds of others, was "particularly striking." She said that this type of social behavior is rarely seen in nonhuman species.

An chimpanzee female, Roxy, applies an insect to a wound on the face of an adult chimpanzee male named Thea. Tobias Deschner/Tobias Deschner

"It is just fascinating to see that after decades of research on wild chimpanzees they still surprise us with unexpected new behaviors," Deschner said in a statement. "Our study shows that there is still a lot to explore and discover about our closest living relatives, and we therefore need to still put much more effort into protecting them in their natural habitat."

Deschner said the next step is to study what types of insect are actually used by collecting the samples that are left over on the wound. They will then try to understand us why they are using them in this way.

Researchers say the insects might have anti-inflammatory or antiseptic properties. Humans have used insects for self medicating purposes since 1400 B.C. and it is still popular in countries including India, Mexico, Korea, China, and Brazil. Some insects have also been scientifically proven to have antibiotic and antiviral effects. Maggots have been used to heal chronic and post-surgical wounds, while bee and ant venom has been used to reduce swelling in joints.

The team also said the insects may have no medicinal benefits at all, but are used as part of the chimpanzees culture.

Chimpanzees, along with the bonobo, are our closest living relatives. They demonstrate a range of other socially complex behaviors and live in large communities, often led by an alpha male and a group of male allies.

Pika said the act of treating one another's wounds with insects is an example of prosocial behavior within chimpanzee communities: "This is, for me, especially breathtaking because so many people doubt prosocial abilities in other animals. Suddenly we have a species where we really see individuals caring for others."