Scientists bugged by chimpanzee medicine | Interviews

When you have a nasty cut, or scrape, you will naturally heal your wound. Now, this can include knocking on an antiseptic or applying pain-relieving cream and wrapping it in a bandage. But a family was recently discovered using an unconventional approach. Harry Lewis heard about it from Simone Pika and Lara Southern, who are at the University of Osnabrück…

Lara – In this video you will see the mother sit down and reach out to grab a small object under a leaf, which she then moves to her mouth before moving it to her son’s injured foot. She repeats these last movements several times, working her way up from her mouth to her son’s wound, essentially healing him.

Harry – What is Susie trying to grasp?

Simone – What we know at the moment is that it is a flying insect. We haven’t identified the species yet because if you look closely at what Susie does, she grabs it and puts it in her mouth. There are probably two things she is doing here. First, she could immobilize it, so the insect doesn’t just fly out of her mouth. But it seems she’s also squeezing it to get something out of it and then putting it in the wound. Sometimes they also remove it from the wound, put it back in the mouth, squeeze it again, and then reapply it. But that means that after a bug application event, there isn’t much left of these tiny little bugs and so far we haven’t been able to identify it yet.

Harry- Alright. And we should probably tell everyone the secret. Shouldn’t we Simone, it’s actually a group of chimpanzees, isn’t it?

Simone – Oh yeah.

Harry- Oh yeah.

Simone – Yeah. Chimpanzees live in a “fission-fusion system”, meaning they are not always together. We currently have, in one of our groups, about 45 individuals with adult males, females and their offspring. But then, during the day, the chimpanzees split up into small groups. What you see here is a small party, just Susie with her family, but later in the clip there’s another woman and a man wanting to see what happened.

Harry – So we think it’s for medicinal purposes, but have we seen that elsewhere? Is it completely new?

Lara – In fact, self-medication is quite common in many animal taxa. Even in other chimpanzee subspecies, they self-medicate with plants by digesting certain plants and leaves. It’s to fight intestinal parasites, but this is the first time we’ve seen topical application of any type of animal material to a specific wound.

Harry – I guess by putting it in your mouth, either by deactivating it or by crushing it, they release the active ingredient.

Simone – We looked at the literature and in fact there is a huge literature on substances present in insects or larvae. These substances range from antibacterial, antifungal and antiviral substances to anti-inflammatory and even simply soothing substances. We think it’s really possible that they turn to insects, which contain these substances. But to truly understand this, we must first identify the insects, and then we must investigate and analyze the substances involved.

Harry – And I also suppose, Simone, that it’s not something unique. You have seen this happen more than once. Did it spread outside the troop or is it rather within this single family of chimpanzees?

Simone – In the last 15 months we have recorded 76 different wounds and in 25% of these cases the chimpanzees picked up insects and applied them to the wounds. At the moment, we think it’s a phenomenon that the majority of our individuals use. We saw it in 22 different chimps out of our 45 chimps.

Harry – From what we’ve already discussed I know you don’t know what the bug is, are there any guesses at this point?

Simone – We can reduce it to a steering wheel. Also, maybe you have seen this before. When you have a wound and there is fluid coming out of it, there are a lot of insects that like to land on the wound. If we speculate a bit on how such behavior was invented, it could be one of those flies that lands on the wound and wants to get something out of it. Then the chimpanzee tried to chase him away but ran him over, he landed in the wound and then there was a direct effect that eased his pain. This could be a possible scenario, but we don’t know. Maybe it’s something different and hopefully we’ll find out soon.