Back in November 2019, Alessandra Mascaro, a volunteer working at the Ozouga Chimpanzee Project in Loango National Park, Gabon, West Africa, saw something she couldn’t quite believe – one of the apes named Suzee noticed her son Sia had hurt his foot. After seemingly thinking about the best course of action, she then plucked an insect out of the air, licked it and applied it to the wound.
Luckily, Mascaro captured the whole touching moment on film her supervisors, Tobias Deschner, a primatologist working for the Ozouga project, and Prof Simone Pika, a cognitive biologist based at Osnabrück University.
The Ozouga team then set about monitoring the chimpanzees in the park and looking for other examples of the behaviour. Over the following 15 months they captured 76 incidences of the apes applying insects to wounds on themselves or other group members.
The researchers are uncertain why the chimps use the insects, or even which insects they are, but suspect they might have soothing properties that could provide pain relief.
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Though other animals such as bears, elephants and bees have been observed applying ‘medicines’ to themselves, this study marks the first time animals have been seen treating the wounds of others.
Pika argues that the act of applying an insect to treat another’s wounds is a clear example of prosocial behaviour that echoes the acts of empathy displayed by human beings.
“This is, for me, especially breath-taking because so many people doubt prosocial abilities in other animals. Suddenly we have a species where we really see individuals caring for others.
“Humans use many species of insect as remedies against sickness – there have been studies showing that insects can have antibiotic, antiviral, and anthelmintic functions.”
The team now aims to identify the insects being used by the chimpanzees and investigate who is applying insects to whom to establish whether the behaviour is based on a hierarchy.
“Studying great apes in their natural environments is crucial to shed light on our own cognitive evolution,” said Deschner. “We need to still put much more effort into studying and protecting them and also protecting their natural habitats.”