Model Organism

Roman Mars:
This is 99% Invisible. I’m Roman Mars.

Roman Mars:
If I’m being honest, I’m not a big pet guy, but I’ve had a couple over the years. My favorite was a snake named Chewbacca that I had in grad school while I was studying corn genetics. He was pretty cool.

Emmett FitzGerald:
I am definitely a pet guy. Right now, I have a dog and a cat. Shout out to Donnie and Louis, but my first pet was kind of an odd one.

Roman Mars:
That’s producer Emmett FitzGerald.

Emmett FitzGerald:
At a party in college, my friend, Will, handed me this Tupperware filled with water. I took off the top, and there was this little animal floating there. It looked like an adorable, chubby tadpole with legs and this delicate feathery boa of gills wrapped around its neck. Its face was locked in a placid, almost enlightened smile, like it knew something I didn’t know about the secret of life. Will told me that I was holding a kind of salamander called an axolotl and that he was giving this axolotl to me.

Roman Mars:
Oh, yes, my favorite kind of gift, the kind you have to work really hard just to keep alive.

Emmett FitzGerald:
I put the top back on the Tupperware and named her Lenny. It turned out that Will had taken about 20 axolotl embryos from a biology lab where they had been discarded. He was raising baby salamanders out of his bedroom and distributing them to friends across campus, along with detailed instructions on how to care for them. I got Lenny a big fish tank and put her right on my mantelpiece.

Roman Mars:
Axolotls are amphibians. They hatch from eggs laid in the water, but while most amphibians will eventually transform into an adult form that lives on land and walks on four legs, axolotls are different. They never transform.

Emmett FitzGerald:
They live their whole lives in the water, like teenagers that never grow up. And that’s not even the coolest thing about them. It turns out that axolotls have a superpower. People discovered it after observing axolotls biting off each other’s tails and legs.

Jeramiah Smith:
They realized that these animals would grow back whatever was bit off or cut off of them.

Emmett FitzGerald:
This is Jeramiah Smith, a biologist at the University of Kentucky who works with axolotls. He says that they are nature’s great regenerators.

Jeramiah Smith:
So they can regenerate their arms. They can regenerate their tail, a piece of their liver, parts of their hearts.

Emmett FitzGerald:
They can even regenerate pieces of their brain. As long as they’re still alive, axolotls will regrow basically anything.

Jeramiah Smith:
You can’t chop their head off and have them regrow their whole head, but most other things can regenerate.

Emmett FitzGerald:
Those remarkable superpowers have turned the axolotl into a scientific superstar. Biologists have devoted their careers to this salamander that never grows up and can regrow its toes and tail.

Roman Mars:
And the dream for many of these scientists is that we might one day figure out how exactly axolotls do what they do and maybe even learn to harness that power for humans.

Emmett FitzGerald:
And this scientific obsession has turned the axolotl into one of the most abundant laboratory animals in biology. Today, smiling salamanders like Lenny can be found swimming in tanks in universities all around the world, which is a little strange because in the wild they’ve only ever been found in one place.

Luis Zambrano:
Okay, well, my name is Luis Zambrano. I work in the National University Autonomous of Mexico as a researcher in the Biology Institute.

Emmett FitzGerald:
Luis Zambrano is a biologist based in Mexico City.

Luis Zambrano:
One of my fields is the conservation of one of the most iconic species in Mexico, which is the axolotl.

Emmett FitzGerald:
There are a few different aquatic salamanders in Mexico, but Luis studies the Ambystoma Mexicanum, also known in Spanish as the ajolote and in the Nahuatl language as axolotl and in English as axolotl.

Luis Zambrano:
Which is the most iconic of these sort of bunch of species of salamanders that lives only in Mexico City.

Emmett FitzGerald:
The axolotl has only one natural habitat, and it’s not some protected wilderness area. It’s one of the largest cities in the world.

Roman Mars:
Mexico City is located in a highland valley, and hundreds of years ago, the valley was filled with five lakes. Over centuries, various indigenous groups lived around these lakes, including the Aztecs.

Emmett FitzGerald:
The Aztecs farmed on top of artificial islands called chinampas, and it was in and around these floating farms that the axolotl thrived.

Roman Mars:
The Aztecs were fascinated by these strange salamanders. They ate them, and they used them to make medicines, and they considered the axolotl a sacred animal.

Emmett FitzGerald:
The name axolotl comes from the God Xolotl, who was a sort of shape-shifting, trickster figure. According to Aztec mythology, when our sun was created, it was stuck in one place all the time, and so the gods decided to sacrifice themselves to try and get the sun to move across the sky. But when his turn was up, Xolotl decided he didn’t want to go through with it.

Luis Zambrano:
He ran away, and he tried to transform himself in many different things.

Emmett FitzGerald:
He turned himself into an ear of corn and an agave plant.

Luis Zambrano:
Finally, he transformed himself in an axolotl.

Emmett FitzGerald:
These aquatic salamanders have been important symbols in Mexican culture and art. You can find them in the murals of Diego Rivera and in the poems of Octavio Paz.

Luis Zambrano:
So it was really, really attached to the Mexican culture for many, many years, more than 2,000 years basically, since we, as Mexicans, are here in the valley.

Emmett FitzGerald:
And for all those years, the axolotl remained confined to that valley. You basically couldn’t find them anywhere else in the world-

Roman Mars:
Until a French expedition to Mexico in 1863. During the trip, French officials collected a bunch of plants and animals to bring back with them to Europe, including a group of axolotls.

Richard Griffiths:
So what we do know from historical records is that 34 animals were collected and taken to the museum in Paris.

Emmett FitzGerald:
This is amphibian expert, Richard Griffiths. He is a professor at the Durrell Institute of Conservation and Ecology at the University of Kent. Richard says that in Paris, scientists started breeding some of those 34 salamanders that were taken from Mexico City.

Richard Griffiths:
And that proved very successful, and those descendants of those animals from the Paris museum have been spread around the world.

Emmett FitzGerald:
From the very beginning, European scientists were fascinated by the axolotl’s strange appearance and its perpetual tadpole lifecycle, and they started using them as model organisms for laboratory research.

Roman Mars:
And axolotls were suited for the job. They survived well in captivity and were easy to breed.

Emmett FitzGerald:
Their cells were also large and simple to study. And later on, their genes proved to be easy to manipulate.

Richard Griffiths:
This means that you can use them as a good model for carrying out laboratory experiments on things such as the development of embryos, our hormonal systems, such as the control of metamorphosis.

Roman Mars:
Axolotls were important collaborators in a lot of 20th-century science. They helped us understand how organs developed in vertebrates and the causes of diseases like spina bifida.

Emmett FitzGerald:
And scientists had always been interested in the salamander’s regenerative talents. But it’s only in the last few decades, as we’ve come to better understand axolotl genetics, that we’ve really started to unlock the secrets of their superpower.

Jeramiah Smith:
Their genome is utterly fascinating.

Emmett FitzGerald:
Jeremiah Smith has spent years of his professional life pouring over the axolotl’s massive genome, in part to try and figure out how they got so good at regeneration.

Jeramiah Smith:
Presumably, somewhere amongst all of that DNA, all of that information, is the information of how a salamander grows back a limb.

Emmett FitzGerald:
One theory has to do with scarring. When humans have a large cut or some other kind of wound, the tissue that grows back is scar tissue.

Roman Mars:
But axolotls don’t scar.

Jeramiah Smith:
Part of what’s thought to be responsible for their ability to regenerate is that they resolve the initial wound in a way that doesn’t involve scarring. It involves much less scarring.

Emmett FitzGerald:
Jeremiah and his colleague, Dr. Randall Voss, recently finished building this comprehensive map of the axolotl genome.

Roman Mars:
And as scientists learn more about axolotl genetics, there is a growing optimism that humans might actually one day learn how to imitate them.

Emmett FitzGerald:
And so I had to ask Jeremiah the question that I imagine he’s been asked dozens of times by annoying science journalists like me.

Emmett FitzGerald:
“From your perspective, how possible is it that humans are ever going to be able to grow back an arm?”

Jeramiah Smith:
“Yeah, I mean, it’s a hard question to answer with any certainty. I mean, one person that interviewed me a couple of years ago, I said, I’ll be dead before I would have a chance to grow an arm back. I don’t know if that’s the right perspective anymore.”

Roman Mars:
We’re probably not going to be regrowing entire arms anytime soon. But Jeremiah thinks that with the help of new genetic techniques like CRISPR, the lessons that we’re learning from axolotls could help humans heal more minor wounds.

Jeramiah Smith:
I would say in the next 10 years, we might be effectively mimicking what salamanders can do. I don’t think that’s beyond the scope of reality.

Emmett FitzGerald:
Largely because of all of this regeneration research, axolotls have proliferated in research institutions all around the world.

Roman Mars:
But even as we continue to breed these animals in the name of scientific progress, we are driving the wild population in Mexico to the brink of extinction.

Luis Zambrano:
In the last 50, 60 years, the population of the axolotl is becoming very, very low.

Emmett FitzGerald:
That’s Luis Zambrano again, and he says the decline really traces all the way back to the 1500s and the Spanish conquest of Mexico.

Roman Mars:
In the centuries that followed, people drained the water out of the Valley of Mexico, and a megacity developed on top of the dry lake bed.

Emmett FitzGerald:
Today, the historic lake system is all but gone. There’s really only a small, marshy remnant left in the south part of Mexico City, an area known as Xochimilco.

Luis Zambrano:
So now we have a huge problem because we only have the 2% of the huge lake system. We only have 2%, which is Xochimilco. And this area is the only place that the axolotl now can survive.

Emmett FitzGerald:
As a young biologist, Luis wasn’t all that interested in salamanders. He was more of a fish guy.

Luis Zambrano:
I used to be a fisherman. I used to study and work with fish.

Emmett FitzGerald:
Then in 1998, a colleague enlisted him to help with this big survey that they were doing of all of the axolotls in Xochimilco, and it ended up being surprisingly difficult work.

Luis Zambrano:
So at the beginning, I didn’t like it at all. So I said, “Okay, I will do this, and I will never work with axolotls or Xochimilco again.”

Emmett FitzGerald:
But then one of the most important axolotl scientists, Dr. Virginia Graue, tragically got cancer, which meant that she wasn’t going to be able to finish her research, and she went to Luis.

Luis Zambrano:
To say, “Okay, I got cancer, but we need to finish this research. Please finish it because I won’t be able to do that.” And I remember Dr. Graue as a very, very important piece of my life now.

Emmett FitzGerald:
“Yeah. She gave you a mission.”

Luis Zambrano:
“Yeah. She gave me a mission actually. In this second wave of projects, I fall in love with the axolotl and with Xochimilco. It was like falling in love within a second date basically.”

Emmett FitzGerald:
But as he was falling in love with Mexico’s much-loved salamander, he was also discovering just how much trouble it was in. In Dr. Graue’s last survey of Xochimilco in 1998, she had found that there were about 6,000 salamanders per square kilometer. But when Luis completed his follow-up in 2003-

Luis Zambrano:
We only found 1,000 per square kilometer.

Emmett FitzGerald:
It was a huge decline. And from the data, Luis could see that lots of juvenile axolotls weren’t surviving into adulthood, and so he had to figure out why not. Why were all these baby salamanders dying?

Luis Zambrano:
I mean, I can tell you this in less than 10 minutes, but it took us about 10 years to understand that. Science is like that.

Roman Mars:
The arc of science is long, but it bends towards the truth that you can explain in 10 minutes, if you’re lucky.

Emmett FitzGerald:
Luis and his colleagues eventually determined that there were a few different things contributing to the collapse of the population, including invasive fish species, like carp and tilapia, poor water quality, and illegal development.

Luis Zambrano:
We saw that the population is going… It would be going to extinction really, really fast if we don’t do anything.

Emmett FitzGerald:
The combination of human obsession and human neglect has turned the axolotl into this bizarre contradiction. It’s so common in universities that someone just handed me one in college, and yet at the same time, it’s an endangered species.

Richard Griffiths:
It’s a paradox that you have this species that is probably the most widespread amphibian in captivity in the world, and yet it is critically endangered in the wild.

Emmett FitzGerald:
That’s Richard Griffiths again.

Richard Griffiths:
I can’t think of any other species – mammal, bird, fish, reptile, or amphibian – that has a parallel with that really.

Roman Mars:
Given that dynamic, you can’t help but wonder if they should just release a bunch of the laboratory axolotls into the wild.

Emmett FitzGerald:
Yeah, I thought about that too. I mean, as much as I loved Lenny, I would have happily donated her to the cause.

Roman Mars:
You’re a monster.

Emmett FitzGerald:
Well, don’t worry. It’s not going to happen because everybody that I talked to for this story said it was a pretty stupid idea. For one, the animals probably wouldn’t survive anyway, and two, you run the risk of spreading diseases. But the more fundamental problem with that plan is that the wild axolotl and the laboratory axolotl, they aren’t really the same animal anymore.

Jeramiah Smith:
There’s a very good argument to be made to say that those laboratory animals are not axolotls.

Emmett FitzGerald:
That’s Jeremiah Smith again. He says that over their long history in scientific institutions, the laboratory axolotl changed. At some point, scientists introduced an albino tiger salamander into the population. So today, the salamanders in labs are more like axolotl-tiger salamander hybrids. And they’ve changed in other ways too.

Jeramiah Smith:
They’re a little bit cuter and cuddlier, less like a wild creature, I guess, than like an axolotl from Xochimilco. If they’re cute, you won’t forget to feed them, then they’ll live to make their own offspring, right?

Emmett FitzGerald:
They’re still great at regeneration. But at this point, the laboratory axolotl is more like a poodle than a wolf.

Dr. Randall Voss:
For example, I walk into my laboratory, and there’s a whole bank of tanks with axolotls full of them.

Emmett FitzGerald:
This is Dr. Randall Voss. He’s a Professor of Biology at the University of Kentucky and the head of an axolotl research lab there.

Dr. Randall Voss:
And I just walk around the facility, and they just follow me just to watch me because they know that humans feed them.

Emmett FitzGerald:
They’re like my dog following me around the apartment.

Dr. Randall Voss:
Oh, absolutely. No, absolutely. And you have something that’s really different, I think, than what we think of the axolotl from Mexico, the natural population. In my mind, it’s already a different species.

Emmett FitzGerald:
A species created by science and a species that probably shouldn’t be released back into the wild.

Jeramiah Smith:
Just like we’re not going to release poodles into the Yukon to hunt moose.

Emmett FitzGerald:
But we have to do something, right? Don’t we owe it to this animal that has given us so much? Luis Zambrano certainly thinks so. His devotion to the axolotl has only deepened over the years.

Luis Zambrano:
It’s less intense, but by far stronger. That is my feeling about the axolotls. In some moments… Well, not in some moments. Most of the time, I have them in my emotion and my heart, basically, that say, “Okay, I have to do more things to save this very nice species.”

Emmett FitzGerald:
Luis knew that they needed to do everything they could to clean up the ecosystem at Xochimilco and deal with the various issues that were sending the axolotl to extinction.

Luis Zambrano:
First, we have to reduce the population of carp and tilapia. Second, we have to improve the water quality. And third, we have to stop the illegal and legal urbanization in the canals of Xochimilco.

Emmett FitzGerald:
But Luis also knew he didn’t really have time to wait around for the government to implement some big, top-down restoration program.

Luis Zambrano:
So we decided to change the focus in terms of restoration and not to see the authorities as a solution, but the local people as the solution.

Emmett FitzGerald:
In particular, they focused on the farmers or the chinamperos who still farm on islands in the water. Luis and his partners started working closely alongside them. And the idea was to try and give farmers money and the tools that they needed to improve the habitat around their own piece of land.

Roman Mars:
They designed simple, low-tech filters that farmers can use to seal off individual canals.

Luis Zambrano:
The filter helped to increase the water quality and avoid the in transfer of carp and tilapia.

Emmett FitzGerald:
They might not be able to fix Xochimilco all at once, but they want to create pockets of clean, tilapia-free water, where the axolotl population can recover. It’s hard to say how well these efforts are working. In his most recent surveys, Luis hasn’t found a single axolotl, although he says that local farmers that he’s working with have reported seeing them inside their canals. And so there’s a lot at stake in Luis’s work — the fate of an ancient ecosystem and its iconic animal.

Roman Mars:
And what happens in Mexico City could also have ramifications for all those scientists studying regeneration.

Emmett FitzGerald:
In addition to being a professor at Kentucky, Randall Voss is the head of the university’s Ambystoma Genetic Stock Center. They breed axolotls and distribute them around the world.

Dr. Randall Voss:
We provide axolotls to people for their research efforts.

Emmett FitzGerald:
In fact, they’re basically the place to go if you want axolotls to do research with. And the amazing thing about these salamanders that are being bred at Kentucky today is that they’re descendants of the 34 animals which were taken from Xochimilco in that French expedition 150 years ago. They are the oldest population of laboratory animals in the world.

Roman Mars:
Which means that Emmett’s axolotl, Lenny, probably was related to those 34 animals that were brought to Paris.

Emmett FitzGerald:
Yeah, she almost certainly was. And while that lack of genetic diversity is great for doing experiments, it can also be a problem. It can lead to inbreeding.

Dr. Randall Voss:
I mean, I think there are a lot of species that if you applied the same kind of management strategy over the time the axolotls have been in captivity, they probably would be extinct.

Emmett FitzGerald:
Randall says that there is no immediate cause for alarm with his laboratory salamanders.

Dr. Randall Voss:
But yeah, it’s a concern. I mean, I do think it’s important to consider that there may be other sources of genetic variation out there in the world that could be used to invigorate our population.

Emmett FitzGerald:
In an ideal world, they would introduce some more wild salamanders into the lab population, but those are pretty hard to come by these days. And if the wild axolotl were to go extinct at Xochimilco, there would be no pool of genetic material left for scientists to pull from.

[MUSIC]

Emmett FitzGerald:
Somewhere in the long story of the Mexican axolotl, the narrative diverged. It became two stories, one about science and biomedical innovation and the other about habitat loss and an iconic, but increasingly endangered animal. And these stories may very well continue on their separate paths, but it’s also possible to imagine a world where they loop back together again, where Luis’s conservation efforts in Mexico are successful and a healthy population of wild axolotls is able to provide Randall’s laboratory salamanders with some much-needed genetic variation.

Dr. Randall Voss:
Wow! That would be the ultimate happy ending. If what you just said could happen, that would be fantastic.

Emmett FitzGerald:
But Randall and the other laboratory scientists that I spoke with were really clear that the dream of regrowing a human arm is not the reason we should protect this endangered species. They just don’t want to live in a world where magical creatures like the axolotl cease to exist. After all, it was the magic of the natural world that got them interested in science in the first place. Jeremiah Smith might spend his days in a lab now, but growing up, he used to search for tiger salamanders in the fields of Wyoming. And even now, when he’s not in the office, he’s usually tramping around Kentucky with his kids, looking for amphibians.

Jeramiah Smith:
Not with the intent of collecting them or sampling them or doing any experiments or genetics. We just sort of like to see them and appreciate them and then move on.

Emmett FitzGerald:
“Is there any… Have you done it recently? Have you seen a salamander in the wild recently?”

Jeramiah Smith:
“Yeah, last weekend. And probably I’ll end up going out this weekend again to see some other ones. Even as old as I am, I still really get a kick out of it.”

Emmett FitzGerald:
My Lenny was not a wild salamander. I didn’t find her flipping over rocks in some pristine forest stream, but I got a kick out of her too. She was a sunny presence on my mantelpiece for over a year. And then without warning, she died in the night. I still don’t know exactly what happened, although after talking to Randall and Jeramiah, I’m a little worried that it was probably my fault. Like most of her kind, Lenny lived her whole life in tanks. And so we decided to give her a sendoff befitting a water god, a proper Viking funeral. We built a raft out of clementine crates and laid her atop a pyre of shredded cereal boxes. I think there were at least seven people in attendance. I said a few words. My friend, Will, read a slightly too long Keats poem. Then we lit the makeshift boat on fire and pushed her out into the Narragansett Bay. For a second, it looked like the wind was going to blow the boat back to shore and it would smolder there awkwardly against the rocks, but then it changed directions and took Lenny out to sea.

Roman Mars:
Coming up, Emmett and I talk about the possibility of resurrecting extinct species, after this.

[BREAK]

Roman Mars:
Okay. We’re back with Emmett FitzGerald. Hey, Emmett.

Emmett FitzGerald:
Hello.

Roman Mars:
And so, you have another aspect of this story that you wanted to share.

Emmett FitzGerald:
Yeah. So towards the end of my conversation with Jeramiah Smith, he brought up a kind of wild idea that I hadn’t considered before. Basically, he told me that if the wild axolotl were to go extinct in Mexico City, he thinks he could bring it back.

Jeramiah Smith:
Yeah. I mean, I guess there’s this deeper question of like de-extinction, right?

Emmett FitzGerald:
Are you familiar with this concept of de-extinction, Roman?

Roman Mars:
Well, I mean, I think I was made most familiar with it in the movie and the book Jurassic Park, but that’s basically what you’re talking about, right?

Emmett FitzGerald:
Yeah. That’s basically the gist of it. I mean, the idea is that with modern gene-editing techniques, we could recreate something that no longer exists in the wild or something very similar. And with Jurassic Park, the idea was to profit off of that and to build a theme park. But when conservationists and conservation biologists are thinking about this, the idea would be that you would reintroduce that animal into the ecosystem where it “belongs.” And real conversations are happening in the world of conservation biology around this. People have talked about trying to resurrect the wooly mammoth and the passenger pigeon and this relative of the zebra called the quagga.

Roman Mars:
And is the notion of this is like a stunt, as it was in Jurassic Park, or as something actually valuable to ecology?

Emmett FitzGerald:
Yeah. I mean, there’s a whole debate about this. Some people think it’s our duty to bring back species that we made extinct, and others think it’s an extravagant waste of resources. I don’t want to get too into the debate, but the axolotl is sort of an interesting case study. It’s not extinct yet. That’s important to say. But if it were to happen, in a way, it would be a better candidate to bring back than something that’s been extinct for centuries because you have that population of laboratory axolotls. And Jeremiah thinks that if they could figure out exactly on a genetic level what are the differences between the lab axolotls and the wild ones, then they could basically back-engineer a salamander from the lab population that was more like the wild ones and then release it into Xochimilco.

Jeramiah Smith:
We could probably generate and extract the information to sort of make a more axolotlly axolotl from the colony.

Emmett FitzGerald:
“What do you think about that?”

Jeramiah Smith:
“Well, I mean, you would hope you would never have to do it, right? It’s like I hope my house never burns down, but if it does burn down, well, then I’ll probably rebuild it. You wouldn’t want to do it, but if you had to do it, maybe you could.”

Roman Mars:
Yeah. I mean, he seems appropriately ambivalent about it, like being cautious and not just wanting to do it because you can. Obviously, the best way to do things is to conserve.

Emmett FitzGerald:
Yeah, exactly.

Jeramiah Smith:
But if the choice is between not having wild axolotls and having wild axolotls, then, I mean, I’m for it. I think it would be a good, last-ditch, important thing to do for them.

Roman Mars:
I mean, in a way, it would be a way for the biomedical scientists to lend their knowledge and expertise to help bring back the animal in the wild. Like, this is a way to reciprocate all that the axolotl has given us.

Emmett FitzGerald:
Yeah. I think that’s right. And one of the big critiques of this sort of thing over the years has been that humans are meddling too much in nature, that it feels like we’re playing God.

Roman Mars:
Right. Oh, that was certainly the narrative with Jurassic Park, that we deserved to be eaten by Tyrannosaurus Rex if we bring Tyrannosaurus Rex in the world.

Emmett FitzGerald:
Right, right. That’s like the role the Jeff Goldblum character is playing in the movie. He’s like, “These arrogant humans think they can mess with nature,” sort of thing.

JEFF GOLDBLUM:
[GEE, THE LACK OF HUMILITY BEFORE NATURE THAT’S BEING DISPLAYED HERE STAGGERS ME.]

Emmett FitzGerald:
But I do think human impacts on the natural world are so obvious and omnipresent now that the concern… To my mind, the concern about playing God almost feels a little bit quaint. Like, we’re already playing God. Destroying the lake system that was this animal’s habitat, that’s playing God.

Roman Mars:
Right. If we’re going to play God, why don’t we be a benevolent God?

Emmett FitzGerald:
Right, right.

Roman Mars:
At least we can try to do our best to do that.

Emmett FitzGerald:
Yeah. I mean, I guess one concern that I have personally with a concept like de-extinction, and the axolotl is a good example here, is that in situations like this, if you know you have the possibility of bringing an animal back, you could really… I can see that people might begin to think, “Well, oh well, we don’t need to worry that much about that endangered animal, that axolotl or whatever endangered animal we’re talking about, because we always can just use their DNA to bring them back later on.”

Roman Mars:
Oh, totally. It creates a moral hazard. If you know that there’s this kind of safety valve to stop extinction down the line, then it could encourage us to do bad things in the present. I totally agree with you.

Emmett FitzGerald:
Yeah. And when I was talking to Luis, for him, it’s as much about the health of the ecosystem at Xochimilco as it is about the axolotl on its own. He wants to save that animal because he wants to save the ecosystem that that animal is a part of. And the interesting thing about this is, even if you brought back the axolotl 50 years from now, it would still need a place to live. All those concerns are still relevant. You still need to have a healthy ecosystem to release that animal into.

Roman Mars:
Absolutely. I mean, you could create thousands of de-extincted axolotls and introduce them into the Valley, and they would just die all over again. I mean, it’s not like those conditions have changed that make it poor for axolotls.

Emmett FitzGerald:
Yeah. And to my mind, the extinction is interesting, and I think it’s an interesting thing that we should talk about, but it doesn’t change the need to deal with the water quality and the invasive fish and the illegal development. If you want to have some place for a de-extincted salamander to go, you need to still work on those things. You need to make space in Mexico City for Mexico City’s beloved salamander.

Roman Mars:
Yeah. Yeah. So it’s a good thing to have in our back pocket, but we have to fix everything else in addition to it. So but that’s still really fascinating science, and it’s an interesting thing to keep in mind as we’re deciding what to do as the world changes, as the baseline shifts even more and more. Cool. Well, thank you, Emmett. I appreciate it.

Emmett FitzGerald:
Thank you.

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Roman Mars:
99% Invisible was produced this week by Emmett FitzGerald. Mixed by Jim Briggs. Music by our director of sound Sean Real. Delaney Hall is the executive producer. Kurt Kohlstedt is the digital director. The rest of the team includes Vivian Le, Joe Rosenberg, Chris Berube, Christopher Johnson, Lasha Madan, Sofia Klatzker, and me, Roman Mars.

Special thanks to Will Cioffi.

We are part of the Stitcher and SiriusXM podcast family, now headquartered six blocks north in the Pandora Building — in beautiful uptown Oakland, California.

You can find the show and join discussions about the show on Facebook. You can tweet at me @romanmars and the show @99piorg. We’re on Instagram and Reddit, too. You can find links to other Stitcher shows I love as well as every past episode of 99pi at 99pi.org.

Credits

Production

Producer Emmett FitzGerald spoke Jeramiah Smith, professor of biology at the University of Kentucky; Luis Zambrano, Professor at the Biology Institute at UNAM; Dr. Randal Voss, director of the Ambystoma Genetic Stock Center at the University of Kentucky; and Richard Griffiths, professor of biological conservation at the Durrell Institute of Conservation and Ecology at the University of Kent.

  1. Robert Kelly

    Emmett, this episode was incredible–so much to learn. One part of axolotl lore that you left out was the way that many of us in my generation learned that axolotls existed: Mad Magazine. Mad used the word “axolotl” constantly. My uncle introduced me to Mad way back in the early history of the magazine when I was 7 or 8. Being curious about all the things that appeared here and there in Mad (I learned that Moxie was a drink, for example, and it was my first exposure to the joys of Yiddish) I found in the encyclopedia (something you might want to do a 99 PI episode about some day) axolotl was a kind of salamander. Aside from being incredibly funny and warping my sense of humor to this day, reading Mad was a learning experience!

  2. Gregory W Bloch

    I can’t be the first person to tell you that there is, in fact, a very obvious close analogue to the situation of the axolotl… THE HORSE. The entire horse family would be *completely extinct* on earth if it weren’t for domestication. It used to be said that there was one remnant of a truly wild horse population in Eastern Europe, but newer genetic research has shown that even those animals are actually descendants of domesticated animals. Horses were, apparently, simply not suited to the new environment as the last ice age ended, but were so useful to humans that the entire species survived (in a significantly changed form) only due to domestication. There is a good episode of the BBC podcast “In Our Time” that tells this story.

  3. Rhubarbjin

    “They are at once common in laboratory settings and critically endangered in the wild.” It’s a paradoxolotl!

  4. Octopteryx

    It’s so weird hearing Narragansett Bay being mentioned in anything; it makes me wonder if I could get an axolotl embryo from URI? 👀

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