B (1:55)

Hi, Molly.

A (1:56)

So not only is Christina a Brains on fan, she's also one of the voices of Brains on and Espanol. If you haven't checked it out yet, there are currently six episodes of Spanish Brains On. You can find it by searching for Brains on en Espanol at our website or wherever you get your podcasts. So, Christina, I'm curious, what was your favorite fact you learned working on Brains on en Espanol?

B (2:19)

Learning why our shoes smell. And the reason is because our glands get bigger and they can trap more odors.

A (2:27)

Exactly. You learn so much. So, Christina, you also have another podcast that you host as well, right?

B (2:34)

Yes, it is called Catalina Starr's Young and Famous with Christina Ru. And I'm Christina Ruhl.

A (2:40)

That makes sense. So what do you do on your podcast?

B (2:43)

I interview young Latinx stars.

A (2:46)

Very cool. So like, who are some of the stars you've talked to recently?

B (2:50)

Natalia, Clement, and Justina.

A (2:53)

Well, you're an accomplished podcaster, but you also happen to be a super fan of sloths. So, Christina, what is your favorite thing about sloths?

B (3:04)

That they move slow.

A (3:07)

Why do you like that about them?

B (3:09)

Because it's just so Cute. They move slow even though they can't move fast. And they're the slowest mammal on earth.

A (3:17)

I am also a very big sloth fan. I wrote a report on three toed sloths back in third grade and have been in love ever since. And it turns out our listeners are obsessed too. You all send us so many sloth.

B (3:30)

Questions, so we're going to start by answering this one. Why are sloths so slow?

A (3:37)

Thanks to Camilla and Arthur for that question. If there's one thing sloths are famous for, it's being slow.

B (3:44)

They move slowly, they digest slowly, they even blink slowly. If a sloth were a Brains on cohost, the beginning of the show would sound like this. You're listening to Brains on or serious about being curious.

A (4:13)

Okay, yeah, we should probably stop there because that could take a while. But yeah, sloths are slow, but it's.

B (4:19)

Not because they're lazy. It's because they're really, really efficient.

A (4:24)

That means they use every bit of energy they have very wisely because it's really hard for sloths to get energy.

B (4:32)

Yeah, they live in trees and eat flowers and leaves, but those things don't have a lot of nutrients so they have to make the most of what little they get.

A (4:44)

For example, sloths have multi chambered stomachs like a cow that let them slowly digest that food and squeeze out every bit of nutrition from this limited diet.

B (4:54)

They also move as little as possible to save energy. And when they do move, they move slowly.

A (5:01)

They also have three extra vertebrae in their neck so they can swivel their heads almost all the way around. Another neat energy saving trick. Why move to see something when you can just turn your head?

B (5:13)

Sloths have so many fascinating adaptations that let them live in this very specific tree dwelling lifestyle.

A (5:22)

Here to tell us more about how amazingly cool sloths are is zoologist Lucy Cook.

B (5:28)

She's the founder of the Sloth Appreciation Society. Welcome Lucy.

D (5:33)

Hello. Hello. Hello. Hello.

B (5:35)

What inspired you to start the Sloth Appreciation Society?

D (5:40)

Well, that's a very good question. I started the sloth Appreciation site. It was about 10 years ago now. I felt that sloths were getting a bad rap and that people didn't really understand how amazing they are. And I still remember very clearly the first time I saw a sloth and it kind of blew my mind, you know, I mean, I just, I just was mesmerized by how slow they are. You know, as a zoologist I just wanted to understand them. But also on top of that, they have these amazing faces that look a bit like they're humans, you know, with these wonderful smiles. So, you know, there's a lot to love.

B (6:20)

We're going to ask you a few questions sent in to us from our listeners. This one is from Ivy in Austin, Texas. How are sloths able to swim, sail?

D (6:35)

Sloths live on leaves and when they are digesting their leaves they generate quite a lot of gas. As if there wasn't enough reasons to love sloths. They're the only mammal that we know of that doesn't fart. And so what happens with all this gas is that forms an inbuilt buoyancy device that basically makes them bob along in water.

B (7:00)

Wow.

A (7:01)

Could you just describe what it looks like when they do swim?

D (7:04)

When sloths do swim, it's incredibly cute because they do a sort of a doggy paddle, a slothy paddle I should say really. The legs don't do much but the arms do a sort of, a sort of slothy doggy paddle out the front whilst their big inflated fart filled belly bobs keeps them, keeps the body.

B (7:27)

So cute.

D (7:28)

Yeah.

A (7:30)

And do they swim like as slow as they do everything else?

D (7:34)

No, no, that's the amazing thing. They can actually, I think it's something like when they swim they're actually three times faster than they are when they're crawling along the ground. So yeah, they swim a lot faster than they crawl, which is amazing.

B (7:57)

Our next question is from Lillian in California. Are sloth babies just as slow as their parents or do they have more energy like human kids?

D (8:08)

I would say I don't, you know, I don't know the answer to that. So I mean, how wonderful to be asked a question that's so imaginative that I've not been asked it before and I don't know the answer. So thank you very much for that. I've watched sloth mothers and babies together and the babies are also very slow like their mothers. And you know, the thing is about being fast is it burns a lot of energy. And when you're a little baby you want to use all your energy for growing and getting bigger. So my guess would be that they are as slow if not slower than their parents. So that all of their energy goes into growing, into, into adults and isn't wasted on, on, on whizzing around unnecessarily.

B (8:54)

Luke from California wrote in with this question, why do sloths have loinclaws?

D (9:00)

Well, so sloths have claws because it helps them dangle from trees. You know, sloths are just amazing energy savers. They really kind of Wrote the book on sustainable living. And you know, one of the ways that they save a lot of energy is by hanging from trees. And the way that they dangle is using those claws which are actually very long and curved. And so they sort of, they sort of grip on like a, like a, like a clothesline peg and just dangle there.

B (9:36)

Levi from Knoxville, Tennessee wrote in with this question. If sloth sleeps upside down, why don't their hands let go when they are sleeping?

D (9:46)

They just clamp those claws tight. And so I suspect that the control of that muscle that clamps that claw and that limb onto the tree, that's not controlled by their consciousness. That's something that's an unconscious control so that it can't be overridden by being asleep.

B (10:08)

Marina from Milwaukee was wondering, how do sloths not get headaches when the blood rushes to their head?

D (10:15)

I mean, exactly. How, how do they.

E (10:18)

Right.

D (10:19)

My understanding is that they have the valves in their blood vessels such that they pump blood against the force with more efficiency against the force of gravity. And then the other thing that's really cool is because they're upside down, they have these really huge stomachs that they eat a lot of food and that because they're upside down could crush their lungs and make breathing really difficult. So they also have, scientists have discovered that they have sticky bits on their ribs that prevent the stomach from collapsing on their lungs and make breathing easier. So they have all of these extraordinary adaptations to leading an inverted life.

B (11:03)

I have a question, how heavy are sloths?

D (11:07)

So this is surprising, right? So a lot of their size is taken up by their fur. They have a very deep and dense fur coat and that's one of their energy saving tactics that even though they live in the tropics where it's really, really warm, they wear this really thick coat like they're an arctic creature and that keeps all their body warmth in. So they seem a lot bigger. And in fact, when you see sloths that have got wet, they look like drowned rats. I mean you can see then, but. And they have these sort of skinny limbs and you know, they have this big old belly which is full of digesting leaves. But their limbs are long and skinny, so they're actually really light. And a three toed sloth is about the size of a large house cat, but it doesn't weigh anything like as much as a house cat.

A (11:57)

That is amazing. Sloths are so cool. And so, you know, as the founder of the Sloth Appreciation Society, do you feel like there's like any lessons that like humans could learn from the sloth way of life.

D (12:09)

You know, we're all very aware these days about the need to be much more clever and careful about our energy use and how to recycle energy and how to respect the planet. And I just think sloths are really icons of sustainable living. They've survived tens of millions of years on this planet because they're really good at saving energy. And so I think they've got a whole lot to teach us about that. And they're the original tree huggers. So they should encourage us all to go out there and hug a tree.

B (12:46)

Thanks for answering our questions, Lucy.

D (12:49)

I really enjoyed this interview. Really, really good question. So I'm really impressed. Thank you everybody.

B (12:56)

Thank you, Lucy.

A (13:02)

Brains on sloths have lots of incredible adaptations or biological tricks that allow them to live the most efficient lives.

B (13:12)

But there's one sloth behavior that confused scientists because it wasn't efficient at all. You see, sloths live their whole lives up in a big tall tree.

E (13:24)

About every week, a three toed sloth will descend. It'll climb down from that big tall tree and it'll poop at the base of it.

A (13:32)

That's Jonathan Pauley, he's an ecologist at the University of Wisconsin, Madison, and he studies sloths.

E (13:38)

And then it will crawl right back up. Well, this is really ritualized. By ritualized, I mean it's really every week. It's really something that they do kind of on a weekly basis.

A (13:50)

This poop behavior was surprising because it seemed to be the opposite of what sloths usually do, which is try to use as little energy as possible.

B (13:59)

Climbing down a tree and then back up again takes a lot of energy. Why would they do this just to poop? Why not just poop way up in the tree and let it fall down?

A (14:12)

Plus, being on the ground is dangerous for sloths. They are much more likely to be eaten by predators like a jaguar or dog or coyote.

B (14:21)

Lucky for us and all curious people everywhere, Jonathan Polly is something of a sloth sleuth.

A (14:32)

He and his research partner Zach Peary started studying sloths about 10 years ago.

B (14:37)

And one of the things they wanted to understand was why sloths make this weekly trek to go to the ground just to poop.

E (14:45)

It must be important. There must be a benefit if they're literally dying to do it, but also really working hard to do it too.

A (14:52)

In just a minute, Jonathan is going to walk us through a sort of scientific detective story.

E (14:58)

It is a detective story. It was a lot of fun.

A (15:01)

But first it's Time for your ears to play detective. It's the mystery sound. Here it is. Okay, super short. So we will hear it again. I feel like it's so short we should hear it three times. Here it is. All right, Christina, what is your guess?

B (15:29)

My guess is it's something banging against something metal.

A (15:36)

Wonderful, wonderful thought. Well, we're gonna hear it again, so have another chance to guess in just a little bit. We are working on an episode all about generations and what we call them. You may have heard people mention baby boomers, millennials or Gen Z. Every kid, sixth grade or younger is part of generation Alpha. But that name doesn't mean much. If you could give your generation a new name, what would it be? Record yourself telling us about what you would name your generation and why. Then have your grown up head to brainzon.org contact and send us your answer. We'll play some of them on our upper episode. Thanks. You are listening to Brainz on I'm Molly and here is the mystery sound again.

B (16:30)

I have a new idea on what it is.

A (16:33)

Let's hear it one more time and then I'm gonna love to hear your new idea. Okay, one more time. All right, what is your new thought?

B (16:43)

It's a bird.

A (16:44)

Oh, did talking about birds sort of jog that in your memory? Yeah, I love that.

B (16:50)

And it sounds like a bird's flapping its wings really hard.

A (16:55)

Excellent guess. You ready for the answer? Yes. All right, here it is.

B (17:01)

Hello, my name is Phaedra Myers and that was the mystery sound of my chicken flapping.

A (17:07)

Hey.

B (17:07)

I knew it was a bird. I knew it was a bird.

A (17:10)

You got it 100%.

B (17:12)

I knew it was a bird.

A (17:14)

Nice work. Really great. It was a bird. It was a chicken flapping its wings really hard just like you said. Yes, excellent.

B (17:21)

I just didn't know what type of bird it was.

A (17:24)

Yeah, I think it would be very difficult to identify what kind of bird just by the sound. That seems probably impossible. So I think you got it as right on as you possibly could. Well done. Braaaaaaaaaaaaaaaaaa. Alright, we've solved that mystery, but now it's time to solve the case of the perilous poop journey.

B (17:53)

You recall our detective scientist, Dr. Jonathan Pauli was on the case.

A (17:59)

He and his research partner were trying to figure out why sloths would poop.

B (18:05)

The first clue? Moths.

A (18:12)

Sloths have a kind of flightless moth living in their fur. A sloth moth if you will.

B (18:18)

Like the best roommates, the moth don't play loud music or leave their dishes in the sink. They don't harm the sloth at all. They just keep it company.

A (18:29)

And it turns out the moths wouldn't exist without sloth poop.

B (18:34)

When the sloth comes down for its weekly poop, female moth will jump down onto the poop and lay their eggs.

E (18:44)

Now, those eggs develop into larvae, and those larvae then eat the poo. They actually create a really cool chamber within each sloth dung. And it'll eat that. It'll eat the sloth dung for its own energy and its own nutrition. And eventually it will eat enough and grow enough that it will pupate and it will turn into a moth. And for one beautiful fleeting moment, this moth, it has the ability to fly. And so what does that flying moth do? Well, it drifts up into the tree. At the top of that tree is often a sloth, and they land in the fur of the sloth. And when they land in the fur of the sloth, they actually lose the ability to fly. Their wings get so beaten up that they're not really able to fly effectively. So then they're stranded. And so the cycle continues.

B (19:34)

Okay, the moth need the sloth to survive and make more moth babies. But it doesn't seem like the sloth ain't getting anything out of it.

A (19:43)

That brings us to the second clue. Algae.

E (19:48)

And so what we realized is that the more moths that a sloth has on its fur, the more algae that a sloth has on its fur. Sloths carry really thick mass of green algae that make them blend in very well with the trees. The idea being that if you're really green and you carry this algae is things like harpy eagles which use vision to hunt, won't see you as well. So maybe you'll be able to avoid being killed.

A (20:19)

So as these moths live their whole lives in the sloth's fur, they eventually die and start decomposing, feeding the algae on the sloth's back and making it more protective from predators.

E (20:32)

Now, this is not something that they're thinking of. They're not thinking, oh, I gotta go poop so I can keep my algae alive. Not at all. It's one of those indirect benefits that those sloths that do this behavior and maintain their moths have the algae and live longer.

B (20:48)

And that's how Jonathan solved the case of the perilous poop journey.

A (21:00)

And it all started with a question.

E (21:01)

It's good to ask questions. That's what we should be doing every day.

A (21:06)

And thanks to Jonathan's questions and detective work, we also know Sloths are the slowest mammals in the world. But there are some other slow animals that deserve to be recognized as well.

B (21:17)

Sounds like the perfect time for so you Think youk Can Slow Mo?

F (21:24)

Welcome back to so youo Think youk Can Slow Mo. Your top time consuming talent show. I'm your host, Sid Slothworthy. Let's meet today's contestants. Kenny Koala.

C (21:38)

G', day, mate. Brock the Banana Slug Super Slime to be here, bro.

F (21:45)

And Tina the Tortoise.

A (21:48)

Hi.

F (21:50)

Each of you will have a chance to showcase your slowest skills today. So, are you ready for the Slow Mo show off?

C (21:59)

Oh, you know it.

A (22:01)

Yes.

C (22:02)

Bet.

F (22:04)

Kenny Koala, what will you be doing for us today?

C (22:08)

Crikey. I reckon my talent is napping. First, I slowly scale a eucalyptus tree, find an ace spot and get comfortable. Then I'll start to doze off. I usually sleep for at least 18 hours a day. And if I get hungry, I'll just nab a bit of eucalyptus to snack on.

F (22:33)

But Kenny, isn't eucalyptus poisonous?

C (22:39)

Well, mate to most everyone else, yes. But koalas can flush out the toxins. Meaning I can eat pounds of leaves without ever getting sick. The leaves don't give me much energy though. So I have to nap.

F (22:53)

Wowee. That's mighty impressive. Thanks, Kenny. Uh, Kenny. And he's fallen asleep. Well, on to the next contestant. Here to perform the world's slowest and slimiest samba, it's Brock the Banana Slug.

C (23:17)

A shimmy to the right, a shimmy to the left.

F (23:22)

Just look at him slide across that stage. It's taking him ages.

C (23:28)

I move at a whopping six and a half inches per minute. And that's if I'm in a rush.

F (23:36)

I'm absolutely mesmerized by your moves. What's your secret, Brock?

C (23:42)

It's all in the slime, dude. Not only does it help me glide, but it protects me from predators trying to cop these moves. And from eating me. This slime is most poisonous.

F (23:56)

A defensive dancer. We love to see it. Thank you, Brock. Okay, last but not least, all the way from the Galapagos Islands, we have Tina the Tortoise. Tina, what talent do you have for us?

A (24:15)

I brought a snack because I'm the.

C (24:18)

Most gradual grazer I know.

F (24:22)

Let me get this straight. Your talent is eating?

A (24:27)

Well, kind of. I have a super slow metabolism, which means it takes a long time for my body to transform food into energy. I can go up to a whole year without eating or drinking a single thing.

F (24:48)

Legit lethargic, that is one slow stomach.

A (24:54)

And now we wait. This could take a while.

F (25:01)

Looks like that's all the time we have for today. We'll check back in with Tina in a couple of weeks. Thanks for watching. So you think you can Slow mo.

A (25:24)

Sloths aren't lazy. They just live extremely energy efficient lives.

B (25:29)

They have all sorts of amazing adaptations that allow them to live happily and slowly up in the trees.

A (25:37)

Three toed sloths make a dangerous pooping journey once a week. But they do it in support of their moth friends and algae camouflage.

B (25:45)

Just like sloth sloths, other animals use their slow nature as a way to survive.

C (25:52)

Wow, these facts are totally slothsome. Anybody? Come on.

B (26:00)

Oh, Sandon.

A (26:02)

That's it for this episode of Brains On.

B (26:05)

Brains on is produced by Manica Wilhelm, Sandon Totten, Mark Sanchez and Molly Bloom.

A (26:12)

We had production help from Ruby Guthrie and Christina Lopez and engineering help from Veronica Rodriguez and Alejandro Juan. Special thanks to Kathy Aru, Lupe Dos Santos, Rosie Dupont, Paul Guthrie and Jack Silvernagel. Now it's time for the Brains honor roll. These are the incredible kids who keep the show going with their questions, ideas, mystery sounds, drawings and high fives. Avni from Los Gatos, California Oliver from Arunga, Australia. Gordon from Hong Kong. Ophelia and Guinevere from Panama City Beach. Florid, Henry from Walden, New York Lyra from Atlanta, river from Pennsylvania. Nora and Ethan from Overland Park, Kansas Nico from South Bend, Indiana Zaina from Portola Valley, California. Everly and Sutton from Ojai, California. Daniel from London, England. Robert from Midland, Georgia Uriah, Ari and Bodhi from Chango, Illinois. Emerson from Jonesboro, Tennessee Madeline and Juliana from Maple Valley, Washington Malaya and Nia from Albany, California. Ishan from Sacramento. Archie from Melbourne, Australia. Amelie from Oxford, England. Ollie and Emmy from from Clovis, California. Milan from Cambridge, Ontario Gibran from Dubai Blaze from Pennsylvania Benton from Alexandria, Virginia Oscar from Cincinnati. Penelope from Newark, Delaware Adena and Ariz from Austin, Texas. Paisley from Australia. Arthur and Andre from Atlanta. Joe from Portland, Oregon Grayson from Brooklyn, New York Emerson from British Columbia. Vera and Audrey from St. Paul, Minnesota. Jeffrey from Los Angeles. Rachel and James from Edmonton, Alberta. Jack from Whitby, Ontario marlo from Bristol, UK Marley from Toronto, PJ from Evanston, IL Zach from Blue Haven, Australia. Harvey from Sheffield, England. Keon from Calgary, Alberta. Margaret and Galen from Littleton, Colorado. Luca from Greensburg, Pennsylvania Tessa from Massachusetts Henry from Phoenix, Sanjana from Concord, North Carolina. Lucy, Jack, Guthrie and Rose from Arlington, Texas. Matthew from Dayville, Connecticut Harper from Detroit Frankie from Georgia Marshall from Redmond, Washington. Carmen from Utah, Edie from Victoria, Australia Sean from Wayne, New Jersey Frances and Hansi from Asheville, North Carolina, sky from Niskayuna, New York Evelyn from Houston, Texas Mira from Santa Cruz, California and Estrella Geo, ncc from Saugus, Massachusetts. We'll be back soon with more answers to your questions.

B (28:21)

Thanks for listening.