[RADIOLAB INTRO]

RACHAEL CUSICK: If you've ever stepped foot on an American boardwalk, you've likely encountered a deep fried Oreo, a roller coaster you're surprised still functions, and maybe even a hermit crab.

LATIF NASSER: This is Radiolab. I'm Latif Nasser.

LULU MILLER: And I'm Lulu Miller.

LATIF: And today's episode is a—I guess you could call it a double-decker crab cake.

LULU: [laughs]

LATIF: Two stories about crabs that will scuttle all over your brain.

LULU: And if you stick with them, end up teaching you something pretty deep about how to be a human on this planet.

LATIF: The first comes to us from our producer Rachael Cusick. She originally told it live before an audience at Pop-Up Magazine. Lulu and I were both in that audience in different cities. Picture her in a fantastic purple jumpsuit. And behind her is a huge animation of a Ferris wheel and an oceanside boardwalk.

RACHAEL: The first time I saw a hermit crab I was 11, spending the weekend with my grandpa in Atlantic City. The crab was a boardwalk souvenir, tucked inside a shell painted to look like Spongebob SquarePants. I didn't know then that that hermit crab wasn't born on a boardwalk or in a pet store or a lab, he was snatched from the wild, likely from Indonesia or Central America, and given a one-way-ticket to the armpit of New Jersey.

RACHAEL: Virtually every single hermit crab you've ever seen has been stolen from its home in this way, and that's because no one has figured out how to mass-breed hermit crabs in captivity, not even biologist Chris Tudge.

CHRIS TUDGE: I think I could probably honestly say I've done more work on the reproductive biology of hermit crabs than anybody else pretty much ever.

RACHAEL: Now hermit crabs are elusive creatures. They change color and even the shells they call home.

CHRIS TUDGE: They pass through multiple stages, and change their shape and their size. And the environmental conditions you need for them are really quite specific.

RACHAEL: I first read about all of this in a science article by Samantha Edmonds in The Outline. She says hermit crabs are hard to study, even harder to breed. A few people tried to reproduce them, but none could crack the code of breeding them in large numbers. Partially because we didn't care enough about them to learn. They're not tasty, they're not cute. No one saw enough value in them. But then Mary came along.

MARY AKERS: They say scaly is the new fluffy.

RACHAEL: Who says that?

MARY AKERS: [laughs] I don't know.

RACHAEL: Mary Akers is an artist who fell into hermit crabs a few years back when her last kid left for college.

MARY AKERS: When I became an empty nester, my three kids had graduated, I said, "Now I can do what I wanna do, right?" I was going through menopause. It was kinda like get rid of all that estrogen. I'm 12 again!

RACHAEL: Mary needed hobbies. She started doing pottery again, and one day a woman in her group said she was looking to offload a hermit crab after her kid lost interest.

MARY AKERS: And I was immediately like, "Oh, could I? Do I? Will I? I hesitated more because of my husband. Like, and I didn't confess to him right away that I said yes. I said, "We're gonna crab-sit while they go on vacation."

RACHAEL: Eventually she came clean to her husband. Said she wanted the crab to stay for good. But she quickly realized she didn't know much about how to care for her new pet.

MARY AKERS: And I Googled and I was like, "Oh my gosh, they need friends. They need more room. They need sand. They need real food."

RACHAEL: She learned they can live for decades if cared for properly. And when she realized her own hermit crab was stolen from its home, she felt a profound sense of injustice.

MARY AKERS: Any other creature that lives 50 years, we think of elephants, we think of whales, we think of even the great tortoises, right?  We revere. But we don't do that with hermit crabs. They are literally throw-away pets.

RACHAEL: These cracks in our world that most of us skip over or never see at all, they suck Mary in. Mary is the child of an alcoholic father, the sister of someone with mental illness, and a nurturing mother of three. She's spent her entire life caring for others, hoping she could protect them if she just loved them hard enough. Now in these hermit crabs, Mary found a new space for her love to fill.

RACHAEL: So Mary went out and bought more hermit crabs. Put 'em in a tank the size of a grand piano, and declared them the new tenants of her daughter's old bedroom.

RACHAEL: What is that called?

MARY AKERS: Oh, the—the crabs are in their crabitat.

RACHAEL: Things escalated. Mary watched them run on a hamster wheel for hours. She'd share her leftovers with them, and then give them popcorn as a midnight snack. She even named each crab—Artemis, Garbo, Lola—then started learning what made them tick.

MARY AKERS: I've noticed that some of them have personalities where they like either the blingy-er shells, and I have one that likes a green shell pretty much all the time. Sometimes I know, like, "He's gonna love that shell!"

RACHAEL: Then one day Mary saw one of her crabs walking funny.

MARY AKERS: And I got my little flashlight and I shone it in there and I'm like, "What is that in your sh—what? Do you have a growth? Do you have a tumor? Like, what is that?" Well, it was eggs in her shell. And I was like, "Oh yeah, baby!"

RACHAEL: That summer, Mary's Crabitat morphed into a laboratory, one dedicated to delivering these eggs into crabhood, and one that was a daily construction of love. She built a series of pools so the pregnant crab could pick which water she liked best to release her eggs into. Once the eggs hatched, Mary used a turkey baster to swap out the dirty water the crabs swam around in, changing the metaphorical diaper of thousands of baby crabs.

RACHAEL: All along the way, Mary lingered above her crabitat, cooing to babies.

MARY AKERS: And these little guys, I think about it sometimes, have been seeing my big moon face, you know, hovering over them, staring at them. What do they think? Like, am I the landscape of their life?

RACHAEL: Mary would have a few good days, but then the number of babies would plummet. The crabs' struggles, their needs, they consumed Mary.

MARY AKERS: What am I not giving them, right? That's the recurring refrain in my head. What do they need? What am I not giving them?

RACHAEL: She wanted to smooth out every speed bump life put in their way. Still the number of babies continued to drop until there were none left.

MARY AKERS: I got to the final stage. That's the closest they get to being a land hermit crab before they're a land hermit crab.

RACHAEL: She felt gutted, but not wholly defeated. Because the next summer, when one of her crabs waddled with eggs yet again, she got back to work.

MARY AKERS: I had a plan. I had a lot more things I wanted to try.

RACHAEL: She built a new kind of tank, grew a different seaweed, bought better foods. She even built a ramp inside one of her tanks to simulate a hermit crab's journey from the ocean onto dry land. But far more radically, Mary did something she really, really does not like to do.

MARY AKERS: I had to figure out how to not care so much. I can't be God. I can't be God. I don't wanna be God, right? But I can be the ocean. I can be the ocean.

RACHAEL: That phrase—be the ocean—it became Mary's companion through all this.

MARY AKERS: A little mantra which sometimes I recite. "Be the ocean."

RACHAEL: Every time she found herself wanting to rescue the hermit crabs from some amorphous potential harm ...

MARY AKERS: "Be the ocean."

RACHAEL: ... Mary would imagine the vast waters that raise hermit crabs. How these microscopic specks managed to float around in the maelstrom, and make it out the other side.

MARY AKERS: So I would actually agitate them more and move it around and give them, like, a low tide and a high tide. Today I'm the ocean, and today the ocean is dirty and mean!

RACHAEL: Eventually, the babies grew. They survived major milestones, they formed limbs, and then flew through the water like Superman. And then one day, Mary watched a single hermit crab pull its body up onto the staircase, and break through the border between water and land.

MARY AKERS: I cried. I wept. I wanted a soundtrack playing.

RACHAEL: Meanwhile, more crabs kept coming. Mary took out a piece of paper and began making a tally mark for each crab that made it to land.

MARY AKERS: And then by, like, day five, it's the march of the penguins, right? I'm like, "Oh God. Okay, there's another one. There's another one."

RACHAEL: By the end of the summer, Mary had added 204 new hermit crabs to the world. With a turkey baster and tender loving care, Mary accomplished the impossible. It's been five years since that first hermit crab climbed out of the water in Mary's crabitat. Each year she breeds a new batch. Some years she reaches up to 700 crabs. She's bred so many hermit crabs that now she adopts them out, making sure they go to responsible homes.

RACHAEL: Learning about all of this, I wondered why it was Mary who could figure out this thing and scientists couldn't. It was the question Chris Tudge asked himself too. Remember Chris? He was the guy who should have figured out what Mary did but couldn't. Late one night, he found himself reading Mary's blog, where she'd been documenting her entire breeding process.

CHRIS TUDGE: And by the end of it, my first impression was, "Oh my God, she actually did it!"

RACHAEL: The thing Chris found most impressive was Mary's ability to be the ocean.

CHRIS TUDGE: It's just stunning. You know, you have to keep the waste levels down, you have to keep the oxygen up. The light levels have to be right. The ocean's a constantly changing entity, and here she was reproducing the ocean in little tiny bowls.

RACHAEL: Why is it so hard to recreate? Like, what about it is hard to copy?

CHRIS TUDGE: The chaos. In the same piece of ocean, there's millions of other species who are trying to do the same thing that need slightly different conditions, so the chaos is benefitting everybody a little bit.

RACHAEL: That turbulence Mary originally resisted, it's the very thing Chris said the crabs needed to survive. I like to think these hermit crabs gave Mary the chaos she needed to survive too.

MARY AKERS: I could literally all day every day do nothing but try to get it perfect. But that's not best for the crabs, that's definitely not best for me. So it's a balance of how much do I allow myself to feel responsible.

RACHAEL: If you share your life with another creature—a hermit crab, a human—I think this is the maddening fact we're faced with every day: that our love can only do so much.

MARY AKERS: You're not responsible for everyone. You're not responsible for saving everyone. Well, I wanted to save my dad. I can't save my dad, I was a kid, you know? My kids, letting go—like, life for me, my lesson has always been just let go, Mary. Let them be crabs.

RACHAEL: Thank you.

LATIF: Producer Rachael Cusick. We should add real quick: Mary and Chris actually struck up a friendship after Rachael interviewed them for this story. Mary sends Chris photos of her crabs under the microscope. Chris regularly presents at Mary's annual hermit crab conference—CrabCon. He even started up a few projects in his lab inspired by Mary's online hermit crab society. It's beautiful.

LULU: Now when we come back, we are going to go even deeper into that strange relationship between crabs and chaos, and ask if it's not just that crabs that need chaos to be born—like, that was the secret ingredient the hermit crabs needed—but does chaos need a crab? Or, like, want a crab? Sort of. You'll see. The scientists are gonna straighten it out. Stick with us.

LATIF: Don't scuttle away.

LULU: Radiolab.

LATIF: Latif.

LULU: Lulu.

LATIF: Crabs.

JO WOLFE: Hi!

LULU: Hello!

LULU: So on to our next layer of the crab cake, our next crab story. We are here with this Harvard crab scientist, Dr. Jo Wolfe.

JO WOLFE: Am I allowed to say any, like, swear words?

LULU: Oh!

JO WOLFE: I should not do that, right?

LULU: You can!

LULU: And she probably should because she recently uncovered something f-ing bonkers about crabs that I have been dying to talk about on the radio.

LULU: So excited about this, Jo!

JO WOLFE: Yeah, awesome.

LULU: So the whole thing really starts with this kind of dry scientific crafting project.

LATIF: Okay.

LULU: Jo, along with her colleagues Heather Bracken-Grissom and ...

JAVIER LUQUE: Hello, hello!

LULU: ... Javier Luque, wanted to take all crabs in the world and just make a massive crab family tree.

JAVIER LUQUE: The crab tree of life.

LULU: So to actually build this crab family tree, they're not taking photos and scrapbooking, they're taking DNA. They sequenced the DNA from hundreds of different crabs.

JAVIER LUQUE: Dungeness crabs.

LULU: Snow crabs.

JO WOLFE: The coconut crab.

LATIF: Huh!

LULU: They've got ...

JAVIER LUQUE: Chesapeake Bay blue crabs.

LULU: Porcelain crabs.

JO WOLFE: They look more like a lobster ...

LULU: Aren't lobsters crabs?

JO WOLFE: No, lobsters are not crabs.

LULU: Okay.

JO WOLFE: Lobsters are lobsters.

LULU: [laughs] Okay, sorry.

LULU: There are hairy crabs, mud crabs, tree crabs.

LATIF: Trees? There are tree crabs?

LULU: Yeah!

LATIF: What? In my head, crabs go with water. You're telling me crabs can live in trees.

LULU: Yeah!

LATIF: Amazing.

LULU: So they're putting all this data into some super powerful computer. And when they're done, they press a button and they're watching this computer build this tree. Branches and branches and crabs and crabs ...

JAVIER LUQUE: It would have been great if it was like that, but no it was less—less dramatic. It was more like ...

JO WOLFE: You put all your data in, you press a button, and you wait.

LULU: For a pretty long time.

JO WOLFE: For, like, months.

LATIF: Whoa!

LULU: The computer takes a while to do its thing.

JO WOLFE: And then you get the email, and it's like, "Your analysis is finished!" And ...

LULU: And it is shortly after that that they realize crabs have evolved five separate times.

LATIF: What does that mean?

LULU: Like, on five completely different branches, from creatures that are not crabs, five different times the crab form has evolved. It's just like—it's like, bloop! Here's a crab over here! Bloop! Here it is over there. Bloop! Whoa! Way over there!

LATIF: And the thing that you're say—and it's the—it's the body shape is what we're talking about. So it's like, this body shape came up again and again and—and—hmm.

LULU: A pancake. A pancake with 10 legs, two of which—at least two of which have pincers. Yeah. Yeah. Exactly.

JO WOLFE: That these multiple different lineages that start from things that are kind of different turn out to look kind of the same. That's just weird, right?

LULU: This is why I called Jo. Because when she published that paper, the internet freaked out.

[ARCHIVE CLIP, TikTok: Creatures that are not related to crabs are eventually evolving into crab-like shapes.]

LULU: People were making TikToks.

[ARCHIVE CLIP, TikTok: So we're talking, like, shrimp and lobster and other crustaceans. All of them are evolving into similar forms.]

LULU: There were ...

[ARCHIVE CLIP, TikTok: [singing] I could be hurtful, I could be purple, I could evolve into a crab.]

LULU: ... songs.

[ARCHIVE CLIP, TikTok: [singing] I could be crab, I could be crab, I could be crab.]

LULU: It seemed to open this speculative trap door.

[ARCHIVE CLIP, TikTok: My first thought is when are—when am I gonna be a crab, you know? When are wolves gonna be crabs, right?]

LULU: I mean literally, tens of thousands of likes and comments ...

[ARCHIVE CLIP, TikTok: Everything is slowly turning into a crab.]

LULU: ... that were converging around a pretty similar interpretation—which was honestly, the one that I had—which was basically: does evolution want a crab?

LATIF: Hmm.

LULU: Is it just, like, right for life?

[ARCHIVE CLIP, TikTok: What this also means is that statistically speaking, there are space crabs out there somewhere in the universe.]

JO WOLFE: I think crabs might be Mother Nature's favorite shape. I mean, it's such a surprise to me that it became a meme.

LATIF: Okay. Okay, not to, like, denigrate the scientists who, like, put a lot of—I think it's super fascinating sort of the evolutionary tree that they're building. The crab appearing five times? Like, I don't know. I don't—I don't see it as, like, a profound thing. Five times out of how many times? Like, out of how many things that are being created? Like, is it—is it so crazy that, like, bats fly and birds fly and they figured out how to do that separately! Or, like—like, giraffes have long necks but also brachiosauruses had long necks. Or, like, worms are, like, long and stringy and snakes are long and stringy. Like, you're like, "Oh, okay. Like, yeah, that makes sense." Like, with the crabs, I don't know. It doesn't seem so much crazier than all the other stuff.

LULU: Okay but, like, you're talking about a neck or a wing, like, one body part, one nifty adaptation. With the crabs, it's like this whole complex situation. You've got multiple limbs, some of which have pincers, and a little pancake body and the googly eyes and you often walk sideways. It's like a very bizarre beast that keeps rising from the ocean again and again and again and again and again.

LATIF: Right.

LULU: And so inaccurate, wild speculations aside about what that means for all life, where all life is heading, a real scientific question remains, which is why does it keep reappearing? Like, what does the crabby shape actually help you with? What does it give you?

LATIF: Yeah, right. Right. So what is it good for?

LULU: So ...

JAVIER LUQUE: [clears throat]

LULU: ... Javier Luque has thought a lot about this, and he said that scientists think a very important clue lies in this one moment about a hundred million years ago.

JAVIER LUQUE: It was a world that was warming up. It became really, really hot. The temperature of the globe rose several degrees. The poles melted, so it raised also the sea level several hundred meters. And those floodings also made very shallow seas that can get into the lands.

LULU: It was a moment that looked eerily like the one we're entering now. And like now, a bunch of species began dying off.

JAVIER LUQUE: So lobsters and shrimp dwindled.

LULU: Because they just couldn't survive all that change. But crabs ...

JAVIER LUQUE: They radiated and bursted all over the world.

LULU: And scientists think that that goofy, leggy complex body shape is what allowed crabs to MacGyver their way into surviving.

JAVIER LUQUE: They can use their body as a Swiss army knife with a bunch of different tools.

LULU: So the legs, you know, they can scuttle on land of course, but they can also swim or fight or grab prey.

JAVIER LUQUE: Some of those legs grab a sea urchin, an anemone, and just use them as hats and camouflage themselves.

LULU: [laughs] Whoa!

LULU: And that sleek little pancake body? It helps them hide from predators way better than, say, lobsters with that big, honkin' tail to grab. And then there are all these subtler parts we don't really see, like these incredible gill-like things that allow them to breathe in both air and water, which lets them live, like, anywhere. They can live underwater, they live on beaches, they can live in marshes, they can live in rocky shores, they can live in trees. So that, like ...

LATIF: How do they climb the tree? That's the thing I don't understand.

LULU: I don't—I mean, I don't know, dude. If you've got 10 legs, it makes it a little easier, right? And you weigh like a paper clip.

LATIF: But they're so little! Like, they can't hug the tree. Like, they don't—what kind of—how do you get purchase on there?

LULU: Yeah, but if they weigh nothing, you just like, then you just—like, how do beetles climb trees? Why does every bug climb a tree? Because it has a hundred legs and it weighs nothing. I don't know. [laughs] Sorry. I'm, like, angry at you. But I actually don't have—I'm like, "Duh!" But I don't know why.

LATIF: Okay, keep going. Keep going.

LULU: But let me just land the grand point here. The scientists think that what the crab body plan actually gets you, the reason it keeps evolving again and again is that its niche, the thing it is particularly good at is change.

LATIF: Hmm!

LULU: Upheaval. Chaos. Which Javier thinks will give crabs an edge in whatever world we humans are making for all of us.

JAVIER LUQUE: If we keep the world we're going, we are gonna be gone from here in the not-so-distant future, but crabs might start becoming more creative and using things and playing with sticks. Who knows, given enough time they might become the next us.

LULU: Given enough time, we probably won't become crabs, we'll more likely become obsolete and the crabs will keep surviving.

JAVIER LUQUE: [laughs] Exactly. Exactly. [laughs]

LATIF: This episode was reported by Rachael Cusick and Lulu Miller, and produced by Becca Bressler with help from Ekedi Fausther-Keeys.

LULU: With mixing help from Arianne Wack. It was edited by Pat Walters, who would love us all to take a brief hiatus on pitching crab stories.

LATIF: Yeah.

LULU: No promises, Walters. No promises.

LATIF: Rachael's Pop-Up Magazine piece had live music by Minna Choi and the Magic Magic Orchestra with sound design by Jeremy Bloom.

LULU: Special thanks to Heather Bracken-Grissom and her crab lab at Florida International University, Franz Anthony and the entire team at Pop-Up Magazine, Randi Rotjan, Jan Pechenik, Renae Brodie, Samatha Edmonds, whose story from The Outline introduced us to Mary.

LATIF: Also, we are looking for an intern to join us remotely this summer. If you are interested in getting paid to hang out with us and learn how we make Radiolab, our deadline for submitting applications is on Wednesday March 15 at 5:00pm Eastern time.

LULU: Applications are open to students and recent graduates. You can find out more about how to apply at Radiolab.org/about. And thanks!

LISTENER: Radiolab was created by Jad Abumrad and is edited by Soren Wheeler. Lulu Miller and Latif Nasser are our co hosts. Dylan Keefe is our director of sound design. Our staff includes Simon Adler, Jeremy Bloom, Becca Bressler, Rachael Cusick, Ekedi Fausther-Keeys, W. Harry Fortuna, David Gebel, Maria Paz Gutiérrez, Sindhu Gnanasambandan, Matt Kielty, Annie McEwen, Alex Neeson, Sarah Qari, Anna Rascouët-Paz, Sarah Sandbach, Arianne Wack, Pat Walters and Molly Webster. With help from Andrew Viñales. Our fact checkers are Diane Kelly, Emily Kreiger and Natalie Middleton.]

[LISTENER: Hi, I'm Erica in Yonkers. Leadership support for Radiolab’s science programming is provided by the Gordon and Betty Moore Foundation, Science Sandbox, a Simons Foundation initiative, and the John Templeton Foundation. Foundational support for Radiolab was provided by the Alfred P. Sloan Foundation.]

 

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