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Speaker 1: Hey you welcome to Stuff to Blow your Mind. My

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Speaker 1: name is Robert.

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Speaker 2: Lamb and I'm Joe McCormick, and it's Saturday. We are

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Speaker 2: bringing you an episode from the vault. This one originally

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Speaker 2: published on June thirtieth, twenty twenty two, and it's part

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Speaker 2: two of our series The Lesser of Two Crab Claws,

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Speaker 2: about asymmetry in the natural world.

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Speaker 3: Enjoy Welcome to Stuff to Blow Your Mind, a production

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Speaker 3: of iHeartRadio.

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Speaker 1: Hey, welcome to Stuff to Blow your Mind. My name

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Speaker 1: is Robert Lamb.

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Speaker 2: And I'm Joe McCormick, and we're back with part two

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Speaker 2: of our series on asymmetry in life. Now. In the

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Speaker 2: last episode, we talked about the concept of bilateral symmetry,

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Speaker 2: where basically all of the higher animals have body plans

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Speaker 2: where the left and the right sides are more or

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Speaker 2: less a copy of one another. In other words, along

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Speaker 2: one of the three dimensions of space, our bodies are

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Speaker 2: approximately mirrored, at least on the outside. Now, in most organisms,

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Speaker 2: there are minor variations on this type of symmetry, but

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Speaker 2: occasionally there are species with isolated but radical deviations, where

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Speaker 2: like one feature on the outside of an otherwise mirror

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Speaker 2: flipped half of the body is drastically different from what

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Speaker 2: you find on the other side. Examples that came up

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Speaker 2: last time were the tusk of the nar wall, where

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Speaker 2: in most cases it's actually the left maxillary canine tooth

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Speaker 2: so weird it's the left fang basically of this whale

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Speaker 2: stabbing through the upper lip and it becomes a single tusk.

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Speaker 2: We also talked about the blowholes and skulls of toothed whales,

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Speaker 2: such as the sperm whale, where in many cases these

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Speaker 2: have developed left right mismatches that seem to have evolved

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Speaker 2: to support the capacity for echolocation. We also talked about

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Speaker 2: the cock eyed squid, which has two extremely different eyes

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Speaker 2: for looking into extremely different worlds, one for the water above,

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Speaker 2: which is filtering sunlight, and one for the water below,

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Speaker 2: which may contain flashes of bioluminescence. And so today we

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Speaker 2: wanted to pick up the series by talking about some

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Speaker 2: more fascinating examples of lopsided animal evolution. Animals with halves

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Speaker 2: that mostly match but in one capacity or another do not,

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Speaker 2: and why that would be. Now, there are many great

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Speaker 2: examples of asymmetrical evolution incrustations, and we may actually save

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Speaker 2: some of these for the next part in the series.

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Speaker 2: I know we're going to go to at least three

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Speaker 2: parts here, but for today's episode, I wanted to start

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Speaker 2: by getting out the lemon and the drawn butter, because

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Speaker 2: this is an asymmetry that you don't have to be

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Speaker 2: a specialist a marine biologist to notice for yourself. If

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Speaker 2: you've ever eaten, or even just seen a cooked lobster,

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Speaker 2: you probably have noticed a weird mismatch between the lobster's

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Speaker 2: two claws. Rob, I assume you've you've seen this for yourself.

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Speaker 1: Yes, yes, they're not not as recently as you have.

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Speaker 1: Because I believe this this was the inspiration for this episode. Right,

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Speaker 1: you recently ate a lobster?

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Speaker 2: Oh, I don't. I don't think I even told you that,

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Speaker 2: But yeah, this probably had something to do with it.

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Speaker 2: I can't confirm the inner workings of my subconscious mind.

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Speaker 2: But not too long ago, I was in the I

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Speaker 2: was in New England where where lobster is king. I'm

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Speaker 2: not gonna do the accent, but lobster is king. And

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Speaker 2: I did. I did, in fact eat a lobster, and yeah,

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Speaker 2: and I noticed stark differences between the claws, even not

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Speaker 2: just looking at them, but in my fingers, you know,

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Speaker 2: one claw was sort of a pleasure to crack open

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Speaker 2: and get the meat out of, and the other one.

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Speaker 2: When I handled the inside of the pincers, they were

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Speaker 2: much sharper, and the spines within them were much smaller

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Speaker 2: and kind of were irritating and unpleasant to the fingers.

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Speaker 1: Fascinating.

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Speaker 2: So what's going on with this claw mismatch? Oh and

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Speaker 2: by the way, we should be clear that we're talking

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Speaker 2: specifically about the American lobster or Homarus americanas this is

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Speaker 2: the lobster you find along the northern edge of the

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Speaker 2: eastern coast of North America, so all up through like

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Speaker 2: the north half of the eastern United States and up

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Speaker 2: into Canada.

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Speaker 1: This is like the red lobster lobster, the lobster from

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Speaker 1: your grocery store that has rubber bands on its claws,

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Speaker 1: not like the Caribbean lobster.

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Speaker 2: Yeah, not the rock lobster, though I hear those can

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Speaker 2: be good eating too. I've never had man. But anyway,

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Speaker 2: so the American lobster. So you look at these two claws,

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Speaker 2: and what you'll notice is that usually one claw is

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Speaker 2: longer and flatter, with a longer I don't know what

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Speaker 2: the technical term for this is the danger zone, the

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Speaker 2: space between the two pincers and the insides of the

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Speaker 2: pincers on this flatter, longer claw seem to be sharper,

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Speaker 2: more like a kind of spiky pair of scissors. And

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Speaker 2: then the other claw is shorter in length but bulkier,

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Speaker 2: thick with muscle, and the inside edges of its pincers

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Speaker 2: have a sort of rounder, larger grain texture, almost pebbled,

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Speaker 2: rather than with tiny spines. These claws are commonly referred

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Speaker 2: to as the cutter and the crusher, respectively. I think

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Speaker 2: the cutter is sometimes called the pincher also, But yeah,

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Speaker 2: they are what they sound like, the cutter and the crusher.

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Speaker 2: So what's going on? Why the two different claws on

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Speaker 2: the same lobster? How does a lobster end up with

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Speaker 2: two very different claws and what are they for? Well,

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Speaker 2: to answer this question, I was reading what I thought

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Speaker 2: was a really interesting older article in American Scientist magazine.

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Speaker 2: So this is from nineteen eighty nine by an author

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Speaker 2: named C. K. Govind who was a professor of zoology

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Speaker 2: at the University of Toronto, and it's called asymmetry in

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Speaker 2: Lobster claws. Seems like a lot of Govin's research focused

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Speaker 2: on crustaceans, and so Govin begins by pointing out a

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Speaker 2: number of different examples of asymmetry and animals. He talks

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Speaker 2: about lateral dominance or handedness in humans and even mentions

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Speaker 2: I thought this was interesting. In some songbirds, such as canaries,

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Speaker 2: you have bilateral asymmetry in their singing apparatus. Song production

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Speaker 2: seems to be centered on structures in the left half

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Speaker 2: of the syrinx, And so when you see asymmetries like this,

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Speaker 2: you can ask all kinds of questions about them. But

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Speaker 2: one thing is that you might just assume them to

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Speaker 2: be permanent, fixed features of anatomy, hard coded by genes

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Speaker 2: and express through early development. But it's interesting that there

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Speaker 2: are some cases where asymmetry in an animal's body seems

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Speaker 2: to be reversible. Just for one example, In some cases

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Speaker 2: of lateral dominance, damage to the dominant side of the

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Speaker 2: brain or body can cause the non dominant side to

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Speaker 2: assume some functionality previous localized to the side that has

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Speaker 2: now been incapacitated, and this can lead us to wonder

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Speaker 2: how do these asymmetries develop in the first place. So

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Speaker 2: Govind argues that by examining the lobster, and this is

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Speaker 2: the American lobster Homarus americanas we can see an example

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Speaker 2: of a symmetry emerging not purely as a result of

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Speaker 2: genetic coating, but actually as a result of how the

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Speaker 2: lobster interacts with its environment during a crucial early period.

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Speaker 2: And this is what brings us back to the crusher

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Speaker 2: claw and the cutter claw. So I want to read

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Speaker 2: from Govin's introduction here quote. As any self respecting gourmet knows,

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Speaker 2: the paired claws of the American lobster have decidedly different morphologies.

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Speaker 2: One claw, called the crusher or major claw, is short, stout,

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Speaker 2: and heavy, with molar like teeth on its biting surface.

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Speaker 2: I think that's a good comparison, molar like teeth. It's

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Speaker 2: the pebbles are like your back teeth. It's hard to

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Speaker 2: imagine them snipping something off. Instead, it's like they would

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Speaker 2: sort of grab hold of it and be able to

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Speaker 2: smash it real good.

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Speaker 1: Yeah. When I'm looking at a picture of this, I

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Speaker 1: can't help but imagine the lobster putting on a puppet

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Speaker 1: show with just its pincher and its crusher and each

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Speaker 1: of them have you know, different characters like like hey

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Speaker 1: on the crutcher, Hey on the pincher, and they interact.

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Speaker 2: You know, definitely the cutter claw has the higher voice.

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Speaker 1: Yeah.

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Speaker 2: Yeah, Let's say if they're street fighter characters, crusher claw

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Speaker 2: is zangief and cutter claw is is what maybe maybe embison?

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Speaker 1: Yeah yeah maybe so longer does.

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Speaker 2: That cheap spinning move? Yeah? Okay, So anyway, so that's

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Speaker 2: what that is. That that's the molar teeth on the

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Speaker 2: biting surface. But then, to continue the quote, the other

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Speaker 2: called the cutter or minor claw is long and slender

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Speaker 2: with incisor like teeth or your incisors are your front teeth,

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Speaker 2: the ones that you use to bite off things, you know,

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Speaker 2: not to mash them up, but to separate them from

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Speaker 2: what they're originally stuck to and pull them into your mouth.

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Speaker 2: They're for cutting. So what Govind writes is quote what

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Speaker 2: the gourmet might may not know, and what lobstermen know

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Speaker 2: painfully well, is that the cutter claw can give a quick,

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Speaker 2: nasty pinch. Indeed, it's dactyl, meaning the part of the

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Speaker 2: claw that moves, the closing part can close against the

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Speaker 2: opposing polyx within twenty milliseconds, which is several times faster

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Speaker 2: than any human reflex. In contrast, the crusher claw closes

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Speaker 2: very slowly, but with enough force to crack open the

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Speaker 2: shells of oysters, muscles, and other bivalves. And it's true,

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Speaker 2: molluscs such as muscles are a big source of food

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Speaker 2: prey for the American lobster. So it crawls along the

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Speaker 2: ocean floor in its adult phase, and what does it eat. Well,

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Speaker 2: it might eat some worms of various types and stuff,

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Speaker 2: but it's really going to be looking for mollusks such

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Speaker 2: as muscles. It wants to crack those shells open and

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Speaker 2: get that meat inside. Also, while we're mentioning anatomy, this

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Speaker 2: is unrelated, but I just have to say American lobsters

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Speaker 2: pe out of their faces. You kind of can't bring

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Speaker 2: lobsters up without mentioning that they face pee, and they

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Speaker 2: face peece specifically at each other, whether it's a mate

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Speaker 2: or rival. So lobster sees another lobster, they're probably going

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Speaker 2: to be peeing out of their faces at them. Though,

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Speaker 2: is best I can tell. The face peeing is symmetrical.

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Speaker 1: Okay, well that's good to know, But coming.

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Speaker 2: Back to the claws. So the difference in the speed

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Speaker 2: of pinching between the two claws is evidence of an

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Speaker 2: underlying difference, and not just the shape of the claw,

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Speaker 2: but its muscular composition. These claws have different types of

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Speaker 2: muscle in them. About ninety percent of the space of

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Speaker 2: a lobster's claw is taken up by the closer muscle.

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Speaker 2: This is the muscle responsible for bringing the pincers together.

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Speaker 2: Only a relatively tiny muscle is devoted to opening the claw,

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Speaker 2: which is why a lobster might be able to pinch

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Speaker 2: with massive force, but a simple rubber band can render

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Speaker 2: its claw harmless by holding it closed. It has way

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Speaker 2: more strength for closing than it does for opening.

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Speaker 1: I think that's a great point.

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Speaker 2: Yeah, I didn't double check this, but I just remembered

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Speaker 2: hearing a fact that may or may not be true

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Speaker 2: about alligator and crocodilian jaws like that when I was

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Speaker 2: a kid. That you know, So they can close their

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Speaker 2: jaws with massive force, but you can actually quite easily

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Speaker 2: hold their jaws together and they can't open them back up.

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Speaker 1: Oh, so this would be the secret of the feet

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Speaker 1: of the crocodile or alligator wrestler. Yes, Okay, Now coming

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Speaker 1: back to the lobster, does that mean that the closer

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Speaker 1: muscle is the delicious part? This is like that prize

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Speaker 1: sliver of meat from the claw.

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Speaker 2: Well, I don't know about relative flavors. The closer would

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Speaker 2: be the big one, and the opener is obviously you know,

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Speaker 2: it's like ten percent. It's like one ninth the size

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Speaker 2: of the closer muscle. So I don't know exactly what

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Speaker 2: you're getting. When you have a cooked lobster and you

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Speaker 2: pull it out of there and eat it, you probably

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Speaker 2: some combination of the two.

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Speaker 1: Well, I guess in my experience, like the bigger the

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Speaker 1: meat you pull out of a crustacean, like the greater

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Speaker 1: the sense of victory. Yeah, And likewise, the more that

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Speaker 1: one is picking through the crustacean with and removing tiny

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Speaker 1: slivers to consume, the delicious they may be. But the

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Speaker 1: more I feel like I'm some sort of like a

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Speaker 1: creature stooped on a primordial shore scavenging pieces from a

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Speaker 1: dead animal.

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Speaker 2: Getting the pieces from the tiny legs and the tiny

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Speaker 2: parts makes you feel more like it's the road, you know,

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Speaker 2: like looking for seeds or something to eat.

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Speaker 1: But pulling out that big piece of claw meat. You

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Speaker 1: feel like a king.

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Speaker 2: That's right, that's luxury. Okay, So you got these different muscles.

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Speaker 2: You got the closer muscle, the opener muscle. What makes

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Speaker 2: the difference in the speed of pinching between the crusher

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Speaker 2: claw and the cutter claw is the type of muscle

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Speaker 2: fiber that the closing muscle is composed of. The cutter

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Speaker 2: claw is made of about ninety percent fast muscle fiber,

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Speaker 2: which is exactly what it sounds like. It's designed to

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Speaker 2: move quickly along with what Govind calls a quote small

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Speaker 2: ventral band of slow muscle, whereas the crusher claw is

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Speaker 2: almost entirely or not almost, I think is entirely one

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Speaker 2: hundred percent slow muscle fiber. So it closes more slowly,

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Speaker 2: but can close with incredible force. And as a result,

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Speaker 2: cutter snaps fast and sharp. Crusher closes slowly, but but

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Speaker 2: it's massive. So you could compare this to handedness in humans,

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Speaker 2: but Govind notes that while the majority of humans are

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Speaker 2: right handed, the distribution of claws on adult lobsters seems

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Speaker 2: equally probable both ways. It's not like the crusher claw

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Speaker 2: is always on the left side. It's it's a coin flip.

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Speaker 1: Which, which would mean that there's that natural selection is

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Speaker 1: not pushing it one way or the other.

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Speaker 2: Right, it's not, I mean it's push. It's clearly pushing

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Speaker 2: the lobsters to have two different types of claws for

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Speaker 2: the asymmetry to exist. But it doesn't seem to matter

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Speaker 2: which side is which, at least not in a way

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Speaker 2: that's universal across lobsters. It is it is decided by

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Speaker 2: each individual lobster in development. So a great question then is, Okay,

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Speaker 2: if the bilateral asymmetry is individual to each lobster and

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Speaker 2: it's a random coin flip at least from a statistical

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Speaker 2: point of view, what causes the change? How does the

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Speaker 2: individual lobster's body when it's growing pick which side becomes which. Well,

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Speaker 2: we can look at lobster larval development to see this.

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Speaker 2: So when they're tiny little things swimming around before they

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Speaker 2: become the big lobster, as we recognize, during the early

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Speaker 2: larval stages, the claws of the lobster are undifferentiated. They're

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Speaker 2: exactly the same. Both claws have what Govind calls quote

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Speaker 2: a central band of fast fibers sandwiched dorsally and ventrally

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Speaker 2: by slow fibers. Then during the later juvenile stages this

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Speaker 2: would be like the fourth and fifth molting stages, there

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Speaker 2: begins to be some variability in the amount of slow

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Speaker 2: and fast fibers in each claw. But then the changes

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Speaker 2: really start to become apparent during the sixth stage of molting. Quote,

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Speaker 2: when the putative crush sure claw becomes slightly shorter and

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Speaker 2: stouter with a central molar like tooth, while the putative

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Speaker 2: cutter claw remains long and slender with a central incisor

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Speaker 2: like tooth. A corresponding asymmetry in the composition of the

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Speaker 2: closer muscle also develops. The muscle of the cutter claw

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Speaker 2: gradually acquires fast fibers by transforming the slow fibers of

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Speaker 2: most of its cross sectional face. The exception is a

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Speaker 2: ventral band. The muscle of the crusher claw gradually transforms

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Speaker 2: all of its fast fibers to slow fibers. In succeeding

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Speaker 2: juvenile development, the paired claw's further diverge toward well defined

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Speaker 2: cutter and crusher claws. So the divergence happens sometime in

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Speaker 2: the childhood of a lobster, sometime around its fourth and

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Speaker 2: fifth molting stages and really starts to appear during the

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Speaker 2: sixth molting. But then Govin mentioned something I thought was

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Speaker 2: really intriguing, an experiment going all the way back to

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Speaker 2: nineteen o eight, way back to a researcher named Victor Immel,

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Speaker 2: who found that if you remove one of the lobster's

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Speaker 2: claw during the fourth or fifth stage, so you just

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Speaker 2: pull that claw off, the claw that is left behind,

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Speaker 2: still attached to the lobster, always becomes a crusher claw,

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Speaker 2: and meanwhile the animal regenerates a new claw where the

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Speaker 2: old one was torn off. A lot of crustaceans can

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Speaker 2: do that. It grows a new claw, and the new

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Speaker 2: claw always becomes the cutter claw. But this only happens

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Speaker 2: if you do it early. So if you pull off

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Speaker 2: a lobster's claw after the larval stage, when it's already

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Speaker 2: approaching adulthood, when the asymmetry is already beginning to show up,

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Speaker 2: the original arrangement stays intact. The claw you pulled off

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Speaker 2: will regenerate as whichever type it already was. So this

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Speaker 2: seems to show that claw laterality is determined sometime during

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Speaker 2: the molting stages of like four to five, and it

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Speaker 2: probably won't change after that, so what causes asymmetry to

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Speaker 2: become fixed to during this stage in a young law's life?

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Speaker 2: And here begins a long, twisting and to my mind

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Speaker 2: fascinating journey of experiments trying to pin down how this happens.

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Speaker 2: Most of these experiments Govind himself was in some way

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Speaker 2: directly involved in, and for the sake of brevity, I'm

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Speaker 2: going to gloss over some details in this section, but

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Speaker 2: you can look up the article for yourself if you

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Speaker 2: want the more zoomed in version with all the details

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00:17:24,080 --> 00:17:28,280
Speaker 2: and citations. I'll try to give a more sky level view. So,

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Speaker 2: first of all, Govin and colleagues notice some things we

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Speaker 2: already know leading into these experiments. One is that the

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00:17:34,359 --> 00:17:39,800
Speaker 2: triggers for developing different claws must be randomly distributed under

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Speaker 2: normal conditions to explain the random distribution of claws in

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Speaker 2: the wild, but not random once a claw is lost.

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Speaker 2: And this naturally suggested something about use the way the

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00:17:52,600 --> 00:17:55,359
Speaker 2: claw is used. When one claw is pulled off and

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Speaker 2: has to grow back and new, it isn't getting used,

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Speaker 2: so the remaining cl law is getting used, and maybe

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Speaker 2: it's something about getting used more that makes a claw

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Speaker 2: into a crusher. This would align with the fact that

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Speaker 2: the juvenile stage in which the claws become asymmetrical also

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Speaker 2: coincides with a change in the lobster's lifestyle. So when

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Speaker 2: the claws start to become asymmetrical is around the time

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Speaker 2: when lobsters transition from swimming amongst the plankton to living

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Speaker 2: on the ocean floor and crawling around on the substrate

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Speaker 2: and burrowing in the substrate substrate meaning the stuff that

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Speaker 2: lines the ocean floor. Now, some research had been done

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Speaker 2: which found that if you take a bunch of lobsters

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Speaker 2: and you raise them in smooth plastic trays environments with

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Speaker 2: no stuff to mess with on the bottom of the water,

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Speaker 2: lobsters do not, in fact develop crusher claws at all.

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Speaker 2: In smooth environments. They just get symmetrically paired cutter claws,

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Speaker 2: two cutters exactly the same. But if you put a

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Speaker 2: lobster that's already reached the stage where its claws split

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Speaker 2: into different types into a smooth environment, it keeps its

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Speaker 2: crusher claw, So again it gets fixed sometime early on.

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Speaker 1: All right, So it seems like it's the environment that

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Speaker 1: is key here, right.

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Speaker 2: It seems to be something about the texture of the

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00:19:14,880 --> 00:19:19,120
Speaker 2: environment at the right stage that causes crusher claws to emerge.

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00:19:19,480 --> 00:19:22,719
Speaker 2: So here's a new experiment. You raise lobsters in a

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Speaker 2: smooth plastic environment versus one scattered with pieces of broken

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00:19:26,960 --> 00:19:30,800
Speaker 2: oyster shells? Does a lobster grow up differently with different

340
00:19:30,800 --> 00:19:35,040
Speaker 2: distributions of claws on smooth plastic versus oyster chips? And

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00:19:35,080 --> 00:19:39,119
Speaker 2: the results were oyster shells give you normal asymmetrical lobsters

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00:19:39,160 --> 00:19:42,919
Speaker 2: with a crusher and a cutter. The smooth, no substrate

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00:19:43,040 --> 00:19:47,480
Speaker 2: gives you a pair of identical cutters. This was fascinating

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00:19:47,480 --> 00:19:50,120
Speaker 2: to me. Okay, so it's like what it's crawling around

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00:19:50,240 --> 00:19:54,840
Speaker 2: on determines how its claws develop. So they wanted to

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00:19:54,880 --> 00:19:58,479
Speaker 2: refine this answer further. Why is this it? Is this

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00:19:58,560 --> 00:20:01,720
Speaker 2: result something about oyster chips in particular, or could it

348
00:20:01,800 --> 00:20:05,280
Speaker 2: be any substrate. So they tried the experiment again, but

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00:20:05,359 --> 00:20:08,920
Speaker 2: instead of oyster shells, they used different stuff. They used gravel,

350
00:20:09,200 --> 00:20:12,880
Speaker 2: they used mud with debris, and they even used tanks

351
00:20:12,920 --> 00:20:17,479
Speaker 2: with plastic shirt buttons and all of these produced normal

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00:20:17,560 --> 00:20:22,560
Speaker 2: lobsters with one crusher, one cutter normally randomly distributed crusher claws,

353
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Speaker 2: and in a control they had a flat smooth substrate

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Speaker 2: that had been painted to look like oyster chips, but

355
00:20:30,840 --> 00:20:33,520
Speaker 2: it did not but did not have any actual stuff

356
00:20:33,560 --> 00:20:36,199
Speaker 2: to crawl or burrow around in, and this did not

357
00:20:36,359 --> 00:20:39,080
Speaker 2: facilitate differentiation. So on the one that was flat and

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00:20:39,119 --> 00:20:44,600
Speaker 2: smooth but painted, it still produced identical symmetrical cutters. Another

359
00:20:44,680 --> 00:20:48,520
Speaker 2: experiment to refine this what about lobsters in smooth plastic trays,

360
00:20:48,600 --> 00:20:52,800
Speaker 2: but putting them together instead of by themselves. This plays

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Speaker 2: on the fact that lobsters are not very friendly to

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Speaker 2: each other. They are aggressive and tend to fight each other,

363
00:20:58,840 --> 00:21:01,720
Speaker 2: and typically when they were put in together, they would

364
00:21:01,880 --> 00:21:04,399
Speaker 2: duel a bit and one of the lobsters would often

365
00:21:04,400 --> 00:21:08,199
Speaker 2: get one or both claws removed in battle. Yeah, I know,

366
00:21:08,280 --> 00:21:11,439
Speaker 2: this is kind of going into bug fights territory, but

367
00:21:11,480 --> 00:21:13,840
Speaker 2: the lobster. So what they found was the lobster with

368
00:21:13,840 --> 00:21:16,800
Speaker 2: both claws left would split like in the wild with

369
00:21:16,840 --> 00:21:21,040
Speaker 2: an asymmetrical distribution with one crusher claw. So if there

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00:21:21,119 --> 00:21:23,560
Speaker 2: is no substrate, if you don't have any mud or

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00:21:23,600 --> 00:21:26,720
Speaker 2: oyster chips to root around and fighting will also do

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00:21:27,119 --> 00:21:29,240
Speaker 2: to split your claws into different types.

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Speaker 1: Okay, that this makes sense. It's about having It would

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00:21:32,480 --> 00:21:34,639
Speaker 1: seem to have something to do with the sorts of

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00:21:35,080 --> 00:21:39,320
Speaker 1: things you're encountering with your claws, be it chunks of

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00:21:39,359 --> 00:21:43,560
Speaker 1: oysters or the hard body of another lobster combatant.

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00:21:43,840 --> 00:21:45,879
Speaker 2: Right, it seems to have something to do with doing

378
00:21:46,040 --> 00:21:50,400
Speaker 2: something with the claws that produces one crusher of the two.

379
00:21:51,080 --> 00:21:53,240
Speaker 2: Oh and as a control I thought this is also interesting.

380
00:21:53,280 --> 00:21:54,720
Speaker 2: They're like, well, we want to make sure it's not

381
00:21:54,800 --> 00:21:58,120
Speaker 2: just the appearance of another lobster that causes a crusher

382
00:21:58,160 --> 00:22:01,120
Speaker 2: to develop. So they tried one with a smooth container

383
00:22:01,160 --> 00:22:04,080
Speaker 2: but a mirror, so that if the lobster could see

384
00:22:04,119 --> 00:22:07,040
Speaker 2: its reflection, would this make a differentiate But nope, heerio,

385
00:22:07,040 --> 00:22:08,160
Speaker 2: you just got two cutters.

386
00:22:08,280 --> 00:22:10,119
Speaker 1: It's got to be the tactile experience.

387
00:22:10,200 --> 00:22:13,359
Speaker 2: Okay, yeah, so so far this is all lining up

388
00:22:13,359 --> 00:22:16,639
Speaker 2: with the hypothesis that it's something about the claw getting

389
00:22:16,840 --> 00:22:19,199
Speaker 2: used more that caused them to split and one to

390
00:22:19,200 --> 00:22:22,679
Speaker 2: become a crusher. So they tried a new experiment with

391
00:22:22,720 --> 00:22:25,040
Speaker 2: the hypothesis that if you put a lobster in a

392
00:22:25,080 --> 00:22:29,400
Speaker 2: normal environment with a substrate, but you prevent only one

393
00:22:29,440 --> 00:22:32,679
Speaker 2: of a lobster's claws from opening and closing, that's going

394
00:22:32,760 --> 00:22:34,879
Speaker 2: to get less use. That's going to turn into the

395
00:22:34,920 --> 00:22:38,479
Speaker 2: cutter claw and the other one will become a crusher. Okay,

396
00:22:38,800 --> 00:22:41,720
Speaker 2: So they tried this with various methods, such as holding

397
00:22:41,760 --> 00:22:43,960
Speaker 2: one claw shut with a rubber band or with a

398
00:22:44,040 --> 00:22:47,840
Speaker 2: dab of glue, and they found, to their surprise, this

399
00:22:48,000 --> 00:22:51,320
Speaker 2: did not produce the result they expected. They thought, if

400
00:22:51,320 --> 00:22:54,080
Speaker 2: a claw can't open and close, that the other one's

401
00:22:54,119 --> 00:22:56,760
Speaker 2: going to become the crusher. But no, Instead, with these lobsters,

402
00:22:57,000 --> 00:23:00,280
Speaker 2: you still got random lateralization. In some the right became

403
00:23:00,320 --> 00:23:02,960
Speaker 2: a crusher and some of the left became a crusher. Wow.

404
00:23:03,040 --> 00:23:05,800
Speaker 1: So it because that was going to be my guess

405
00:23:05,800 --> 00:23:09,359
Speaker 1: that it depends on how that particular claw is being used,

406
00:23:10,240 --> 00:23:15,040
Speaker 1: But we see this random distribution occurring even when that

407
00:23:15,160 --> 00:23:18,359
Speaker 1: one claw is, say, rubber banded shut right.

408
00:23:18,640 --> 00:23:21,399
Speaker 2: So here they were like, well, maybe it has something

409
00:23:21,400 --> 00:23:23,719
Speaker 2: to do with the claw being used, but not with

410
00:23:23,800 --> 00:23:26,360
Speaker 2: it being able to open and close, and maybe it's

411
00:23:26,400 --> 00:23:29,720
Speaker 2: something else. So from here they proceeded to a number

412
00:23:29,760 --> 00:23:33,400
Speaker 2: of different anatomical experiments and to try to quickly summarize

413
00:23:33,400 --> 00:23:35,960
Speaker 2: their findings. First of all, they found if you cut

414
00:23:35,960 --> 00:23:38,960
Speaker 2: a tendon, preventing only one of a lobster's claws from

415
00:23:39,000 --> 00:23:42,680
Speaker 2: opening or closing. This does stop it from becoming a crusher,

416
00:23:43,440 --> 00:23:47,280
Speaker 2: possibly by preventing fast muscle fibers from transforming into slow

417
00:23:47,359 --> 00:23:50,920
Speaker 2: muscle fibers. And they reason from this maybe it could

418
00:23:50,920 --> 00:23:55,240
Speaker 2: be a result of severing reflexive nerve pathways in the process.

419
00:23:55,760 --> 00:23:58,080
Speaker 2: So they tried to see what happened if you sever

420
00:23:58,200 --> 00:24:01,600
Speaker 2: a nerve running from the claw to the sort of

421
00:24:01,600 --> 00:24:05,960
Speaker 2: central nervous system control for the claw. A lobster's nervous

422
00:24:05,960 --> 00:24:08,040
Speaker 2: system is not exactly like ours. They don't just have

423
00:24:08,119 --> 00:24:11,560
Speaker 2: one central brain leading out to everything. They've got ganglia,

424
00:24:11,680 --> 00:24:15,840
Speaker 2: you know, the centralized nodes sort of within the nervous system.

425
00:24:16,160 --> 00:24:18,480
Speaker 2: So you would want to be severing the reflexive fiber

426
00:24:18,600 --> 00:24:22,080
Speaker 2: running from the claw to the ganglia. Unfortunately, when they

427
00:24:22,080 --> 00:24:24,760
Speaker 2: did this by severing that nerve somewhere in there, it

428
00:24:24,960 --> 00:24:28,400
Speaker 2: almost always resulted from the lobsters after they came out

429
00:24:28,400 --> 00:24:32,959
Speaker 2: of anesthesia, they would perform what's known as autotomy on themselves,

430
00:24:32,960 --> 00:24:36,720
Speaker 2: So the lobster's nerve is cut, and then the lobster says, okay,

431
00:24:36,760 --> 00:24:39,600
Speaker 2: don't need this claw anymore, and they would sever their

432
00:24:39,640 --> 00:24:42,879
Speaker 2: own arm and grow a new one. This is a

433
00:24:42,960 --> 00:24:46,280
Speaker 2: standard reaction. Actually of crustaceans, when a limb is trapped

434
00:24:46,359 --> 00:24:48,800
Speaker 2: or damaged, they just cut it off and grow a

435
00:24:48,800 --> 00:24:51,240
Speaker 2: new one, which is a fantastic thing to be able

436
00:24:51,280 --> 00:24:55,639
Speaker 2: to do. And apparently severing the nerve within the claw

437
00:24:55,920 --> 00:24:59,879
Speaker 2: seemed to trigger something in the lobster that suggested it

438
00:25:00,119 --> 00:25:04,040
Speaker 2: needed to do that. That causes the behavior in the lobster.

439
00:25:04,080 --> 00:25:06,359
Speaker 2: It says, something's wrong with this lamb. I'm removing it

440
00:25:06,400 --> 00:25:07,639
Speaker 2: and I'll just get a new one.

441
00:25:07,880 --> 00:25:10,720
Speaker 1: Fun tie in for tomorrow's Weird House Cinema episode.

442
00:25:10,800 --> 00:25:14,119
Speaker 2: Oh brilliant. I didn't even make that connection. Yeah, So

443
00:25:14,359 --> 00:25:17,959
Speaker 2: instead the researchers tried to incapacitate the part of the

444
00:25:18,000 --> 00:25:22,040
Speaker 2: central nervous system leading to the clause, so incapacitating it

445
00:25:22,080 --> 00:25:25,480
Speaker 2: more centrally to the body. This did work as expected.

446
00:25:25,520 --> 00:25:29,560
Speaker 2: It did prevent the claw in question from becoming a crusher.

447
00:25:30,320 --> 00:25:32,760
Speaker 2: So it has it must have something to do with

448
00:25:33,080 --> 00:25:38,200
Speaker 2: nerve inputs from the claw that causes the asymmetry to develop.

449
00:25:38,800 --> 00:25:43,160
Speaker 2: And they tested this with some target exercise regimes. Actually,

450
00:25:43,480 --> 00:25:45,560
Speaker 2: and here I thought this was great. So I just

451
00:25:45,600 --> 00:25:48,919
Speaker 2: wanted to read from the article. So Govind writes quote

452
00:25:49,400 --> 00:25:53,200
Speaker 2: in an inspired moment we thought of enhancing activity by

453
00:25:53,320 --> 00:25:57,400
Speaker 2: exercising one of the paired claws in a substrate free environment.

454
00:25:57,960 --> 00:26:01,480
Speaker 2: The lobster was held and its claw law gently stroked

455
00:26:01,520 --> 00:26:04,440
Speaker 2: with a small paint brush so that the bristles were

456
00:26:04,520 --> 00:26:08,879
Speaker 2: gripped several times during a sixty second session. This regimen

457
00:26:09,040 --> 00:26:12,200
Speaker 2: was repeated three times daily at five hour intervals through

458
00:26:12,240 --> 00:26:16,879
Speaker 2: the entire fourth and fifth stages, the molting stages, that is,

459
00:26:16,960 --> 00:26:19,840
Speaker 2: for about a month. A control group of lobsters was

460
00:26:19,880 --> 00:26:24,840
Speaker 2: reared under identical conditions, including being handled but not exercised.

461
00:26:25,480 --> 00:26:29,040
Speaker 2: While the lobsters in the control group developed paired cutter claws,

462
00:26:29,440 --> 00:26:35,840
Speaker 2: the experimental lobsters developed a crusher on the exercised left side.

463
00:26:36,000 --> 00:26:38,560
Speaker 2: The fact that the only perceived difference between the two

464
00:26:38,600 --> 00:26:42,520
Speaker 2: groups of lobsters was the amount of exercise strengthened our

465
00:26:42,520 --> 00:26:45,840
Speaker 2: belief that some minimal level of reflex activity in the

466
00:26:45,880 --> 00:26:51,000
Speaker 2: claw is probably needed to differentiate a crusher claw. However,

467
00:26:51,280 --> 00:26:53,560
Speaker 2: then they said, okay, what happens if we do the

468
00:26:53,640 --> 00:26:56,679
Speaker 2: exact same thing, but we exercise both claws with the

469
00:26:56,680 --> 00:27:01,119
Speaker 2: paint brush, will this give us two crusher claws, which is,

470
00:27:01,200 --> 00:27:04,240
Speaker 2: by the way, something that we basically never find in nature.

471
00:27:04,359 --> 00:27:07,280
Speaker 2: I think they cite one example of a lobster that

472
00:27:07,400 --> 00:27:11,080
Speaker 2: had two external morphologies looking like crusher claws, but the

473
00:27:11,240 --> 00:27:14,480
Speaker 2: muscles inside did not match. So that pretty much never

474
00:27:14,520 --> 00:27:17,840
Speaker 2: happens in nature, and they found no. In fact, their

475
00:27:17,880 --> 00:27:21,200
Speaker 2: experiment could not produce two crusher claws either. In fact,

476
00:27:21,720 --> 00:27:24,480
Speaker 2: it was not only not able to produce two crusher claws,

477
00:27:24,480 --> 00:27:27,800
Speaker 2: it gave them just the opposite. Whereas tickling only one

478
00:27:27,840 --> 00:27:30,480
Speaker 2: claw with a paint brush and making the claw close

479
00:27:30,520 --> 00:27:33,800
Speaker 2: around the paint brush by reflex that made that the

480
00:27:33,840 --> 00:27:37,639
Speaker 2: crusher boss claw. Tickling both claws but the paint brush

481
00:27:37,680 --> 00:27:41,600
Speaker 2: equally turned the lobster into a symmetrical beast with two

482
00:27:41,720 --> 00:27:45,520
Speaker 2: identical cutter claws only. Huh.

483
00:27:45,560 --> 00:27:49,240
Speaker 1: So, if there are any chefs out there who believe

484
00:27:49,280 --> 00:27:53,040
Speaker 1: that the crusher claw is superior, and they're looking for

485
00:27:53,119 --> 00:27:58,320
Speaker 1: ways to create the pure crusher lobster, it thus far

486
00:27:58,480 --> 00:28:00,960
Speaker 1: seemsossible to pull off.

487
00:28:01,119 --> 00:28:04,280
Speaker 2: It does not seem possible, though, though I will say

488
00:28:04,280 --> 00:28:06,920
Speaker 2: this is an older article, I've not looked into subsequent

489
00:28:06,920 --> 00:28:09,840
Speaker 2: attempts to create two crusher claw lobsters, but I doubt it.

490
00:28:09,880 --> 00:28:12,000
Speaker 2: I don't think you can do that. That's just not

491
00:28:12,119 --> 00:28:16,240
Speaker 2: part of the lobster's destiny, not part of its genetic destiny.

492
00:28:16,840 --> 00:28:18,439
Speaker 2: So a lot of this seems to add up to

493
00:28:18,480 --> 00:28:23,439
Speaker 2: show that it's not just stimulation or use of a

494
00:28:23,560 --> 00:28:27,040
Speaker 2: claw that causes it to become a crusher. But that's

495
00:28:27,080 --> 00:28:29,240
Speaker 2: something that seems to be important, is that it is

496
00:28:29,560 --> 00:28:35,600
Speaker 2: differential use, which is somehow weighed or compared internally by

497
00:28:35,600 --> 00:28:39,760
Speaker 2: the lobster's nervous system or ganglia, and the side that

498
00:28:39,840 --> 00:28:43,000
Speaker 2: gets more use becomes a crusher. So it's not you

499
00:28:43,040 --> 00:28:46,400
Speaker 2: can't exercise both sides and make them two crushers. If

500
00:28:46,400 --> 00:28:49,920
Speaker 2: you do them equally, you get no crushers. You've got

501
00:28:49,920 --> 00:28:54,200
Speaker 2: to get one side getting more stimulation or reflex exercise

502
00:28:54,320 --> 00:28:58,400
Speaker 2: than the other one, which suggests that there is I

503
00:28:58,400 --> 00:29:01,920
Speaker 2: don't know that there is some kind of internal comparison

504
00:29:02,040 --> 00:29:06,600
Speaker 2: module going on in the nervous system. And so Govin concludes,

505
00:29:06,680 --> 00:29:10,000
Speaker 2: quote in nature, as in the laboratory, initial use or

506
00:29:10,040 --> 00:29:13,400
Speaker 2: contact of one claw with a substrate sets in motion

507
00:29:13,600 --> 00:29:18,000
Speaker 2: an increasingly greater activity on that side. The greater neural

508
00:29:18,080 --> 00:29:21,240
Speaker 2: input of that side determines in the central nervous system

509
00:29:21,440 --> 00:29:24,400
Speaker 2: its fate as a crusher, and at the same time

510
00:29:24,640 --> 00:29:28,840
Speaker 2: inhibits the opposite side from ever becoming a crusher, and

511
00:29:29,000 --> 00:29:31,800
Speaker 2: Govin ends up using an analogy of a teeter totter.

512
00:29:32,320 --> 00:29:35,600
Speaker 2: I thought this was funny, actual illustrations of crab claws

513
00:29:35,680 --> 00:29:39,640
Speaker 2: on a playground teeter totter. So he shows, okay, you

514
00:29:39,640 --> 00:29:41,800
Speaker 2: can have a balance where one side is a crusher

515
00:29:41,840 --> 00:29:44,160
Speaker 2: and one's a cutter, and so cutter is up in

516
00:29:44,160 --> 00:29:47,360
Speaker 2: the air, crusher is down. You can have balanced with

517
00:29:47,800 --> 00:29:50,520
Speaker 2: both sides straight. You know, they're both hanging up in

518
00:29:50,560 --> 00:29:52,840
Speaker 2: the air and they're both cutter claws. But if you

519
00:29:52,960 --> 00:29:56,320
Speaker 2: tried to have two crusher claws, something doesn't work there.

520
00:29:56,360 --> 00:29:58,600
Speaker 2: It's like the pole in the middle of the teeter

521
00:29:58,680 --> 00:30:02,120
Speaker 2: totter will break, it won't support it. So whatever the

522
00:30:02,200 --> 00:30:05,960
Speaker 2: exact calculus of experience in the nervous system leading to

523
00:30:05,960 --> 00:30:08,520
Speaker 2: claw development, these experiments seem to make it clear that

524
00:30:08,680 --> 00:30:12,719
Speaker 2: claw asymmetry is a prime example of what Govind calls

525
00:30:12,800 --> 00:30:18,040
Speaker 2: quote experience modulating inherent programs, and this seems to be

526
00:30:18,080 --> 00:30:21,920
Speaker 2: the underlying principle behind much of how any organisms body

527
00:30:22,160 --> 00:30:25,240
Speaker 2: is formed and how it behaves, which kind of cuts

528
00:30:25,280 --> 00:30:28,840
Speaker 2: through a lot of naive all or nothing nature nurture

529
00:30:28,880 --> 00:30:32,880
Speaker 2: reasoning like much of what an animal is is necessarily

530
00:30:32,920 --> 00:30:37,960
Speaker 2: a product of both it's genetically innate materials and programs

531
00:30:37,960 --> 00:30:40,720
Speaker 2: that are the starting sort of the building blocks, and

532
00:30:40,760 --> 00:30:44,160
Speaker 2: then life itself, the experience of living in an environment

533
00:30:44,240 --> 00:30:48,400
Speaker 2: and the experiences that the organism has those determine how

534
00:30:48,440 --> 00:30:52,400
Speaker 2: those innate materials and programs are expressed, leading to vastly

535
00:30:52,440 --> 00:30:57,360
Speaker 2: different outcomes, even completely opposite outcomes, flipping the sides on

536
00:30:57,400 --> 00:31:01,040
Speaker 2: which the crusher claw exists. So in the case of

537
00:31:01,040 --> 00:31:03,040
Speaker 2: a lobster, the metaphor is kind of profound.

538
00:31:03,080 --> 00:31:03,240
Speaker 4: You know.

539
00:31:03,320 --> 00:31:06,120
Speaker 2: It starts with potential for a crusher on the right,

540
00:31:06,520 --> 00:31:09,200
Speaker 2: a crusher on the left, or no crusher at all,

541
00:31:09,360 --> 00:31:14,400
Speaker 2: but probably not two crushers, and then eventually the fixed

542
00:31:14,440 --> 00:31:18,360
Speaker 2: form of its adult body depends on some early experience,

543
00:31:18,800 --> 00:31:22,160
Speaker 2: whether and how it digs around in oyster shell chips

544
00:31:22,280 --> 00:31:26,640
Speaker 2: or even shirt buttons, some early experience, some experience of

545
00:31:26,760 --> 00:31:29,920
Speaker 2: moving one claw more than the other, or getting having

546
00:31:29,920 --> 00:31:33,560
Speaker 2: some kind of sensory input causing reflexes. Maybe something that

547
00:31:33,720 --> 00:31:38,960
Speaker 2: is information fed into the central ganglia through the nerves

548
00:31:38,960 --> 00:31:42,040
Speaker 2: and the claws determines Okay, this claw is getting more

549
00:31:42,160 --> 00:31:44,400
Speaker 2: use than the other one. That's the one that's going

550
00:31:44,440 --> 00:31:46,360
Speaker 2: to be the crusher for the rest of my life.

551
00:31:46,840 --> 00:31:49,680
Speaker 1: Fascinating. Now. I had to look this up real quick

552
00:31:49,720 --> 00:31:52,040
Speaker 1: to see if there was any information about the taste

553
00:31:52,160 --> 00:31:56,120
Speaker 1: debate between these two claws. I did find an article.

554
00:31:56,160 --> 00:31:58,520
Speaker 1: This is a two thousand and eight Associated Press article

555
00:31:58,840 --> 00:32:02,480
Speaker 1: titled the Great Lobster Debate, Claws Versus Tails. As the

556
00:32:02,520 --> 00:32:06,880
Speaker 1: title implies, this is mostly about taste differences between the

557
00:32:06,880 --> 00:32:10,040
Speaker 1: claws of a lobster and the tails of a lobster,

558
00:32:11,440 --> 00:32:16,000
Speaker 1: and it points out that that of the two claws,

559
00:32:16,200 --> 00:32:19,920
Speaker 1: the crusher claw generally is tougher than the pincer claw.

560
00:32:20,480 --> 00:32:23,200
Speaker 1: It doesn't get into the taste differences between the two,

561
00:32:23,360 --> 00:32:25,640
Speaker 1: but it does point out that the tail, on the

562
00:32:25,640 --> 00:32:29,640
Speaker 1: other hand, is meteor and more flavorful, in part due

563
00:32:29,640 --> 00:32:31,840
Speaker 1: to the fact that or in large part due to

564
00:32:31,880 --> 00:32:34,040
Speaker 1: the fact that the tail is used more the tail

565
00:32:34,080 --> 00:32:37,160
Speaker 1: muscle is used more than the claw muscles. And this

566
00:32:37,880 --> 00:32:41,840
Speaker 1: is cited to Brian Beal, a lobster expert and professor

567
00:32:41,880 --> 00:32:43,040
Speaker 1: at the University of Maine.

568
00:32:43,120 --> 00:32:46,840
Speaker 2: How many how many lobsters did he have to eat

569
00:32:46,880 --> 00:32:47,800
Speaker 2: for that experiment?

570
00:32:49,080 --> 00:32:53,120
Speaker 1: But it does make me think that maybe, certainly, if

571
00:32:53,120 --> 00:32:55,640
Speaker 1: you're talking about claw vers's claw. It's probably going to

572
00:32:55,640 --> 00:32:58,800
Speaker 1: be a matter of personal preference, but it could be

573
00:32:58,840 --> 00:33:03,040
Speaker 1: wrong on that. Perhaps lobster are aficionados out there have

574
00:33:03,120 --> 00:33:06,000
Speaker 1: some input on this. Maybe there's one claw they find

575
00:33:06,000 --> 00:33:08,680
Speaker 1: themselves going to before the other. Maybe there are even

576
00:33:09,560 --> 00:33:11,960
Speaker 1: certain dishes where oh, well, you only want to use

577
00:33:12,040 --> 00:33:14,200
Speaker 1: this claw for this dish, and then you want to

578
00:33:14,280 --> 00:33:18,000
Speaker 1: save your pincher or save your crusher for some other dish.

579
00:33:18,000 --> 00:33:18,440
Speaker 1: I don't know.

580
00:33:18,880 --> 00:33:21,120
Speaker 2: Well, wait, which one did you say was the one

581
00:33:21,160 --> 00:33:23,520
Speaker 2: that was usually tougher? Was it the crusher?

582
00:33:23,720 --> 00:33:26,040
Speaker 1: This article says the crusher claw, the larger of the

583
00:33:26,080 --> 00:33:28,720
Speaker 1: two used to crush things generally, is tougher than the

584
00:33:28,720 --> 00:33:29,640
Speaker 1: pincer claw.

585
00:33:29,880 --> 00:33:32,480
Speaker 2: To make sense apart, Yeah, so that the crusher claw

586
00:33:32,520 --> 00:33:35,400
Speaker 2: is the slow muscle fiber and the pincher is the

587
00:33:35,440 --> 00:33:39,239
Speaker 2: fast muscle fiber. And oh, I hesitate to say this

588
00:33:39,280 --> 00:33:41,479
Speaker 2: because they may but they may not be comparable at all.

589
00:33:41,520 --> 00:33:44,560
Speaker 2: I'm not sure how the analogy goes across different you know,

590
00:33:44,680 --> 00:33:46,960
Speaker 2: fi love of animal life, but I mean, if you

591
00:33:47,000 --> 00:33:50,240
Speaker 2: think about a chicken, like the breast meat is generally

592
00:33:50,280 --> 00:33:52,920
Speaker 2: the fast muscle fiber and the dark meat is generally

593
00:33:52,960 --> 00:33:55,760
Speaker 2: the slow muscle fiber, and that translates to different types

594
00:33:55,800 --> 00:33:59,760
Speaker 2: of taste and texture within the meat. Like generally chefs

595
00:33:59,760 --> 00:34:02,640
Speaker 2: would cook dark meat to a higher temperature because it

596
00:34:02,680 --> 00:34:04,880
Speaker 2: has more sort of that needs to render out of

597
00:34:04,920 --> 00:34:06,440
Speaker 2: it to render it tender.

598
00:34:06,800 --> 00:34:11,279
Speaker 1: Yeah, this article indicates that generally speaking, your lobster tail,

599
00:34:11,480 --> 00:34:15,480
Speaker 1: that's what's going to get deep fried or whatever, while

600
00:34:15,520 --> 00:34:18,200
Speaker 1: the claw meat is going to be more tender, and

601
00:34:18,239 --> 00:34:20,759
Speaker 1: that's what's going to go into your lobster rolls and

602
00:34:20,800 --> 00:34:22,320
Speaker 1: your lobster club sandwiches.

603
00:34:23,840 --> 00:34:25,480
Speaker 2: I'm sure there are people who want to fight about

604
00:34:25,480 --> 00:34:27,359
Speaker 2: whether you're supposed to deep fry a lobster or not.

605
00:34:27,719 --> 00:34:31,279
Speaker 2: We're not here to settle that debate. But anyway, I

606
00:34:31,280 --> 00:34:34,000
Speaker 2: found this little research journey fascinating trying to pin down

607
00:34:34,080 --> 00:34:36,920
Speaker 2: how and why this happens in a lobster, and it

608
00:34:36,920 --> 00:34:39,760
Speaker 2: also just seems like somehow rich for metaphor.

609
00:34:40,200 --> 00:34:43,759
Speaker 1: Yeah, yeah, this is fascinating. I don't know that I'd

610
00:34:43,760 --> 00:34:46,839
Speaker 1: really given much thought to this, in part because there

611
00:34:46,880 --> 00:34:51,880
Speaker 1: are certainly clawed crustaceans out there that are more pronounced

612
00:34:51,960 --> 00:34:54,480
Speaker 1: in their asymmetry, and I think we're going to get

613
00:34:54,520 --> 00:34:56,920
Speaker 1: into those more in the third episode in this series.

614
00:34:57,160 --> 00:35:00,440
Speaker 2: Yes, there are some crustaceans, specifically some crowd that take

615
00:35:00,480 --> 00:35:04,440
Speaker 2: claw asymmetry to a ridiculous extreme. That we'll save those

616
00:35:04,440 --> 00:35:05,080
Speaker 2: for next time.

617
00:35:11,719 --> 00:35:15,480
Speaker 1: All right, So sticking to the aquatic world here, I

618
00:35:15,520 --> 00:35:18,319
Speaker 1: thought i'd go in another direction that I imagine a lot

619
00:35:18,320 --> 00:35:20,960
Speaker 1: of people were thinking about as we were talking about asymmetry,

620
00:35:21,000 --> 00:35:22,960
Speaker 1: and particularly in the last episode, you know we were

621
00:35:22,960 --> 00:35:27,319
Speaker 1: talking about the blowhole of the toothed whale migrating up

622
00:35:27,320 --> 00:35:30,840
Speaker 1: to the top of the head. Well, we have to

623
00:35:30,880 --> 00:35:34,200
Speaker 1: talk about the flatfish. There are some eight hundred species

624
00:35:34,239 --> 00:35:37,600
Speaker 1: of flatfish in global waters, and probably one of the

625
00:35:37,640 --> 00:35:42,040
Speaker 1: most famous groups here is the flounder. And if you

626
00:35:42,080 --> 00:35:44,520
Speaker 1: haven't seen a flounder, do look up a picture. The

627
00:35:44,600 --> 00:35:47,560
Speaker 1: pictures are. A picture of a flounder is always amusing

628
00:35:47,800 --> 00:35:52,640
Speaker 1: or unsettling. Basically, what has occurred here is that the

629
00:35:52,680 --> 00:35:56,920
Speaker 1: flatfish's eye left or right, depending on the variety of fish,

630
00:35:57,239 --> 00:36:00,919
Speaker 1: has migrated to one side of its body to facilitate

631
00:36:01,160 --> 00:36:05,840
Speaker 1: a sideways life in which it camouflages itself against the

632
00:36:05,880 --> 00:36:09,880
Speaker 1: ocean floor, like basically living on the floor, kind of

633
00:36:09,960 --> 00:36:12,800
Speaker 1: like array or something would live on the floor. But

634
00:36:14,040 --> 00:36:19,960
Speaker 1: it acquires its flatness by being sideways. Both eyes are

635
00:36:20,000 --> 00:36:21,759
Speaker 1: on the side facing up.

636
00:36:22,680 --> 00:36:27,120
Speaker 2: This looks hilarious, and I think it's different, unless I'm

637
00:36:27,120 --> 00:36:29,080
Speaker 2: forgetting one. I think this is different than any of

638
00:36:29,120 --> 00:36:32,799
Speaker 2: the other asymmetry examples we've talked about before, because I

639
00:36:32,920 --> 00:36:35,000
Speaker 2: think all of the other ones have been cases where

640
00:36:35,040 --> 00:36:38,920
Speaker 2: there is something that's originally symmetrical on both sides of

641
00:36:38,960 --> 00:36:42,040
Speaker 2: the body, and then they develop in different ways, like

642
00:36:42,160 --> 00:36:45,040
Speaker 2: one you know, maybe one hole opens and the other

643
00:36:45,080 --> 00:36:47,520
Speaker 2: one closes, or one claw grows bigger and with a

644
00:36:47,560 --> 00:36:50,120
Speaker 2: different shapes than the other, different muscle fibers or something

645
00:36:50,160 --> 00:36:52,759
Speaker 2: like that. They just develop in different ways or two

646
00:36:52,760 --> 00:36:55,640
Speaker 2: different extents. This is a case of a symmetry where

647
00:36:55,800 --> 00:36:59,239
Speaker 2: something that was originally symmetrical has one of the two

648
00:36:59,280 --> 00:37:04,480
Speaker 2: elements migrate to the opposite side, so they're actually switching

649
00:37:04,680 --> 00:37:07,080
Speaker 2: sides instead of just like one growing bigger than the

650
00:37:07,080 --> 00:37:07,840
Speaker 2: other or something.

651
00:37:08,440 --> 00:37:08,720
Speaker 3: Yeah.

652
00:37:08,840 --> 00:37:11,960
Speaker 1: Yeah, it's it's super weird looking. And one of the

653
00:37:12,000 --> 00:37:15,080
Speaker 1: telling things about these fish is that you can also

654
00:37:15,239 --> 00:37:19,319
Speaker 1: look at larval flounders, for example, and see eyes on

655
00:37:19,440 --> 00:37:23,359
Speaker 1: both sides of the larva's head. So it's only as

656
00:37:23,400 --> 00:37:26,440
Speaker 1: they develop and mature that the eyes move to the

657
00:37:26,480 --> 00:37:29,880
Speaker 1: other side. Also, like with some of the whale examples

658
00:37:29,920 --> 00:37:32,000
Speaker 1: we were looking at, you can look back in the

659
00:37:32,000 --> 00:37:36,600
Speaker 1: fossil record and make out a halfway point in the evolution. Particularly,

660
00:37:36,640 --> 00:37:39,640
Speaker 1: you can look at the fifty million year old fossil

661
00:37:40,000 --> 00:37:44,279
Speaker 1: of Anthistium, which has an eye that has migrated to

662
00:37:44,400 --> 00:37:46,640
Speaker 1: the top of the head, but no farther.

663
00:37:46,920 --> 00:37:49,680
Speaker 2: Oh that's interesting. So it would have like it's evolved

664
00:37:49,760 --> 00:37:52,040
Speaker 2: enough that it has one eye pointing up and another

665
00:37:52,040 --> 00:37:55,640
Speaker 2: one sort of pointing perpendicular to that right right, Okay.

666
00:37:55,560 --> 00:37:58,040
Speaker 1: It has not reached its final form. I guess you

667
00:37:58,040 --> 00:38:02,440
Speaker 1: would say. Was reading an article from two thousand and

668
00:38:02,440 --> 00:38:06,720
Speaker 1: eight in the journal Nature by A. Matt Friedman titled

669
00:38:06,880 --> 00:38:11,080
Speaker 1: the evolutionary origin of flatfish asymmetry, and he points out

670
00:38:11,160 --> 00:38:17,120
Speaker 1: that Eocene fossil evidence here with Amphistium and another species,

671
00:38:17,360 --> 00:38:21,560
Speaker 1: heteronic ties, both demonstrate the intermediate form.

672
00:38:22,000 --> 00:38:24,880
Speaker 2: I mean, I guess isaat right angles is better than

673
00:38:24,920 --> 00:38:26,440
Speaker 2: one eye just looking down in the dirt.

674
00:38:26,800 --> 00:38:30,719
Speaker 1: Yeah, yeah, but it's it's again. This one makes me

675
00:38:30,719 --> 00:38:32,840
Speaker 1: think back to the cock eyed squid. It makes me

676
00:38:32,880 --> 00:38:36,160
Speaker 1: think of just some of the strange challenges of aquatic

677
00:38:37,160 --> 00:38:41,960
Speaker 1: life in general that lead to these adjustments in a

678
00:38:42,040 --> 00:38:45,960
Speaker 1: creature's form. It's so fascinating.

679
00:38:46,320 --> 00:38:46,520
Speaker 2: Yeah.

680
00:38:46,600 --> 00:38:49,400
Speaker 1: Yeah, And of course, well one might ask, well, you know,

681
00:38:49,400 --> 00:38:51,640
Speaker 1: why don't we see more examples of things like this

682
00:38:52,440 --> 00:38:54,239
Speaker 1: in the surface world. And I think the answer to

683
00:38:54,280 --> 00:38:57,200
Speaker 1: that is we do. You know, we talked maybe not

684
00:38:57,280 --> 00:39:01,279
Speaker 1: in so much in terms of asymmetrical solutions, but in

685
00:39:01,360 --> 00:39:04,360
Speaker 1: terms of like eyes moving with the evolution of a

686
00:39:04,400 --> 00:39:07,799
Speaker 1: particular species. I mean, we talked about, we've talked about

687
00:39:07,800 --> 00:39:10,400
Speaker 1: on the show, the difference between the position of eyes

688
00:39:10,640 --> 00:39:14,440
Speaker 1: on a herbivore versus the eyes on a predator. You know,

689
00:39:14,520 --> 00:39:16,319
Speaker 1: do you need your eyes in a position where you

690
00:39:16,360 --> 00:39:19,480
Speaker 1: can basically see all around you as much as possible

691
00:39:19,520 --> 00:39:21,319
Speaker 1: at a given time, or do you need those things

692
00:39:21,400 --> 00:39:24,040
Speaker 1: hyper focused on the thing that's in front of you?

693
00:39:24,040 --> 00:39:27,920
Speaker 1: You know, these are positions that are reached via evolution.

694
00:39:28,440 --> 00:39:31,319
Speaker 2: Yeah, and actually, to take that even further though, this

695
00:39:31,360 --> 00:39:33,040
Speaker 2: has less to do with the placement of the eyes,

696
00:39:33,040 --> 00:39:36,040
Speaker 2: but more about the shapes of the actual eyeballs themselves.

697
00:39:36,120 --> 00:39:38,680
Speaker 2: You know, we talked not too long ago about research

698
00:39:38,719 --> 00:39:43,760
Speaker 2: even finding differences in common eye shapes based on whether

699
00:39:43,840 --> 00:39:46,880
Speaker 2: a predator is like is an active predator or an

700
00:39:46,880 --> 00:39:50,200
Speaker 2: ambush predator you know that tends to specialize for different

701
00:39:50,280 --> 00:39:52,439
Speaker 2: types of vision, Like do you need to have really

702
00:39:52,440 --> 00:39:58,040
Speaker 2: good vision for estimating the distance needed for one pouncing jump,

703
00:39:58,160 --> 00:40:00,279
Speaker 2: or do you need the kind of vision needed for

704
00:40:00,760 --> 00:40:02,520
Speaker 2: chasing over a period of time.

705
00:40:03,000 --> 00:40:06,000
Speaker 1: Yeah, yeah, exactly. So that's a fun example that I

706
00:40:06,080 --> 00:40:08,279
Speaker 1: just had to bring up. But I have another one here,

707
00:40:08,320 --> 00:40:11,160
Speaker 1: and this is another famous example of asymmetry, and this

708
00:40:11,280 --> 00:40:16,600
Speaker 1: time we are dealing with surface species and surface creatures.

709
00:40:17,040 --> 00:40:19,960
Speaker 1: And it's also an interesting example because it's an example

710
00:40:20,040 --> 00:40:24,680
Speaker 1: of a symmetry leading to more asymmetry. What happens when

711
00:40:24,920 --> 00:40:31,440
Speaker 1: an asymmetrical creature is your preferred prey, Perhaps you become

712
00:40:31,480 --> 00:40:34,239
Speaker 1: more asymmetrical in order to take advantage of it.

713
00:40:34,600 --> 00:40:38,240
Speaker 2: Oh that's interesting. So you'd imagine, like I'm just making

714
00:40:38,239 --> 00:40:40,760
Speaker 2: this up, but if you're fighting some kind of giant

715
00:40:40,800 --> 00:40:43,440
Speaker 2: lobster and one of its claws is bigger and more

716
00:40:43,520 --> 00:40:46,880
Speaker 2: dangerous than the other, if over evolutionary time, your species

717
00:40:46,960 --> 00:40:50,080
Speaker 2: develops i don't know, tougher skin or defenses on the

718
00:40:50,160 --> 00:40:53,800
Speaker 2: side that matches the more dangerous lobster.

719
00:40:53,480 --> 00:40:57,440
Speaker 1: Claw, Yeah, assuming there's some consistency in which side of

720
00:40:56,960 --> 00:40:59,719
Speaker 1: the giant lobster of the money claws on.

721
00:41:00,120 --> 00:41:01,800
Speaker 2: That's true. I guess if it was the American lobster

722
00:41:01,800 --> 00:41:03,959
Speaker 2: would be random. So you're just out of luck there.

723
00:41:04,160 --> 00:41:07,839
Speaker 1: Yeah, but in this case we're dealing talking about the food. First,

724
00:41:07,880 --> 00:41:12,440
Speaker 1: we're dealing with snails, and snails are obviously asymmetrical, possessing

725
00:41:12,480 --> 00:41:18,200
Speaker 1: either clockwise or counterclockwise spiraling shells, and as as a

726
00:41:18,320 --> 00:41:23,920
Speaker 1: side note, slugs are also asymmetrical. Slugs, of course, are

727
00:41:24,160 --> 00:41:28,120
Speaker 1: evolutionarily speaking, they are snails that no longer need to

728
00:41:28,120 --> 00:41:31,080
Speaker 1: carry their homes with them, have put that sort of

729
00:41:31,080 --> 00:41:35,040
Speaker 1: lifestyle behind them, but they really retain the asymmetry.

730
00:41:35,160 --> 00:41:37,880
Speaker 2: Wow, I did not know this. So if I understand right,

731
00:41:37,880 --> 00:41:42,120
Speaker 2: you're saying that the slugs evolved from ancestral snails, they

732
00:41:42,160 --> 00:41:45,320
Speaker 2: evolved from creatures that did have shells, and they evolved

733
00:41:45,320 --> 00:41:48,239
Speaker 2: to lose them to internalize them.

734
00:41:48,360 --> 00:41:51,560
Speaker 1: Yeah. We cover this on an old episode of Stuff

735
00:41:51,560 --> 00:41:53,320
Speaker 1: to Blow your Mind many years back, and so some

736
00:41:53,440 --> 00:41:55,960
Speaker 1: of the details are a bit foggy, but yeah, this

737
00:41:56,040 --> 00:42:00,160
Speaker 1: is the basic story of slugs and snails. And by

738
00:42:00,160 --> 00:42:01,879
Speaker 1: the way, if you look at a slug, you can

739
00:42:01,920 --> 00:42:06,200
Speaker 1: still you can visually mark the asymmetry if you look

740
00:42:06,239 --> 00:42:09,280
Speaker 1: for a particular it looks like a little circular feature,

741
00:42:09,360 --> 00:42:12,799
Speaker 1: a little hole or orifice on their body that is

742
00:42:12,840 --> 00:42:15,640
Speaker 1: the Numa stone. And yeah, it's on one side as

743
00:42:15,640 --> 00:42:16,439
Speaker 1: opposed to the other.

744
00:42:16,760 --> 00:42:19,239
Speaker 2: That's really cool because that's another case where it's like,

745
00:42:20,480 --> 00:42:24,880
Speaker 2: I don't know, just imagining evolution operating in a direction

746
00:42:25,000 --> 00:42:27,799
Speaker 2: opposite to what you would have just naively assumed. It's

747
00:42:27,800 --> 00:42:31,000
Speaker 2: like knowing that whales evolved from mammals that used to

748
00:42:31,000 --> 00:42:34,680
Speaker 2: be land walkers, you know, the four quadrupedal land mammals

749
00:42:35,320 --> 00:42:37,319
Speaker 2: spent more and more time and water and eventually became

750
00:42:37,360 --> 00:42:40,440
Speaker 2: fully aquatic. So here these would be not that slugs

751
00:42:40,480 --> 00:42:43,719
Speaker 2: evolved to gain shells, but that snails evolved in some

752
00:42:43,800 --> 00:42:45,400
Speaker 2: cases to lose their shells.

753
00:42:45,760 --> 00:42:47,919
Speaker 1: Yeah. I mean, like we've covered time and time again,

754
00:42:48,040 --> 00:42:51,160
Speaker 1: nature is flexible when it comes to evolution. The card

755
00:42:51,239 --> 00:42:55,520
Speaker 1: is always subject to change. The card will change, and

756
00:42:56,120 --> 00:43:01,000
Speaker 1: it's the species that evolved in sells into a corner

757
00:43:01,080 --> 00:43:05,880
Speaker 1: sometimes that find it the hardest to survive long term.

758
00:43:06,200 --> 00:43:11,439
Speaker 2: Okay, So in modern snails and slugs, you've got this asymmetry,

759
00:43:11,440 --> 00:43:14,040
Speaker 2: You've got some part of their biology having a kind

760
00:43:14,080 --> 00:43:18,320
Speaker 2: of clockwise or counterclockwise component, and this would of course,

761
00:43:18,400 --> 00:43:22,520
Speaker 2: be of relevance to any kind of creature that interacts regularly,

762
00:43:22,640 --> 00:43:25,000
Speaker 2: especially with the snail that's got a hard external part,

763
00:43:25,040 --> 00:43:27,720
Speaker 2: that's got this clockwise or counterclockwise.

764
00:43:27,000 --> 00:43:29,799
Speaker 1: Shell right, and that brings us to a species of

765
00:43:29,840 --> 00:43:34,800
Speaker 1: snake known as Awasaki's snail eater also known as Awasaki's

766
00:43:34,880 --> 00:43:39,000
Speaker 1: slug snake, and these are found in the Yayama Islands

767
00:43:39,040 --> 00:43:43,560
Speaker 1: of Japan, and they specialize in eating snails, and they

768
00:43:43,600 --> 00:43:49,320
Speaker 1: have specialized jaw structures that enable them to prey on clockwise,

769
00:43:49,360 --> 00:43:53,640
Speaker 1: spiraling or dexterraal snails. However, as a result, they have

770
00:43:53,719 --> 00:44:00,319
Speaker 1: a harder time preying on counterclockwise or sinestral snails. Soasically,

771
00:44:00,320 --> 00:44:03,480
Speaker 1: the way this works out is the snake's mandibles have

772
00:44:03,600 --> 00:44:09,200
Speaker 1: evolved for extracting snail bodies from their shells, and this

773
00:44:09,320 --> 00:44:13,359
Speaker 1: evolved independently, apparently in at least three subfamilies, according to

774
00:44:13,760 --> 00:44:18,279
Speaker 1: Hoso and Hori, writing in The Herpetological Review in two

775
00:44:18,320 --> 00:44:22,480
Speaker 1: thousand and six, the snake inserts its mandibles into the

776
00:44:22,520 --> 00:44:26,799
Speaker 1: snail's aperture and moves each mandible forward and back to

777
00:44:26,880 --> 00:44:30,879
Speaker 1: extract the body. And these two individuals Hoso and Horri,

778
00:44:31,200 --> 00:44:34,560
Speaker 1: they've written several papers on the snake. If you look

779
00:44:34,600 --> 00:44:40,160
Speaker 1: up Ilasaki Snail Leader, you'll all often or always find

780
00:44:40,200 --> 00:44:43,720
Speaker 1: these researchers involved, including a two thousand and seven paper

781
00:44:43,800 --> 00:44:49,800
Speaker 1: titled right handed Snakes Convergent evolution of asymmetry for functional specialization.

782
00:44:50,280 --> 00:44:51,960
Speaker 2: This is one where you should look up a picture

783
00:44:52,000 --> 00:44:54,439
Speaker 2: if you can. The one I'm looking at now, Rob

784
00:44:54,480 --> 00:44:57,600
Speaker 2: that you supplied has the snake biting onto the snail shell,

785
00:44:58,120 --> 00:45:00,880
Speaker 2: and it's got its upper jaw position on the outside

786
00:45:00,880 --> 00:45:03,000
Speaker 2: of the shell and its lower jaw. I guess that's

787
00:45:03,000 --> 00:45:06,919
Speaker 2: the mandible reaching in underneath the tube of the shell.

788
00:45:07,000 --> 00:45:09,440
Speaker 2: So the lower jaw is what's getting inside.

789
00:45:09,880 --> 00:45:12,560
Speaker 1: Yeah, yeah, And just looking at the pigure it can

790
00:45:12,560 --> 00:45:14,759
Speaker 1: be kind of hard to work out exactly what's going on.

791
00:45:14,880 --> 00:45:17,200
Speaker 1: So I want to read a quote here from this

792
00:45:17,320 --> 00:45:20,960
Speaker 1: two thousand and seven paper. They right. We found that

793
00:45:20,960 --> 00:45:25,880
Speaker 1: snakes in the subfamily Peritinae, except for non snail eating specialists,

794
00:45:26,200 --> 00:45:29,320
Speaker 1: have more teeth on the right mandible than the left.

795
00:45:29,719 --> 00:45:35,560
Speaker 1: In feeding experiments, a snail eating specialist pere Iwasaki, completed

796
00:45:35,640 --> 00:45:41,320
Speaker 1: extracting a dextraal soft body faster with fewer mandible retractions

797
00:45:41,520 --> 00:45:45,520
Speaker 1: than a sinestral body. The snakes failed in holding and

798
00:45:45,600 --> 00:45:51,200
Speaker 1: dropped sinnestral snails more often owing to behavioral asymmetry when striking.

799
00:45:51,560 --> 00:45:54,359
Speaker 2: Wow, so it's been preying on these snails so long

800
00:45:54,440 --> 00:45:58,320
Speaker 2: that it's specialized for having one side of its mouth

801
00:45:58,680 --> 00:46:01,280
Speaker 2: ready to get at a certain side of the tube

802
00:46:01,400 --> 00:46:05,160
Speaker 2: of the snail's shell. And if it attacks a snail

803
00:46:05,320 --> 00:46:08,560
Speaker 2: of the opposite handedness in its spiral, it's going to

804
00:46:08,560 --> 00:46:10,000
Speaker 2: be at a real disadvantage.

805
00:46:10,200 --> 00:46:15,120
Speaker 1: Exactly. Yeah. So again a fascinating example of asymmetry leading

806
00:46:15,160 --> 00:46:17,600
Speaker 1: to more asymmetry in the food chain.

807
00:46:17,840 --> 00:46:20,359
Speaker 2: I'm so scared that at some point here I've said

808
00:46:20,400 --> 00:46:22,920
Speaker 2: snail when I'm at snake and vice versa. I apology,

809
00:46:23,560 --> 00:46:25,560
Speaker 2: I apology, I apology if I did that.

810
00:46:26,880 --> 00:46:30,040
Speaker 1: So anyway, Yeah, definitely look up images of the snakes,

811
00:46:30,239 --> 00:46:33,120
Speaker 1: especially if you find an image of it actually feeding

812
00:46:33,360 --> 00:46:36,239
Speaker 1: on a snailshell. All right, Well, we're going to go

813
00:46:36,239 --> 00:46:38,400
Speaker 1: ahead and cap this one off right here, but we

814
00:46:38,440 --> 00:46:40,600
Speaker 1: will be back. I think it's going to be the

815
00:46:40,640 --> 00:46:44,600
Speaker 1: episode after next in which we return with part three

816
00:46:44,800 --> 00:46:47,960
Speaker 1: in this series, but there will be more creatures of note.

817
00:46:47,960 --> 00:46:52,040
Speaker 1: There will be more fascinating evolution and adaptation, and the

818
00:46:52,080 --> 00:46:55,759
Speaker 1: crabs will finally arrive on the scene, don't they always Yes,

819
00:46:55,920 --> 00:46:58,600
Speaker 1: there's no stopping them in the meantime, if you would

820
00:46:58,600 --> 00:47:00,200
Speaker 1: like to check out other episodes of Stuff to Blow

821
00:47:00,239 --> 00:47:04,359
Speaker 1: Your Mind, our core episodes publish on Tuesdays and Thursdays.

822
00:47:05,320 --> 00:47:08,879
Speaker 1: You can also enjoy, if you like, our listener Mail

823
00:47:08,920 --> 00:47:11,640
Speaker 1: episodes on Mondays, our short form Artifact or Monster Fact

824
00:47:11,680 --> 00:47:14,839
Speaker 1: episodes on Wednesdays and on Fridays. We set aside most

825
00:47:14,840 --> 00:47:17,480
Speaker 1: serious concerns and just talk about a weird film.

826
00:47:17,960 --> 00:47:20,919
Speaker 2: Huge thanks as always to our excellent audio producer Seth

827
00:47:21,040 --> 00:47:23,480
Speaker 2: Nicholas Johnson. If you would like to get in touch

828
00:47:23,520 --> 00:47:25,719
Speaker 2: with us with feedback on this episode or any other,

829
00:47:25,800 --> 00:47:27,920
Speaker 2: to suggest a topic for the future, or just to

830
00:47:27,960 --> 00:47:30,800
Speaker 2: say hello, you can email us at contact at stuff

831
00:47:30,840 --> 00:47:39,279
Speaker 2: to Blow your Mind dot com.

832
00:47:39,840 --> 00:47:42,759
Speaker 4: Stuff to Blow Your Mind is production of iHeartRadio. For

833
00:47:42,840 --> 00:47:45,640
Speaker 4: more podcasts from my Heart Radio, visit the iHeartRadio app,

834
00:47:45,800 --> 00:48:01,560
Speaker 4: Apple Podcasts, or wherever you listen to your favorite shows.

835
00:47:56,520 --> 00:48:02,000
Speaker 1: The lat