The Builders

Summary

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Radiolab: "The Builders" (April 10, 2026)

Host: Lulu Miller, Latif Nasser
Key Guests: Ana Gonzalez (producer), Ben Goldfarb (beaver expert), Dr. Emily Fairfax (fire ecologist/beaver researcher)
Theme: How beavers, through their unique behaviors, become nature’s master builders—reshaping entire ecosystems, sparking revival in damaged landscapes, and even helping to mitigate wildfire and pollution.

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Episode Overview

In celebration of Earth Day, Radiolab re-airs a special story from their kids' spinoff, Terrestrials. The episode is a joyous, deeply informative look at the overlooked but extraordinary ecological role of beavers. Through storytelling, interviews, and investigative journalism—sprinkled with humor and musical interludes—Lulu, Latif, and their guests trace how beavers transform environments, heal damaged rivers, and even protect landscapes from wildfire, culminating in an inspiring message of ecological hope and the ripple effects of small acts.

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Key Discussion Points & Insights

1. A Beaver's Perspective (01:42–02:44)

• Lulu and Ana set the stage by urging listeners to imagine "waking up as a beaver," leading into a playful theme song.
• Quote:
  Lulu Miller: “As you kick and glide, you grow fur, really thick fur, and an extra set of eyelids that act like goggles underwater.” [02:03]

2. Why Do Beavers Build Dams? (04:06–06:35)

• Ben Goldfarb (beaver expert) explains beavers’ dam obsession: awkward on land, they build dams to create safe aquatic refuges where predators can’t reach them.
• The damming instinct is both a survival mechanism and a transformative force for the landscape.
• Quote:
  Ben Goldfarb: “The classic beaver behavior... is they build dams.” [04:43]

3. The Historical Beaver Boom & Bust (06:35–08:22)

• Centuries ago, North America was teeming with hundreds of millions of beavers.
• Beaver populations (even in places like Manhattan) collapsed over 400 years due to the fur trade, dramatically altering local ecologies.

4. The Bronx River Resurrection (08:22–10:56)

• The Bronx River suffered massive pollution, becoming an “open sewer.”
• In the 1970s, local residents—later joined by Congressman Jose Serrano—started a cleanup that restored the river’s vitality.
• Beavers returned after 200 years, a sign of the river’s rebirth.
• Quote:
  Christian Murphy: "This river could be beautiful. This river could be full of life." [09:00]

5. What Beavers Do for Ecosystems (10:56–14:11)

• Key ecosystem impacts of damming:
  • Dams filter pollution and cool surrounding air
  • Richer, more fertile soils
  • Ponds, marshes, and increased biodiversity (insects, amphibians, birds, predatory mammals—all supported by beaver activity)
• The ripple effects are fast: “Within a couple of months, there’ll be cattails and lily pads and swamp roses blooming.” [14:02]

6. Fire-Fighting Beavers: The Little Last Chance Creek (16:47–24:47)

• Dr. Emily Fairfax recounts researching beavers in Northern California.
  • Wild government attempts: Beavers parachuted from planes in the 1940s/50s to repopulate wildlands.
  • Beavers' engineering creates fire refugia—patches of green wetlands that resist wildfires.
  • When a major wildfire hit Little Last Chance Creek (2021), satellite images confirmed: the land with beaver dams survived, forming an “island” of unburned habitat that sheltered wildlife.
• Quote:
  Dr. Emily Fairfax: “Sometimes it feels like we’re all out of ideas and it’s not working. But then right in front of me, something is clearly working.” [22:01]
  • “I have come to see beavers as firefighters. … They are really good at making fireproof patches pretty much everywhere.” [24:35/24:47]

7. Beavers as Environmental Engineers—"Let the Rodent Do the Work" (25:01–25:40)

• Ben Goldfarb: “Let the rodent do the work. They’ll store water for us. They’ll capture pollution. They’ll help us fight wildfires. … They do all of this stuff for us if we let them.” [25:20]

8. The Ripple Effect & Human Agency (24:07–26:21)

• The story circles back to the Bronx: If small clean-up efforts can bring a beaver back (and even dolphins!), humans too can engineer positive change.
• Quote:
  Lulu Miller: “How might we all create a little refuge around us for the other beings of this world, even if we are clumsy and awkward and waddling and tired?” [23:40]

9. Musical Send-Off: "Beaver Believer" Song (26:21–27:45)

• Upbeat tune celebrating beavers as overachievers and “awkward engineers.” (Theme: Just a few critters can change the world.)

10. "Badgers" Q&A Segment (28:07–30:06)

• Kids (and adults) ask quirky beaver questions, with Dr. Fairfax answering:
  • Baby beaver teeth? (“Yep. … Cheek teeth.”)
  • What’s beaver poop like? (“Double poop” process—results in “a sawdust marshmallow,” actually a great firestarter!) [28:36]
  • How do beavers know how to build dams? Instinct and local learning.
  • Regional dam "architecture"? (“Yeah… some built really weird dams,” even with cow bones at Halloween! [29:48])

11. The Unexpected Beaver Fact (30:11–end)

• Early vanilla ice cream and perfume once used beaver gland oil (“castoreum”) for flavoring. [30:11]

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Memorable Quotes & Moments

• Lulu Miller (on beaver transformation):
  “Imagine if everywhere you walked you just sprouted flowers and life followed you.” [13:43]
• Dr. Emily Fairfax:
  “It was completely green, completely unburnt. Not even just like a little burnt, like they were unburnt. … Honestly, it was like tears in my eyes.” [21:41]
• Ben Goldfarb:
  “Let the rodent do the work.” [25:20]
• Lulu Miller:
  “Be more beaver.” [25:40]

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Notable Timestamps

• 01:42–02:44: Opening “imagine you’re a beaver” scene and playful theme song
• 04:06–06:35: Introduction of beaver behavior and Ben Goldfarb's insights
• 08:22–10:56: History and cleanup of the Bronx River, birth of "Jose" the beaver
• 11:07–12:13: How dams filter pollution, cool the air, enrich soil, increase biodiversity
• 16:47–18:15: Beaver parachuting and fire-fighting beavers introduced, Dr. Emily Fairfax segment begins
• 21:03–22:43: Post-fire beaver oasis discovered; “Refugia” defined
• 25:01–25:40: Core beaver believer mantra: “Let the rodent do the work”
• 26:21–27:45: “Beaver Believer” original musical number
• 28:07–30:06: Badgers Q&A (beaver biology, behavior, poop, etc.)
• 30:11–31:32: Skeleton dam anecdote and the castoreum ice cream fact

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Tone and Style Notes

• Playful, musical, and hopeful: Humor, whimsy, and musical storytelling are melded with serious ecological insight.
• Optimism through specificity: Repeated focus on ripple effects—how small acts (both human and beaver) yield visible, meaningful change.
• Educational but accessible: The science is clear yet approachable, aimed at all ages.

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Takeaways

• Beavers' dam-building is not just personal survival—it repairs and revitalizes entire ecosystems, with ripples that benefit countless other species.
• Human efforts, even if awkward and small, can likewise accumulate, creating powerful change.
• Beavers don’t just fix rivers; they may help “fireproof” landscapes in the midst of climate change.
• Sometimes, letting nature do the work is the wisest (and most hopeful) move.
• “Be more beaver”—an invitation for humans to contribute positively, collaboratively, and sometimes unexpectedly, to the healing of the world.

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For more, subscribe to the Radiolab or Terrestrials feeds, and check out Ben Goldfarb’s book: Eager: The Surprising, Secret Life of Beavers and Why They Matter.

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Transcript

[A]

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[B]

Yes to adventure. Yes to escape.

[A]

Yes to right now the all new Audi Q3.

[B]

Made for the.

[A]

Yes Life.

[C]

Hey, it's Latif.

[A]

Earth Day is coming up on April 22nd. So this week I wanted to bring you a story that is just a wholehearted celebration of nature from from Radiolab spinoff Terrestrials. We released it last fall in the Radiolab for Kids feed. But look, I am a card carrying grownup and I really enjoyed this one and I think you will too, no matter how young or old you are. Lulu will tell you more in a second, so without further ado.

[B]

Wait, you're listening. Okay.

[C]

All right.

[D]

Okay.

[C]

All right.

[B]

You're listening to Radiolab Flick in from wny. 3, 2, 1.

[E]

Imagine you wake up in the dark.

[B]

Your eyes dart around to see a

[E]

little circle of blue shimmering light.

[B]

You waddle over on your webbed feet and realize it's water.

[E]

So you dive in head first.

[B]

As you kick and glide, you grow fur, really thick fur, and an extra

[E]

set of eyelids that act like goggles underwater.

[B]

And then you look behind you to

[E]

find a big black scaly paddle.

[B]

It's your tail, which you can slap on the water with a nice loud. You have become a beaver. Okay, now is the part where I make you sing the theme song with me.

[E]

Okay, I'm ready.

[F]

Terrestrials.

[C]

Terrestrials.

[B]

We are not the worst. We are the first. Try again. Opposite of worst is the best. Bestreal. Yeah, you got it.

[E]

Okay, I like it.

[B]

Terrestrials is a show where we uncover the strangeness waiting right here on Earth. I am your host, Lulu Miller, joined as always by my songbud, Take me

[C]

to the River Alan Swimming with the beaver.

[B]

So here we are, kicking off this brand new season of terrestrials. While all around us, really hard things are going on. Wildfires, wars, climate change. And so we wanted in this moment to look to creatures that might give us hope. Creatures that actually mend the world around them. And there is maybe no mammal that has such an outsized positive effect on the planet than beavers. Yep, those buck toothed, waddling, funny looking rodents. By the end of the episode you will see how a single family of beavers can have such a positive impact on the world around them. You can literally see it from space. So our story today is going to center around one little beaver named Jose. He will rise out of murky waters in a place where no one expected he could survive. And to tell us his tale is producer bud Ana.

[D]

Yup, that's me.

[E]

Yeah, you know, Jose is this incredible

[D]

symbol and here to help me is

[E]

Ben Goldfarb, who's a writer and beaver believer.

[D]

Don't stop bee flavin. So Jose, he waddles out into the world with little webbed feet and whiskers and very large buck teeth are bright

[E]

orange because apparently beavers teeth actually contain iron.

[D]

Whoa, metal teeth.

[E]

Yeah, like a chisel chop.

[D]

The iron makes their teeth excellent for chopping down trees. Because beavers have one single obsessive hobby. It's not drawing or knitting or doing puzzles.

[E]

The classic beaver behavior that most people know about is they build dams.

[D]

A dam is basically a wall in the water that beavers build by dragging the trees that they chomp a flowing stream blocking the water and sometimes adding mud or other stuff to keep that wall sealed up tight.

[E]

And you see them sometimes carrying rocks around and their little front paws waddling on their hind legs. It's like the cutest thing ever.

[D]

A beaver dam makes water accumulate behind the barricade, turning a trickling stream into a new pond in the middle of the forest.

[B]

Ah, time for a swim. Anna, can I just interrupt to ask why? Why like I've always wondered this about beavers. Like a beaver like Jose, Why is it driven to go through all this work to chop down trees and make a wall that creates pools? It just feels so random.

[E]

That's a great question. I mean, a beaver out on land is basically a fat, slow package of meat. Think about wolves and mountain lions and bears and coyotes. All of those big animals are gonna want to eat a beaver.

[D]

According to Ben, it all stems from the fact that beavers are super awkward on land. With their webbed feet and huge tail that drags on the ground. Beavers are not good at running, making them easy pickins for land predators.

[E]

So if you're a beaver, you want to spend as little time on land as possible.

[D]

So

[C]

camper.

[D]

By making dams, they create deep pools of water which allows them to transform form from wobbly wolfsnax into elegant professional Swimmers who can spin and twirl and

[E]

can hold their breath for up to 15 minutes.

[D]

15 minutes.

[E]

Yeah. They're like a magical animal. Yeah, they're just incredible.

[D]

Pretty epic hiding place. Now, hundreds of years ago, in the time of Jose's great great great great great great great great great great grandparents, the woods of North America was full of beavers.

[E]

There were probably several hundred million beavers

[D]

making dams and ponds everywhere. Even in New York City, there would

[E]

have been beavers all over New York City.

[D]

That's right. The Big Apple was once the beaver city. And the beavers of Beaver city would wake up every evening. That's right. Beavers are mostly nocturnal in their beaver homes. And hit the road or the stream, I guess, and get to work.

[B]

Hey, I'm waddling here, Hauling stones and

[D]

sticks and redirecting water and finishing off each day with a nightcap of sweet wood juice.

[E]

Manhattan island was one of the most lush, incredible ecosystems on the eastern seaboard, and beavers were part of what made it that way.

[D]

But about 400 years ago, all of that would change because of the arrival of Europeans and their insatiable desire for

[C]

hats, hats, top hats and cocked hats. Trapper hats with ear flaps, Wellingtons and sugarloafs.

[D]

That's another name for witch hats made of beaver fur. Sorry, guys. They killed them off by the millions for the fur trade. And as the beavers began to be killed off, the land and waterways began to change pretty dramatically. Like take the river that slides through the northern part of New York City, winding beside train tracks and beneath highways. Today, it's called the Bronx River.

[G]

It was described as an open sewer.

[D]

That's Christian Murphy. He works on the Bronx river today.

[G]

It was really just an elongated landfill.

[D]

And over the centuries, more and more animals disappeared from the river, including the few remaining beavers. And by the 1970s, parents told their

[G]

kids, don't go down there. It's not safe.

[D]

Because for decades, companies all along the river used it as a convenient dump for their waste. And people had just given up on the Bronx River. They thought it was just too polluted to care about.

[G]

In many places, you couldn't see the water because of how thick the trash was.

[D]

Until one day someone said, you know what?

[G]

This river does not need to look like this. This river could be beautiful. This river could be full of life.

[D]

Inspired in part by the first earth day in 1970, a couple of folks from the neighborhood, like a lady named Ruth and a guy named Fred, they put on gloves and boots and began picking up the bag by bag, day by day. And at first, people kind of laughed. They thought, what good is a couple of bags of trash gonna do this whole river's polluted. But then some kids joined in. Let's do this.

[F]

High five.

[D]

Scooping out trash by the huge garbage bag full. And eventually, someone very powerful joined in, too.

[B]

Hello.

[D]

Hello, Congressman. His name was Jose Serrano, with a big, friendly smile and a bigger, bushy mustache.

[C]

Roll up our sleeves and start to clean.

[D]

Who directed millions of dollars to the cleanup project, ordering in trucks with big cranes to fish out refrigerators and cars, and helping to change the rules over where factories could dump their toxic waste.

[G]

And soon, the river began to respond.

[D]

The water got cleaner, and the forest began to regrow around it, bringing in more bugs and birds, until

[B]

a little

[D]

creature popped its whiskered head out of

[G]

the water, and it was a beaver.

[D]

Jose.

[E]

After an absence of more than 200 years, the Beaver has come back to New York City.

[D]

And so they named him Jose in honor of that congressman who'd been an early bee lever that a little awkward human effort could make a big difference.

[C]

What an honor.

[D]

And the fact that Jose the beaver showed up in the Bronx river wasn't just a sign that the water was getting cleaner, because beavers clean the river, too, just by being there and being beavers. See, there's a hidden power to beaver dams. They actually make everything around them healthier.

[E]

And that happens in a few different ways.

[D]

So, first, there's the water. The dams act like purifiers that filter out pollution, like trash and even chemicals

[E]

from agriculture, which get trapped in the

[D]

dam and drop down into the soil instead of getting carried out to sea. Second, dams cool the air because the pools that dams create mean more water is being evaporated into the air. And so when it's hot, damn, it's kind of like a mini air conditioning unit, making it more hospitable to all kinds of creatures. Third, dams enrich the soil. Nutrients in the water get stuck and drop down into the earth, which creates more fertile ground. And fourth, the real biggie. All of this combined allows new life to sprout algae, grasses, cattails, and flowers,

[E]

which attract baby trout and salmon and

[D]

dragonflies and butterflies and frogs and salamanders.

[E]

And then birds come, woodpeckers and herons

[D]

and pretty soon, coyotes and foxes and

[E]

in some regions, moose will come down there to eat all of the aquatic vegetation growing in the ponds.

[C]

Thank you, Beeves.

[D]

And in Jose's case, after just a few years of him hanging out in the Bronx River.

[G]

Somebody looked and squinted their eyes and said, wait a minute, there's a second beaver there. There are two beavers.

[D]

Sacre beeves. Another beaver.

[G]

And so Jose and the second beaver, they were roommates.

[D]

Classic New Yorkers.

[G]

Sharing rent on the river, sharing groceries, you know, cutting down the same trees together. And it gets better.

[B]

I can't imagine it getting any better.

[D]

But it does, because you've maybe heard of a little known popsicle star named Justin Bieber. Well, they held a naming contest and.

[G]

And the second beaver was named Justin.

[B]

Beaver.

[C]

Beaver. Beaver. Beaver.

[D]

Thank you, Alan. Jose and Justin lived together for years, munching on wood, swimming with their eyes peeking out of the water, and slowly but surely increasing the biodiversity of the river and the forest around it. And as time has ticked on, the river has only grown healthier, welcoming back snapping turtles and sunfish. And even, as was spotted in 2023,

[G]

two dolphins swimming around in the Bronx River.

[B]

No.

[D]

Yes, dolphins. Uh huh. Yep.

[B]

Okay, go beavers. I can, I mean, imagine if like everywhere you walked you just sprouted flowers and life followed you.

[D]

That would be nuts.

[B]

I mean, how long does it actually take? Like once a dam goes in, is it years before you start seeing this greening effect?

[D]

No, that's the thing. It's super fast. Like within a couple of months, there'll be cattails and lily pads and swamp roses blooming.

[C]

Wow.

[B]

Okay, so just to recap everything these funky little guys are doing to the world around them, their dams are cleaning the water, cooling the air, making the soil richer and increasing biodiversity in these pretty dramatic ways. Yep, but that's it, right? Like there's no, there can't be anything else.

[F]

There's so much more.

[B]

Our next storyteller thinks beavers can even fight fire. Find out how after this break.

[H]

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[A]

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[B]

You know Every day on Up First, NPR's Golden Globe nominated morning news podcast. We bring you three essential stories at the heart of each story our what really happened?

[G]

What really mattered, what happens next.

[B]

At NPR we stand for your right to be curious and to follow the facts. Follow up first wherever you get your podcasts and start your day knowing what matters and why.

[C]

Look up in the sky.

[B]

It's a bird.

[D]

It's a plane.

[B]

No, it's beavers. Parachutes shooting down from the clouds. Crates full of beavers part of a

[C]

shipment to be dropped from an airplane.

[B]

No, this is not an old fashioned cartoon. It's something that our governments actually did in the 1940s and 50s.

[F]

Some folks in a couple of different states put them in boxes and then drop those boxes out of airplanes with parachutes on them and let them land in the mountains to do good for us. Like move them from the cities to the mountains.

[B]

You're kidding right now, right?

[F]

They literally pushed them out of planes. Idaho did this. California did this.

[B]

This is Dr. Emily Fairfax and she explains that this was the government's weird idea for pest control. They took beavers that were being nuisances, turning people's yards and farmlands to swamps and then just dropped them off in the mountains.

[C]

They are live, trapped and moved to distant mountain lakes and streams where their efforts will aid to conserve water, provide fishing pools.

[F]

Instead of like taking them out on a horseback or car, they dropped them out of planes. But you know, I give him credit

[C]

for trying now into the air and down they swing down to the ground near a stream or a lake.

[B]

Emily gives them credit because she too is trying to bring more beavers out into the wild where they might be able to do some good for the Planet. Although that did not used to be her job, far from it. She used to be an engineer who worked on weapons. Weapons.

[F]

Nuclear weapons.

[C]

Whoa.

[F]

Very different group, Beth.

[B]

But she happened to turn on the TV one night and catch a nature documentary.

[F]

And they were showing all these aerial shots of beaver dams and wetlands in the desert. And they were bright green. And I was like, what? Beavers live in the desert. How can they keep it green when everything's so dry?

[B]

And she realized that just like her,

[F]

beavers were engineers, using all of their engineering to live a good life and

[B]

mend the world around them.

[F]

And I wanted that for myself. So I started studying beavers. And I haven't looked back since.

[B]

Emily hung up her nuclear weapons coat and put on some rubber overalls for a new job, following beavers through wetlands to try to learn how they do what they do. And eventually she came to focus on this one little family of beavers that lived up high in a mountain in Northern California in a creek.

[F]

It's called Little Last Chance Creek.

[B]

So she called the family the Little Last Chance Beavers. There was a mom, a dad, and

[F]

there were definitely three to four babies there.

[B]

Aww. And she started watching them, literally taking notes as they timber constructed their intricate dams and lodges.

[C]

We're logging a busy day at work.

[B]

And she discovered that on really hot, sweaty days inside a beaver's house.

[F]

It's cold in there.

[B]

You've been in a beaver lodge?

[F]

I have.

[B]

And on super cold days outside, it's super toasty.

[F]

So the beavers sleep in a big snuggle pile in, like, one room. It's very sweet. That's really cute. They kind of snore sometimes. It's extremely cute.

[B]

And Emily learned that their family members weren't the only ones staying warm in there.

[F]

They might have mice that want to come live inside the lodge with them. They might have muskrats that want to live inside the lodge with them. They might have little snakes that want to live inside the lodge with them.

[B]

They allow this? They allow these trespassers?

[F]

Oh, absolutely. It's kind of like they're running a little bed and breakfast, which I call a bee and beef my horrible jokes.

[B]

Winter turned to spring, spring to summer. And then one day, there was a spark. And the dry grasslands and forests around the Little Last Chance beaver family caught fire and began burning and burning.

[F]

It was a really devastating fire. It burned a lot of forests.

[B]

This was back in the summer of 2021, and it became one of those mega fires we're seeing more and more of because of climate change, thousands of people had to be evacuated. Hundreds of houses burnt down. And as for the plants and critters

[F]

of the mountains, it seems like absolutely everything has burned.

[B]

By October, humans were finally able to extinguish the fire. But Emily had no idea what happened to those beavers.

[F]

Could they have survived the fire?

[B]

So one day, she began the long drive up the mountain.

[F]

And the drive up is very disheartening because everything is just blackened and it's silent, which was the creepiest and strangest part to me. So I'm not feeling, like, super confident. But she keeps driving and we find a route in.

[B]

They get out of the car and begin walking.

[F]

And suddenly it is loud, it is splashing water. There's all sorts of birds, There's. There's lots of bugs. There's a lot of wind in the trees and the grasses and the rustling. You expect, oh, wait.

[B]

And even there being wind in the trees means there's still trees standing.

[F]

There's still trees. The pine trees that were near it are fine. The trees that are in the wetland are fine. It was completely green, completely unburnt. Not even just like a little burnt, like they were unburnt. And when I got there, like, honestly, it was like tears in my eyes.

[B]

Why tears?

[F]

Because I drove past the burned houses coming up and the burned roads and all the things that we wanted to protect and couldn't, and thinking about the future of climate change and knowing that this is the future that's coming, that's a really difficult reality to wrap your head around. I was living in California at the time. Like, I was seeing my future there. And then getting up to the beaver wetland, it was a very hopeful moment because sometimes it feels like we're all out of ideas and it's not working. But then right in front of me, something is clearly working. And even if we don't know exactly why or how yet, we can learn from it.

[B]

And as for the little last chance

[F]

beavers, I did stay out in the evening and saw both mom and dad swimming. And when they were out swimming, I could hear three, maybe four different young beaver wines coming from where the lodge was.

[B]

They made it.

[F]

Yeah.

[B]

And it wasn't just them. When Emily looked at the area from way high up in space, from a satellite, she saw something incredible. This halo of green around the beaver's dams. She guessed that this one little family, these five or six awkward beings, had saved about seven and a half acres of land from burning.

[F]

Yeah. That effect is called making fire refugia. It's a patch that doesn't burn that other things can use.

[B]

Refugia is a fancy word, sort of like for refuge. It's just like place that is safe. Okay.

[F]

Exactly.

[B]

Refugia. I love this word. I have not stopped thinking about it since Emily taught it to me. How might we all create a little refuge around us for the other beings of this world, even if we are clumsy and awkward and waddling and tired. I think about the people in the Bronx, those first two or three people who started picking up trash.

[F]

We got this.

[B]

And eventually created a ripple effect that cleaned up the river. These things can happen. They do happen in the human world and in the animal world. That day at the beaver dam, Emily saw frogs and birds and even a bear, creatures she suspects might not have survived the fire without that beaver family. And that's why she has come to see beavers as firefighters.

[F]

Yeah, they're spreading water out across the whole landscape. That's keeping everything nice and green and healthy and stopping it from being easy to burn.

[B]

Emily has tested this effect in mountains and forests and deserts.

[F]

And so far, what we've seen is that they are really good at making fireproof patches pretty much everywhere.

[B]

Little rings of green that you can literally see from space.

[E]

You know, when we talk about restoring nature, we don't always know how to do that. But guess what? Beavers instinctively know what it's supposed to look like.

[B]

That's beaver believer Ben again. He and Emily both work in different ways to inspire and convince people to protect beavers.

[E]

One of the mantras of the beaver believer goes, let the rodent do the work. They'll store water for us. They'll capture pollution. They'll help us fight wildfires. They'll create habitat for all of the fish we like to eat and the birds we like to watch and so on. They do all of this stuff for us if we let them.

[B]

Another mantra. Be more beaver. What if we, too, worked to build structures that actually mended instead of harmed? The land as pie in the sky? Or impossible as that may seem, there are people already out there doing just that, following in the beaver's footsteps, waddling awkwardly toward a better world. One step at a time,

[C]

You little overachiever. I'm a beaver believer. Beaver, beaver. We see the ripple effect. You make a big splash. A believer fever believer. Beavers, Beavers. Oh, oh, oh, oh. You little overachiever. I'm a beaver believer. Beaver, beaver, let's get to work. If you believe, roll up your sleeves and let me see that tail slap we're small and awkward and the challenge is tough if we work together, we can rise above we waddle on into the job is done so don't cry as a river, you know we'll just dam it up I'm a beaver believer Beaver, beaver oh, oh, oh, oh. You little overachiever. I'm a beaver believer Beaver, beaver, let's get to work. If you believe. Roll up your sleeves and let me see that tail slap. Even though they're kind of weird, the beaver's got it going on to those little awkward engineers. Sometimes it only takes just one, maybe two, just a few little critters to chew what needs to be done and change the world for everyone.

[B]

Ellen, Gopher, and See Govinski, everybody. He used real beaver tail slaps as percussion in that. And that's it. There's nothing else cool about to have a. What's that? Excuse me, I have a question.

[C]

Me two, me three, me four.

[B]

The badgers. Listeners with badgering questions for our experts. Are you ready?

[F]

Absolutely. Hi, my name is Felix and I'm 6 years old.

[B]

Do baby beavers have baby teeth?

[F]

Yep.

[B]

Not the big buck teeth, but some of the side teeth, which are called cheek teeth. Cheek teeth. Cheek teeth. Cheek teeth. Say that ten times fast. My name is Remy and I'm six years old.

[D]

Since beavers eat wood, what does their poop look like?

[F]

Well, they do the double poop.

[B]

The double poop? What does that mean? They poop once and then what?

[F]

They eat that again, and then when it comes out, it looks like a sawdust marshmallow. And the little sawdust marshmallow is. If you dry them out, they're actually great fire starters.

[B]

What? Have you ever done that?

[F]

I have burned one to see if it could burn, and it burned just fine.

[B]

Now that's what I call a useful nugget. Hi, my name is Tyler. I'm 39 years old. I am trying to figure out how do beavers raised in captivity know how to build a dam even if they've never seen a river?

[F]

They learn from their instincts and also from following around their parents and brothers and sisters and trying to do what they do.

[B]

Wait, so are there regional differences in architectural style? Like how you get Swedish modernism or Southwestern adobe?

[F]

Anecdotally, yeah, there are. And some of them built some really weird dams.

[B]

Really? Like how so?

[F]

Like, at, like, 90 degree angles from one another, like zigzagging instead of having nice curvy shapes.

[B]

Huh.

[F]

They, like, teach their kids what's available to build with. It could be garbage, mud, I have seen cowbones. I have seen all sorts of interesting things.

[B]

Spooky. A dam made out of bones. Like a skeleton dam.

[F]

No joke. I saw that on a Halloween field tour and I thought someone had like set it up for me.

[B]

Haunted lodge, haunted dam.

[F]

There's like cow knuckle bones and a femur and they're just like integrated into this dam. It was like unreal.

[B]

And that's where we got to leave

[C]

it with the spooky beaver dam.

[B]

And I won't tell you that vanilla ice cream, candy, yogurt and many perfumes used to be made with an oil that came from the beaver's booty. It was called castoreum. And that's true. If you used to eat like vanilla ice cream or certain candies back in the time of like your great great grandparents, you were actually tasting beaver bum. I won't tell you that because I'm nice. But I did learn it in Beaver Believer, Ben Goldfarb's great book called the Surprising Secret Life of Beavers and why they Matter. Highly recommend you check it out and that'll do it for today. Terrestrials was created by me, Lulu Miller with WNYC Studios. Our executive producer is Sarah Sambach. This episode was produced by the naughty gnawing on wood Ana Gonzalez. Tale slappingly good sound design by Mira Burton Tonic. Our team also includes Ellen Gaffinski, Tanya Chawla and Joan Plord. Fact checking by Diane Kelly. She would not let us get anything wrong. Would spelled W o o D. Support for Terrestrials is provided by the Simons foundation, the Arthur Rhyning Davis Foundations and the John Templeton Foundation. Thank you you we have got new episodes turning out every two weeks. We hope you'll listen and subscribe to the Radiolab for Kids feed and tell your friends. It really helps our chances of getting to keep going. We also have social media where Alan drops Frog Fact Friday videos every Friday.

[D]

Frog Fact Friday.

[B]

And we also have animated music videos, contests and just like me saying hello in various natural places, that's Terrestrials podcast. And if you want to submit a badger's question, sign up for our newsletter or check out past episodes. Just head on over to www.terrestrialspodcast.org. okay. Hopefully all those links would work for you. Would work. Would work. Okay, Be very careful out there. Go sink your teeth into some good stuff and see you in a couple of spins of this dirty old planet of ours.

[C]

Bye.

[B]

Hi, I'm Maddie and I'm from Frederick, Maryland. Leadership support for Radiolab science programming is provided by the Simmons foundation and the John Templeton Foundation. Foundational support for Radiolab was provided by the Alfred P. Sloan Found

[C]

Foreign.

[A]

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[E]

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