It’s a quiet morning in the Gabonese rainforest. Only crickets are chirping and sometimes a bird calls.
Suzee, her infant daughter, Sassandra, and an adolescent son, Sia, are resting at a foot of a tree. Sassandra is playfully swinging around, while Sia is laying on his back. He has a day-old open wound on his left foot and his mother decides to do something about it.
She sits up and with a swift movement of her hand catches an insect from under a leaf. She inspects it and places it carefully between her lips. She then grabs Sia’s foot, takes the insect with her fingers and presses it to his wound. Little Sassandra is watching what’s going on. Suddenly Suzee catches the insect with her lips again. But then picks it up with her fingers and reapplies it to the wound. This repeats once or twice while some other group members approach the family to look.
This scene was the first recorded case of chimpanzee applying an insect to a wound. But it was not the only one. Other group members also did it and one of them (Freddy) applied insects to its own wounds on many occasions. Self-application was most common, but chimpanzees also used insects on the wounds of other individuals (even unrelated ones).
But it is unknown whether this behaviour is specific to this group and how it appeared.
Is insect treatment medicinal?
So far only humans have been known to use insects to treat wounds. For example, maggots are used to clean away dead tissue, especially in diabetic patients. However, although we know that what we do is clearly effective, it is less clear whether the chimpanzees’ insects use has any positive effect.
But medication is definitely a possible explanation of the behaviour. The insect was always applied to an open wound and never eaten. The insect was often moved on the surface of the wound. It is difficult to imagine a different reason for this specific behaviour than some healing or pain-relieving effect. Especially since chimpanzees (and many other animals) seem to commonly use plants as medicines, for example to fight parasites. Additionally, some insects (ants) are known to contain substances that have antifungal properties.
What insects are used?
Unfortunately, the researchers couldn’t specify the insect (or insects) chimpanzees used. It was around 5 mm long, usually dark and found under leaves or branches. And it seems to be a flying insect as apes used fast movements to catch it.
Many questions still need answering, but who knows, maybe this observation of insect application will be an inspiration for new wound treatment in humans? It wouldn’t be the first example of animal-inspired medicine.
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Photo: USAID Africa Bureau – Chimpanzees in UgandaUploaded by Elitre, Public Domain, https://commons.wikimedia.org/w/index.php?curid=21460178