Short Wave - How scientists discovered that animals are doctors, too

Episode Date: September 11, 2026

When people are sick, we seek out medications and treatments to help heal. For a long time, scientists thought that was a uniquely human ability. But it turns out, many other animals do a version of it too! And since the late 1980s, western researchers have been trying to get a peek behind the curtain. And aside from just cataloguing all the cool examples just to know, there’s a real hope that studying animals’ medical cabinets may be the most promising way to expand our own. We get into the weeds with freelance science journalist Mandy Nguyen.Interested in more animal stories? Email us your ideas and questions to explore at [e-mail]. They may become a future episode!Support public media with NPR+ and enjoy perks for over 25 podcasts like this one. This show’s perks include sponsor-free listening. Learn more at plus.npr.org. See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Hey, shortwavers. It's Nate Rott with science journalist Mandy Nguyen. Hi there. Hey. Okay. Today, you're bringing us a story on animal behavior, specifically what animals do when they get sick. Yeah. So when we humans get sick, we take cough syrup, antibiotics. You know, we have thousands of treatments for thousands of ailments. For sure, yeah. And for a long time, scientists thought medicine would be able to be.

was a uniquely human trait. There's a famous quote by one of the physicians who founded the Johns Hopkins Hospital. He said, the desire to take medicine is one feature which distinguishes man, the animal, from his fellow creatures. Sounds very much like a guy that founded Johns Hopkins would say, you know, very lofty. But yeah, it's like a common through line in the history of science to think that humans are very special. But there's a whole field of growing research showing that a lot of other animals treat themselves too. It's goats and it's bears and it's porcupines and it is ants and it's bees and it's fruit flies. So I think the more we look, the more we find that animals can use medicine. That's Yap de Rota. He's a biologist at Emory University.

And he and other scientists in this field are looking at how animals heal themselves when they're feeling under the weather. Whoa, cool. So give me some examples. So they've studied how bears chew on willow bark to relieve their post-hybernation aches, how apes apply chewed up leaves to their wounds. Whoa. And even how some ants perform surgery on other ants to prevent infection from spreading through a colony. Like surgery on another ant? What does that even mean?

Like they cut off their limbs or what? It means they chew it off with their mandibles. Oh, dude. All right. Hardcore. Let's go, ants. Exactly. There's just this whole other world of wild animal medicine.

One that's as complicated and important as her own. And scientists like primatologist Elida Fryman at Brown University are helping us uncover it. Across the animal kingdom, self-medication and medication by animals take so many different forms. It depends on the species. It depends on the behavior and it depends on the medicine. So today on the show, animal doctors, how they treat themselves, each other, and what we humans can learn from them. You're listening to Shortwave, the science podcast from NPR. Okay, Mandy, so taking a step back. How did scientists even learn that animals could use medicine in the first place?

Well, it started with an observation in 1987. Biologist Michael Huffman was following a group of chimps in Tanzania. He was studying what they ate, how they behaved, the way they interacted with each other, when he noticed something new. So one of the mothers of the group named Chow Sikou was eating something that she usually didn't. It was a tropical shrub. It was called the bitter leaf plant. And this plant is usually kind of toxic, so it's not a regular.

part of their diet. Whoa, so could it have just been like a random craving for like a bitter taste in the same way that I desire sweets every hour of the day? I mean, maybe. But the thing that Michael took note of was that she was acting differently. She was lethargic and she seemed sick. Gotcha. She also was eating this plant in a really specific way. She would peel off the bark and the leaves and then chew and suck at the juicy kind of inside part and then she would spit it out like all the fibrous parts. Oh, so not really eating? Exactly. Turns out it's a widely used medicinal plant by humans treating very similar symptoms that

Chow Shuku was showing and that she recovered from in 24 hours, roughly the time that humans recover from illness when they use that plant as well. In particular intestinal upsets, malaria. Wow. So this is something that people have been using too. Right. And Michael only learned this because of his guide, who was a game officer at the Mahali Mountains National Park.

His name was Mohamedi Kalundi. And he said it wasn't just this one plant they used. Mohamedi told him, Oh yeah, my ancestors, my grandfather, my mother, all of my mentors in traditional healing have stories about plants named after the animals that they saw use and treat themselves for sickness. And I literally almost fell off the log that I was sitting on in the mountains

and I was talking with Mohammed about it. Michael immediately started wondering what other hidden knowledge animals had. Yeah, but I imagine that like other Western researchers that Michael was talking to were maybe skeptical of this. For sure. I mean, when he came back to camp after watching Chausakou and told the others on his research team, no one bet it and I. First thing that I got back from my senior colleagues in camp was, oh, we've seen the chimps eat that all the time. Wild animals never get sick. But that sounds so intuitively wrong.

I mean, like, an animal never gets sick. We are animals, right? One. And, like, my dog gets sick, I feel like every other week. I mean, yes. But keep in mind that this is the 80s. This sort of thing was unthinkable to most scientists back then. Okay.

Plus, drawing a hard line between food and medicine is also kind of difficult. Like, even in our own diets, food and medicine overlap. Chicken soup is a staple for a cold, but I'd eat it just because it's good. I would eat it, too, because I love chicken noodle soup. So it's a question of like, are they eating it because it's just food or because they actually want to treat an illness or a disease? Right. And it takes a lot of following around chimps to figure it out. So Michael had to sample a lot of chimp poop to test for parasites to prove they were sick and then watch their behavior to see if they sought out particular plants when they were. Then the chimps had to actually get better. His team also tested the bitter leaf itself to see if it had any bioactive compounds. And it did. It had about 13.000. chemicals new to science at the time.

Whoa. So it took Michael a decade of more work to prove that his suspicions were true, and to confirm what his guide and plenty of traditional healers already knew, that animals use medicine on themselves. And of course, the animals themselves have known about it forever and ever. Animals are wise. I agree with that. And since then, scientists have realized, or realized again that all kinds of animals use

medicines, or treatments. We're talking cats and dogs, bears, lizards, and it's not just medicinal plants that they're making use of. Lots of animals like buffaloes, elephants, and primates eat dirt, which might strengthen their immune systems by diversifying their gut microbiome. Over 200 species of birds do something called anting, which is when they take ants in their beaks and rub them on their feathers so that the ants spray formic acid which kills lice on them. Dolphins might also rub themselves against corals and sponges to treat skin diseases. Well, yeah, I think I've heard about that. I mean, I feel like, you know, apes and monkeys, they're very similar to us, right?

Just a little hairier. So it's like easier to picture them using medicine, but like lizards and dolphins and birds, too? Yeah, and I'm going to take us a step further because it doesn't just stop with animals like lizards and birds. Insects can do this too. Whoa. For example, monarch butterflies. Just a few decades ago, there were still a lot of scientists who said there's no way that monarch butterflies can do that because they're just not smart enough. They've got these tiny little brains.

That's biologist Yapda Rota again. And he says that medication and insects is a lot easier to study because it's easy to keep a lot of them in a lab and study them directly. Oh, yeah, that checks out. I mean, you can get specific bugs sick and see if they go for a certain kind of plant that they're non-sick friends don't. Yeah, and that's exactly what he did, specifically with monarch butterflies and milkweed. Monarchs lay their eggs exclusively on milkweed because that's the only thing their caterpillars eat. Sometimes they lay their eggs on a kind of milkweed that's known to be toxic. And part of why they do so is because the toxins the caterpillars consume,

it helps them repel predators when they're butterflies. Whoa, cool. But Yap thought that another reason that they might be doing so was as a way to treat parasites intentionally. And I'm guessing our guy Yap was correct. Yes. So his team released parasite infected butterflies and healthy ones in a big flight cage with both kinds of milkweed to see where they laid their eggs. And the infected butterflies laid a lot more eggs on the toxic milkweed. And did they get better?

Well, actually, this does nothing for the infected butterfly who laid her eggs. She's not eating the toxic milkweed or anything. But it helps the babies that she passes the parasites to. What she can do is essentially preventatively cure her offspring that are going to be infected in the future. And I think that's something that insects have told us is that animals medicate not just themselves, but each other. Other insects do this too. Some bees mix antimicrobial tree resins and wax to line their hives if there's an infection to counter the spread. Whoa. And there are Florida carpenter ants that do life-saving amputations on other ants in their

nest that have infected wounds. Are metal ants. Heck yeah. So even the smallest, like, tiniest brain little creatures use medicines in all sorts of ways. Yeah, and they can treat each other. I mean, this is all super fascinating, but I'm wondering, like, beyond being cool, can any of this information help people? Am I just being too selfish? So there are actually a lot of practical applications for this research. So the first area is in how we manage our domestic animals and livestock. For example, Honeybees. There's a whole industry around them as pollinators for agriculture, but they're at risk of die-offs. Knowing that they line their hives with the sticky medicinal resin and wax for medicine,

it should encourage beekeepers to facilitate that process instead of cleaning it away, which is what's usually done. And with livestock like sheep and goats, we usually give them drugs when they're sick, but over-reliance on drugs like antibiotics has caused widespread resistance to them. These animals also know how to self-medic. And scientists say that we should help them, help themselves by diversifying their access to medicinal plants and foods in pastures. So healthier animals also means healthier people. I dig it. Okay. So knowing that animals use medicine means better care of the animals that we live with and manage, better results for us. What else? So the second thing has to do with finding new medications. Primatologist L.E. Fryman, one of Michael Hoffman's former students,

says that there's a lot of potential here. I think a lot of people don't realize just how many of our modern-day pharmaceuticals are derived from or inspired by natural products, meaning medicinal plants, medicinal resources that exist in nature. Like aspirin is derived from the bark of willow trees, and penicillin, our first antibiotic, is from a fungus. And so by looking at animals, scientists might be able to find potential medicines in places we've overlooked. And in fact, they already have. By studying chimps in Uganda, scientists have found two anti-malarial compounds new to science. And the chemicals of the bitter leaf plant that Michael Hoffman was studying all the way back in the 80s,

scientists have looked at its effects on various kinds of cancer, and it was shown to inhibit tumor growth. Dang, so maybe I should start paying more attention to what grass my dog is eating when he gets an upset tummy, right? Or try to learn from him. I mean, that's basically what researchers like LOD are doing. It's not like we have people medicine and animal medicines. A lot of these medicines are shared in these kind of complex ecosystems that we're all existing in. And oftentimes when animals have found a medicine, we found them as well and vice versa. When Elid is in the field, she works a lot with local healers to see if they recognize the plants and treatments that the animals use. And she's come to realize that the planet is just one big shared medical cabinet. That also has a really important conservation implication. because it means that if these medicinal resources start to disappear,

it's not just animal health care that's at risk. It's also human health care as well. I personally think this is a beautiful, fascinating science that shows us another thing we have in connection with a lot of the animals around us. It's another way that their health and our health and the health of the planet is interconnected. Turns out we're all on this same spinning rock together, right? It turns out. Mandy, thank you so much for taking us on this tour of the amazing world of animal medication.

I learned a lot. Thank you. If you like this episode, please share it with a friend. It really helps out our show. This episode was produced by Hannah Chin. It was edited by Hannah as well and Rebecca Ramirez. Tyler Jones checked the facts. Jimmy Keely was the audio engineer.

I'm Nate Rott. Thanks for listening to Shortwave, the science podcast from NPR. Thank you.