The Builders: How Beavers Mend Our Planet
LULU: 3, 2, 1. Imagine
Ben: You wake up in the dark.
LULU: Your eyes dart around to see
BEN: a little circle of blue shimmering light,
LULU: You waddle over on your webbed feet and realize: it's water
BEN: So you dive in, head first
LULU: as you kick and glide, you grow fur
BEN: really thick fur
LULU: and an extra set of eyelids
BEN: That act like goggles underwater.
LULU: And then you look behind you to find
Ben: a big black scaly paddle.
LULU: It’s your tail! Which you can slap on the water with a nice loud -
SLAP!
LULU: You have become,
Ben: A beaver!
LULU: OK now is the time I make you sing the theme song with me
BEN: Okay. I'm ready
SONG: Terrestrials Terrestrials. We are not the worst. We are the–
Ben: First!
LULU: Try again. Opposite of worst is -
BEN: the best!
SONG: Bestrials.
LULU: yeah you got it
BEN Okay haha I Iike it.
LULU: 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—
ALAN [sings]: take me to the river
LULU: Alan,
ALAN [sings]: swimming with the beaver
LULU: ha ha. So, here we are kicking off a 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 who has such an outsized positive effect on the planet than beavers.
Yup! Those bucktoothed waddling funny-looking rodents. By the end of this 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.
LULU: So our story centers around one little beaver named José. He will rise out of murky waters where no one expected he could survive. And to tell us his tale is producerbud Ana!
ANA: Yup, that’s me!
BEN: yeah, you know José is this incredible symbol.
ANA: And to help me is Ben Goldfarb, who is a writer
BEN: And beaver believer.
ANA[sings]: DON’T STOP BEAVLEIVIN!
BEN: giggles
ANA: So, Jose, he waddles out into the world with little webbed feet and whiskers and very large buckteeth, that are bright orange because apparently…
BEN: beaver’s teeth actually contain iron
ANA: WHOA. Metal teeth?
BEN: Yeah like a chisel
ALAN: CHOMP
ANA: The iron makes their teeth excellent for choppin’ down trees. Because beavers have one single obsessive hobby. It's not drawing or knitting or doing puzzles.
Ben: The classic beaver behavior that most people know about is they build dams,
ANA: A dam is basically a wall in the water beavers build by dragging the trees they chomp down across a flowing stream, blocking the water. And sometimes adding mud or other stuff to keep that wall sealed up tight.
BEN: And you see them sometimes carrying rocks around in their little front paws, waddling on their hind legs. It's like the cutest thing ever.
ANA: A beaver dam makes water accumulate behind the barricade, turning a trickling stream into a new pond in the middle of the forest.
ALAN [as a BEAVER]: Ahhh, time for a swim.
LULU: Ana, can I just interrupt to ask: why? I’ve always wondered this about beavers, like Why is a beaver like José driven to go through all this work to chop down trees and make a wall that creates pools? It just feels so random?
BEN: That's a, a great question there. 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.
ANA: According to Ben, it all stems from the fact that beavers are super awkward on land.
LULU: giggles
ANA: With their webbed feet and huge tail that drags on the ground, beavers are not good at running making them easy pickings for land predators
BEN: So if you're a beaver. You wanna spend as little time on land as possible,
ANA: So,
ALAN [as BEAVER]: CHEW / TIMBER!!!
ANA: By making dams, they create deep pools of water, which allows them to transform from wobbly wolf snacks into elegant professional swimmers, who can spin and twirl and
BEN: can hold their breath for up to 15 minutes.
ANA: FIFTEEN minutes?
BEN: Yeah. They're like a magical animal. Yeah. They're just incredible.
ANA: Pretty epic hiding place. Now, hundreds of years ago, in the time of José’s great great great great great great great great great great grandparents…the woods of north america was FULL of beavers.
Ben: There were probably several hundred million beavers,
ANA: Making dams and ponds everywhere. Even in New York City!
BEN: There would've been beavers all over New York City,
ANA: That's right, the Big Apple was once
BEN: The beaver city.
FUNKADELIC FUNK MUSIC
ANA: 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
ALAN [as NYC BEAVER]: "Hey! I’m waddlin’ here!"
ANA: Hauling stones and sticks and redirecting water and finishing off each day with a nightcap of sweet wood juice slurp ahh
BEN: Manhattan Island was, one of , the most lush, incredible ecosystems on the eastern seaboard. And beavers were part of what made it that way.
ANA: But about 400 years ago, all that would change, because of the arrival of Europeans and their insatiable desire for…
BEN: Hats.
ANA: Hats?
ALAN [sings]: HATS. Top hats and cocked hats and trapper hats with ear flaps! Wellingtons and sugarloaves! That’s another name for witch hats!
ANA: 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.
Christian: It was described as an open sewer.
ANA: That's Christian Murphy. He works on the Bronx river today.
Christian: It was really just an elongated landfill.
ANA: And over the centuries, more and more animals disappeared from the river, including the few remaining beavers. And by the 1970s…
Christian: Parents told their kids, don't go down there. It's not safe.
ANA: 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.
CHRISTIAN: In many places you couldn't see the water because of how thick the trash was.
ANA: Until one day someone said:
CHRISTIAN: “You know what? This river does not need to look like this. This river could be beautiful, this river could be full of life.”
ANA: 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 trash. Bag by bag, day by day. And at first, people kinda laughed. They thought “What good is a couple of bags of trash gonna do? This whole river is polluted!"
ANA But then kids joined in
ALAN [as kids]: Let’s do this! High five!
ANA: Scooping out trash by the huge garbage-bag full. And eventually someone very powerful joined in too -
ALAN [as congressman]: Hello hello.
ANA: A congressman. His name was José Serrano. With a big friendly smile and a bigger bushy moustache.
ALAN [as congressman]: Let’s roll up our sleeves, and start to clean!
ANA: 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, and soon....
CHRISTIAN: The river began to respond.
ANA: The water got cleaner. And the forest began to regrow around it, bringing in more bugs and birds, until –
BEAVER: bark bark
ANA: a little creature popped its whiskered head out of the water.
CHRISTIAN: And it was a beaver.
ANA: José!
FANFARE MUSIC
TV: After an absence of more than 200 years the beaver has come back to NYC!
FANFARE MUSIC ENDS
ANA: And so they named him Jose in honor of that congressman who had been an early beavliever that a little, awkward, human effort… could make a big difference.
ALAN {as congressman]: Haha! What an honor!
ANA: And the fact that Jose the beaver showed up in the bronx river wasn’t just a sign that the river was getting cleaner. Because beavers clean the river too!. Just by being there. And being beavers. See, there's hidden power to beaver dams. They actually make everything around them healthier.
BEN: And that happens in a few different ways.
ANA: So first, there’s the WATER!. The dams act like purifiers that filter out pollution like trash, and even
BEN: Chemicals from agriculture,
ANA: which get trapped in the dam and drop down to 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, it’s kinda like a mini little 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! First algaes and grasses and cattails and flowers, which attract…
BEN: baby trout and salmon
ANA: And dragonflies and butterflies, and
BEN: Frogs and salamanders
ANA: and then birds come
BEN: Woodpeckers and herrings
ANA: And pretty soon, coyotes and foxes, and in some regions
BEN: Moose will come down there to eat all of the aquatic vegetation growing in the ponds..
ALAN [as moose]: Haha thank ya, Beavs!
ANA: And in José’s case, after just a few years of him hanging out in the Bronx river.
CHRISTIAN: Somebody looked and squinted their eyes and said, wait a minute. There's a second beaver there. There are two beavers.
ANA: SACRE BEAV! Another beaver
CHRISTIAN: And so Jose and the second beaver, they were roommates.
ANA: Classic new yorkers!
Sharing rent on the river, sharing groceries, you know, cutting down the same trees together, and it gets better.
Ana: I can't imagine it getting any better.
ANA: But it does. Because you’ve maybe heard of pop star Justin BIEBER? Well....they held a naming contest and
CHRISTIAN: The second beaver was named Justin Beaver.
ANA: Laughs
ALAN [SINGS LIKE JUSTIN BIEBER]: BEAVER BEAVER BEAVER OH! There’s gonna be one less lonely beaver.
ANA: Haha, thank you Alan. José and Justin lived together for years. Munching on wood, swimming with their eyes peaking out of the water. And slowly but surely increasing the biodiversity of the river and the forests 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...
CHRISTIAN: Two dolphins swimming around in the Bronx River.
LULU: No!
ANA: Yes.
LULU: Dolphins?
ANA: Uh huh. Yep
- dolphins squeaking and splash
SFX SPARKLE FLOURISH
MUSIC
LULU: CLAP GO BEAVERS. I mean imagine if everywhere you walked you just sprouted flowers and life followed you..
ANA: That would be nuts
LULU: How long does it take, once a dam goes in is it years before you start seeing this greening effect?
ANA: No, that’s the thing. It's super fast. Like within a few months it’ll be cattails and lily pads and swamp roses blooming.
LULU: Wow. Ok 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.
ANA: Yup.
LULU: But that’s it, right? Anything else? There can't be more.
EMILY: Oh, there’s so much more.
LULU: Our next storyteller thinks beavers can even fight fire. Find out how after this break!
BREAK
OLD TIMEY NEWSREEL MUSIC COMES IN
LULU: Look! Up in the sky! It’s a bird! It’s a plane! NO! It’s..beavers? Parachuting down from the clouds?
NEWSMAN: Crates full of beaver. Part of a shipment to be dropped from an airplane.
LULU: And no, this is not an old-fashioned cartoon. It’s something that our governments actually did in the 1940s and 50s
EMILY: Some folks in a couple of different states put them in boxes and then dropped 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.
LULU: You, you are kidding right now, right?
EMILY: They literally pushed them outta planes. Idaho did this. California did this.
LULU: 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.
NEWSMAN: They are live-trapped and moved to distant mountain lakes and streams where their efforts will aid to conserve water, provide fishing pools,
EMILY: Instead of like taking him out on a horseback or a car , they dropped him outta planes. But, you know, I give 'em credit for trying.
NEWSMAN: NOW into the air and down the swing down to the ground near a stream or lake…
LULU Emily gives them credit for trying because in a way, she’s also trying to get more beavers in the wild, where she hopes they can do good for the planet! But that wasn’t always her job, far from it, she used to be an engineer who worked on:
EMILY: Weapons
LULU: Weapons?!
EMILY: Nuclear weapons. Very different career path.
LULU: Whoa.
LULU: But she happened to turn on the tv one night and catch a nature documentary
EMILY: 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?”
LULU: And she realized that just like her, beavers were engineers
EMILY: Using all of their engineering to live a good life.
LULU: and mend the world around them
EMILY: And, I wanted that for myself. So, I started studying beavers, and I haven't looked back since.
LULU: 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 family of beavers, who lived in a little creek up high in the mountains of Northern California in a creek.
EMILY: It's called Little Last Chance Creek,
LULU: So she called the family, the Little Last Chance beavers. There was a mom, a dad, and
EMILY: There were definitely three to four babies there.
LULU: Aw, and she started following them around, watching as they
ALAN [as beaver]: Timber!
LULU: Constructed their intricate dams and lodges
ALAN [AS BEAVER]: Hi ho, hi ho, we’re logging a busy day at work!
LULU: And she discovered that inside their homes on scorching hot days..
EMILY: It's cold in there.
LULU: You've been in a beaver lodge?
EMILY: Haha I have!
LULU: And on super cold days outside, it’s super toasty.
EMILY: The beavers sleep in a big snuggle pile in like one room. It's very sweet. Um, they kind of snore sometimes. It's extremely cute.
LULU: And Emily learned that their family members weren’t the only ones staying warm in there.
EMILY: they might have mice that wanna come live inside the lodge with them. They might have muskrats that wanna live inside the lodge with them. They might have little snakes that wanna live inside the lodge with them.
LULU: They allow this, they allow these trespassers?
EMILY: Oh absolutely. It's kind of like they're running a little bit in breakfast, which I call a “B & Beav”. It was one of my horrible jokes.
LULU: Winter turned to spring turned to summer. And then one day, there was a spark. And the dry grassland and forest around the little last chance beaver family caught fire and began burning and burning
EMILY: It was a really devastating fire. It burned a lot of forest.
LULU: This was back in the summer of 2021, and it became one of these mega fires we are seeing 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 of the mountains?
EMILY: It seems like absolutely everything has burned.
LULU: By October, human beings finally were able to extinguish the fire. But Emily had no idea what happened to those beavers.
EMILY: Could they have survived the fire?
LULU: So one day she began the long drive up into the mountain.
EMILY: 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.
LULU: But she keeps driving.
EMILY: And we find a route in.
LULU: They get out of the car and begin walking, and suddenly
EMILY: It is loud. It is splashing water. There's all sorts of birds, there's lots of bugs, there's a lot of wind in the trees, and the grasses and the rustling you expect
LULU: Oh wait. And even there being wind in the trees means there's still trees standing.
EMILY: There's still trees, the pine trees that were near it are fine. The trees that are in the wetland are fine.
LULU: It was completely green.
EMILY: 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.
LULU: Why tears?
EMILY: 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
LULU: Mm.
EMILY: 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.
LULU: And as for the Little Last Chance beavers?
EMILY: I did stay out in the evening and saw both mom and dad swimming,
LULU: gasps
EMILY: And when they were out swimming, I could hear three, maybe four different, young beaver wines coming from where the lodge…
LULU: Aw. They made it!
EMILY: Yeah
LULU: And it wasn’t just them. When Emily looked at the area from way high up in the air, from a satellite in space… she saw something incredible. This halo of green around the beavers’ dams. She guessed that this one family, these 5 or 6, awkward beings, had saved about 7.5 acres of of land from burning
EMILY: Yeah, that effect is called making fire refugia. It's a patch that doesn't burn that other things can use.
LULU: Refugia as a fancy word, sort of like for refuge, it's just like place that is safe.
EMILY: Yeah. Exactly.
LULU: Okay. Okay.
LULU: 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 refugia around us? 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,
ALAN [as Bronx people]: We got this!
LULU: 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 sees beavers as firefighters.
EMILY: They're spreading water out across the whole landscape. And that's keeping everything nice and green and healthy and stopping it from being easy to burn.
LULU: Emily has tested this effect in mountains and forests and deserts
EMILIY: And so far what we've seen is that they are really good at making fireproof patches pretty much everywhere.
LULU: Little rings of green you can literally see from space.
Ben: 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.
LULU: That’s beaver believer Ben again, he (and Emily) both work to inspire people to protect beavers.
BEN: One of the mantras of the Beaver Believer goes, let the, 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.
NEW LULU: Another mantra? “Be more beaver.” What if we, too, worked to build structures that 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 beavers’ footsteps, waddling awkwardly towards a better world, one step at a time.
ALAN SINGS:
Buh buh buh beaver believer
Buh buh buh beaver believer
Buh buh buh beaver believer
I’m a beaver believer (beaver, beaver)
You little over achiever.
I’m a beaver believer (beaver, beaver)
We see the ripple effect
you make a big splash (tail slap)
I’m a beaver believer (beaver, beaver)
You little over achiever.
I’m a beaver believer (beaver, beaver)
We see the ripple effect
Lets get to work! If you believe, roll up your sleeves and
Let me see the tail slap. (tail slap)
Buh buh buh beaver believer
We’re small and awkward and the challenge is tough
But if we work together, we can rise above
We waddle on until the job is done.
Don’t cry us a river. We’ll just dam it up!
I’m a beaver believer (beaver, beaver)
Oooh oooh oh, You little over achiever.
I’m a beaver believer (beaver, beaver)
We see the ripple effect
Lets get to work! If you believe, roll up your sleeves and
Let me see the tail slap. (tail slap)
Buh buh buh beaver believer
Even though they’re kinda weird
The beavers got it going on.
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.
Buh buh buh beaver believer (beaver, beaver)
LULU: Alan Gopher-inksy, Goffinskyeveryone. He used real beaver tail flaps as instrumentation in that piece. And that’s it. There’s nothing else cool about to happ -– Huh! What's that?
BADGER 1: Excuse me, I have a question
BADGER 2: Me too!
BADGER 3: Me three!
BAADGER 4: Me four!
LULU: The BADGERS! Listeners with badgering questions for our expert. Ready?
EMILY: Absolutely.
Felix: Hi, my name is Felix and I'm six years old. Do baby beavers have baby teeth?
Emily: Yep
LULU: Not the big buck teeth, but some fo the side teeth, which are called cheek teeth. Cheek teeth, cheek teeth, cheek teeth. Say that 10 times fast.
REMY: My name is Remy, and I’m six years old. Since beavers eat wood, what does their poop look like?
EMILY: Well, they do the double poop
LULU: What do you mean? They poop once and then....what?
EMILY: They eat that again.
LULU: Ugh!
EMILY: And then when it comes out it looks like a sawdust marshmallow. And the little sawdust marshmallow is if you dry 'em out, they're actually great fire starters.
LULU: WHAT? Have you ever done that?
EMILY: Hahaha I have burned one to see if it would burn, and it burned just fine.
LULU: Now, that’s what I call a useful nugget.
TYLER: 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?
EMILY: They learn from their instincts and also from following around their parents and brothers and sisters and trying to do what they do.
LULU: Wait, so are there regional differences in architectural style - like how you get, like, Swedish modernism or Southwestern adobe?
EMILY: Anecdotally. Yeah, there are!
LULU: huh!
EMILY: And some of them built some really weird dams and
LULU: Like how so?
EMILY: Like at like 90 degree angles from one another, like zigzagging, instead of having nice curvy shapes..
LULU: Wow.
EMILY: They like teach their kids what's available to build with // It could be garbage, i mud. Uh, I have seen cow bones
LULUL ohhh
EMILY: I have seen all sorts of interesting things.
LULU: A dam made out of bones??
EMILY: No joke. I saw that on a Halloween field tour and I thought someone had like set it up for me
LULU: Haunted Lodge! Haunted dam!
EMILY: There's like cow knuckle bones and a femur, and they're just like integrated into this dam. It was, like, unreal.
LULU: And that’s where we gotta leave it, with the spooOOOOOky beaver dam. 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 vanilla ice cream or certain candies, in the time of 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 Eager: The Surprising Secret Life of Beavers and Why They Matter. I 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 Sandbach. This episode was produced by the GNAW-ty (gnawing on wood) Ana González, tail-slappingly good sound design by Mira Burt-Wintonick. Our team also includes Alan Goffinski, Tanya Chawla and Joe Plourde. Factchecking by Diane Kelley. She wood not let us get anything wrong. “Wood” spelled “w-o-o-d”.
Support for Terrestrials is provided by the Simons Foundation, the Arthur Vining Davis Foundations, and the John Templeton Foundation. Thank you!
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Ok, hopefully all of those links woodwork for you. Woodwork? Woodwork? Ok, beavery careful out there. Go sink your teeth into some good stuff. And see you in a couple spins of this dirty old planet of ours.