For The First Time, Chimpanzees Seen Applying Insects To Wounds. New Study Explains Why

For the first time, chimpanzees have been observed applying insects to their own wounds and the wounds of conspecifics, which are all organisms belonging to the same species.

New Delhi: For the first time, chimpanzees have been observed applying insects to their own wounds and the wounds of conspecifics, which are all organisms belonging to the same species. The observations were made by a research team from Osnabrück University, Germany, and the Ozouga Chimpanzee Project dedicated to research on a chimpanzee population in the Central African rainforest of Gabon since 2005. 

The findings of the study titled "Application of insects to wounds of self and others in chimpanzees in the wild" were recently published in the journal, Current Biology. 

Equatorial Africa, including the Loango National Park in Gabon, is home to chimpanzees. 

Investigating Chimpanzee Behaviour In Loango National Park

Researchers investigate the behaviour of a community of about 45 chimpanzees in Loanga, as part of the Ozouga Chimpanzee Project. Led by primatologist Dr Tobias Deschner and cognitive biologist Professor Simone Pika at Osnabrück University, the project has a special focus on the chimpanzees' social relationships, interactions and disputes with other groups, their hunting behaviour, tool-use and their cognitive and communicative skills. 

Quoting Pika, a statement issued by Osnabrück University said that self medication, where individuals use plant-parts or non-nutritional substances to combat pathogens or parasites, has been observed across multiple animal species including reptiles, birds, and mammals. Pika cited the examples of man's two closest living relatives, chimpanzees and bonobos, and said that they swallow leaves of plants with anthelmintic properties and chew bitter leaves that have chemical properties to kill intestinal parasites. Anthelmintic is the term used to describe a drug which helps treat infections of animals with parasitic worms.

First Evidence That Chimpanzees Apply Insects To Open Wounds

Despite research spanning decades from other long-term field sites in west and east Africa, external application of animal matter on open wounds has never been documented, until now. Quoting primatologist Tobias Deschner, the statement said that their observations provide the first evidence that chimpanzees regularly capture insects and apply them onto open wounds. He added that the researchers now aim to investigate the potential beneficial consequences of such surprising behaviour.

Observing The Behaviour Of Suzee, Sia, Littlegrey & Carol

Recalling her first observation, Alessandra Mascaro, at the time a volunteer in the project, said that she was following a female chimpanzee named Suzee in 2019, and watched as she tended to the injured foot of her adolescent son, Sia. Mascaro said she noticed that Suzee appeared to have something between her lips that she then applied to the wound on Sia's foot. 

PhD student Lara Southern observed an adult male, Freddy, demonstrating a similar behaviour, a week after Mascaro's observation. On the basis of the location in which the tiny objects were found and the manner in which they were caught, the research team worked out that they were most likely flying objects, the statement said.

The researchers started watching and filming all individuals with injuries during the following year, and gradually built up a record of 22 events. These mostly involved individuals applying insects to their own wounds.

Southern observed another event, almost a year after Mascaro's observation of the first insect application to another individual. The PhD student said that 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 that what struck her the most was that Carol handed the insect to Littlegrey, after which he applied it to his wound, and subsequently, Carol and two other adult chimpanzees also touched the wound and moved the insect on it. 

Why Do Chimpanzees Apply Insects On Their Wounds?

According to the authors from the Ozouga Chimpanzee Project and Osnabrück University, the applied insects might have anti-inflammatory or antiseptic properties. Humans started using insects for therapeutic purposes in 1400 BCE.

Use of insects as therapeutics is still popular across human populations covering a variety of insect species with scientifically proven antibiotic and antiviral effects, according to the statement. 

An explanation for this behaviour of chimpanzees could be that the practice does not have any beneficial consequences but is part of the local chimpanzee culture.

Pika said that for her, it was particularly striking to witness that individuals not only treat their own but also the wounds of other non-related individuals. 

The researchers aim to uncover remaining insect parts to identify the species and to conduct bioassays to investigate the potential pharmaceutical properties. The team will try to determine who are the main actors and who are the aim receivers of the "treatment",and the social learning processes that allow for the transmission of the behaviour.