In short
Radiolab explores “grass” as an overlooked force shaping human life—its ecology, defenses, and deep cultural/biological impact—framed by listener reactions in NYC parks and a conversation with biologist David George Haskell.
Guests/backgrounds
David George Haskell is a writer and biologist, described as grass’s “number one fan,” affiliated with Emory University. Hosts/production staff include Molly Webster, Anissa Vitsa, and Joe Strogatz (reporting/production).
Key claims
Grasslands expanded as Earth cooled and dried; grasses thrive in fire-prone climates by keeping growth tissue low. Grass seeds contain large food stores that helped early humans adopt grass-based foods. Wheat, corn, rice (and other grains) underpin much of human calories; humans are “grass-fed.” Grass may also have shaped bipedalism and even modern calm via sound/aroma/soil microbes.
Notable examples
silicate “glass-like” particles in grass blades; fire regrowth after burns; grass seed “lunchbox” embryo + starch/protein/oils; “grass apes” (Homo poaceae); grass dampening high-frequency sounds and releasing calming aromas.
Written by AI. May contain mistakes. Listen to the episode to check what was said.
Chapters
Tap a time to open that second in VOThe Fanny Pack Vision
1:00 to 3:16
Anissa shares her design ideas for the new Radiolab fanny pack.
“I will just say I am a good pairing for you on this fanny pack promo because I love a fanny pack slash crossbody bag.”
Introduction to Today's Topic
3:29 to 4:01
Molly introduces the theme of grass and its significance.
“Thank you, Anissa, for making this fanny pack.”
Conversations About Grass
4:01 to 5:24
Exploring public perceptions and memories associated with grass.
“It was a little more complicated than that, but basically they were like, can you make a story out of the space that we're in?”
The Fascination of Grass
5:24 to 7:18
David George Haskell discusses the importance of grasses in human history.
“Do you feel like it's a weird question to ask?”
Grasslands and Ecosystems
7:18 to 8:13
Learn about the ecological changes that led to the spread of grasslands.
“Indeed, if you had to pick one group of plants that we could count as our co-creators, a group of plants that are vitally important to the appearance of humans on this planet, it would have to be the grasses.”
Grasses' Survival Strategies
8:13 to 10:39
Discover the unique adaptations of grasses to survive environmental changes.
“The planet was cooling, the polar ice caps were expanding, and places were getting just a little drier.”
Grass as Food: Human Connection
10:39 to 12:28
Understanding how grass seeds became vital to human diets.
“It's very hard to say grass and glass, right?”
Human Diets and Grasses
12:28 to 14:00
Exploring the significance of grasses in modern human food sources.
“So the grass sends up a flower stalk and it flowers, it makes, holds little eggs on the flower stalk and pollen joins with the egg and then the grass seeds are held up on what was the flower stalk.”
Exploring Our Grass-Based Diet
14:00 to 17:44
Learn how grasses like corn, wheat, and rice form the foundation of human diets.
“So at lunchtime and at dinnertime and at breakfast, the oats in your oatmeal, that's a form of grass.”
The Evolution of Grass Apes
18:03 to 23:15
Understand how our evolution is linked to grasslands and bipedalism.
“The most lethal weapon in mass shootings is a handgun.”
Show all 11 chapters
Soundscapes and Aromas of Grass
23:16 to 24:57
Discover how grass can calm and connect us to our ancestral habitats.
“that was the sign of good life for our ancestors for literally hundreds of thousands of years, if not millions of years.”
Transcript
Automatic transcript. May contain errors.0:00Radio Lab is supported by Progressive Insurance. Do you ever think about switching insurance companies to see if you could save some cash? Progressive makes it easy to see if you could save when you bundle your home and auto policies. Try it at Progressive.com. Progressive Casualty Insurance Company and Affiliates. Potential savings will vary. Not available in all states. Hey, I'm Molly Webster from Radio Lab and I am in studio today with Anissa Vitsa. Rhymes with pizza. Hi, Molly. Who is our assistant producer, but also a really amazing artist. And so we have her do a lot of our cool visuals for the show.
0:37And Anissa, you're here to talk about this awesome thing you just made for us. What is it? I have been wanting a Radiolab fanny pack slash crossbody bag for probably as long as I've worked here. But everyone hated the idea. And then some listeners asked us for it. And now all of a sudden everyone's finally ready. I'm ready to do my vision. You're vindicated. I will just say I am a good pairing for you on this fanny pack promo because I love a fanny pack slash crossbody bag. So what does this one look like and how often will I use it? So I wanted to do some drawings that were Radiolab related. Okay.
1:15It's sort of like blue, almost woodblock print-like drawings of a couple of recent, my favorite recent episodes. One of them is actually your episode, Molly. I made it, I did not know this. I made it onto the bag. Yes, you made it onto the back. Which one? What was it? I feel like grass has become a huge part of our lives here in the office. Now I've learned more about grass than I ever possibly could have imagined and appreciated it more. So I wanted that to make it on the back. And then I've also drawn a bird from Annie's Nigel episode, Nigel the Gannet. I just wanted these two things that have been little joyful Radiolab stories.
1:53I heard you paid extra for an interior pocket. Yes, we did. That was important to me. Kick it. Can't say that on the radio. If you want to get your hands on this finally, finally, we've got one fanny pack, please join The Lab, which is our membership program. Membership starts at just$7 a month, and it comes with extra perks like sponsor-free episodes, bonus content, members-only swag, this fanny pack, and lots more. And if you join The Lab now and get this crossbody bag, then I will be vindicated that people really do want a fanny pack. But more than that, really what you're doing is you're helping us make Radiolab.
2:30Listener support is so, so central to what we do. We just made it through our first year without federal funding. Thanks in large part to you, to people, individuals helping us, supporting us each month. It's totally true. Like individual donations let us get out into the field and report on that infamous moment when a reporter threw a shoe at former President George W. Bush. or report on stuff like the resurgence of flesh-eating screwworms. That was a good one. We also just had our Holy Shivers episode about goosebumps. Basically, if you have learned something or been moved by Radiolab in the last few months or you just really love a fanny pack, please consider becoming a member of the lab.
3:12It is easy and it really does go a long way in making Radiolab possible. To become a member, go to radiolab.org slash join or you can text LAB to 83763. That's 83763 to make your donation. Thank you in advance. Thank you, Anissa, for making this fanny pack. Of course. I can't wait to wear it. And now you get to listen to the show.
3:39Wait, you're listening. Okay. All right. Okay. All right. You're listening to Radiolab. Radiolab. From. W-N-Y-C. C. C? Yeah.
3:57Hey, I'm Molly Webster. This is Radiolab. And today's show is inspired by an invitation that I got last spring, which was essentially to tell a story for a park about parks. It was a little more complicated than that, but basically they were like, can you make a story out of the space that we're in? Which happened to be this shady glade. It had a lawn down the middle and trees around the side and rocks and things. So I looked around the space and I was like, okay, maybe there's something to do with mushrooms or, I don't know, squirrels. It's New York City. and as I was talking about these scintillating ideas with people, I started having a conversation with a horticulturist and they said, you know what I think about all the time?
4:53Grass. And I completely ignored them because I thought, what could be interesting about grass? Then they started talking about how landscapers use grass and that grass is like an instrument that makes sound. and I felt myself get a little pulled toward grass, like maybe there was something there I wasn't seeing. Okay, okay. So I wrangled producers Anissa Vitsa and Joe Strogatz to go out into the parks of New York City and ask people this question. What do you think about grass? What do I think about grass? Grass? You mean this grass? They got a lot of blank stares. Do you feel like it's a weird question to ask?
5:36That's all right. But people had a lot to say. Let me think. In general, I would probably be thinking about... They talked about... Rolling around. Mowing lawns. My daughter. Grass memories. Playing cats. Girlhood. Feelings. Horses chewing it. Grass stands. Grudges. Their square teeth grind it, grind it, grind it up. I like all the trees, the shrubs, flowers. Random associations. The other type of grass comes to mind as well. I like the smell. But no one... Feels great on your feet. Oh, God. I love it. ...told us a story about grass itself. Grass. Grass. Grass. Grass. It was like grass was everywhere, but also...
6:22Grass. ...invisible. I mean, we even have a term in our culture, the green screen, right? Which is the screen that will be removed, that will be erased for the important stuff to stand out in the foreground. And I think grass, for many of us, is that green screen. Honestly, that's how I thought about grass, too, as that green screen, until I talked to this guy. I am David George Haskell. I'm a writer and a biologist. And David is grass's number one fan. Because grass is, when you do start to learn about their lives, their transformative effect on the whole planet, and their role in catalyzing human evolution, suddenly they become extraordinarily fascinating.
7:10David says, if we ignore grass, if we look past it, we don't just miss out on the story of grass, but we miss out on one of the most incredible stories of human history. Indeed, if you had to pick one group of plants that we could count as our co-creators, a group of plants that are vitally important to the appearance of humans on this planet, it would have to be the grasses.
7:40And that story starts, according to David, a very, very, very long time ago. When you go way back, so if you go 30 million years ago, Our ancestors and the ancestors of all the apes were mostly forest-dwelling creatures, eating insects, eating fruit. And back then, there weren't many grasslands around. But then, things started to change. These little patches of grasses started to appear in the forest. The planet was cooling, the polar ice caps were expanding, and places were getting just a little drier. And then 10, 20 million years ago, those grasslands expanded more and more. So different timescales on different continents, but the overall pattern is a move away from a very wooded planet to a planet that's wooded but has a lot of different grasslands mixed in as well.
8:45But does that mean grasses are like stronger than trees and they just started taking over and like saying, trees, get out of here. We're taking over your space. Or was something else happening that led to this reconstruction of the landscape? The grasses have all sorts of inner tricks to take advantage of external changes. So, for example, over this time period, the concentration of carbon dioxide in the atmosphere really dropped. And grasses are really good at sucking up carbon dioxide and using it to make sugars. They're also very good in seasonally arid climates. These are climates where it can be very lush and rainy for part of the year, but then you go for months where it's just dry, dry, dry.
9:30And that's the kind of situation where you get fire moving in. And the genius of most grasses was that they figured out how to thrive in a very fire-prone environment by keeping their growing tissue very low to the ground or in the ground. So if fire comes through, all those disposable leaves get burned up. They're gone. but when the fire moves on the sensitive tissues from which new stems, new roots, new leaves will grow, they're unharmed and the grass sprouts right back up.
10:15So after grasslands appeared, lots of mammals like horses and hippopotamuses and other creatures because it started moving out of the forest and eating the grass. But grass blades, you know, they're long, they're stringy, but they're also tough. And they've got little bits of glass-like material inside them. Glass. All grasses have these little pieces of silicate, which is essentially like grass. It's very hard to say grass and glass, right? Grass, glass, blah, blah, blah, yeah. But wait, there's little bits of silicate in the blades of all grasses? Of almost all grasses, and some have more than others.
10:51And this is a defense against, you know, the wind tearing the grass up, but also against animals being overenthusiastic and grazing too much on them. Really? It makes me think of like, you know, when I was growing up, like my dogs would eat grass to throw up. Like they would eat grass and then vom. Yeah, so your dogs are probably actually eating it to purify their gut. It can act as a dewormer because it will cause the animal to vomit or it will poop it out the other end. and all of that grass tangle physically will just bind up with some of those worms and get rid of them. Oh my God, you're literally just like scraping out your insides, which you can't reach with your hand.
11:29Yep. That's cool. Yeah. Puking dogs aside, many mammals are actually good at eating grass. They got tougher teeth. For some, they evolved very complex, multi-parted stomachs with bacteria and protists that can digest grass. Wait, do you think that We tried to eat the grass like our ancestors did. And how did that go? Yeah, well, it probably gave us some stomach upsets. I'd imagine for some ancestors, grass, just grass leaves were part of the diet. Also, some other vegetation. I mean, they can be nutritious, but so can a lot of other things that don't have glass-like particles inside of them. So we didn't really bother.
12:13But there's another way to eat grass. and that is to eat the seeds. So through some series of experimentation that we don't really know about, our ancestors started to eat grass seeds and this is where the story of grass and humans really heats up. So the grass sends up a flower stalk and it flowers, it makes, holds little eggs on the flower stalk and pollen joins with the egg and then the grass seeds are held up on what was the flower stalk. And those seeds contain two really important parts. There's the embryo, which will grow into the new little baby grass plant. But then most of the inside of the seed is a food store that the mother plant puts into the seed, is literally taking food out of their own, their body, the grass plant's body, and putting it into the seed, that when the seed leaves and lands somewhere, the embryo will eat that food store to power its first few days and weeks of life.
13:23So the mother is sending the offspring out with little food supplies, like a little lunchbox or something. Except it's a lunchbox that is eight times the size of the kid who's carrying it. Is that unusual for seeds? I think in my mind, I would kind of expect that that's how a seed works. So grasses have got especially big food stores, which can be 80 percent of the inside of the seed filled with starch and proteins and some oils. And when our ancestors discovered these nutritious little packets, they were like, oh, this is something we can eat. And I think learning and realizing that most of our food comes from grasses completely transforms and transformed how I even experience eating dinner.
14:11Wait, say more on that. What do you mean most of our food? So at lunchtime and at dinnertime and at breakfast, the oats in your oatmeal, that's a form of grass. The bagels are made from wheat, which is another kind of grass. Rice is a grass. Corn, maize, those are grasses. So one food after another, and if you add it all up, a very large portion of calories that humans consume around the world come directly from grasses. In fact, wheat, corn, and rice together comprise about 60 % of all the calories that humans eat on this planet. Wait, are they grasses like the grass in my backyard grass, or are they like a different type of grass?
14:51They're a different species, but it's basically the same body plan. And if you were to not mow your lawn, it would grow up. It would produce little flower stalks. And those flower stalks would mature and have lots of tiny little seeds attached to this stalk sticking up above the leaf blades. That is essentially corn, wheat, and rice. They're just a little bit. Just a mini? Yeah, it's a bigger version of that that has, you know, over the last 10 ,000 years at least, humans have been working with these plants to get fatter kernels and kernels that stay on the stem rather than falling off when they're mature, all sorts of things that benefit us.
15:29Wait, so do the list again. What are food items that are grasses? Corn, wheat, and rice. And oats and millet and barley and sorghum and sugarcane. So like the sugar I eat comes from a grass. Yes. If you're eating high fructose corn syrup, which is probably not a great idea, that came from corn. But sugar cane, just imagine your lawn, but then it gets about a thousand times bigger and stockier. And then cow, you know, beef and lamb and even chicken. These are animals that even though we might be eating meat, they either ate grass out in a pasture or were fed corn or oats or other kinds of plant-derived food.
16:13Yeah, mostly grass-based, but with soybeans and other things. But almost everything on our plate are founded on grasses. The idea of eating grass makes me think about, like, when you go over to your friend's house and, like, their parents feed you. And you're like, ooh, I'm, like, it's like the grass mothers are feeding the grasses, but I get to go over and be the friend that comes over after school and, like, benefits from, like, that mother's cooking. And, you know, the grasses are doing that for all of us. I mean, so they are mothering their own offspring, their own seeds, but they're also mothering us when we eat pasta or tamales or a nice rice dish.
16:58We are being nurtured by grass motherhood. so grasses took over the planet and they became the foundation of our diet and in a very real sense we are actually made of grasses we are grass-fed just as much as a grass-fed cow but grasses also shaped us in a deeper way one that may have helped us to become well us
17:32That part of the story is after our break.
17:44WNYC Studios is supported by WISE. WISE, the smart way to manage the currencies you need around the world. With a WISE account, you can send, spend, and receive in up to 40 currencies with only a few simple taps. Be smart. Get WISE. Download the WISE app today. Terms and conditions apply. This week on the New Yorker Radio Hour, Malcolm Gladwell on where the gun control movement gets it wrong. The most lethal weapon in mass shootings is a handgun. Why we have this kind of notion that just because a weapon is large and scary looking, it is more dangerous to us than one that's small and concealable is crazy.
18:19Malcolm Gladwell on his new book, The American Way of Killing. That's the New Yorker Radio Hour from WNYC. Listen wherever you get your podcasts.
18:33I'm Molly. This is Radiolab. And we are back with David George Haskell and our ancestors who are spending more and more of their time out in the grasslands. If you're in a grassland, there's no more branches to cling on to. So your forelimbs are freed up to do clever things with your hands. And so in a way, being bipedal probably evolved to walk around in the grassland. Really? Yep. Okay, so obviously there are many, many different things that led us to being bipedal. In regards to grass, you know, there's this idea that maybe grasses were tall, and so we wanted to see above them, and so we got up on our hind legs to do that.
19:14But more so, if you're out in an open field, it is much more energy efficient to move through space on two legs instead of four. In fact, our bodies have become so good at walking on two legs. I recently learned that our feet have tons and tons of receptors in them that are sensitive to the topography of grass down to being able to feel a single blade. And that sort of foot sensitivity is still true today. like physical therapists for certain mobility issues will actually prescribe barefoot walking in grass. I mean, the times that I've walked on grass, it's extraordinary the amount of information that we're getting from our feet.
20:04And of course, the bottoms of my feet are quite soft because I wear shoes a lot. So I realized, wow, I really need to do some work here to reclaim my grass ape ancestry. I love thinking of us as grass apes, not jungle apes, Because I think I think about apes as living in mostly forests or just at the edge of grasslands. Yeah. And it's just this fun idea. Absolutely. If we were named for our primary food source and for the habitat in which we evolved, we would be the grass apes. Best softball team in the county, yeah. Yeah. Homo poaceae. Poaceae is the family of grasses, which distinguishes us from the bonobos and chimpanzees.
20:45Homo poaceae. I'm trying to get that into the... Into the common language. Yeah. So Gen Z is winning with their, like, touch grass campaign is what I'm hearing. Yep.
21:00We have spent so much time in grasslands that grasses are sort of squeezed inside of us into our furthest corners. So much so that if you're playing in your backyard or lying in a field somewhere, your body is connecting to grass in a deep, timeless way on many different levels. For example, listen to the soundscape in the pod. I'm imagining Prospect Park here with the planes flying over to LaGuardia every two minutes. you got people honking at Grand Army Plaza but then you put your head down close to the grass and the grass absorbs high frequency sounds and it dampens and softens all the other sounds around us if you think about the texture on the surface of the grass each grass blade is pointing in a somewhat different angle and so the sound waves bounce off in all kinds of different directions and we experience that as a softening of the sound and you lose some frequencies, especially the higher pitched frequencies get absorbed by the grass.
22:20So if I go and lay in some grass, it's not just calming because I'm not doing anything and I'm away from buildings. It's calming because it's literally dampening and quieting the sounds. The sound is different, a lot less harsh. You're also inhaling the aromas of the grass itself, especially if you rub the grass. A lot of those aromas bind to our nerve cells. Some of them might even get into our bloodstream. And those calm us down. And you've got soil aromas, particularly if it rained a couple of days ago, the soil is activated. So the microbes and the fungi in the soil that are working with the grass roots, that's all part of one big community, we're smelling those as well.
23:07And that's our original human habitat, right? Grasslands that are healthy and growing really well. So we're immersing ourselves in the aroma that was the sign of good life for our ancestors for literally hundreds of thousands of years, if not millions of years.
23:40It is the last day of summer. The sun still feels hot on my skin. My shoes are off. I'm in shorts and a tank top. And I'm sitting in some grass. I'm going to try the credits out here. This episode was produced by Sarah Kari with reporting and production help from Joe Strogatz, Anissa Vitsa, and me, Molly Webster, Vocals by Joe Strogatz, editing by Pat Walters, and fact-checking by Nora Belbledia. You can find David George Haskell down at Emory University in Atlanta. I bet you there's a lot of grass down there. Or in a bookstore. His latest book is How Flowers Made Our World, the Story of Nature's Revolutionaries.
24:23This episode is based on a live show we did all about grass. It was at Little Island in New York City. It featured David, Foley artist Stephen Wendt, and dance company Palabolos. Special thanks to Sarah Sandback and Natalia Ramirez. And, of course, Grass. Another plane is going by, but I'm going to keep going. Our newsletter this week has absolutely nothing to do with Grass, but I still think you should sign up. Radiolab.org slash newsletter. There's ants all over my bag, and I'm going to go. See you next time. This is Radiolab. I'm Molly Webster. Goodbye.
25:02Hi, I'm Josh, and I'm from Plainfield, New Jersey, and here are the staff credits. Radiolab is hosted by Lulu Miller and Latif Nasser. Soren Wheeler is our executive editor. Sarah Sandback is our executive director. Our managing editor is Pat Walters. Dylan Keefe is our director of sound design. Our staff includes Jeremy Bloom, W. Harry Fortuna, David Gable, Maria Paz Gutierrez, Sindh Yannan Sambandam, Matt Keelty, Mona McGaucher, Annie McEwen, Alex Neeson, Sarah Kari, Natalia Ramirez, Joanna Strogatz, Anissa Vitsa, Ariane Wack, Molly Webster, and Jessica Young, with help from Aya Appleby Malamed.
25:51Our fact checkers are Nora Belblidia, Hillary Elkins, Rachel Gross, Diane Kelly, Emily Krieger, Natalie Middleton, and Sophie Samai.
26:07Hi, I'm Aubrey calling from Salt Lake City, Utah. Leadership support for Radiolab's science programming is provided by the Simon Foundation and the John Templeton Foundation. Foundational support for Radiolab was provided by the Alfred P. Sloan Foundation.
From the publisher
When you think about grass, what do you think of? Pool parties? Suburbs? Allergies? What about: human history? It turns out, unassuming grass, which exists on every continent, has an epic story to tell. One of transforming the planet, and … us. From what we eat, to how our body might be shaped and the ways we perceive the world. Senior Correspondent Molly Webster speaks to biologist and writer David George Haskell in this tiny ode to Grass.
This episode was inspired by “Grass Fed”, a Radiolab outdoor theatre performance at Little Island in New York City. “Grass Fed” featured biologist and writer David George Haskell; Foley artist Steven Wendt; and dance company, Pilobolus. Special thanks to all the artists, and to Little Island, Sarah Sandbach, Natalia Ramirez, and Soren Wheeler.
EPISODE CREDITS:
Hosted by - Molly Webster
Reported by - Molly Webster
with help from - Jo Strogatz and Anisa Vietze
Produced by - Sarah Qari
with help from - Jo Strogatz, Molly Webster
Original vocals from - Jo Strogatz
with mixing from - Jeremy S. Bloom
Fact-checking by - Nora Belblidia
and Edited by - Pat Walters
EPISODE CITATIONS:
Articles -
- The Other Almanac 2026 (https://www.otheralmanac.com/), by David George Haskell a print-only magazine contains an essay All Hail Grass, Maker of Humans! by David George Haskell all about grass’s role in human history.
Books -
- How Flowers Made Our World” (https://zpr.io/r4ybZJea8WV9) by David George Haskell which has a chapter all about grass in it (it’s a flowering plant, if you didn’t know!)
Sign up for our newsletter!! It includes short essays, recommendations, and details about other ways to interact with the show. Signup (https://radiolab.org/newsletter)!
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Leadership support for Radiolab’s science programming is provided by the Simons Foundation and the John Templeton Foundation. Foundational support for Radiolab was provided by the Alfred P. Sloan Foundation.
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