The hunt for a lost species

Summary

Podcast Summary: Unexplainable — “The Hunt for a Lost Species”

Podcast: Unexplainable (Vox)
Episode: The hunt for a lost species
Date: May 11, 2026

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Episode Overview

This episode of Unexplainable dives into the captivating mystery of the Blanco blind salamander—a species last officially sighted over 70 years ago in Texas. Reporters Mandy Nguyen and Benji Jones join herpetologist Andy Glusenkamp on a real-world quest: searching caves, creeks, and the vast Edwards Aquifer for any trace of the elusive salamander. Along the way, they unravel the broader science and stakes behind “lost species,” exploring what it means for biodiversity, ecosystem health, and conservation.

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Key Discussion Points and Insights

1. Introduction to the Blanco Blind Salamander Mystery ([01:53]–[04:46])

• The Blanco blind salamander, a pale, eyeless, underground species, was last recorded in the early 1950s in San Marcos, Texas.
• Only one preserved specimen exists, now stored at the University of Texas at Austin.
• The tale of its discovery and the mishap with a heron at the time—leaving only two survivors, one lost and one preserved—sets the stage for a decades-long mystery.

“It's one of the most famous amphibians that no one's ever seen.”
— Mandy Nguyen ([02:27])

2. The Concept of ‘Lost Species’ and Challenges in Proving Extinction ([05:05]–[06:52])

• Lost species are neither officially extinct nor confirmed alive, existing in a state of scientific limbo.
• Proving extinction is extremely difficult due to the need for exhaustive searches, especially in inaccessible habitats.
• Many species rediscovered after decades show the value of not giving up on those presumed lost.

“To prove an animal is extinct is actually really difficult… It's a really severe thing to say that something is extinct.”
— Benji Jones ([06:00])

3. The Search Begins: Exploring the Edwards Aquifer ([08:33]–[10:49])

• The aquifer is a massive, biodiverse underground system—porous rock rather than open chambers—making searches extremely challenging.
• The last live salamander was found near a natural spring connected to this vast subterranean network under central Texas.

“Imagine trying to like search for a hair tie in a warehouse of Olympic sized pools using a bucket in the dark.”
— Benji Jones ([10:49])

4. The Science of Environmental DNA (eDNA) ([11:34]–[13:26])

• Modern searches rely on eDNA: capturing free-floating genetic material from water samples.
• A significant roadblock: no DNA sample exists for the Blanco blind salamander, so only indirect matches can be made—scientists must compare unknown DNA to known relatives and look for distinctive discrepancies.

“There will never be a positive match with the DNA of the salamander because you don't have the DNA of the salamander. So you're looking for something close to that.”
— Benji Jones ([13:17])

5. Journey Into the Underground: A Firsthand Cave Expedition ([14:17]–[23:03])

• Mandy, Benji, and Andy embark on a caving and snorkeling expedition into Honey Creek Cave—cold, dark, and filled with unique, eyeless creatures.
• The team encounters a different species, the Kamal blind salamander, highlighting the aquifer’s endemic biodiversity and the evolving nature of research (e.g., how even finding relatives can be informative for ecosystem health).

“Oh, my God.”
— Benji Jones, upon witnessing the mass of “spider-like arachnids” on the cave entrance ceiling ([21:19])

“It's a good sign for the health of the aquifer. But if he can't [find a Blanco], it could be a sign of bigger problems.”
— Narrator ([24:30])

6. Broader Impact: Conservation, Urban Development, and Ecosystem Health ([23:03]–[26:49])

• The search is not just about one species; loss or rediscovery has ripple effects for understanding aquifer health.
• Urban development threatens these underground water systems, which also provide drinking water for two million people.
• The Blanco blind salamander could act as a “canary in the coal mine” for the ecosystem’s overall well-being.

“Writing off a species is tantamount to burning all the books in the library that you haven't read yet.”
— Mandy Nguyen ([26:31])

7. Reflections & Closing Thoughts ([27:09]–[28:01])

• Benji and Mandy visit the San Marcos river, experiencing the beauty and clarity of the aquifer’s gift to the community—a reminder of what’s at stake.
• The episode concludes with a call to remain curious, persistent, and hopeful about mysteries hidden just beneath our feet.

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Notable Quotes & Memorable Moments

• On the preserved salamander:
  “It looked like…a glass jar with a label on it. And the jar is 70% ethanol… it kind of looks like a 70-year-old salamander.”
  — Benji Jones ([04:24])
• On conservation urgency:
  “You can't protect what you don't know exists.”
  — Benji Jones ([06:30])
• On the search’s significance:
  “We've got the resources, the technology. We can keep this around.”
  — Mandy Nguyen ([26:06])
• Philosophical Reflection:
  “An entire world right under our feet, spilling out and sustaining the world above.”
  — Narrator ([26:49])

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Timestamps for Important Segments

| Timestamp | Segment Description | |-----------|-------------------------------------------------------------------| | 01:53 | Introduction to Andy Glusenkamp and the Blanco blind salamander | | 04:21 | Description of the preserved specimen at UT Austin | | 06:00 | Why proving extinction is hard; explanation of “lost species” | | 10:49 | The Edwards Aquifer’s vastness and difficulty of searching | | 12:31 | Introduction to eDNA as a detection tool | | 14:17 | Expedition into Honey Creek Cave | | 22:51 | Discovery of the Kamal blind salamander during dive | | 23:03 | Bigger picture: what finding (or not finding) means for all | | 26:06 | Reflection on the challenge and importance of searching | | 27:09 | Closing at the San Marcos River; connecting the ecosystem to people|

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Tone and Style

The episode balances scientific rigor with a sense of adventure and wonder. The tone is curious, sometimes irreverent (“Imagine searching for a hair tie... with a bucket in the dark”), and reverent about both the investigative process and the natural mystery at the episode’s core.

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Summary Takeaway

The hunt for the Blanco blind salamander is part scientific investigation, part adventure, and part philosophical reflection on what it means to lose—and possibly rediscover—a hidden world. The episode is a reminder of how much remains unknown, even in well-trodden places, and how critical curiosity and perseverance are to conservation. The search for lost species is not only about the creatures themselves, but the fate of whole ecosystems—and maybe, by extension, ourselves.

Transcript

[Benji Jones]

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[Mandy Nguyen]

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[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Andy Glusenkamp is kind of like a detective for animals.

[Mandy Nguyen]

So basically, if it's creepy, crawly, slimy, or has scales, especially if it lives underground. Yeah, I'm kind of interested.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Andy's a herpetologist, which means he studies reptiles and amphibians. He works at the San Antonio Zoo, and For the last 20 years, he's been working on a case, searching for a missing creature.

[Mandy Nguyen]

It's my white whale.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

It's actually a white salamander, a blind one called the blanco blind salamander.

[Mandy Nguyen]

If you asked herpetologists, most of them have heard of it. It's one of the most famous amphibians that no one's ever seen.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Except for one time, 71 years ago, and then never again.

[Mandy Nguyen]

During the early 1950s, Texas suffered the worst drought in Texas history. It was called the drought of record. And it's the drought that we compare all other droughts to. And a lot of major springs went dry.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

A gravel company was looking for water and so they tore up some ground near a natural spring in San Marcos, a city between San Antonio and Austin.

[Mandy Nguyen]

They basically dug a big trench along this water filled crevice, hoping that they could get to some pocket of water.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

And at the bottom of the trench were some of the weirdest creatures these workers had ever seen. These four pale white salamanders with no eyes. They looked like they were from another world.

[Mandy Nguyen]

And so the foreman at the time had the foresight to gather up a few in a bucket.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

The crew went to lunch. But while they were gone, a heron,

[Mandy Nguyen]

which are super common there, ate almost all the salamanders.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

So there were two left.

[Mandy Nguyen]

One salamander went to Texas State University and it was immediately lost.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

And then there was one.

[Mandy Nguyen]

And the other specimen actually rolled around at my predecessor's trunk for a number of years before he was finally convinced to deposit it in the University of Texas at Austin's collections.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

No one has seen another live one since. The salamander that was sent to UT Austin is the only specimen on the planet. It's not alive, but it's preserved.

[Benji Jones]

And they have this warehouse that's just filled with all kinds of specimens, all kinds of reptiles and amphibians. And then there is this jar with the salamander in it.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Vox science reporter Benji Jones.

[Benji Jones]

It was in a, it looked, I mean it could have been a pickle jar. It was in just like a glass jar with a label on it. And the jar is 70% ethanol. You open the lid, it smells a little bit like vodka and then it's just kind of floating on the bottom.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

A dead preserved salamander isn't exactly glamorous.

[Benji Jones]

It looks like about like a 3 inch long, pale, no color, no eyes, just like hunk of flesh. And it was like furrowed like very wrinkly and hard as well. And that's just because it's literally so old and so, yeah, it kind of looks like a 70 year old salamander.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Benji wasn't impressed by what he saw in front of him. But the mystery of the blanco blind salamander captured his imagination.

[Benji Jones]

It's just a really intriguing idea because I love like murder mysteries. And then I think about animals that have gone missing as well. And I think there are just a lot of interesting questions you can answer in looking for them and understanding how they even went missing at all. Given that the world is so explored,

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

you may have heard of categories like endangered or threatened. These are animals that are at Risk of extinction. But there's this whole other category, lost species. Species that have gone missing.

[Benji Jones]

They could be extinct, they could be at risk of extinction, and we're just not sure because we haven't seen them for at least 10 years. And by some definitions, lost means no one has seen them for at least 50 years.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

But if something hasn't been seen in such a long time, how do we know it's not extinct?

[Benji Jones]

To prove an animal is extinct is actually really difficult. It requires that you do exhaustive searches across all the potential habitat that it could live in and prove that it does not exist there. So it's really, it's a really severe thing to say that something is extinct.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

A lost species is more like a big question mark. It's missing, but there's not enough information to say that it's gone for good. And scientists all around the world have been looking for these lost species.

[Benji Jones]

There is this broader need to understand and take stock of what lives on this planet. Both because it's like really cool to know what we live with and what we share our world with. But also I would say one thing I hear a lot from researchers is that is that you can't protect what you don't know exists.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

There is some hope though. Hundreds of species have been found after disappearing for decades. The Jackson's climbing salamander was rediscovered in Guatemala in 2017. And in 2019, the Chevrotain, which is this animal the size of a big rabbit that somehow also looks like a deer, that was rediscovered in Vietnam. Finding these lost species might be the only way to help them avoid extinction because when they're found, we can take action.

[Benji Jones]

There are also limited amounts of resources to protect species and they'll often go towards the animals that are at risk of extinction. And so we need to know what those animals are.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

People like Andy have been searching for them and so far Andy's only lead is that sole preserved specimen of the Blanco blind salamander, this dried, jerky looking vodka drenched hunk in a jar. But even though no one has seen a live one for decades, Andy's convinced it's still out there.

[Mandy Nguyen]

Rather than writing that species off and saying, well, it must be extinct because no one's seen it since 1951, I think we really need to focus on looking for it. No one's actually looked for it.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

I'm Manning Nguyen and this is unexplainable. On this week's show, Benji and I go to Texas to join the search for the missing salamander and to try and answer an even bigger question. How do species go missing? And if they do, how do we find them? Holy hell, it's hot. Oh my God.

[Benji Jones]

90s, 95 degrees.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

As with any detective case, we start our investigation around where the salamander was last seen.

[Mandy Nguyen]

This is the portal, one of these extremely rare portals. This one, Is it too hot to lift? It's heavy. Can I help you? Yeah, sure. Let's slide it sideways.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

The last time anyone saw a live Blanco blind salamander, it was near a natural spring that connects to a huge underground world of watery caverns, lakes and streams that can reach more than 1,000ft deep and that stretches for thousands of miles under south central Texas. This is the world of the Blanco blind salamander, the Edwards Aquifer. Oh wow.

[Benji Jones]

So there is water down there?

[Mandy Nguyen]

90ft down.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Echo.

[Benji Jones]

And this is how deep?

[Mandy Nguyen]

360.

[Benji Jones]

360ft.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

All we can see is a smooth pool of water that dips into black.

[Mandy Nguyen]

I'll walk up to one of these, be totally unimpressed till I look down it and then I get, you know, dizzy. The mind starts to reel just thinking about what's going on down there.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Staring into the well, I try to imagine what's going on deep beneath the surface. The Edwards Aquifer is one of the most biodiverse aquifers in the world, right in the middle of Texas. The creatures that call this aquifer home have been evolving in isolation for tens of millions of years. And many of them aren't found anywhere else in the world. There are blind catfish, countless tiny invertebrates, a lot of creatures which never needed to evolve eyes in the perpetual darkness. But despite how huge this aquifer is, most of it is pretty hard to access.

[Mandy Nguyen]

There's big water, but a lot of the water that moves in the aquifer is moving through essentially Swiss cheese.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Most of the aquifer is packed with layers of sediment with openings just big enough for water and small creatures to slip through.

[Mandy Nguyen]

It's more like a very large area of porous rock than a giant underground ocean.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

And hidden in this world somewhere, we think, is the Blanco blind salamander.

[Benji Jones]

Imagine trying to like search for a hair tie in a warehouse of Olympic sized pools using a bucket in the dark. Like it just, it is very difficult to try to find this thing.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Andy has been looking for over 20 years, but hasn't found a single one. A big problem for him has been access.

[Mandy Nguyen]

Well, in the area around the discovery site, there aren't accessible portals to, to the aquifer. There aren't many.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Most of Texas is private land and Andy's found that landowners don't really like biologists coming onto their land and digging into their water sources, trying to catch salamanders. Thankfully he doesn't need to catch the blanco blind salamander itself to know it's out there. All he needs is a clue.

[Benji Jones]

Is this equipment made for sampling like this?

[Mandy Nguyen]

Yeah.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Andy has this plastic container to sample water and he throws it into the well.

[Mandy Nguyen]

There we go, we hit water.

[Benji Jones]

So this is like the modern version of dropping a bucket in the well?

[Mandy Nguyen]

Yeah, not that modern.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Andy pulls up some well water and then puts it in a little syringe

[Benji Jones]

and then you're gonna shoot this through a filter that hopefully will capture the DNA.

[Mandy Nguyen]

Yeah, it's 0.8 nanometers.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Wow.

[Mandy Nguyen]

And then we push some preservative in, screw the caps on the filter and

[Benji Jones]

what you're preserving is the DNA.

[Sponsor/Ad Voice]

Yeah.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

All living organisms are constantly shedding DNA through our hair, our skin cells, our blood. Scientists can take these clues, compare them to a large database of animal DNA and then hope for a match. It's a process called EDNA sampling.

[Mandy Nguyen]

EDNA is free floating DNA shed by

[Benji Jones]

living organisms and it just stands for environmental DNA.

[Mandy Nguyen]

Environmental DNA. And it could be airborne, soil borne or waterborne.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Scientists have been using EDNA to find animals for about a decade now and it's been a game changer for monitoring wildlife. EDNA sampling can't tell scientists an animal's age or the population size, but it's been used to detect invasive species and to rediscover lost ones. But there's one problem.

[Mandy Nguyen]

There's no sequence data available for this species.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

The DNA of the original salamander was never preserved. So even if Andy finds the EDNA he's looking for, he might not know it. He has no original blanco blind salamander DNA to compare it to.

[Benji Jones]

So basically there will never be a positive match with the DNA of the salamander because you don't have the DNA of the salamander. So you're looking for something close to

[Mandy Nguyen]

that that is not, but not you. So maybe your third cousin.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Andy basically needs to take the EDNA he finds, compare it to the DNA of other living salamanders and other animals in the aquifer. And if it's different in just the right way, it might belong to the blanco blind salamander. It's like trying to figure out where a puzzle piece goes. You need to put the other pieces in place to see which one is missing and where it fits. So what else lives in this aquifer? What's their world like? And do we know enough of this puzzle to place this missing salamander?

[Mandy Nguyen]

This amazing world full of undescribed vertebrates that are crazy looking things. Well, they don't look at all. They're blind, but they're really strange to look at. Is literally right below our feet.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

We had to get down there ourselves to find out.

[Benji Jones]

All right, you guys ready? Whoa.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

At after the break, we go spelunking.

[Sponsor/Ad Voice]

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[Mandy Nguyen]

No, sir.

[Benji Jones]

I ate a salamander and jumped out the window.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

My daughter just got accepted to Nootopia University. Unexplainable. I'm manding went. We've been following Andy's journey to find the missing Blanco blind salamander. Its last known location, the Edwards Aquifer, and the best clue to find it, its DNA. But finding the Blanco blind salamander would only be the starting point to unraveling its mysterious life.

[Mandy Nguyen]

It would be wonderful to be able to have some sort of closure on this mystery. Not just what is it? What are its relationships? Where does it live? How is it doing? It's an extraordinary animal.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

If the Blanco blind salamander were a missing person, we'd be interviewing close friends, family, community members. Because to Noah salamander, you need to know what it's connected to.

[Benji Jones]

And so how long of a drive to the cave from here?

[Mandy Nguyen]

10 minutes.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Sweet. Benji and I wanted to see the world of the salamanders for ourselves, to know the other pieces that make up the whole. So Andy took us on a field trip.

[Mandy Nguyen]

We are driving across a private ranch on our way to the entrance of Honey Creek Cave.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

The Edwards aquifer is through this cave over here.

[Mandy Nguyen]

Yep. Here's a northern cricket frog, whole bunch of them.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Wait, where?

[Mandy Nguyen]

That's where. So we are standing in Honey Creek and we're looking at the upstream end of the pool that is formed by water spilling out of the cave and down the spring run into Honey Creek.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Looking downstream at the creek, it's green and pristine blue as far as the eye can see.

[Benji Jones]

There's like beautiful fish swimming under a blanket of lily pads. The waterfall literally looks like it was sculpted by, like, Home Depot's Garden Center.

[Mandy Nguyen]

This is literally the cleanest creek for 75 miles in any direction. It's an absolute jewel.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Standing at the edge of this creek, listening to the birds and the water flowing, it's hard to imagine that the source of all this is beyond that cave and deep underground, that crevice that

[Mandy Nguyen]

you see right there is the dry Entrance.

[Benji Jones]

Oh, it's so non des. Like it's almost hidden.

[Mandy Nguyen]

Yeah. We try and make them that way.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Is that where we're going to be heading into?

[Mandy Nguyen]

We're going to go in then.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

So cool. Immediately, cold air. Oh, wow. Pitch black already. We slip into the cave entrance and the temperature drops dramatically. There's cool air from deep within the cave system, which always remains at 68 degrees Fahrenheit, no matter what temperature it is outside.

[Mandy Nguyen]

Just sit down and cool down with your lights off. Let your eyes adjust a little bit.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Whoa.

[Benji Jones]

Are we going in that hole right there?

[Mandy Nguyen]

Just that hole this big?

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

All we can see ahead of us is a ledge that leads into still water. And past that, complete darkness.

[Benji Jones]

Lights on.

[Mandy Nguyen]

Well, I don't want to trip on these rocks.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

We zip up our wetsuits, put on our helmets and snorkels, and turn on our flashlights. By this point, I've left my audio equipment on dry land. And Benji starts recording with his phone in a waterproof case.

[Benji Jones]

Okay. Oh, wow. There are spiders everywhere.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Shining our lights on the cave walls, we see a giant mass of spider like arachnids. They're stretched across the ceiling of the cave and they almost look like they're dancing.

[Mandy Nguyen]

Some caves, you look down into the cave and it looks like just a pulsing beard because virtually the whole entrance is a solid. All the walls are a solid map of those.

[Benji Jones]

Oh, my God.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Benji and I are trying not to freak out at the carpet of spider like creatures on the ceiling, but Andy's cheery.

[Mandy Nguyen]

It's really fun when you're caving with buddies. You scoop up a handful of those

[Benji Jones]

and shove them down the back of

[Mandy Nguyen]

someone's shirt and they smell like Mark's a lot pens, you know.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

As we walk deeper into the cave, there are fish, frogs, and insects that greet us along the way.

[Benji Jones]

All right, you guys ready to put my mask on?

[Mandy Nguyen]

Deep breath.

[Benji Jones]

Whoa.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

The ledge drops out beneath us and we're swimming.

[Mandy Nguyen]

So if you turn. Clear water.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Yeah.

[Mandy Nguyen]

If you turn right, you come out the spring. If you turn left, you got a lot of cave right.

[Benji Jones]

Spring left. Deep into the cave.

[Mandy Nguyen]

Yep. Wow.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Andy leads the way. We can't see anything except what's illuminated by the narrow rays of our flashlights. We swim and we duck under stalactites that jut out from the ceiling, their points hovering barely a foot above the water. It's okay to hold onto these.

[Mandy Nguyen]

Be very gentle.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Maybe not.

[Sponsor/Ad Voice]

Then

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Andy scans his flashlight across the bottom of the cave about 15ft down, looking for something.

[Mandy Nguyen]

Can you see it?

[Benji Jones]

Yeah, you can see all the way to the bottom. That's incredible.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

He shines his light on a little white blob sitting still on the cave floor.

[Benji Jones]

There's a salamander.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

It's hard to hear him because his phone is literally underwater. But Benji's yelling, I saw it. Andy dives down to catch the blob and brings it back up in a little net. We're bobbing in the cold water, trying to see this little creature. It's not the Blanco blind salamander. It's a different one, the Kamal blind salamander. It's tiny, barely 2 inches long. And it doesn't have eyes. It doesn't need them. Here in the perpetual darkness, the Kamal blind salamander, like many other creatures in the Edwards Aquifer, is only found here. 13 other species here have been categorized as threatened or endangered. And a lost mosquitofish that was last seen in 1983 in the aquifer was recently listed as extinct. Finding our missing salamander, the Blanco blind salamander, is about a lot more than just saving one species. Andy says it could teach us a lot about this underground world. These salamanders probably have very sensitive skin, which makes them susceptible to pollution. So if Andy can find one alive, it's a good sign for the health of the aquifer. But if he can't, it could be a sign of bigger problems, both for the creatures here and the humans who live above it. The Edwards Aquifer provides drinking water for 2 million people in the region. And urban development above the aquifer is threatening its delicate ecosystem. So the Blanco blind salamander could be like a canary in the coal mine. If we can find it. Swimming back to the entrance, I can feel the cold deep in my bones and I can't catch my breath. So we stop to sit on a rock ledge on the way out. Then someone suggests that we turn off our lights. Pure darkness. All I can hear is our breath and the lights splashing of water. I stop feeling cold. I don't notice my own short breath. I can't register anything. For a moment, I feel myself disappear, dissolving into the dark world of water and salamanders. Turns out there's maybe another explanation for what I was feeling. When we get back to the entrance, Andy says that the cave has bad air. Limestone releases carbon dioxide and the cave restricts airflow, so there's literally too much CO2 in there. I may just have been experiencing low grade hypoxia, but still I can see why Andy keeps coming back to this world and to the salamander again and again.

[Mandy Nguyen]

To be honest, why am I working on the Blanco Blind Salamander? Because it captured my imagination.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

How often do you get the chance to chase a decades old mystery in an eerie underground world that just happens to be in your backyard?

[Mandy Nguyen]

And this one is a great challenge. It's been over 70 years since this species has been seen. There are species and ecosystems disappearing all the time. It seems like at an accelerating rate. We need to focus on the things that we can make a positive difference. We've got the resources, the technology. We can keep this around.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

So even though it's missing, there's no reason to write it off.

[Mandy Nguyen]

Writing off a species is tantamount to burning all the books in the library that you haven't read yet. My goal is to fill in all those blanks that we need to make sound decisions.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

The Blanco Blind Salamander's ecosystem is our ecosystem. An entire world right under our feet, spilling out and sustaining the world above. Before Benji and I leave Texas, Andy tells us that we have to go visit the San Marcos river, which is fed by the Edwards Aquifer.

[Benji Jones]

It is just like a perfect summer day. Oh, everyone's out.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

The water looks so lovely.

[Benji Jones]

It is so enticing. Literally comes out of the aquifer, which means that the water is pretty clean. And you can see it looks like. It looks clear, like crystal, crystal clear. Make a little bit of a greenish blue hue.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

We stand at the river's edge and for a moment we just take in the bright sun, the blue sky, the sparkling water, and all the people enjoying it. This is really beautiful.

[Benji Jones]

There's literally nothing you can do but get in the water when it's this hot. And that is what everyone here is doing.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

You think they're going to find salamanders?

[Mandy Nguyen]

No.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

All right, shall we? We're gonna get in the water.

[Benji Jones]

All right, let's see how this feels. Oh, it is chilly. Oh, my God. It's. I mean, it's incredible. It is so chilly, but it's exactly what I want to feel right now.

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

Yay.

[Benji Jones]

This episode was reported by me, Benji Jones, and Mandy Nguyen, who produced this episode. There was editing from Meredith Hodnot, Katherine Wells, Brian Resnik, and Noam Hassenfeld, who also scored the episode. Christian Ayala did the mixing and sound design. Richard Seema did the fact checking, and Bird Pinkerton is off hiking into the woods in search of buried treasure. If you want to read more about lost species and the missing salamander Check out the story I wrote for Vox.com titled why Scientists Are Dusting Desperate to Find a Salamander that's been missing for 71 years. Additional thanks to Barney Long, Devin Murphy and Lena Valencia at rewild, Travis leduc and Adam Cohen at UT Austin, as well as Ben Hutchins, Ben Schwartz and Scott Nicholson. If you have thoughts about this episode or ideas for the show, please email us. We're unexplainableox.com we'd also love it if you left us a review or a rating. Unexplainable is part of the Vox Media Podcast Network. Ryan Reynolds here from Mint Mobile with a message for everyone Paying Big Wireless Way Too much. Please, for the love of everything good in this world, stop with Mint. You can get premium wireless for just $15 a month. Of course, if you enjoy overpaying. No judgments. But that's weird. Okay, one judgment anyway. Give it a [e-mail] Switch upfront payment

[Narrator/Interviewer (possibly Mandy Nguyen or Benji Jones)]

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[Benji Jones]

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