Orangutans seek out medicinal plants - University of Exeter News

June: Welcome to Kindred Minds — I'm June, a primatologist and science communicator, and this is the show where we tell true stories about our closest relatives on this planet: the other primates. Stories that are funny, surprising, heartbreaking, and above all — deeply human, in the best possible way. June: Before we dive in, a huge thank you to today's sponsors: Ada, who helps companies integrate A I into their workflows in ways that actually make sense; Ago Consulting — pronounced "Ahh-Go" — silicon development consultants working across everything from A I to full SoC design; and Zen Semiconductor, an umbrella company with a remarkable portfolio spanning the silicon industry. We are so grateful for their support. June: Today on the show — a chimpanzee who learned to read Chinese characters and lived one of the most extraordinary lives in the history of animal cognition research. An orangutan in the wild who found his own medicine. Snow monkeys doing something in hot springs that scientists genuinely did not predict. And a piece of news that made me actually gasp out loud — twin primates born at a zoo, a tiny conservation miracle. June: And woven through all of it, the thing I want you to feel by the end of this episode: how thin that line really is between us and them. How much of what we think of as uniquely human — intelligence, culture, healing, grief — is actually just... primate. Which means it was always bigger than us. June: Let's get into it. June: So let's start with cognition, because I have to tell you about a chimpanzee named Ai. A-I. And I want to be clear right away — that's her name, it means "love" in Japanese, and she had nothing to do with artificial intelligence, though honestly, what she could do with her mind might give some algorithms a run for their money. June: Ai was born in West Africa around 1976, and she came to the Primate Research Institute at Kyoto University as a very young chimpanzee. And what the researchers there, led by primatologist Tetsuro Matsuzawa, set out to do was genuinely ambitious — they wanted to understand the nature of chimpanzee intelligence, not by asking chimps to do human things for human rewards, but by creating a real collaborative relationship. A partnership. They called it "friend work" — research done with the chimpanzee, not on her. June: And Ai rose to the occasion in the most spectacular way. Over decades, she learned to identify, label, and remember colors, numbers, and objects using a computer touchscreen. She learned Arabic numerals and what they meant — she understood that the symbol "5" represents the quantity five. She could look at a collection of objects and correctly identify how many there were. June: But here's what really got the world's attention. Ai learned to read and use Chinese characters — kanji. She could associate written characters with their meanings. She could recognize and use over a hundred symbols. And she didn't just memorize them by rote — she demonstrated understanding. Context. Flexibility. The hallmarks of genuine cognitive grasp, not just pattern-matching. June: Now, I want to be careful here, because this is a place where science communication can go sideways. Ai wasn't "reading" the way you and I read right now — processing narrative, inferring meaning between the lines. But she was doing something remarkable: symbolic representation. She understood that an arbitrary visual symbol could stand in for a real thing in the world. And that is a cognitive leap that we used to think was exclusively human. June: Ai passed away recently at the age of 49. Chimpanzees in captivity can live into their 50s, but 49 is a long, full life. And she had a son, Ayumu, who went on to become famous in his own right — his working memory for number sequences was tested against university students, and he beat them. Consistently. Humans tend to find that uncomfortable. I find it wonderful. June: What Ai's life tells us is something really important: that the cognitive architecture required for symbolic thought, for learning, for memory, for what we might even call scholarship — it didn't appear out of nowhere in homo sapiens. It was already there, sketched into the primate blueprint, waiting to be expressed. Ai didn't become intelligent because humans taught her. She was always intelligent. The research just gave her a vocabulary to show us. June: And I think about Professor Matsuzawa, who worked alongside her for nearly fifty years, and the grief that must come with losing a research partner, a mind you've known that long. That's not nothing. That's a relationship. That's kinship. June: Now, from one form of primate intelligence to another — and this one I find quietly astonishing, because it doesn't involve a lab or a keyboard. It involves a wild orangutan, a wound, and a plant. June: Researchers studying wild Sumatran orangutans — this is work coming out of the University of Exeter and their collaborators — documented something that stopped them in their tracks. A male orangutan, who they'd been observing, had a facial wound. And over the course of a few days, they watched him repeatedly chew the leaves of a plant called Akar Kuning — Fibraurea tinctoria — and apply the resulting paste directly to the wound. Deliberately. Repeatedly. June: Now, this plant is not a food source for orangutans. They don't eat it. They sought it out specifically, processed it in a very particular way, and applied it to an injury. And here's the thing — within weeks, the wound had healed completely, with no sign of infection. June: Akar Kuning is known in traditional human medicine across Southeast Asia. It contains compounds — furanoditerpenoids and protoberberine alkaloids — that have documented antibacterial and anti-inflammatory properties. Human folk medicine has been using this plant for exactly this kind of purpose for generations. This orangutan was doing the same thing. Independently. In the forest. June: What does that mean? It means that medicinal knowledge — the understanding that certain plants have healing properties — is not a human invention. It's a primate discovery. And it may have very deep roots. Chimpanzees have been documented swallowing whole leaves of Aspilia plants — a genus with known antiparasitic compounds — in ways that appear to deliberately target internal parasites. They also rub themselves with plants that have insecticidal properties. Gorillas have been seen consuming plants with known medicinal value at unusual times, seemingly when ill. June: There's a whole field now — ethnoprimatology and zoopharmacognosy — studying how animals self-medicate. And primates are at the forefront of it. They are not just surviving in forests. They are practicing something. Something that looks, if you squint, like the very beginning of medicine. June: And think about what that requires cognitively. You have to notice that you feel unwell or that a wound is there. You have to connect a plant — something outside yourself — to an internal state. You have to remember what worked before, or perhaps learn from watching others. You have to have a body that communicates its own needs clearly enough that you listen. June: We do all of that. Every time we reach for an aspirin or brew a chamomile tea because our stomach hurts, we're doing a version of what that orangutan did in the Sumatran forest. We just have thousands of years of accumulated knowledge helping us. He had to figure it out fresh — or remember it from somewhere deep in his lineage. June: That orangutan's wound healed. He's still out there. And I find that so moving — this quiet, capable animal, taking care of himself, using knowledge we once thought only we possessed. June: Okay, so we've talked about cognition. Now I want to go a little deeper into the biology — into what I think of as the shared recipe. Because I think the stories are even more powerful when you understand the molecular foundation underneath them. June: Here is the fact that I never get tired of saying out loud: chimpanzees and humans share approximately 98.7 percent of their D N A. Depending on how you measure it — whether you're counting single base-pair differences or looking at larger structural variations — you get numbers that range from about 96 to nearly 99 percent similarity. But the point is the same: the instruction manual for building a chimpanzee and the instruction manual for building a human are almost identical. June: That's not a metaphor. That is the literal molecular reality of life. The same genes that govern your brain development, your immune system, your capacity for learning and emotion — they are running, with tiny variations, in every great ape on this planet. The recipe is shared. June: And here's where the snow monkey story gets really interesting, because it illustrates something about that shared recipe in a very unexpected way. June: Japanese macaques — snow monkeys — are famous for bathing in natural hot springs. You've seen the photos: these round, fluffy, pink-faced monkeys sitting in steaming water, looking utterly serene, snow falling around them. It's one of the most iconic images in nature. June: For a long time, the assumption was straightforward: they do it to stay warm. And that's probably part of it. But researchers in Japan have now been looking more carefully at what regular hot spring bathing actually does to these macaques biologically — and the results are surprising. June: When they compared macaques who regularly bathe to those who don't, they found differences in lice patterns and in the composition of gut bacteria — the microbiome. Now, you might expect that sharing a warm pool with lots of other monkeys would be a parasite's dream — a perfect transmission opportunity. But that's not what they found. The bathers didn't have more parasites. In some respects, the patterns were more nuanced and complex than a simple "communal bathing equals more disease" story. June: And the gut bacteria piece is fascinating. The microbiome — the community of microorganisms living in your digestive system — is increasingly understood to be deeply intertwined with health, immunity, and even behavior. And the microbiomes of these bathing macaques were different from their dry counterparts. The hot water, the shared environment, the whole ritual — it's shaping their invisible inner world. June: Now why does this belong in the "shared recipe" section? Because the relationship between gut microbiome and health is one of the hottest areas in human medicine right now. We are learning that the trillions of bacteria in our own guts influence everything from digestion to inflammation to mood. And here are macaques, demonstrating that their social bathing behavior — something that looks, frankly, like a spa day — has measurable biological consequences through that exact same mechanism. June: The recipe is the same. The relationship between our bodies and our microbial passengers, between our behavior and our biology — it's the same in these mountain-dwelling Japanese monkeys as it is in us. Different environment, different species, same underlying system. June: And there's something else worth saying here. These macaques learned to use the hot springs culturally. It spread through the group. Young macaques learned it by watching adults. It became a tradition — a practice passed down through observation, not genetics. That is culture. Small-c culture, but culture nonetheless. And culture shaping biology is something we talk about a lot in humans. Here it is in a troop of monkeys sitting in a mountain hot spring in winter. June: The more you look, the more the line blurs. Not because we're pulling primates up to our level — but because we're finally understanding that the level was always shared. June: Now I want to end today's episode with something that made me put my hand over my heart when I read it. And it's a small story, in terms of the numbers involved. But the numbers are exactly what make it matter. June: At the Lake Superior Zoo — in Duluth, Minnesota — twins were born. Primate twins. The species is the Coquerel's sifaka — say that with me: "sih-FAH-kah" — a lemur from Madagascar. And I need to tell you a little about sifakas, because once you know them, you'll understand why this birth is such a big deal. June: Lemurs are the most endangered group of mammals on Earth. Let that land for a moment. Not the most endangered primates — the most endangered mammals, full stop. Madagascar, their only home, has lost roughly 90 percent of its original forest cover. The pressures on lemurs — habitat destruction, hunting, the climate crisis — are immense and ongoing. June: Coquerel's sifakas are listed as critically endangered. Their wild population is shrinking. And they are notoriously, legendarily difficult to breed in captivity. They have very specific social, dietary, and environmental needs, and captive breeding programs have struggled for years. A single birth is cause for celebration. Twins — twins are extraordinary. June: These two tiny sifakas at the Lake Superior Zoo represent something real. They represent genetic diversity preserved, a lineage continued, a small counterweight to the losses happening in Madagascar's forests right now. June: And sifakas — I have to tell you, if you've never seen one move — they are unlike any other primate. They can't really walk quadrupedally on the ground. Instead, they hop sideways on two legs, arms out, bounding along in this joyful, almost ridiculous-looking dance. They look like they're perpetually delighted. And when they're in the trees, they leap — huge, graceful leaps, sometimes six meters or more, arms spread wide. June: These twins won't know any of that freedom yet. But the people caring for them at Lake Superior Zoo are part of a coordinated conservation effort — the Species Survival Plan — that exists precisely so that when the time and the conditions are right, these animals and their descendants have a future. It's not a perfect solution. No zoo is a substitute for a living forest. But it is a bridge. It is people saying: we are not willing to let this end. June: And I think that impulse — that refusal — matters. It matters that human beings look at a sifaka and feel something. That we recognize something in them. Maybe it's the eyes. Maybe it's the way they hold their young. Maybe it's something older, something in our shared primate heritage that reaches across the millions of years of separate evolution and says: I know you. You're family. June: I believe that recognition is real. I believe it's biological. And I believe it's our best argument for doing the hard, expensive, unglamorous work of conservation. Not because it's noble. Because it's true. They are family. And we don't abandon family. June: So today we met Ai — a chimpanzee who spent 49 years demonstrating that symbolic thought and scholarship are not exclusively human gifts. We watched a wild orangutan dress his own wound with a medicinal plant that human healers have known about for generations. We learned that snow monkeys soaking in hot springs are reshaping their own microbiomes — their invisible inner ecosystems — through a culturally transmitted tradition. And we welcomed two tiny sifaka twins into a world that we are, slowly, trying to make worthy of them. June: What strikes me every single time I sit down to tell these stories is how much courage it takes to really look at these animals. Because once you see them clearly — once you understand how they think, how they feel, how similar their biology is to ours — there's no comfortable distance anymore. They're not out there. They're with us. They're us, in so many of the ways that matter. June: Intelligence and feeling are not ours alone. They never were. They are primate inheritances, ancient and shared, written into the same molecular recipe that wrote us. And the more we remember that, the better we tend to be — to them and to each other. June: This is Kindred Minds, brought to you by Ada, Ago Consulting, and Zen Semiconductor. If today's stories stayed with you — share this episode with someone you think would love it. Subscribe wherever you listen, so you never miss a story. And check the link in show notes for all the sources and reading behind today's episode. June: I'm June. Stay curious. These are your kindred minds.