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Radiolab

Grass Apes

September 25, 2026

AI Summary

5 min read

Grass Apes

Molly Webster from Radiolab was standing in a shady New York City park, tasked with creating a story about the space itself. She considered mushrooms, squirrels, anything. Then a horticulturist said: "Grass." Molly ignored her. Grass was the green screen of the natural world—the background that gets erased so the important stuff can stand out. But the horticulturist kept talking, and Molly started to wonder whether she was missing something. So she went out into parks and asked strangers what they thought about grass. They talked about rolling around, chewing it, the smell. But nobody talked about grass itself. It was everywhere and invisible.

Then she met David George Haskell, a biologist and writer who is grass's number one fan. And he told her a story that transformed how she sees every lawn, every park, every dinner plate.

The Grass Takeover

Thirty million years ago, our ancestors were forest-dwelling apes eating insects and fruit. Grasslands barely existed. But the planet began cooling, the polar ice caps expanded, and the climate got drier. Little patches of grass appeared in the forests. Then, over millions of years, those patches expanded into vast grasslands.

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What you'll learn

  • 1 (00:00) **Show Intro and Host Banter** - Molly Webster and producer Anisa Vizza discuss a new Radiolab fanny pack/crossbody bag featuring art from recent episodes, including the "Grass" episode.
  • 2 (04:04) **The Invitation That Sparked the Episode** - Molly explains how a request to tell a story for a park led her to dismiss grass as boring, until a horticulturist planted the idea that grass is like an instrument.
  • 3 (06:42) **Grass as the "Green Screen"** - Molly introduces biologist David George Haskell, who argues that grass is not a backdrop but a co-creator of human history.
  • 4 (08:03) **The Ancient Rise of Grasslands** - Haskell describes how 30 million years ago, our forest-dwelling ancestors encountered small patches of grass that eventually expanded into vast grasslands.
  • 5 (10:31) **The Challenge of Eating Grass** - As mammals moved onto grasslands, they faced the problem of grass's toughness, including tiny silicate "glass" particles in the blades.
  • 6 (12:35) **The Grass Seed "Lunch Box"** - Haskell explains that grass seeds are a concentrated food source, containing a massive "lunch box" of starch and protein for the embryo, which our ancestors learned to exploit.
  • 7 (14:27) **We Are Made of Grasses** - Haskell reveals that wheat, corn, and rice—all grasses—make up about 60% of all human calories, and that almost everything on our plate is ultimately grass-based.

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Show Notes

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 - 

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!)
     

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