This is Origin Stories, the Leakey Foundation podcast. I'm Meredith Johnson. Before we get to the episode, I wanted to say thank you so much for all of your support with our matching fundraiser for Origin Stories. We were blown away by your generosity, and we're thrilled to tell you that thanks to you, we met our goal.
So thank you to Jean Bainbridge, Richard Blanchette, Bernadette Brenkus, Chinzia De Santis, Robert Jonas, Amie Kaufmann, Luzie Lenzner, Cahail Mc, Kevin Miller, Charles Musiba, and 31 other donors who wanted to stay anonymous. Today on the show we have two stories about medicine. As humans, we have a vast toolkit of remedies to help ourselves and each other when we're sick or injured.
We don't know exactly how long we've been practicing medicine or what medical care was like for our ancient ancestors, but there's plenty of prehistoric evidence of individuals who survived accidents, blunt force injuries, broken bones, and trauma of many kinds. The earliest evidence is from about 1.7 million years ago, a Homo erectus individual who had periodontal disease and infections at the jaw. They lost all their teeth,
but they somehow survived. How? we don't know, but in biological anthropology, when we want to understand the roots of human behavior, we look to our ape cousins and it turns out that our cousins are using medicine. Origin Stories Producer Ray Pang has our stories. A few months ago I heard about a sumatran Orangutan named Rakus - who was seen making and smearing a peculiar plant paste into a fresh wound on his face.
While chimps have been documented using plant medicine, this is the first known instance of an orangutan treating a wound with plants. To learn more about Rakus, I called up Caroline Schuppli - an evolutionary biologist at the Max Planck Institute. Yeah, rakus is one of the orangutans we have observed for many years at our study site. Caroline's a Leakey Foundation grantee and director of the SUAQ Balimping Orangutan Research Project in Sumatra, where she studies how orangutans learn.
The peat swamp forest there has the highest density of orangutans on earth, A typical day starts before sunrise so they can reach the apes before they wake up. So we follow the orangutans from their morning nests, so when they leave their nest in the morning to the point in time when they make a new nest in the evening. We have some individuals that like to snack late into the evenings and those go to bed at around eight, but mostly it's around six or seven.
I think most of us can relate to an orangutan that likes to snack at night. Absolutely. From morning till night. Every two minutes they write down the orangutans asactivities. How far away it is from other individuals. If it's eating, we write down what it is eating and what species, which part of the species. We usually follow individuals up to 10 days in a row, and then we give them at least a month break.
Caroline's team was out in the field conducting their everyday observations when they saw an orangutan named Rakus doing something they'd never seen before. He's a fully flanged male now for three years. Before that, he was an unflanged male. In orangutans, males can be flanged and unflanged. Flanges are these wide thick fleshy pads that grow around a male's face when they reach full adulthood.
These pads are used to attract mates and to amplify their loud long calls, a kind of hybrid signal that means, welcome to my land, and no males allowed . One day. Shortly after he has become a flanged male and he started to kind of claim a dominance position in SUAQ. One day we found him with a big wound in his face or several wounds in his face. Ulil Azhari and Armas Safruddin are two field assistants who work with Caroline. They were the ones who first noticed Rakus looked hurt.
They hardly ever get injured. They're surprisingly good at preventing injuries and wounds, but with this case, we had actually some signs that Rakus was kind of challenging the current dominant male and claiming a dominance position. And so we believed that the wound stemmed from a fight with another flanged male. Just under his right eye, a large chunk of flesh was missing from his cheek. The wound was a couple inches wide, but as they kept watching him, they saw him do something surprising.
And shortly after that he was seen to chew a plant and smear the resulting mash of that plant onto his wounds. He seemed to deliberately pick some leaves, chew them up, spit the plant mush into his hand and rub it onto his hurt cheek. The researchers later took a few leaves from the plant and brought it back to camp. And we realized that this is actually a plant that's very well known for its medical properties.
Akar Kuning - a fast growing flowering vine that has long been used in traditional medicine across Indonesia and is known to have anti-bacterial, anti-inflammatory, anti-fungal and antioxidant properties.And the mushed up Akar Kuning leaves seemed to have a healing effect on Rakus' face. Day by day, the researchers watched his wound get smaller and smaller. And then kind of the significance of the events started to sink in.
Because we hardly ever find wounded orangutans in our study site it it's difficult for us to compare this wound healing to other wound healing, but from what we can tell, from what we have observed, there was no signs of infection. Wow. What was most exciting to you about this finding and observation? It was kind of an escalating excitement because first of all, we hardly ever have injured orangutans then.
I've never heard of an orangutan walk chewing up a plant and smearing it onto his wound and then realizing that this is a plant with medical properties. It was this gradual but quite quick increase of excitement and realizing that we're onto something here. This was the first time a primate had been seen using a medicinal plant that humans also use. And for Caroline as an evolutionary biologist studying how orangutans learn, she wondered how did Rakus learn to do this?
That was of course the first burning question for us. The thing that's most interesting for us, given our research area, animals can either learn something by individual exploration, so figuring it out themselves or they can learn it from other individuals. So that's what we call social learning. The question is, which one? But the problem with the social learning theory is that orangutans are hardly ever wounded.
So the likelihood that he observed another individual being wounded, which would've most likely been another flinched male with him being close by and observing and realizing what he's doing is quite low. So it's unlikely that Rakus learned this from mom. I wouldn't exclude the possibility. It's just given how rarely orangutans are injured, especially mothers or infants, it's quite unlikely that it happens frequently enough to really be passed on from generation to generation.
So in orangutans learning opportunities are quite skewed towards the first part of development. Then they leave their mothers and they spend around half of their time on their own and half of their time with one or two other individuals. Even though these individuals are significantly less tolerant than their moms, so they get less time to observe these individuals from a close distance.
And then if they're male and then they become flanged, they even have less opportunities because other males won't interact with them anymore. Yeah, exactly. So as unflagged males, especially when they arrive in a new area, we find loads of evidence that they seek the presence of residents to learn from them. But as soon as they transition into the flanged mail stadium, it's quite a solitary life for the rest of their lives.
Caroline says, the other possibility is that Rakus figured out the leaves have healing properties all on his own. You would assume that he somehow realized while treating this wound or a previous wound that he sustained, that chewing up this plant is soothing his pain or is helping with the healing process. But it must have been some quite immediate effect that he could
connect with the plant. And that made him realize, okay, so maybe if I apply this plant to my other wounds, that will make the pain go away as well. This is what Caroline thinks most likely happened. Rakus found his way to plant medicine through what she calls individual exploration.
We don't know how much Rakus really understands that applying this plant to his wound will make the wound heal better, but because the plant has pain relieving properties, we think that that might be the mechanism that makes them connect the benefits of applying this plant to the wounds. The problem with this wound healing is that it's not immediate, right? So they chew up the plant, they apply it, and then over the next couple of days or weeks, the wound will heal.
But he was only applying the plant material to the wound, so he wasn't smearing it on any other body part, but he was really just applying it to his wound in the face and it lasted for seven minutes. So it seemed very intentional. It's pretty incredible to know that they could be out here either knowingly or unknowingly using substances in a way that has a very delayed gratification. Yeah, that's the interesting thing about it, the delayed gratification or the delayed effect.
How did they connect this effect to the action if the action is so rare and hardly ever performed? So what do you think the implications of this finding are? We have to think about what cognitive foundation is behind this behavior. Since humans also use plants to treat their wounds and all kinds of medical conditions, that most likely the last common ancestor between the non human apes and the humans also had the cognitive foundation that is needed to perform these
behaviors.We know that ape relatives can use these medical plants, it is highly likely that early, very early humans could also use medical plants.The question is, what is needed to perform this behavior? And for this, I believe we have to look at what other species can do and what we see in other species. Wow, there's so much good stuff that we've talked about. I just want to say thanks again for coming on the podcast and talking with us. Thanks, Ray, for having me.
It was a pleasure to talk about our orangutans and the fancy things that they can do. This next story takes us to Luongo National Park in Gabon and chimpanzees. As I said before, chimps have been known to use plants on wounds. Alessandra is a PhD student at the University of Osnabruck and back in 2019, she was conducting field research on the Recambo community - a group of around 35 chimpanzees.
She was studying how group members dealt with wounds when she recorded a video of Susie - an adult female chimpanzee - her adolescent son Sia, and her young daughter Sassandra. So I recorded this video in November, 2019, and this is my first observation of insect application to wounds. The three family members are all close together. Sia appears to have a wound on his foot. Susie looks concerned. Susie catches a fly.
She places the fly between her lips and we can see little Sassandra close to her attempting to get what Susie has. And Susie then approaches the foot of her adolescent son, Sia, and she applies the fly on a wound that Sia had just on his foot. And we can see Susie taking back the fly and reapplying it again. As she does this, Susie gets some more spectators. And the cool stuff.
When I noticed that something cool was going on is because there is this female chimpanzee, her name is Joy, and the baby Jumbo, she came to observe. And usually in chimpanzees, when there is something cool going on, you notice it immediately because if there are group members around somebody or somebody else, they are coming and they look what's going on. So your mind must have just been exploding, like what's going on here?
Did you realize in the moment that they were catching flies or catching flying insects? How could you expect chimpanzees catching insects and putting them into the wounds? It's like chances zero and funny, when I came back to camp and they observed the video, I don't know how many times I watched it, but so many anyway, and I asked to the guys, the eco guides, working with us like, guys, what do you think? Do you think it's possible that she caught something and put it into the wound?
And they were like, well, it looks like that. But no, it's impossible. Impossible. When something cool happens in the field, you never know if you'll see it next week, four years from now or never again. In this case, they had to continue following the chimps with the hope it might happen again. In our case, I was very, very lucky because then after observing Susie tending to Sia's wounds, not even 10 days later, one of the dominant males of the group, Freddy, very well known for his big belly.
He got really badly injured to his arm, and then voila! It happened again. Because they knew what they were looking for. They were able to record the interaction more closely. This second video is much clearer and shows big bellied Freddy catching insects and putting them in his wounds. So how frequently do the chimps in your community get injured? Rekambo, chimpanzees get injured quite often, mainly due to intergroup conflicts.
So meaning that basically are males that they discuss about females, they discuss about wounds, or in some rare occasions they can be injured by the prey they tend to kill. So these kind of situations, they might inflict quite big wounds like big open legs, forearms the back, the back back is one of the most important places for them to be injured. Wow.
They are crazy. What I observe every day, it's individuals taking care of the wound of others that being frequently leaves supplying insect to the wounds of others, which at first it appears like, okay, maybe this is not so common, but I can say after 24 months of observation, this is really, really very common. Chimps treating each other's wounds with insects is groundbreaking for many reasons. First, they're using insects as medicine, which is oddly complicated.
But the deeper implications of this research lie in the fact that the chimps are caring for each other. They're potentially displaying pro-social behavior, which is defined as actions intended to help others or society without a direct and immediate benefit to oneself. Not all species are demonstrably pro-Social. Definitively, yes. In humans, in chimpanzees, we are not sure, and this makes this study very unique.
Usually when researchers test for pro-social tendencies in animals, they look at whether the animals share their food and on that metric, chimps are not pro-social. Chimpanzees. They don't like sharing their food. Not even Italians really like it. But Alessandra's research shows chimps do help each other, even non-family members in other ways. So if they are friends, for example, and one of the two,
see the other friends like licking the tiny wound. Then also the other, they got interested in that. Just like how if you fall off your bike and get scraped up, a nearby friend might see you with a bloody knee and check to see if you're okay or need a bandaid. Chimps do the same, and no matter who gets injured, when one chimp is being treated by another, there are always onlookers. A kind of medical theater, if you will. Watching in chimpanzees is a very important moment.
This is how they learn is the same as in humans. When something cool is happening or we want to learn something, watching is one of the best ways of doing it. And when then they start imitating others, they start maybe sometimes selecting the wrong insects and they put not the right one into the wounds, or sometimes they put it on stuff that is not the wound. And then slowly you notice an increasing in frequency of the behavior, and also it becomes extremely precise.
But sometimes they do more than just watch. Alessandra witnessed young chimps actively get involved in the healing processes of their injured friends. Basically when there is blood or dirt, they take some leaves and then they just clean with the leaves or then adopt the leaves against the surface like a clean towel. Interesting. So what does this kind of care say about how they relate to each other? We do know the chimpanzees. They show behaviors mainly led by
empathy. So for example, we have apart from wound tending, we have reports of chimpanzees, rescue companions from drowning or in very well known as well in Tai, we have many reports of this specific chimpanzee Freddy, and he was mostly adopting orphans and it was so great you had these alpha chimpanzees with everything that was happening around him, like with babies on his back, and that is amazing.
So what this can tell us, socially speaking, I think we can also delve a little bit more about the cognitive abilities and also this new ground that we are starting to define as medical cognition. So that is something extremely interesting because we now realize that, okay, animals use medicines. This is very well known, but what happened when they use medicine to treat somebody else, which is so far was thought to be something exclusive only to
humans. We are currently investigating this idea of chimpanzees. They are treating patients. So. How do these findings cause you to rethink notions of human uniqueness? Pro socially speaking personally, I don't think that we are unique. I understand as well that it might be difficult to test, but I think that many of us, we have dogs. We know that they feel for us, it's just difficult to scientifically prove it. So how do we prove it? Now I have a really good way of proving it.
I go in the wild and I observe something very cool without manipulating the variables involved. They just behave as they want. And me, I document it. So what does this say about how our ancestors might've cared for one another? We have reports of caring in pre early humans already from pre-Neanderthals, so I'm really not surprised of observing it in chimpanzees. And what this might say is that caring for others is older than we thought.
What I hope this new research tool to say to us is maybe to provide us some extra information about the medicines they use, which is something that you cannot find at all in the fossil records. You have no idea about which kind of medicines they were using, which kind of knowledge did they have? That's so cool. There's so many exciting pathways to follow. I agree. Thank you so much for coming on Origin Stories and sharing this incredible story with us. Thanks to you.
Thanks to Alessandra and Caroline for sharing their work. Check your show notes to learn more and see videos of Suzee catching flies and Rakus yelling into the forest. And thank you again to all of you who helped us meet our quadruple match goal. We're so grateful for your support. Origin Stories is a project of the Leakey Foundation, a nonprofit dedicated to funding human origins research and sharing discoveries.
Learn more about the Leakey Foundation or donate to support our work at leakyfoundation.org. Support for Origin Stories comes from listeners like you with additional support from the Ann and Gordon Getty Foundation, Camilla and George Smith, Jeanne Newman, and the Joan and Arnold Travis Education Fund. This episode was produced by me, Ray Pang, with production help from Meredith Johnson. Our editors Audrey Quinn and Meredith Johnson is our host. Theme music by Henry Nagle.
And additional music by Blue Dot Sessions and Lee Roservere. Thanks for listening.