Lulu Miller: Three, two, one!

(Old-timey cartoon circus music enters as Lulu narrates.)

Lulu: Imagine you turn into a tiny tightrope walker.

Aanya: Your tail is balancing you.

Lulu: And you are sprinting–

(Pshoo!)

Lulu: –Across a narrow powerline!

Aanya: The wind is whistling.

(Wind rushes around you as you prepare to jump to the ground.)

Lulu: Suddenly, you leap into the air and begin soaring without wings.

Aanya: You glide in the wind.

Lulu: And when you hit the ground–

(A resounding thump!)

Lulu: –You ready yourself for your wildest trick. Which is to–

(Poof! Could it be magic?)

Lulu: Shut off your brain–and then regrow it!

(Electricity sparks.)

Lulu: You have become … 

Aanya: A squirrel! 

(The music rises up to a high point–a rapturous moment!–then fades.)

Lulu: Alright, now is when we sing the theme song!

Aanya: Cool!

Songbud Alan Goffinski: Terrestrials, terrestrials, we’re not the worst, we are the … 

Aanya: (Having trouble guessing it.) Um. 

Songbud Alan: Bestrials!

(Aanya laughs, a little “hee hee”.)

Lulu: Terrestrials is a show where we uncover the strangeness right here on earth. I am your host Lulu Miller joined as always by my songbud:

Songbud Alan: Hello!

Lulu: Alan.

Songbud Alan: (Signing, autotuned.) Time to get squirrely!

Lulu: This season we are looking at creatures that are usually–

Songbud Alan and Lulu: –Overlooked! [A beat.] Shh!

Lulu: And today’s esteemed squirrel expert is:

Aanya: Aanya! I’m 11.

(Cool skater music picks up.)

Lulu: Aanya lives in Los Angeles and, in many ways, she’s a typical kid.

Aanya: I go to the skatepark a lot ‘cause I like to skateboard.

Lulu: And she used to have a pretty typical relationship with squirrels. 

Aanya: I’d walk past them and I wouldn’t think anything. 

Lulu: They disappeared into the background. They were the definition of ordinary! You could see ‘em in your backyard, in parks, in trash cans …

Songbud Alan: (In a high, squeaky squirrel bro voice.) ‘Sup, bro?

Lulu: But one day, a squirrel ripped–

(Uh oh! A rip!)

Lulu: And I mean literally tore its way into Aanya’s life and revealed this wild secret one species holds in its brain–that just could be the key to sending humans to Mars!

(Space sound.)

Lulu: Alright! So, shall we do this thing?

Aanya: Yeah! 

(A skateboard flies past, the music fades, and the sound of other kids playing on the playground comes up.)

Lulu: So Aanya’s story begins one day when she was nine years old and she dared to pack something enticing in her backpack.

Aanya: Peanuts!

Lulu: During recess, she dropped the bag on the ground during recess, and when she came back—

(Lulu gently gasps.)

Aanya: There was a big hole!

(Riiiiip!)

Lulu: And nearby, a little gray squirrel.

Aanya: He teared [sic] out the literal fabric!

Lulu: He just ripped right through it?

Aanya: Yeah. Probably with his teeth. 

Lulu: And Aayna noticed him–like, truly noticed him. 

Aanya: Its little tongue as it was opening its mouth.

Lulu: Happily chomping peanuts. 

Aanya: Crunch, crunch!

Lulu: And as she watched him chew, she was filled with all kinds of questions about this furry little peanut thief. 

Aanya: Yeah.

Lulu: So she started researching.

(Exciting, inspiring squirrel music plays.)

Lulu: And found out all kinds of neat stuff about squirrels, like how their brains are so sharp, they can remember the location of over a thousand buried nuts or seeds.

Songbud Alan: (As a squirrel, chomping happily.) That’s way more than you humans could! (Chuckles.)

Lulu: And their teeth are so sharp because they never stop growing. So they have to constantly chew on things to file them down.

Like backpacks, or porch furniture–or even electric power lines!

(Songbud Alan gets zapped. Yow!)

Aanya: Squirrels may have disrupted the mainframe more than hackers have.

(Electricity surges!)

Lulu: Really?

Aanya: Yeah!

(Another zap! Ooh!)

Lulu: According to some estimates, squirrels are responsible for one of every five power outages!

Songbud Alan: (As a squirrel.) Sorry, not sorry!

(The music quiets.)

Lulu: But they are not all bad news for human society.

Aanya: Squirrels plant trees!

Lulu: Wait, what?

Aanya: Mhm!

Lulu: Aanya explained that, as good as those little squirrels are at remembering where they hid their treasures, they do forget where they put [Laughing lightly.] up to 25% of them.

Meaning that, when spring comes, with a little rain and a little sun, some of those forgotten seeds …

Aanya: Grow into a tree, which helps us breathe. 

(An atmosphere of calm music, sunshine and sprouting plants, builds.) 

Lulu: Woah! That’s such a poetic image, that this combination of, like, greed and forgetting lets us breathe!

Aanya: Yeah!

(A rush of cool air flows out, reminding you to take a deep breath of the air squirrels help to make!)

Lulu: But Aanya was about to claim something even wilder. 

Of all the hundreds of species of squirrels that exist out there, like flying squirrels and multicolored squirrels–like the ones from India, where Aanya’s mom is from– it turns out there is a squirrel that lives in the Arctic and spends its winters under the snow getting so cold that, according to Aanya, its flesh turns– 

(Tinkling ice signals the squirrels turning to ice.) 

Lulu: –Into a kind of popsicle–or pop-squirrel!

Aanya: Because they have this thing that helps them change their body temperature when they're underground.

Lulu: Can any other warm-blooded creatures turn their bodies that cold?

Aanya: No.

(A beat.)

Lulu: I wanted to believe her, but it just seemed physically impossible for a mammal like us to drop below freezing for months.

Lulu: (Stunned, explaining Aanya’s story.) … And not freeze to death?! Like, is she right?

Dr. Kelly Drew: She is right! 

(Exciting music plays.)

Lulu: This is Dr. Drew.

Kelly: Kelly Drew. I grew up in Alaska. 

Lulu: She spends her life studying arctic ground squirrels, squirrels with light golden fur and stubby little tails that somehow survive a winter hibernating. 

Kelly: These animals can actually go below freezing–their core body temperature can actually go a couple of degrees below freezing.

Lulu: Wow!

Lulu: Now, if our core body temp was to go below freezing, our blood would freeze–and the ice crystals would rip through our flesh and, most of us, we would be dead within a day. 

But for some reason the squirrels are totally fine! … For months on end. And Kelly has invited me up to Alaska to hold one of these frosty squirrels in my hand to see how they do what they do.

(The music fades out, replaced by the sound of wind rushing around.)

Lulu: (On a plane.) Alright, I am buckled in! 

Lulu: So one cold February day, I hopped on a plane.

Lulu: (On the plane.) And we are about to take off.

(An airplane takes off.)

Lulu: And ten hours later, I landed.

Lulu: Hoo!

Lulu: On an even colder February day–

(Lulu lets out a “Wahoo!”)

Lulu: –Just a few hours from the Arctic Circle. 

Lulu: We have reached the tundra! [Whispering.] And I’m about to go see a very special creature. 

Kelly: So that would be this way.

(Footsteps crunch on the snow.)

Lulu: I’m on a snowy hilltop with Dr. Drew–

Kelly: Yeah.

Lulu: –Surrounded by snowy mountains– 

Lulu: (Realizing, laughingly.) Oh, it is cold!

Lulu: –As far as the eye can see.

Kelly: Yeah, it’s a little windy!

Lulu: I’ve got a million layers on, including thick wool mittens.

Lulu: Like, if I took off my mittens, how quickly do you think I’d get frostbite?

Kelly: Many, many minutes.

Lulu: (Laughing at how fast that is for something so serious.) Many whole minutes without my flesh dying!?

Kelly: I mean, you know. Yeah!

Lulu: Meanwhile, right beneath us under the snow, are some creatures!

Kelly: They are hunkered down. And they don't have to worry about it being cold outside.  

(Underground squirrel city music plays, uptempo and soft.)

Lulu: Beneath us, Kelly explained, is an intricate system of burrows.

Kelly: They have really long toenails and they can dig down until they hit ice.

Lulu: After spending the summer fattening up as much as they can, the squirrels line their burrows with soft mosses and lichens and caribou fur. And, as winter descends, each ones curls itself into a tight little ball all by itself.

(Squirrel city music gives way to wind, then quiet.)

Lulu: And they enter a sleep deeper than sleep. They don’t eat, they don’t dream, they don’t even … POOP! 

Kelly: They don't defecate for eight months.

Lulu: (Shocked.) For eight months? (She gasps!)

Kelly: Yeah, ‘cause they’re not eating!

Lulu: These little squirrels are so knocked out you could play catch with ‘em–and scientists in the 1960s did! And they wouldn’t wake up.

Lulu: So to get one of these squirrels, should we just start digging?

Kelly: (She laughs.) Well, we might just go to the lab and find one there.

Lulu: Great, because I’m losing the ability to talk. I think my lips are freezing!

Kelly: Wow!

(The two laugh together. Then, their laughter fades out.) 

Lulu: When we come back, we’ll come face-to-frosty-little-adorable-face with one of these hibernating squirrels and see what their brains may have to do with space travel.

(One last beat of squirrely music, and then it is ad break o’clock!)

(Plucky string music mirrors the excitement of Lulu’s heartbeat.)

Lulu: Alright, Terrestrials is back! I’m Lulu, and my heart is beating very quickly, because I’m about to meet one of the world's most extreme hibernators. 

Lulu: Oh! So excited! 

Kelly: Well good! (Laughter.)

Lulu: Kelly is holding an arctic ground squirrel in the palms of her hands.

Kelly: So this is number 2036.

Lulu: Oh my gosh.

Lulu: It's not moving at all! Its head is curled under its tail.

Kelly: Here, you can hold her.

Lulu: Oh wow! She is freezing! It’s like a furball the size of a grapefruit, say, and it feels like holding a snowball.

Lulu: She truly feels like … [Searching for the right word.] a corpse. She’s motionless. Her eyes are shut, and it’s hard to believe there could be any life inside. 

Kelly: It’s very hard to tell if they're dead or alive until you see them breathe.

Lulu: But after about two minutes … 

(A tiny breath in.)

Kelly: Oh, there’s one!

Lulu: A breath.

Kelly: I mean, I've watched over three minutes and not seen a breath before.

Lulu: (Surprised again – these little guys are amazing!) A single breath?

Kelly: Yeah.

Lulu: Wow!

Lulu: See, to survive the cold without food for the long long winter, the hibernating squirrels slow everything down.

Kelly: You know, like turning down your thermostat in your house? You’re going to save energy.

Lulu: They slow their breath.

(A tiny exhale.)

Lulu: They slow their heartbeat.

Kelly: I mean, their heart goes from 300 beats per minute [A quick heartbeat, slowing down.] down to 5 beats per minute!

Lulu: Whoa.

Lulu: And then …

Kelly: The brain shuts down.

Lulu: They turn off their brain. 

(The music echoes away, leaving behind a moment of quiet.)

Lulu: So, this squirrel in my hands? She’s basically brain-dead.

Kelly: Just on the edge of death …

Lulu: All that noisy chatter and electricity–

(Noisy chatter and electricity grows and grows … !)

Lulu: –That’s normally whizzing through a brain? It just–

(Then, suddenly, with the flip of a switch, the electricity is gone!)

Lulu: –Flatlines. 

(A beat.)

Lulu: And it isn’t just that the electricity powers down, the cells the electricity travels through begin wilting, too. 

These cells in the brain are called neurons. 

Kelly: If you think about a neuron as looking kind of like a tree …

Lulu: Normally they have long branches that reach out to other neurons. That’s how one part of our brain communicates with another. But when Kelly looked inside the hibernating squirrel’s brain, she saw that …

Kelly: The branches get smaller and less complex.

Lulu: They kinda shrivel.

(Bark crunches up as the tree shrinks.)

Kelly: They’re just pruning back.

Lulu: Connections that store memories break and wither away. And their brain stays like that for weeks–shriveled, and, because the heart is beating so slowly–deprived of so much of the oxygen that usually feeds it. If that happened to a human brain for that long … ?

Kelly: It’s dying and not coming back.

Lulu: If it happened to a human brain for even a few minutes, it would be disastrous. We would lose memories. We might have trouble speaking or walking. It would look like the brain of someone who had a serious brain injury, or a disease like Alzheimer’s. 

But these squirrels …

Lulu: Oh, yeah! There–okay, there we go!

Lulu: … Are different. 

Lulu: We got activity!

Kelly: Oh yeah!

(A tiny spark jolts to life.)

Lulu: When an arctic squirrel begins to wake up from its very long, very cold slumber, they shiver awake over the course of three hours.

Kelly: That’s shivering!

Lulu: After about an hour and a half, the little snowball squirrel began to ever-so-occasionally shake her little arms.

Kelly: She’s waking up!

Lulu: Yeah, this is a creature waking up!

Kelly: It’s almost like a little convulsion. They’re shivering to generate heat.

Lulu: Oh yeah! She’s lifting that little head. Those–those big buck teeth are on display.

(Electric trees–neurons–regrow!)

Lulu: And as they’re warming up, their brain regrows! Those wilted neurons start to branch out again, like a forest blooming after a fire.

Kelly: Yeah, that’s a nice way to think about it. Like fire weed coming in after a fire.

Lulu: (Repeating, still surprised.) Completely regrowing–in just three hours!

Kelly: It happens so fast.

Lulu: It just feels like they’re–they’re skirting the laws of nature. 

Kelly: They skirt the rules of just about everything that we know. They definitely have something special going on!

(Gentle droning music plays.)

Lulu: This is why Kelly studies the squirrel. If she and other scientists can figure out how it regrows its brain, we might be able to help humans who've had brain injuries or diseases regain some of what they've lost.

Kelly: I would think it would be cool–no pun intended–but to be able to cool and re-warm as a treatment for emergency medicine, maybe mental health. There’s all kinds of possibilities! 

Lulu: Like helping people … on the very very long journey … to Mars!

Kelly: You can imagine what it’s like being in a small spacecraft, you know.

Lulu: Oh man. The boredom, the drama, the human conflict!

Kelly: Yeah! So if you can stay in a hibernating state, it would be very beneficial. 

Lulu: Because …

(One big snore, big enough to wake up a whole space station, loudly interrupts.)

Lulu: … If the astronauts were sleeping for weeks at a time, not only wouldn’t they be squabbling or getting bored, they wouldn’t have to eat as much.

(The snores continue.)

Lulu: Which means you could pack way less heavy food and make it easier for the spaceship to blast off!

(The music drifts through space, passing by synthesizer stars along the way.)

Lulu: And Kelly has gotten so close to figuring out the brain chemicals that turn the squirrels brains off and and back on that she recently became the official “Hibernation Consultant” for a NASA-funded group working on how to get to Mars.

Lulu: They're going to try to start going to Mars supposedly in, what, like, 2040 or something? 

Kelly: Yeah. 

Lulu: I mean, how realistic do you think it is that we could get humans hibernating in, like, 20 years? 

Kelly: I think that it would be possible.

(A twinkle of synthesizers.)

Lulu: But what really got me interested in these squirrels is this idea that every spring, as they regrow their brain, in some sense, they are emerging anew.

(The music quiets.)

Kelly: They go through puberty all over again, so that’s what spring is for them.

Lulu: Oh! What?!

Kelly: So they have puberty every year.

Lulu: (Still processing.) What?

Lulu: Kelly explained that even though they are adults before they go into those burrows, with adult private parts, adult hormones, adult brains, when they emerge in the spring …

(A rewind.) 

Kelly: They wake up as an adolescent again, really, you know?

Lulu: They power down and almost become kids again? (She laughs at the thought.)

Kelly: Exactly.

Lulu: That's so wild. But, so–for real though, so much of who we are–not all of it, but a lot of who we are–resides in the brain: our likes, our fears, our memories. If some of that is lost during that sort of pruning period, in a real way, like, are they the same self?

Kelly: Yeah, that’s a really good question.

(Wandering music emerges from the burrows with the squirrels.)

Lulu: Scientists are still trying to figure out just how much these squirrels change after hibernation. But some studies show that when they first come out of their burrows in springtime, they’ll explore way further than they did before–almost like they’ve forgotten the boundaries of their territory! Or maybe they’ve just forgotten their fear of what lies beyond …

Lulu: But there is one thing that definitely remains.

Kelly: They remember their buddies. They can remember their friends. 

Lulu: Groggy and disoriented in many ways, they will run right up to their friends they haven’t seen in over half a year and nuzzle their noses.

Kelly: They need each other, and that is something that is retained. 

Lulu: Wow. So they've evolved in a way that, you know, they can–they can forget where they hid their food, or what they used to be afraid of, but if you know who your friends are, that'll–that'll help you survive.

Kelly: Yeah.

Lulu: That’s kinda beautiful. Is that too touchy-feely? 

Kelly: (Laughing.) No, I like it. (Lulu joins in Kelly’s laughter.)

(A beat–another Songbud Alan song this way comes!)

Songbud Alan: (Singing.) I know we’ll claw our way out of this winter.

We will thaw and shiver into spring.

I know we will survive and find each other,

Even if we forget everything.

We will find each other on the other side!

We will find each other on the other side!

(The music picks up pace, just in time for an instrumental break.)

Songbud Alan: We will find each other on the other side!

If you forget who you are 

After months in the dark

Buried in the snow and the cold

If you forget who you are

All the places you’ve been

All the secrets you’ve known

Are now frozen

If you forget who you are

And your memory fades

From your delicate brain

Please just know

We will find each other on the other side!

We will find each other on the other side!

We will find each other on the other side! (If you forget who you are!)

We will find each other on the other side! (If you forget who you are!)

We will find each other on the other side! (If you forget who you are!)

We will find each other on the other side!

(One last drumbeat and the music cuts out before one last line.)

Songbud Alan: We will find each other on the other side!

Lulu: Alan Goffinski, my friend, and yours! And that’s it, there’s nothing else cool about to go down–

(Suddenly, out of nowhere, trumpets … well, uh, trumpet! It’s The Badgers!)

Lulu: (Whispered.) What's that?

Badger #1: Excuse me, I have a question. 

Badger #2: Me too. 

Badger #3: Me three. 

Badger #4: Me four. 

Lulu: (Whispered, but somehow loudly.) The Badgers.

(The Badgers theme song plays underneath the questions.)

Lulu: Listeners with badgering questions for the expert. Are you ready? 

Kelly: Yeah!

Clara: Hello, my name is Clara. I’m 10 years old. Why do squirrels like nuts? They could like literally any food–why nuts?

Kelly: I suppose that they like them because they're packed full of protein and energy. It's like an energy bar. 

(Lulu laughs at the thought as a squirrel chows down.)

Kelly: But they'll eat just about anything. They eat flowers and they eat mushrooms. And, I mean … they'll eat their buddy, you know. (She laughs, maybe a little nervously.)

Lulu: (Incredulous, not able to believe it.) No, they will not. 

Kelly: They do! 

Lulu: Will they eat–will they cannibalize?

Kelly: I've–I've seen them eating roadkill. 

Lulu: (Gasps.) Okay, a–a dead buddy. 

Kelly: Yeah, yeah, yeah. Don't–yeah. They'll scavenge, right? 

Lulu: Okay, okay. 

Chenjerai Kumanyika: Hey, I’m Chenjerai Kumanyika. I’m 51, and I wanna know: Do squirrels have language?

Kelly: Yeah. They’ll alarm others if there’s an aerial predator or a terrestrial predator with different chirps.

Brian Barnes: One is [Imitating a squirrel chirp.] TSK-TSK, TSK-TSK. 

Lulu: This is Brian Barnes, Kelly’s colleague she told us to talk to because he’s basically fluent–TSK-TSK–in squirrel-speak.

Brian: What it means is “Ground predator, watch out!” and it can be a fox or a bear.

(A loud roar comes out of nowhere. Good thing you had that squirrel-speak to warn you!)

Brian: They have a second call, which is [Brian whistles.] and it means “Aerial predator”. 

(Lulu caws loudly–is she secretly part-eagle?)

Brian: Here comes a golden eagle, or a raven.

Lulu: Wow! So, like, different words!

Brian: Yes, absolutely.

Millie: Hello! My name is Millie, and I’m 8 years old. Do any animals actually freeze–like, turn into ice–when they hibernate? 

Brian: The wood frog.

(Lulu ribbits!)

Lulu: Huh.

Brian: The heart freezes, the eyes freeze. They’re [Knock knock!] 70% ice.

Lulu: Wow.

Brian: And if you bent the leg …

(SNAP! Uh oh!)

Brian: It would snap off.

Lulu: Wait! But how does the freezing … not hurt the flesh?

Brian: They turn themselves excessively sweet! 

(A ding! So sweet!)

Brian: Its blood sugar acts to protect it. 

Lulu: So if you snapped off one of its frozen legs ...

(Another SNAP!)

Lulu: … Would it be sweet like a popsicle?

Brian: You know, my grad student has done that.

Lulu: (Gasps.) He ate–he ate it? 

Don Larson: Yes!

Lulu: This is the grad student!

Don: Hi! My name is Don Larson.

Lulu: And he specified this was not a lab frog, but one he caught in the wild with his fishing license, and he said he actually tasted a bit of the frog’s liver.

(The music fades out and, slowly, gives way to the credits music.)

Don: Yeah, just cooked it up in a skillet, fried it. [Lulu laughs. And it was a very sweet liver. You can taste the sugar, yeah. 

Lulu: Alright, I think that’s the best place to leave it, with the curious grad student and the frozen frog. Terrestrials was created by me, Lulu Miller, with WNYC Studios. 

Our team includes Alan Goffinski, Mira Burt-Wintonick, Ana González, Tanya Chawla, Sarah Sandbach, Joe Plourde, Valentina Powers, and me, with fact-checking by Diane Kelly. 

Big special thanks this episode to Aanya and her mom Roli for bringing us this story, and to Amy Loeffler, Clara Goulet, Loi Goulet, Ellie Bell, and Ferris Jabr, the writer who first made the [Icy sounds!] "pop-squirrel" joke. I came across it in a wonderful article he wrote in Scientific American.

Support for Terrestrials is provided by the Simons Foundation, the Arthur Vining Davis Foundations, the Kalliopeia Foundation and the John Templeton Foundation.

Thank youuu!

Teachers! We also wanted to let you know we are now offering all kinds of free teaching materials for many of the episodes. We’ve got handouts, classroom activities, really fun discussion prompts. And we worked with professional educators and the team at PBS Learning Media to make sure everything accords with national curriculum standards for science literacy. And we have ‘em for grades K-8! Check those out on our website, RadiolabForKids.org. 

So many new episodes coming your way over the next few months. Catch ya in just a couple spins of this lumpy old planet of ours. 

Woo woo woo, woo woo woo! 

Bye!

(The credits music plays out.)