Ologies with Alie Ward - Tardigradology (TINY SEMI-INDESTRUCTIBLE WATER BEAR MOSS PIGLET CREATURES CALLED TARDIGRADES) with Paul Bartels
Episode Date: September 18, 2024Smaller than you can imagine. Potato-shaped. Mysterious. Romantic. And tough enough to survive the vacuum of space or decades of desiccation. Join professor and confirmed Tardigradologist Dr. Paul Bar...tels to saunter into a microscopic wonderland of bizarrely long naps, foreign genomes, moon landings, glow-in-the-dark moss piglets, cryptobiosis, kitten claws, knife mouths, balloon butts, spiders on Mars, splicing tardigrade DNA into ours, debunking flim-flam and the friends living in your gutters. Follow Dr. Bartels on ResearchGate and Google ScholarA donation went to the Xerces SocietyMore episode sources and linksSmologies (short, classroom-safe) episodesOther episodes you may enjoy: Bryology (MOSS) with Dr. Robin Wall Kimmerer, Planariology (VERY COOL WORMS, I PROMISE), Benthopelagic Nematology (DEEP SEA WORMS), Radiology (X-RAY VISION), Microbiology (GUT BIOME), FIELD TRIP: My Butt, a Colonoscopy Ride Along & How-To, Diplopodology (MILLIPEDES & CENTIPEDES), Saurology (LIZARDS), Astrobiology (ALIENS), UFOlogy (UNEXPLAINED AERIAL PHENOMENA), Etymology (WORD ORIGINS), Ursinology (BEARS), Carnivore Ecology (LIONS, TIGERS, & BEARS)Sponsors of OlogiesTranscripts and bleeped episodesBecome a patron of Ologies for as little as a buck a monthOlogiesMerch.com has hats, shirts, hoodies, totes!Follow @Ologies on Instagram and XFollow @AlieWard on Instagram and XEditing by Mercedes Maitland of Maitland Audio Productions and Jacob ChaffeeManaging Director: Susan HaleScheduling Producer: Noel DilworthTranscripts by Aveline Malek Website by Kelly R. DwyerTheme song by Nick Thorburn
Transcript
Discussion (0)
Oh hey, it's the sunglasses that you sat on, but you still wear crooked.
Allie Ward with a really big episode on a little creature, let's get into it, with a
warning that this episode is an instant classic.
I'm warning you, you're going to listen to it more than once because it's so good and
it's perfect.
Prepare.
So what is a tardigrade?
You're about to find out more about these water bear, moss piglet, tiny creatures with
extreme survival abilities via the loving eyes of an
expert tardigradologist who also identifies as a bio-felist, simply loves
nature, loves critters, and is up to their eyes in wonder. Their bio literally says,
to me every life form, no matter how gruesome, think tapeworms, flukes, and the
corpse flower of Borneo is beautiful and awe-inspiring. Oh, you're
gonna love them. So they got their bachelor's in zoology in southern
Illinois, a master's in zoology at the University of the West Indies, and a
biology PhD at UC Santa Cruz. They are currently a professor at Warren Wilson
College. They have discovered many new species of tardigrade and is one of the
foremost tardigradologists on earth. Just PS, tardigrade-ology, it's
very much a field, it's an actual term, and you should know that tardigrade means slow
stepper, just a tardigrade-er. They're tiny, they are rotund, and they saunter in no hurry.
We're going to get to them swiftly, but first a heads up to Back to Schoolers. We launched
a new show a few months back on its own feed. Smologies used to be in this feed, but we gave it its own
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Thank you to everyone who does.
I read them all, including this just left one
from Iva Canard, who wrote,
you make it interesting regardless of subject.
It is all interesting and we just didn't know until you showed us.
Oh, Iva, I have a lot of gratitude for that.
And thank you for all the reviews.
Anyone who's left one, they helped the show so much.
And here we go into the episode.
Saunter into a microscopic wonderland of weird business
about mystery naps that last longer than you can imagine.
How a loaf of a critter can deal with a vacuum of space, how to find and marvel at tardigrades, the
various experiments involving their survival, moon landings, cryptobiosis, biodiversity,
kitten claws, knife mouths, their sexual prowess, aka the tantra-grade life, splicing their
DNA into ours, spiders on Mars, flim flam, and so much more with a creature of wonder.
Professor, zoologist, and your new friend
and confirmed tardigradologistigrades. Paul Bartles, he and-
Dr. Tardigrade. Do a lot of people in your life casually, like your neighbors and stuff,
do they know what you study or are you just like, oh, Paul, the cool guy that lives next
door?
Yeah, a lot of them do.
I'm the tardigrade guy.
When do you remember seeing your first tardigrade?
I've never seen one in person, but do you remember when you saw yours?
That's a good question.
I mean, I saw pictures of them in my zoology class in college, but I never saw a live one.
I don't think I ever saw a live one.
I don't think I was successful finding them
until I actually worked with somebody
who helped me learn how to collect them and study them.
And so that would have been around the year 2000
when I started studying them myself.
You're kind of elusive if you don't know the tricks.
Yeah, oh, that's a huge question on my mind
is how do you find them?
I guess first I should ask you to describe to
people what is a tardigrade? Some people will know this word and get thrilled and
some people will be like do I skip this episode? What even is it? You're going to
love this. What is it? Tardigrades are microscopic animals. They're complex
multi-celled but microscopic animals and they are in their own phylum.
The kingdom animalia is divided into about 30 or so phyla.
They're their own phylum, about 1,400 species,
and their characteristics are that they have
five body segments, four pairs of little stubby legs,
and they have a cuticle that they have to mold
when they grow, like nematodes and arthropods,
because they're related to them, and they have these paired stylists that, like nematodes and arthropods, because they're related to them.
And they have these paired stylists that are like little hypodermic needles that they can
poke out their mouths.
And so that's the general characteristic of tardigrades.
And the thing that they're famous for is being champion animal survivors.
That's probably what people know about them, if they know about tardigrades.
1400 species?
If you would have asked me, I would have thought, oh, you know how there's maybe eight species
of bears?
There's like a lower number than you would think.
And probably why you think that is because on the internet, the meme for tardigrades
is this one image that's everywhere, and it is one species.
And so you kind of think, oh, well, they all look like that.
So you may have seen an electron microscopy portrait of what appears to be an inflated species. And so you kind of think, oh well, they all look like that.
So you may have seen an electron microscopy portrait of what appears to be an inflated
sleeping bag with small baguettes for legs and a barbed wire vape pen for a mouth. Or
perhaps you saw an animation based on that photo and it looked like a flying chode with
eight stumpy appendages and a garbage disposal for a face. And perhaps you feel grateful
that they are microscopic.
But in fact, that meme is not a great meme. We can talk about that if you want.
Hell yeah, brother.
Why is that not a representative of the tardigrade family? And also, I wonder if that one particular
tardigrade, that scanning electron microscope image, if that tardigrade knows
how famous it is, like that is the most famous microscopic animal on the planet. What is
that image? It looks like it has a hell mouth. It looks like it has the pit of sarlacc as
a mouth. And one patron described it as like a floating baked potato with legs. They look like floppy baked potatoes, quote patron Megan Walker.
But what is that image?
Where did it come from?
That is a great question.
And I'm glad you asked it because that image is everywhere on the internet.
It drives me nuts because it's so wrong.
In fact, it's so wrong.
I'll show you.
I've got a little toy here.
Oh.
It's a little nightlight.
Everybody needs one of these.
Oh, it's lovely.
A tardigrade nightlight.
And another little tardigrade squeeze toy for anxiety.
We all need those, obviously, in this day and age.
But they all look exactly like that, right?
This is what they all look like.
Yep.
Modeled after that famous internet imagery.
That is so wrong.
It is so messed up.
It is so messed up.
My kids would say it's effed up.
I wouldn't say that on the air, but they weren't raised right.
But yeah, so this image, the one I'm thinking of is an animated image.
They took that scanning electron microscope image and they made
an animated image out of it with computer generated graphics.
It shows this happy little tardigrade swimming along in the water.
It's bright pink and it's got this mouth that's poking out and then alternately
sucking back in forming this giant anus head thing.
Yeah.
Is that what you're talking about?
Yep, yep, yep.
That's what these little toys show, the anus head.
Yep, yep.
It's disgusting.
Is that not what they look like?
It's disgusting.
No, that's not what they look like.
Really?
What?
What are their faces usually doing?
So, that image, let me count the ways it's messed up. What do they look like? Really? What? What are their faces usually doing?
So that image, let me count the ways it's messed up.
Okay, first of all, they're not pink.
They're not pink.
Okay.
I think somebody thought moss piglet, which is one of their common names, and thought,
well, if it's a piglet, I guess it's pink.
But it's not.
That kind of tardigrade is usually white or clearish, sometimes some darker pigments, but never pink.
They don't swim. They're benthic. Tardigrades crawl on the bottom.
And so if you dropped a tardigrade in the water, it would flail its legs helplessly and fall to the bottom.
And the claws are all wrong on those images.
So the popular animation depicts them with kitten claws at the tips of each Michelin man leg.
And this is the way you can tell if it's a anatomically correct image or not. Okay, so
on tardigrades they have four pairs of legs. The first three pairs of legs are all
oriented the same. The fourth pair of legs comes out the very rear of the body and is
oddly turned around at 180 degrees relative to the first three.
Those computer generated images are never right about that.
That's the way to check.
Yeah.
And the worst thing is that mouth thing.
So they do not, live animals don't, their heads don't cave in to form an anus head.
They just don't do that.
They have this cuticle that's kind of continuous
around their head and body, and so that's relatively rigid.
There's a lot of movement going on in the mouth,
but that's internal.
You don't see it in the head.
How did we get it so wrong?
I think what happened is that
those scanning electron microscope images
that you are talking about, they're so beautiful,
and they're also everywhere on the internet. Some of those show the head normally, some of them the
heads contracted. That's an artifact of preparation for scanning electron microscopy. And so I think
the animators saw both of those images and just thought, well, okay, if it's moving around, it
must alternate between those two. That's my conjecture of how that got to be like that.
I'm sorry. It's just wrong. But the head of tardigrades is nicely smoothly round or maybe
tapered forward. It never caves in like that. The internal mouth parts are beautiful. They have a
mouth. They have a buccal tube that's kind of like our esophagus. it ends in a punching bag like pharynx,
and then that goes into a stomach and an intestine.
Pharynx has muscles attached,
and it's going like this all the time,
going in and out to form suction,
like the bulb of an eyedropper.
The stylet's are poking in and out all the time.
All that stuff's going on
in sort of beautifully complex motion, but it's all inside the animal.
You don't see that.
Unreal.
So the other reason I hate that image
is because people that look at it say,
oh, well, there must just be this one kind.
Yes.
But there's several different kinds of tardigrades.
They come in several flavors.
And there's a lot of diversity among the individual species.
And so that one image is the image that almost always gets displayed,
but it's not, I don't even think it's the coolest one.
The best ones, the best ones in pop culture would be, if you ask me.
I do.
Have you seen Ant-Man and Wasp?
No, I haven't seen it. There's Tardigrades in it?
Oh, there's Tardigrades in both the Ant-Man movies.
And in the first one, it's a cameo appearance.
In the second one, they have a really major role.
They almost eat Michael Douglas.
It's very scary.
In case they don't make it.
Don't.
Don't say that.
I can't lose you, too.
I love you, Hope.
So did they do it right?
Yeah.
And the tardigrade scene in Ant-Man and the Lost,
the second one, they're the other kind of tardigrade.
They're not like the one that's all over the internet.
And they're actually very well done,
except for the fact that they're swimming.
But at least they don't have an amazement.
Do they call up tardigradologists and say, hey,
how can we make sure that we do this right?
They must have, because at least in that show they did because they're really well done
So they must have talked to somebody I don't know who next time give you a holler give you a jingle
Invite you to the premiere also
Can you describe also their scale are they all super super tiny or do they vary in size
They do vary in size, but in a very small size range. We say they're microscopic and so what we mean by that, you have to think small. You have to think about a small size scale. So divided into the tiny little marks. Those are the millimeters.
One millimeter is about the size of the period at the end of a sentence.
You read this all the time in microscopy stuff, and I actually measured it.
It's true.
Period is about the size of one millimeter.
The largest tardigrades can get to be about one millimeter in length, the size of that
period.
But those are the TOUs, you know, TOUs like...
Rodents of unusual size?
Tardigrades of unusual size?
Yes!
Yes!
You got it!
I actually use that in a research paper.
It's been published.
That's amazing.
I fact checked this and the man is not lying.
You can see his 2019 Zoological journal of the Linnaean Society paper, Latitudinal Gradients
and Body Size in Marine Tardigrades, which contains the sentence, quote, we did not find
a significant increase in maximum body size with latitude.
Therefore, this is not responsible for body size, latitudinal gradients, and marine tardigrades.
But we examined our database to find out whether there are polar tardigrades of unusual size,
T-O-U-S-s, with our apologies to the Princess Bride."
This is how you publish papers, folks.
Yes, those are the tardigrades of unusual size.
So for a period at the end of sentence, you can see it with your naked eye, of course,
right?
The largest tardigrades could be seen with a naked eye, but you wouldn't even know they're a tardigrade.
They're just a speck. You have to magnify them to study them.
And there are a whole lot of tardigrades that are much smaller than that.
So at the other end of the size scale, the tiny end of the tardigrade size scale,
we have to have another unit of measure that's smaller.
So if you take that millimeter or that period at the end of a sentence
and you divide it a thousand times,
one of those units, a thousandth of a millimeter,
is a micrometer or micron.
The smallest adult tardigrades that I've measured
are between 35 and 40 microns.
And to put that into perspective,
that's about half the width of a human hair.
Oh, tiny. And you can't see that with the width of a human hair. Oh, tiny.
And you can't see that with your naked eye.
Teeny, teeny, tiny.
Here's another thing to think about, about life at small size scales.
We have this huge gap in our biodiversity knowledge, and it's the gap between the number
of known species currently and the total species that are on Earth, including
all those yet to be discovered.
That gap is called the Linnaean shortfall after Carolus Linnaeus, the 18th century naturalist
who came up with our system of classification we still use.
So one end of that gap, that huge gap between the number known and the number not known,
is the number of known species.
So you want to take a guess at that?
How many known species there currently are?
How many described species?
Oh, man.
Because there's, I know there's like 300,000 of just beetles or something, right?
But there are only like 4,000 mammals.
So yeah, you know this.
No, I would guess like half a million.
There's almost a million insect species.
Oh my god, okay.
As a bug lover, a million bugs thrills me.
But what about all the species ever on earth combined?
According to the IUCN, which is the group that keeps track of endangered species, they
say we're a little bit over two million named species right now.
But that's a guess and it's a guess because not all museum collections are digitized and if they are they don't all talk to
one another, the databases don't talk to one another, so it's a big bioinformatics
problem and we're always describing new species so it's a moving target. But
we'll just go with two million for now. And so at the other end of the continuum
is the total number of species, including all those
yet to be discovered.
So if we don't know how many we know, we certainly don't know how many we don't know.
Guess is on that range really widely.
But to make a long story short, one estimate you see a lot is 9 million total species on
Earth.
So that's the Linnaean shortfall, 2 million known, 9 million unknown.
Both of those numbers are huge guesses, but it's clear we have a giant Linnaean shortfall.
There's a lot of life we don't know.
The larger the species, the more we already know, the fewer there are yet to be discovered.
And at the other end, when we look at the microscopic range, especially, the reverse is true.
The fewer we know now, and there are vast numbers
yet to be described.
So life is mostly small, and all those microbes
and all those tiny little plants and animals
literally run the world.
So I'm glad we're doing this episode,
because maybe it'll open door for
other episodes about microscopic organisms because that tiny, tiny little world's huge.
For more on this, you can look into our biology episode on moss, which is excellent, with
Braiding Sweetgrass author, Dr. Robin Wall-Kimmerer. We also have a planaria episode with Dr. One
Pagan and other teeny critters that we're
going to link in the show notes.
Did you start loving science from that tiny level or did you start with like, I love cheetahs
and charismatic megafauna and then get smaller and smaller?
What was your entry point?
Let's see.
I got interested in biology through water.
I was one of those water rep kids and. And somehow growing up in southern Illinois,
about as far away from the ocean as you can possibly get,
I got infatuated with oceans and scuba diving.
And I think the scuba diving part
was because of an old TV show called Sea Hunt.
Oh, I've heard of it, yes.
Lloyd Bridges played Mike Nelson,
and every week there was another daring do underwater.
It was so cool.
What's the matter with you? You want to sit out here in his raft all night?
No, but we might have to.
Well, not if you do something.
So anyway, I got interested in my first love in biology was marine biology and coral reef ecology.
And on coral reefs, the dominant animals are invertebrates, so I immediately started studying invertebrates.
And then I learned about tardigrades
when I took my first zoology course and thought they were cool. I now call them charismatic microfauna. I love that. Cute and cuddly and champion animal survivors, what's not to love.
But I didn't start studying them until about the year 2000. I would teach my classes about them,
but we never could find them. And around the year 2000, I was teach my classes about them, but we never could find them.
And around the year 2000, I was looking for new research directions, and I was looking
for things that would attract undergraduate research interests, because that's who I supervise
in research stuff.
And I heard about the All Taxa Biodiversity Inventory, the ATBI, that was starting up
in the Smokies, Great Smoky Mountain National Park, which is just an hour drive from Warren
Wilson College.
And I knew they were looking for people to study unstudied groups.
I knew tardigrades were one of those groups.
I also knew that I was not a taxonomic expert on tardigrades.
But the park biologists were able to put me in touch
with Diane Nelson, who is a professor at East Tennessee
State University.
And so she became my mentor in tardigradeology. And we still are great friends and we continue
to collaborate. With Diane's help and with a whole army of Warren Wilson students, we
did a large-scale inventory in the Smokies.
By large scale, he means large scale.
And it ended up taking 10 years. It was one of the largest inventories
of tardigrades ever done.
And it was really successful at giving my students
dozens and dozens of research projects.
We took the number of known tardigrades
in the park from zero to 85, including 25 new to science.
Nice work.
Nice work.
Wow.
We published a ton of papers
and I finally developed some expertise with that group of
animals, and at least now I can find them.
Oh, I can't wait to get to tips.
I should ask first, when it comes to what tardigrades are doing in the universe, because
they do run the world, what are they eating?
What are they pooping?
Where are they living?
You said that they're benthic.
Do they live in completely aquatic environments, or do they live as they're called moss piglets
or water bears?
Are they in the moss?
Are they in the water?
Do the 1400 species live in different places?
They live in different places.
They all live in moist sediments, basically, even if they're temporarily moist.
So they live in ocean sediments, both deep and shallow and on
the beach. They live in aquatic sediments like in freshwater habitats,
streams and ponds, and especially they're really abundant in the periphyton. It's
the green scuds that grows on rocks and plants and ponds. And they occur in
temporarily moist areas like moss and lichens and soil, the grit on your gutter,
anything that's got something for them to hide in and is at least temporarily moist.
And they do all kinds of things. There are some that are carnivores that are eating other
microscopic animals in their world. There are some that are herbivores that are eating algae or sometimes the moss tissue that they live in.
There are some that are detritivores or microbivores
sucking up the substrate.
And there's some that are omnivores.
And you can sometimes tell that from their mouth parts.
Those with really robust mouth parts are predators.
Those with really thin light mouth parts are probably. Those with really thin, light mouth parts are
probably herbivores. And those that have like a vacuum hose for mouth parts can
bend their mouth down and kind of suck up the bottom. Those are the detritivores.
And you can sometimes do gut contents analysis. You can look at them through
the microscope and, for example, you can see when a predator has been eating
other animals, you can see the hard predator's been eating other animals, you
can see the hard parts of those animals in their guts.
Take a moment, if you will, to imagine an x-ray vision into your guts right now.
Mine would be stale granola and, yeah, a tin of smoked oysters.
Also, for more on seeing into your own guts, please enjoy the radiology episode on x-ray
vision, and we also have a microbiology episode on how your own zoo of bowel animals affects your vibe.
Also, I have a field trip episode about a colonoscopy prep.
So you're welcome.
Don't turn your nose up.
You're gonna need one one day.
Speaking of, do they have eyes or noses?
How are they finding their prey?
That is a great question.
Some tardigrades have eye spots, some don't.
We know that at least some of them are negatively phototactic.
They can move away from light.
And so they probably, probably most tardigrades have eyes.
But here's the cool thing about this.
So the ones that have eyes have these, some of them have big dark eyes and they're very
cute looking.
So we always were thinking, well, what are
the pigments in these eyes? You know, we still don't know what the pigments are. But a student
in Germany, a PhD student in Germany just a couple years ago published this cool paper
where she was looking at the ultra structure of eyes. And what she found was that, and
we always knew that the eyes, the pigments were actually on the brain itself. It was
part of the brain. What?
So what she found was that, yeah, that's true.
But those pigment eye spots are not innervated.
What does that mean?
There's no nerves running from them to the brain.
And underneath them are two different kinds
of light sensor cells that we know
from other invertebrate animals that are the light sensors.
So it raises the question, well, what are the pigments for? What are they doing with
those things over their eyes? It's like wearing sunglasses. Why do you bother having eyes
if you're going to put sunglasses on? You want to guess? I mean, I don't really know.
She had an idea.
We'll link this paper on our website at alliware.com slash ologies slash tardigrade ology so you
can read it with your own eye spots.
We know they go away from light. Well, her thought was that maybe it's creating shades so that the light gets shaded when it comes from one side so they can tell which side it's coming from, which I thought was a really cool idea.
Well, what about their brains? You mentioned them. So they do have little tiny brains. How big is their brains?
What are they doing with them?
They have a fair sized brain, an average sized brain for a tiny, you know, when you scale
down their body size, they have an average sized brain for a invertebrate animal.
They're sensory.
Depending on the species, they have various sensors coming in from the head and from some
other areas of the body sometimes.
And so they're responding to those,
they're responding to light,
they're helping them orient,
they're sensing smells,
like males can orient to females based on the smell.
They're running their mouth parts and their muscles,
so it's doing all the stuff that brains do.
How are they reproducing?
I didn't even think about that.
They seem just so gender neutral in the images
that I can think of. But how are they finding each other? Are they having litters? Do they
have teeny tiny nipples? What's going on?
Okay. So there are 1,400 species. So there's some diversity in their reproduction. And
there's one species that I know of that's hermaphroditic and probably self fertile, we think,
but we don't really know.
Yes, according to the 2014 study titled,
spermatozoa in the reproductive system
of a hermaphroditic marine tardigrade,
or Xeliscus belopus.
O. belopus is a simultaneous hermaphrodite
and suggests that the reproductive mode
includes copulation and cross fertilization,
which means it's got both bits,
but it still likes to get it on with others.
Also, fun side note, the species was first described
by Evelyn Dubois Raymond-Marcus,
who was a German zoologist and artist
who moved to Brazil at the rise of Nazism
because her husband, another zoologist, was Jewish,
so they fled the country.
She co-wrote a lot of his papers,
but if she got credit, then he wouldn't get paid,
so she was kind of like on the DL, really good at her job.
Also, you should know that there are three main flavors
of tardigrades.
There are the eutardigrades,
which are primarily freshwater bound.
There are the heterotardigrades,
whose jenneys have their own pre-anul gonopore
instead of using the butthole, the eutartigrata.
And then there are a third kind.
These are what Paul calls the Yeti of the water bear world.
Do they exist?
They are mesotartigrades, which if you ask our pal, Workopedia, mesotartigrade is represented
by a single species known from a single specimen found in a hot spring in Nagasaki, Japan,
and that one single specimen is now lost.
Go back to the location, check for more.
We can't because the location from which that specimen was collected has since been destroyed
by an earthquake.
So its reproductive anatomy has not been studied recently.
Did it ever exist or was the person who found it
just mislabeling a different one that was already described?
If we built a time machine,
can we go hot tub and look for it again?
How many are out there that humans haven't found
and will never find?
Mysteries abound.
Let's get sexy.
And then at least half, maybe most of the rest of them
have separate sexes and reproduce sexually.
So males and females reproduce sexually.
And then there's some other ones
that we've never found males
and we know that the females can produce
all daughter offspring.
And so they're reproducing asexually.
But we also know they can switch between those things.
And there was a Japanese researcher
had a culture
of asexually reproducing species going for generations,
all females, and all of a sudden the male popped up
and they made it.
So they probably can go back and forth,
at least occasionally.
And in some species, males are almost equal
to the number of females.
So there's a variation in sex ratio
and this whole switch between asexuality and sexuality.
So yes, females tend to be more numerous than males.
And even in some populations that pump out
bibis with no males, a male might pop up.
Now, other species of tardigrades
have co-ed existences.
And apparently, there is flirting that happens.
Right now, in a slimy gutter near you,
there are teeny creatures that have more
res than you do.
And me.
In the sexually reproducing one, there's been a couple of papers describing mating behavior
in the last few years, and it's pretty cool. In one of them, it's pretty weird, actually.
This was a German team that had a culture of sexually reproducing species going, and
they were able to videotape them.
Well, okay.
And what they saw was that the males were attracted
to females who had eggs,
and they figured it was most likely pheromonal.
And the male, when the male found the female,
he would wrap his body around her head.
And the female, they saw the female using her stylet
to poke out into the belly of the male,
and they presumed that was stimulating him.
And then he ejaculated multiple times for over an hour.
What?
And at the head.
So the sperm was released at the head.
And so these researchers thought, well, that must've been, you know, just an
aberrant observation or maybe a confused male.
But they ended up seeing 30 different matings and it was the same every time.
And then another study came out after that with a different species and they mated like
you would think.
It was cloaca to cloaca-like birds, like cloacal kiss from a bird.
And so my thought on that is maybe it's such a tiny little distance for sperm to travel,
they don't care where they release it.
Wild.
Wild.
Can it get into the reproductive system orally?
That's a great question.
And that's one possibility.
They never really saw where the sperm was going in.
But what happens in that particular species, when the female lays eggs, she kind of scrunches her body up inside the cuticle.
So you see the big empty cuticle
and she's kind of scrunched up
and she starts to deposit her eggs inside that cuticle.
So the front half of her kind of crawling around
and the back half is filled with eggs.
And at that point, there's two openings into the body,
into the cuticle.
One would be the mouth and one would be the cloaca
And so it could have gone in either way
But it got in because it had to fertilize the eggs inside the cuticle so it had to get in some
So really just use either door hold up. What is with this overcoat though? Let's talk about the cuticle. Is that cuticle?
Squishy like a water balloon or is it kind of rigid or
can they change it depending on the external conditions? Yeah there's some
flexibility some places are thicker than others and are more rigid than others so
they have the ability to bend here and there but but generally speaking they're
semi rigid like a cicada shell. Okay. But microstuff. How on earth or how in space can these little wigglers,
how are they surviving?
Desiccated for years,
how can they survive in the vacuum of space?
What is going on with these very resilient
little tiny little badasses?
This is the tardigrade claim to fame.
It's a single most studied aspect of their biology.
So we could talk about this for a long time.
Yeah.
The way they survive, not just drying out,
but all kinds of environmental extremes,
including space exposure, which
we need to talk about, is they go into an inactive resting state called cryptobiosis,
which literally means hidden life.
And in this state, they have no measurable water in their bodies.
They have no gas exchange going on, no energy usage.
They're dead, except they can come back to life.
Spooky.
And when they're in that condition,
they are incredibly resilient.
There's been all these experiments
where they expose them to different extremes
and see what kind of survival there is.
And they've survived complete drying out,
complete vacuum, temperatures over 300 degrees Fahrenheit,
temperatures down to almost minus 300 degrees Fahrenheit,
really high levels of radiation,
like 20 times the estimated maximum dose
from the Nagasaki bomb,
and much higher pressures than you would experience
at the Marianas Trench.
So they can survive really high pressure,
low pressure vacuums, extreme temperatures,
radiation and dehydration like nothing you can imagine.
You're never gonna catch a tardigrade with a hydroflask.
Don't need it.
So incredibly resilient and,
oh, you might think about those experiments.
They're kind of evil scientist stuff from a tardigrade point of view one of them one recent experiment shot them out of guns
Into sandbags to see what kind of impact they could take what how they do
They didn't do very well with that. Okay, sorry little tardigrades. I want all the tardigrades listening to know I've never done these experiments
Sorry, little tardigrades. I want all the tardigrades listening to know I've never done these experiments, by the
way.
So they didn't do very well with that experiment.
But they're incredibly resilient to pretty much every environmental extreme we can throw
at them.
And as you mentioned, they can do it for many, many years.
And this is even, to me, more mind-blowing.
Our understanding of how long they can withstand environmental extremes has changed over time.
We used to say it was about 100 years. They could live maybe 100 years. And that was because some
people found some moss in a museum that was 100 years old, and they extracted tardigrades,
and they said that they got the animals to come out of cryptobiosis. Later, people said,
maybe they just saw movement when the animal filled with water.
Turns out it's not real easy to tell the difference between a cryptobiotic live tardigrade and
a cryptobiotic dead tardigrade.
So we kind of dropped back from that.
And then somebody found some samples that were 35 years old and they definitely got
resuscitation.
So we've been saying recently that we know they can live at least decades.
But I have a prediction that we will soon know that they can live tens of thousands
of years.
What?
How?
And the reason I'll say that is because there have been two papers published in the last
three years that found other cryptobiotic
animals in ice cores from Siberian permafrost.
These are both papers published from Russia.
And they brought those animals back to the lab and they thawed them out and they moved
and they reproduced.
So I think it's fair to say that they were alive.
Long nap, immediate boning. Every day is vacation day for a tardigrade. But how long was this
nap? So in an email after this chat, Paul wrote me, how long can they survive in cryptobiosis?
Indirect evidence of tens of thousands of years. Four exclamation points. Four well-earned
exclamation points. And he elaborates on those Siberian ice core resurrections.
And one of those was dated to 25,000 years ago, and one of them was dated to 46,000 years
ago.
The cores or the tardigrades themselves?
Both.
The ice cores were dated that long, and so we know that animals were there from that
period of time as well.
We had no idea they could live that long.
And so this was really mind-blowing.
And tardigrades have at least as sophisticated of cryptobiotic machinery as do the other animals that were found in these cores.
Those other animals were rotifers and nematodes.
So I think it's just a matter of time before we find tardigrades in those ice cores as
well.
Do we have any idea, and by we I'm using, I'm including myself in this, because I would
like to be, I wish I were a tardigradologist, do the royal we have any idea how on earth
they can survive that and what kind of implications does that have for mortality in general?
Yeah, yeah, yeah.
So that's a good question.
Yes, we do have some idea how they do cryptobiosis.
And before I tell you that, though,
I need to give a little qualification to how tough they are.
Sometimes because of this ability
to withstand all these conditions for so long,
tardigrades are called the toughest animals on earth.
Yeah, that's what I think of when I think of them.
Yeah, and I agree with that, but with two qualifications that are, I think, important.
One is that not all tardigrades are cryptobiotic.
They're 1,400 species.
Cryptobiosis is a trick of the terrestrial tardigrades, the ones in
mosses and lichens. It's what allowed them to colonize terrestrial habitats. The truly
aquatic, either freshwater or marine ones, don't have that ability.
Oh.
And the other thing is, note that the way that they do cryptobiosis, it's an inactive
state. They're able to survive environmental extremes by going inactive.
But an active animal is pretty easy to kill.
So sometimes you read that tardigrades are extremophiles, and they're really not.
They're extremotolerant is the better term.
And that makes a difference if you're an astrobiologist interested in life on other planets and looking
at earth models for what that might look like.
It's really different if you're an extremophile versus extremotolerant.
So my proviso is that some tardigrades are the toughest animals on Earth when they're
sleeping.
Do you think that their brains are just water activated?
Yeah.
So here's what happens.
Here's how they do this.
Back to your question of how they do this.
So imagine you're a tardigrade living on a moss cushion and you're happily crawling around in the water film of that moss doing your little tardigrade life. But the sun comes up and the
water starts to dry up and you're going to die if you don't do something.
Oh no.
So you pull in your legs, you contract all your muscles
and curl up, and that expels all the water from your body.
And you form this little shape called a ton,
T-U-N, which is a barrel shape.
It looks like another word for a cask or barrel.
So they go into this ton state.
And while they do that, they start
producing a whole biochemical toolkit
of protectant molecules. And we're learning more about this every year. And there's some
biotechnological applications about this as well, which maybe kind of gets to your question
about what this means for longevity. And I'm not a biochemist. This isn't my area of study,
so I won't go into much detail about this. But we know that this biochemical toolkit includes antioxidants, heat shock proteins,
these other really cool proteins called intrinsically disordered proteins,
and in some cases they produce a sugar called trehalose.
And what all those molecules do is they help DNA not get damaged during cryptobiosis,
or if it does get damaged, they help fix it.
They can stitch it back together again.
Wow.
They protect the membranes.
They protect all the other cells, the brain.
So they're all working together to protect the whole package.
And we don't know the details, but that's generally what's happening. The one particular piece of that that I think is the coolest is the sugar tree halos.
Again, this is wild.
So, in the ones that produce tree halos, what they do is they start to dry out, they produce this simple sugar,
and some of these other proteins connect with the sugar, and they start to convert the animal from its liquid state
to a glass-like state in the process called vitrification.
So it's like if you had a bag of gummy bears, just regular gummy bears, and they spilled
open and dried out for months and months and months, they would become hardened and they'd
become like a little rigid gummy bear.
That's exactly what's happening with these tardigrades is they become rigid little microscopic
gummy bears that are hardened and glass-like because of the sugar casing that forms a matrix
protecting all the cells in their body.
Oh, wow.
Is it water-soluble then?
It is.
Yeah, it is.
So this is what would happen when it's drying out.
A really cool biotechnological application of that
is a pharmaceutical company has used biomimicry
where they said, hey, that's a cool thing
that some of these animals like tardigrades do,
this vitrification thing.
I wonder if we can use vitrification
to stabilize vaccines for long periods of time.
And they actually, they didn't use the exact same sugar,
but they used another sugar
and they created little tiny sugar globules
that captured the vaccines and it worked.
They have huge long shelf lives.
And when they're injected in the body,
the sugar just disperses and melts
and then the vaccine can be released.
Wow. Oh, I have so many questions from listeners. Can I ask you one million?
Sure. Sure.
Okay. And before we get to your one million questions, patrons, let's first toss a little
money toward a reputable cause. And this week, Paul picked the wonderful Xerces Society.
We love them. For over 50 years, the Xerces Society for Invertebrate
Conservation has protected endangered species and their habitats, produced groundbreaking
publications, trained thousands of farmers and land managers to conserve habitat, and
raised awareness about the importance and plight of invertebrates in forests, prairies,
deserts, and in oceans. So you can find out more about their programs at Xerces.org, which is linked in the show notes.
And that donation was made possible by sponsors of Ologies.
Okay, now into your questions. Patrons submitted these via patreon.com slash Ologies were for $1 a month.
I may ask your question and say your name with my mouth.
We even have tiers to leave us an audio message so you could hear your voice on the show. But yes, this one was asked by patrons Rowentry, Pavka34,
Levi Morris, Laura M. Smith, Bert Gilley, Magsaroni, Gabriel Charbonnet, Christine Hurley,
Stuggy, Rosie Hope-Madeleine, and Gregorius of Tomsk. In their words asked, is it possible
tardigrades had once hitched a ride on an asteroid from another solar system. We were talking about space and how they survive in space.
But essentially, are they aliens?
Did they come from space?
How do they do what they do?
Did they come from another planet?
Ha ha.
Yes, Virginia, they are aliens.
Oh, thank you.
Yes, Virginia is what people say when they allow you to believe in magic and they don't ruin it for you.
In the sense that they're exotic and unusual to most people.
Okay.
But it's not because the tardigrades and where their home planet is, it's because people don't pay attention to the microscopic world.
Hmm.
So, yeah, why do you think people ask that question?
I think that they seem so much heartier, and we maybe compare them to ourselves.
And so we think if we are the standard species on the planet, because that's how humans think,
and they are so different,
they must be from Mars.
And they survive space exposure.
Right, right.
Yeah, yeah, yeah.
Okay, well, let me think about that a while.
No.
No.
Hard no.
No.
Great.
No.
So a couple things come to mind. The studies that expose them to space have a huge fine print qualification that we need
to talk about.
The headline is that tardigrades survived space exposure.
The details are much more nuanced than that, and the reality is they did not survive all
the hazards of space.
So that piece of the observation doesn't really fit.
No, they can't survive long-term travel through space.
And when you look at them, maybe they look unusual
if you haven't seen a whole lot of other related invertebrates,
but their DNA is just like our DNA.
They have gene sequences, base pair for base pair,
that are just like closely related species.
The biochemistry of their cuticle
and their molting processes,
just like other molting animals,
they're obviously very closely related to Earth animals.
Unless all of them came from somewhere else.
Maybe.
Not likely.
Probably not. So flimflam busted. Unless all of them came from somewhere else. Maybe. Not likely.
Probably not.
So flim flam, busted. Tardigrades are not aliens on Earth. It's okay. We'll be okay.
Yeah, that idea, by the way, astrobiology is the study of the possibility of life on other planets,
and they look at tardigrades and other extreme survival animals to see if they can tell them
something about what to look for.
One particular idea that's very controversial from that is this idea of panspermia, which is the idea that maybe organisms have hopped from one planet to another through asteroids. Oh, that experiment
I mentioned about getting shot out of guns, that was the motivation for that. They wanted to determine if they could withstand an impact similar to a meteor hitting a planet. And
the answer was, oh, hell no.
Okay. Carlos Alvarez wants to know.
I read a few years ago that some of them were sent in a lunar module to the moon and it
crashed and now they're still somewhere on the moon.
But an engine fault caused it to crash, scattering into thousands of pieces.
It makes me think of the times we have moved species around on this planet and created
a whole new nightmare.
What are the chances that these are surviving there and what are the unknown things that we may have just done to the Moon,
you know, one day in a million years, it's just covered in tardigrades?
Yeah.
You know, when I heard about that, I thought it was a joke.
You know, it was like an Israeli space mission sent a lunar module to the Moon
and it crashed and it had tardigrades on it.
And I was thinking, OK, yeah, what's the punchline?
But it was real.
It was real.
And yeah, I was kind of shocked.
And my colleagues and I talked about this.
I don't understand the motivation.
They had several things in the payload of that module
that were earth relics, including tardigrades
and cryptobiosis.
And I never quite understood the logic behind that and what they were planning
on with that.
But yeah, it crashed.
The people that studied, did the shooting out of the gun thing said that they wouldn't
even have survived that crash, much less a meteor hitting a planet.
So they don't think that they survived.
There's also no atmosphere on the moon.
And so there's really no way for them to come out of cryptobiosis on the moon. So if they did survive that impact, I think they could still be in cryptobiosis,
but there's no way for them to come out of cryptobiosis.
It does raise, I think, a legitimate, real ethical question about sending
Earth organisms to other places. And in fact, there was a lot of discussion about that. And the authors of that study,
the lunar module study, said, well, we know that that's a problem. We wouldn't do that
any place that actually had an atmosphere where they could survive. So why they did
it to the moon, I don't know still, but they did.
Let's say that some sprinklers went off on the moon and they did rehydrate and they came out of it and all there was to eat were the other tardigrades.
Do they ever cannibalize?
They don't cannibalize.
Okay.
But big ones eat smaller ones.
And so yeah, they could.
They could.
Yeah.
PS, if you saw a headline this week, such as, spiders on Mars fully awakened on Earth
for first time and scientists are shrieking with joy.
Don't take that clickbait, or just do, but know that it's about cracks on the surface
of Mars that look like spiders from afar. Astrogeologists have figured out why they
happen. Hence, these things are called our Aeneiform terrain, named after spiders. But
alas, there are no real giant spiders on Mars. Although, we do have an entire astrobiology episode
with Dr. Kevin Hand, who is a NASA researcher looking
for life on the Jupiter moon, Europa.
We'll link it in the show notes.
But on the topic of animals that will be astronauts,
Katie Oldman, first time question asker,
asked, could, should we, have we already tried sending them
into space?
And other patrons, such as Gwen Hughes, Ruben Nikitjevitz,
Brian Smith, Mary Ann, Rachel Guthrie, Christian Fuller,
Aaron Sorensen, Zephyr, and Sydney Keening,
in Sydney's words, said, wait, how did we
figure out the space thing?
That's a good question.
I thought that they just went into cryptobiosis,
but how did they survive space exposure?
That is, yeah, that's what launched them into fame.
That is, yeah, that's what launched them into fame. They did indeed survive space exposure.
So what happened is there were four different experiments that were done
that included tardigrades in space.
In 2007, there was a photon M3 satellite mission that had three different modules on board with tardigrades.
And then in 2011, there was a fourth one that went up to the International Space Station.
And collectively, they had five different species of tardigrades on board. They had eggs,
animals in cryptobiosis, and in one study, they actually had active animals not in cryptobiosis.
And in one study, they actually had active animals not in cryptobiosis. And they exposed them to different aspects of space, brought them back to Earth, looked
at how many survived.
And what they found collectively is that when the animals were exposed to the microgravity
and the cosmic radiation of space, they survived really, really well,
including the ones that were not in cryptobiosis.
And that was huge news because no animals have ever
survived space exposure.
Of course, that'd be a really nasty experiment to do to,
you know, a little space monkey or something.
But it was huge news, a lot of press about it,
very spectacular results.
But there's a lot of fine print that isn't ever talked about.
And the fine print is that it wasn't
like they had them on little micro tethers on spacewalks
and they brought them back into the spaceship.
They weren't exposed to all aspects of space.
They were exposed to some aspects of space.
They were in enclosed cases.
So in all of those experiments, they were in temperature-controlled
cases. And so they didn't get exposed to the huge temperature fluctuations of space. And in the case
of the active animals, they were not exposed to the vacuum of space, for example. And in all of them except one,
they were protected from UV radiation.
And in the one in which they were exposed to
full spectrum UV, they died pretty quickly.
So the headline was Tardigrades Survive Exposure to Space.
But the details are,
they can handle some aspects of space,
which is shocking and amazing,
but they didn't handle total exposure to space.
So the hard vacuum of outer space,
survivable for many of the tardigrade astronauts.
Now the vacuum plus the solar radiation,
which is true to space, less survivable.
Okay, well that demystifies them
and also probably will be very helpful in busting
the flim flam that they are aliens.
Exactly. Exactly.
I like the idea too that people hear that octopuses are so out there and interesting,
they must also be aliens. I like the idea that an octopus just has armloads of tardigrades.
They're careening on an asteroid. They crash
in and they're like, what's up Earth? We're here to box them shit up.
So if tardigrades and the world in miniature interests you, consider getting your hooks
into this research. And on that note, patron scarletp wanted to know, what are the claw
looking things on the tardigrades' feet and what are they for? And Eating Dog Hair
for a Living asked, what are those flipper-looking things on their stumps used for? And this
topic was also in the minds of Jacqueline Church, Fleshverse, OddOctopus, Spella, AveragePie,
Susan Lynn, and...
Lyle Ornstein Addy Capello said, they're like water
wombats. Look at those talons. What are those claws on their feet for, actually?
Adam Lyle Yeah, the ones that have claws, they use them to hold onto the sediment.
They're crawling around, grasping hold of the sediment.
The ones on the fourth pair of legs that are turned around backwards that I mentioned before,
in a lot of cases they use those like prehensile organs.
They hold on with those, and then when they want to move, they let go of those and crawl
with the first three pairs of legs.
Kind of like a rear wheel drive, I guess.
But not all tardigrades have claws.
And especially the marine ones are really hyperdiverse and have a whole array of different
feet type, including some that have fingers that end in adhesive pads and all kinds of
really cool differences.
And so that's again the problem of kind of thinking about the kind
that floats around on the internet too much.
Amber Penita and Siri Grossman, first-time question asker,
wanted to know about their number of legs.
Siri asked, eight legs, why?
Is that some primal perfect optimal walking number of legs?
Is that some primal perfect optimal walking number of legs? Well they have five body segments and there's a leg for each of the segments except for
the head.
And there's some really cool evo-devo studies that found out that what happened as they
got miniaturized from ancestral lobopodians, which were macroscopic, is that the middle
segments of the body got
chopped out and it left the other segments.
So they evolved from multi-legged, more like millipede-like things.
I mean, those are arthropods with jointed legs, but they look kind of like catapillars
with lobe legs.
As those segments got cut out, five segments were left,
therefore one pair of leg for all the segments except for the head.
Well, Sophie DeVal, first time question asker, says, I'm a dentist and I would love to know
if they have teeth. And if they do, what are they like?
Good question. Some do have teeth and they're thickenings around the mouth. The mouth's a circle, and there are sometimes one, two, or three rows of dentate structures
that poke inward.
And so they're kind of laterally oriented around this circle, and they're poking inward.
And they probably use them for grasping as they try to suck stuff down their buccal tube.
Do they ever suck down any nasties
and get food poisoning?
Farina Runstadler asked,
what kind of immune system does the tardigrade have?
And Janie Jones was concerned.
Do they get sick?
Allie and Julian want to know,
are they affected by bacteria and viruses?
We know there's some parasitic funguses
that have attacked them,
and I think some other
protozoan, I can't remember which, what now.
And there's some marine ones that have these pouches on the head that are packed with bacteria
and apparently they have a symbiosis with these bacteria and are using them for something,
presumably maybe chemo-synthesis or something like that.
Don't really know.
So somehow they're getting, probably getting nutrients from these bacteria.
Oh, there have been a couple studies of tardigrade microbiomes recently.
Really?
Yeah.
And they have found a whole series of bacteria and other things that are in their guts.
Oh, that's exciting.
But I don't know about any bacteria that are
disease causing. Speaking of peril, sad question. Rebecca Fitzgibbon, Pavka 34, Teresa Gleason,
want to know, in Rebecca's words, are they being impacted by climate change?
Rising tides lift all water bears, they ask.
they ask. That's hopeful. Yeah, that's hopeful. Well, there have been some studies of them being impacted by climate change. There's some people doing some really cool studies in glaciers,
and there are these things called cryoconite holes, which are circular tubular holes that form as ice
melts, and then it gathers some gunk in the bottom and then some animals colonize it.
Not very many, but a few things can colonize
those cryoconite holes and they've been talking
about concerns as the glaciers melt
that it's having potential negative impacts.
And this other study recently looked at those stylet's
that I mentioned, the paired stylet's,
have calcium carbonate in them.
So a reminder, a stylet is like a mouth knife and when tardigrades molt
These fall off and then they just secrete new ones with glands near their face opening and are therefore
Potentially impacted by acid and so they have looked at whether or not acidic conditions can erode those
things like in ocean acidification, perhaps.
So there is some indication that it could damage things, and that's right now a lab
study instead of a field study.
Susan Maszrak wanted to know, I wonder since they've survived so much how they'll do with
the microplastic crisis we're currently in.
Did anyone ever find microplastics in their little guts?
You know, that's a funny question. I just saw a paper that was looking at microplastics in microscopic organisms,
and for some reason they found them in all kinds of other microscopic animals that were in their habitats, but not in the tardig tardigrades. Somehow they weren't picking up the microplastics. It was just
one study just came out. I have no idea why that was the case but I do think
it's possible that they could be picking them up. It might be that they, because of
using those stylus, maybe it acts as a filter somehow and they can't pick them
up. I don't know but I would think that eventually we'll find them in there.
And as long as we're growing ever more fond of them,
what is the correct term of endearment?
Josie Rutherford asked, some people call these water bears,
others potato walruses.
Is this one of those tests where what you see
reveals an aspect of your deep psyche?
Andrew McKelvey's Izzy, Emily Heard, Mona Finlayson, Emily Vanco,
and Miranda Panda also had etymological questions as well as. Bell, aspiring garbage archaeologist,
wants to know why did the nicknames water bear and moss piglet, where did those come from,
and which would you say is more accurate? Ah, moss piglets is not very inclusive. Because that's only those that live on moss.
So I wouldn't use that term.
When you look at tardigrades through a microscope,
when you look in that little world,
you see all these wormy things that move in a wormy-like fashion.
But when you see tardigrades, they move really differently.
They're wiggling, they're fat and chubby,
and they have these thick legs that
they're waving gently and their head moves a little bit side to side.
Some of them have these big soulful highs, right?
So they kind of look mammalian.
And the very first person who ever described a tardigrade was Johann Gutz, back in 1773.
And he, in that very first paper ever written on tardigrades, thought that
they looked like Kleiner Wasserbeer, little water bears.
So we have a two-part earthenology episode all about bears, as well as a carnivore ecology
episode with Dr. Rae Wynn Grant.
And yes, they are linked in the show notes.
So that's the most common name.
By the way, there's some pop culture trivia about Gutsa., tell me. You wanna? Yeah, of course. It's trivial trivia. You know the
TV show Star Trek Discovery? Yes, we had people ask about that. Yeah. We had
several people ask about this. Okay, Patricia Evans, Daniel Sucher, Becky
Dasassi, Seagraass Scientist, and Luna Rose.
They have a character that the crew members call Ripper, and it's a human-sized tardigrade-like
alien.
Hello.
Brought you the good stuff. Hello.
Brought you the good stuff. And it allows them to do giant hops through the universe
because, of course, it has a symbiotic relationship
with space mycelia.
Of course.
Of course.
On a side, an offshoot of Star Trek Discovery,
we learn that Ripper's preferred name is
Efraim, which is Johann Gutz's middle name.
Oh, that's very sweet.
That's so sweet.
I love that.
If you win Barcha View with that question, I want half of your winnings.
I just said that in an episode that went up about caves literally yesterday.
I was like, we're winning a lot of bar trade with people.
Where's our 10%?
A few people want to know, Earl of Gremelkin asks, have they been sequenced DNA?
What does it look like?
Any weird shit?
Brian Marlowe, Yngwie, Justin Salucido, Julia Casey, also wanted to know about tardigrade code
and the potential to just splice it into ours.
And patron Justin Saucido would like their loved ones
to live longer, like maybe tens of thousands of years.
When it comes to their DNA,
anything that comes up interesting with that,
I'm sure a lot, but anything that surprised you? I don't really have a good answer for that. I don't think they... their DNA is not very
different than other invertebrate animal DNA. It has been sequenced. There have been a couple of
maybe three or four species now that have full genomes completely done on them.
One paper worth the read is evidence for extensive horizontal gene transfer from the draft genome
of a tardigrade out of the University of North Carolina at Chapel Hill, which reports how
at least one species of tardigrade, probably a lot of them, have a large fraction of its
genome.
About 6,000 of them are foreign genes. That means they are derived from diverse bacteria, as well as plants, fungi, and single-celled
organisms.
A huge fraction of its genome picked up from elsewhere.
One sixth of their genes were acquired from other animals, which the researchers say is
double that ever found in even the most extreme cases of this horizontal gene transfer.
And the paper speculates that animals that can survive extremes may be particularly prone to acquiring foreign genes.
Maybe that's how they do it.
Listen, I know some things feel awful and boring or pointless.
We're all scrolling. We're all seeing a lot of shit going on in the world.
Some days are great for us personally. Some days are hard. But all around you are
unseen creatures with backstories that would leave the world agape if people cared. Also,
Paul casually mentioned that yes, well tardigrades are cute and they have cryptobiotic superpowers.
Some of them fluoresce in these beautiful colors.
He calls them disco bears.
And one of his most recent research projects
was exploring autofluorescence in tardigrades,
which is different from bioluminescence.
Apparently, autofluorescence happens by absorbing light,
and then bioluminescence is chemical and caused by an enzyme.
But we could go on and on.
Let's get to how do you meet one and hopefully befriend a tardigrade. So many
people we gotta know how do you find them? How do you look at them? How do we look at tardigrades?
How do we do it? Now that I can help you with. But basically, you got to have a microscope. How strong?
You know, even a 40-power dissecting scope, you can see them and tell that they're tardigrades.
You can't like look at fine structures to, you know, identify them, but you can tell
that they're tardigrades just with a simple inexpensive microscope. And so what we do
is we make these pie plates, sieves, bareman's funnels they're called. And so what we do is we make these pie plates, sieves,
Baermann's Funnels, they're called.
And so you take a styrofoam plate,
you put another one on top of it
and cut a hole out of the bottom and put a screen on it,
and then put a tissue paper over that,
and then crumble up a moss all over that,
and then fill it with water.
And it helps if you shine a light on them.
And what happens is they move away from the light
and away from the heat,
and they go down through the tissue paper,
the animals go through the tissue paper
and gather down in the water on the bottom pie plate.
And then you can just pour that off into a Petri dish
and you can find them.
So yes, this is called a Bayerman funnel
and there are a lot of ways and materials you
can DIY this, including just using a regular funnel with a little rubber tubing to kind
of stop it at the end, make a J at the end of it.
You can just put like a coffee filter or pantyhose or a cheesecloth at the bottom of the funnel.
You wet your moss so that you have like an inch of that kind of soupy water at the bottom. And 16 or so hours later, your critters will move away from the light and through the filter
and into that tubing. So then you could take that and then you can see them pretty cleanly
in a dish under the microscope.
And if you look in mosses, lichens, leaf litter, soil, grit in your gutter, they will be there. No.
So, a 40 power is enough.
Some of them look transparent, so do you kind of get an eye for it so you don't glaze over
them, or are they pretty obvious?
Yeah, some of them can be very transparent.
Some of them are very small, very transparent, sometimes rare, so you have to be patient.
It helps if you have samples so that the animals are still alive, so you can see that movement,
because the movement is very characteristic.
Nothing else moves like that.
More on those moves in a moment.
The trick is, once you have them and you've found them,
and if you want to look at them at higher magnification,
you've got to transfer them to a microscope slide
and look at a high-powered microscope.
And to do that, you have to have some kind
of permanent mounting medium. And when you do that, you have to have like some kind of permanent mounting medium.
And when you do that, you can't transfer water into it. So what we have is tiny little tardigrade
lassoes. And we can flick them up, catch them on the lasso, and then transfer them over
to the mounting medium.
And do they perish in the process?
Yes.
Probably. Okay. That's what I thought. Sorry, I heard you.
Can you describe that locomotion that is not computer generated?
Yeah, so all four legs are constantly moving.
And especially if you have one on a Petri dish,
so they can't grab hold of something.
They're kind of laying on their backs, kind of just in one spot,
flailing their legs.
And so they're moving their legs,
and they all are moving kind of at their own
rate so they're not synchronized or anything. They're just kind of waving around and then
the head's moving side to side slowly. And so they just immediately look like a little
bear with eight legs instead of four.
With all of this love for tardigrades, because we love them so much, there must be something
about your job as a tardigradologist that sucks or something for tardigrades, because we love them so much, there must be something about your job as a tardigradologist that sucks,
or something about tardigrades that maybe gets your goat anything bad about your job.
We will ask the best thing.
Okay. Let's see.
I think one thing about studying tardigrades is that sometimes it can be dismissed by some people
because they're like a niche animal.
They're like, why would you study a little critter like that?
It doesn't have human impact.
So there's a little bit of that, oh, they're so cute.
It's kind of like, oh, you're doing that cute kind of stuff.
So there's a little bit of that maybe.
Otherwise, I'm not sure I would have studied tardigrades early in my career because I don't think I would have sat at a microscope that maybe. Otherwise, I'm not sure I would have studied tardigrades early in my career, because I don't think I would have sat at a microscope that long. The work for tardigrade
ologists is to go out into the field one day, and then you have weeks and weeks of lab work to do
and microscopy to do. So you've got to be willing and interested in microscopes and be willing to sit in a
lab at a microscope to study them.
It's not like going to the Serengeti and watching tardigrades clash into one another and that
kind of thing.
It doesn't, you know.
Do you have playlists in the lab?
Like you're just jamming out.
Do you listen to books on tape?
Yeah, I have all kinds of playlists.
There's nothing tardigrade specific, though. Someone did ask about Cosmo Sheldrake, speaking of music,
how accurate is the song Tardigrade song by Cosmo Sheldrake?
Lexi Gutschel and Mitt Wald both asked and Dig wrote in, not a question, but I ironically woke up with Cosmo Sheldrake's Tardigrade song stuck in my head this morning.
Dig, Cosmically Connected.
We're going to have to add it to your playlist no matter what.
Yeah, we need that one.
I've heard it, but it's been a long time since I've heard it.
My favorite Tardigrade song is the one by Mal Webb, who's an Australian guy that does all of his music
by mouth sounds.
I wish I were a water bear. And I'd be comfy anywhere.
I think it's hilarious. And it's very accurate really in terms of he talks about centuries
of happy dozing and I want to be a tardigrade. I don't blame them but of course now that we know
the toughest thing what is the best thing about tardigrades? What's the best thing about being a
tardigradologist? You have such a cool job and life. Well the best thing is that they are
charismatic and so people like them and they've gotten to be famous. They weren't famous when I
started studying them and so that was kind of just an accident that they
survived space exposure and
Got famous because of that and that's really it's fun because people know about them now
And so people want to know about them and that's not true for most microscopic life and it's useful to me because my
ulterior motive is for
microscopic life and it's useful to me because my ulterior motive is for students of all ages is to get people interested in microscopic life because it's so abundant and so crazy and so poorly studied.
So tardigrades are a great hook to do that. This has been one of my favorite episodes.
I don't like to name favorite episodes as one of my favorite ever. This has been such a wonderful privilege
to talk to you about tardigrades.
I have a feeling that because of this,
there will be future tardigradologists.
Well, Rochelle Waldman, fellow tardigradologist,
they spent the past year studying tardigrades
for their master's thesis,
and they're currently in the process
of writing up the report for it.
So I know they have a tardigradeologist
to tardigradeologist question here.
So my question for the ologist is what they think
the future of tardigrade research should be
or should look like.
Do they think we need to focus more on their distributions
and diversities or their physiological mechanisms
that are responsible for things like cryptobiosis?
I'm so excited that you're finally getting a
chance to touch up on this topic. It's an extremely interesting study and yeah, I love your podcast and
really excited for this. Did you say Rochelle? Rochelle, yeah. Great question. I'm not sure what
it should do. I know what it's been doing. I mean, the history of tardigrade research
has changed over time, I think, as more and more people have started studying tardigrades and as
molecular biology has kind of moved into the scene. It used to be that a lot of
tardigrade researchers were at small colleges
doing a lot of natural history kind of stuff, taxonomy kind of stuff, a little bit of ecology.
And part of that was because there wasn't a lot of funding for it because they're not human pests,
you know, they're not economically important to humans, which I find kind of charming, really.
They don't need us.
They don't need us. That's great. So it was mostly people with small or no grants kind of messing around having fun.
Now that we are learning a lot more about these biochemical tool kit for cryptobiosis
and possible applications of that, big science is taking over.
Molecular science, I think, is moving in.
And it's great.
I mean, it's opening all kinds of doors.
So I would fear for, this is an old guy talking, this is a dinosaur kind of comment,
but I would fear for us to move all the way into the world of molecular biology
and forget the field natural history because if you don't know the species and where they live
and what they're doing, you can't connect it to real world stuff.
So I hope we continue that we That is a problem. There's not a whole lot of tardigrade
ologists who are doing things that are ecology related or natural history related anymore.
If someone decides tardigrades are their destiny, should they just Google how to become a tardigrade
ologist? No, they can contact me. Email me. I'll help you. I'm always wanting more people to study.
We have very few people that are studying them,
and especially doing the natural history kind of stuff
that us old timers do.
So I help anybody that contacts me,
I help them get started.
Watch out, watch your inbox.
So ask terrific people tardigrade-ological questions.
And actually, wait, one more, okay, what is Paul's favorite species of tardigrade among the numerous out there?
He told me in a note later that it's the marine tardigrade Tenarctis bubulubus. Tenarctis bubulubus, real name.
And in his words, it has a cluster of balloons growing out of its butt. And I looked this up and truly,
it is a little itty bitty creature
trailing what looks like a handful of balloons.
Like imagine if the house from up was microscopic
and it was a water bear instead of a house.
Balloons out his butt.
Paul, you're a treasure.
We adore you.
To find out more about Paul's work,
we have linked to it in the show notes,
as well as to Smologies, which is our spin-off show that is safe for kids.
There's also a link to zersies.org and to so many other episodes you might like, as
well as to our Patreon so you can submit questions yourself.
And there are links to our social media.
We are at Ologies on Instagram and X.
I'm at Allie Ward.
It's just one L and Allie on Instagram and X as well. Erin Talbert, Admin Zoologies podcast Facebook group,
and has also been my BFF since we were four.
So we have slurged around many algae-filled ditches together
among so many tardigrades.
Thank you, Erin, for being my partner in that.
Aveline Malik makes our professional transcripts.
Noelle Dilworth is our wonderful scheduling producer,
and Susan Hale managing directs us as managing director and also does some additional research.
Kelly R. Twyer does the website, and our sole non-woman contributor is the lovely editor
Jake Chafee, and getting all the pieces together so that we are not tardy ourselves is lead
editor Mercedes Maitland of Maitland Audio.
Nick Thorburn wrote the theme music, and if you stick around to the end of the episode,
I tell you a secret.
And this week, it's that, listen, listen sometimes my face gets fuzzy and sometimes I do what is called dermaplaning
which is another word for shaving your face. Just a razor it's a regular razor you would use on your
legs but I used it on my face and I did it and I thought ah that's a little smoother. It's just
peach fuzz but you know what I mean just get it off And I did that and then I just went to record and I want you to know that I have tiny hairs
from my face now stuck to my face and they itch and I want to wash my face.
And I don't want to tell you this, but I needed a secret for this one.
And I thought, why give you a life hack when I could reveal something even more true and
disgusting?
Listen, it's called dermaplaning, okay?
It helps your moisturizer absorb better.
I gotta wash my face.
Okay, bye bye.
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