More than 2,000 species worldwide are considered lost. Could finding them avert extinctions?

AUSTIN, Texas — The room looked like something inside a haunted house. Rows and rows of metal storage shelves held thousands of glass jars filled with snakes and lizards and frogs, each labeled with a catalog number, like a library of the dead.

I was here at the University of Texas at Austin’s herpetology collection on the first day of July to see one particular animal: the Blanco blind salamander.

This creature is not exactly what you would call charismatic. Measuring a few inches long, the salamander has no eyes and translucent skin, with a trapezoidal head and external gills that look like feathery antlers. And after sitting in a jar of alcohol for several decades, the specimen looked like a bit of amphibian jerky.

Yet the Blanco blind salamander, a species native to Texas, is one of the collection’s most prized species.

Not only is this animal rare, but it’s also missing. No one has seen the Blanco blind salamander in the wild for more than 70 years. No one knows whether it still exists. The specimen in UT Austin’s collection is the only known representative of the species, Eurycea robusta, on the planet.

The Blanco blind salamander is one of more than 2,000 kinds of animals, plants, and fungi worldwide that scientists call “lost species.” Unlike the more widely known categories of endangered and threatened — which describe wildlife at risk of extinction — the category “lost” refers to species that scientists haven’t seen for at least a decade or, by other definitions, more than 50 years.

The list, compiled by the environmental group Re:wild, which has a whole program dedicated to lost species, includes a number of odd organisms that tend to lack the popularity of, say, pandas and tigers. There’s a golden mole from South Africa, for example, that has been missing since 1936, and a trapdoor spider from Portugal (last seen in the early 1900s). There’s even a lost mushroom — the Big Puma Fungus — which no one has seen in the temperate forests of South America for three decades.

Lost is a bad state to be in. These species are often at risk of extinction, and governments have trouble protecting what they don’t know exists. Case in point: Earlier this year, the US Fish and Wildlife Service decided not to classify the Blanco blind salamander as threatened or endangered, justifying its decision, in part, by claiming that it might already be extinct.

Finding lost species is not only a strategy to avert extinction, but it can also yield benefits for human communities. Every species has lessons to teach us about how ecosystems work and how they sustain us. Failing to find and study them is “tantamount to burning all the books in a library that you haven’t read yet,” said Andy Gluesenkamp, director of conservation at the San Antonio Zoo’s Center for Research and Conservation.

Which brings us back to that drab-looking salamander in Austin. Gluesenkamp, an eccentric, Ace-Ventura-type amphibian lover, is leading an expedition to find one in the wild — and I traveled to Texas to join him. Our hunt took me inside the Earth (literally) and into one of its strangest ecosystems, where, I learned, it’s very easy for things to get lost.

The last time anyone saw a Blanco blind salamander in the wild was in 1951. A gravel company operating just north of San Marcos, Texas, dug up a spring in the dry bed of the Blanco River. Some water oozed out and in it were several pale-white salamanders.

As the story goes, workers put four of the amphibians in a plastic bucket. A heron later flew by and ate two. One got lost. And the last individual was identified as a new species and eventually made its way to a jar at UT Austin.

No one has seen one of these salamanders alive since.

One possible reason is that it has already gone extinct (more than 40 percent of known amphibians are currently threatened with extinction worldwide). Another is that it’s just incredibly hard to spot, said Gluesenkamp, a talkative scientist who formerly served as the state herpetologist in Texas. “It’s got this reputation for being unfindable,” he said.

Just consider where the Blanco blind salamander lives: deep underground in the Edwards Aquifer, one of the least accessible places on Earth. The aquifer is a complex underground structure made of caverns and porous rock that stretches more than 4,000 square miles across south-central Texas. It boasts a remarkable amount of life, including crustaceans, a handful of eyeless salamanders, and blind fish (one of which is also a lost species). It’s also a vital resource for the region, providing drinking water for nearly 2 million Texans.

The only way for people to enter the aquifer is through caves. Lucky for me, spelunking is Gluesenkamp’s specialty.

One morning in early July, I met Gluesenkamp about 45 minutes north of San Antonio near Honey Creek Cave, perhaps the longest known cave in Texas, which forms a natural opening to the Edwards Aquifer. The bed of his black Toyota Tacoma was filled with wetsuits, masks, and waterproof headlamps. We were going cave snorkeling.

It was like nothing I’d ever experienced. We swam through dark caverns in clear water under a ceiling of stalactites. In just over an hour, we saw a few blind salamanders (though not the missing ones), a red crawfish, and large colonies of long-legged arachnids that moved like shadows across the wall.

While it might sound icky that salamanders live in the water we drink, they tend to signal that it’s clean, Gluesenkamp told me. Their skin is semi-permeable, which makes them sensitive to pollution, such as runoff from farms or septic systems. “They depend on the same water that we do,” he said.

Cave snorkeling is tough work. Limestone rock releases carbon dioxide and the cave’s structure can restrict airflow, making it hard to breathe. Within minutes of exploring the cave, I felt myself gasping for air — not a great feeling when you’re deep inside the Earth, breathing through a snorkel.

Spelunking is also not the best method for trying to find a Blanco blind salamander, Gluesenkamp said. There aren’t many of these natural openings near San Marcos, where the lost species likely lives, Gluesenkamp said. And it’s possible that the salamanders live in pockets of water even deeper underground.

Fortunately, there are ways to bypass caves entirely.

The Edwards Aquifer doesn’t have many entrances that humans can squeeze into, but it does have plenty of exits — cracks and holes in the ground where water sometimes gushes out.

That’s one thing that makes San Antonio and Austin bearable in the sweltering summer: In some parts of the aquifer, the water is under so much pressure that it shoots to the surface, forming artesian cold springs (which are enjoyed by bathers).

This geological wonder makes searching for aquifer animals a lot easier. Springs and wells often blast critters to the surface, where scientists like Ben Schwartz and Ben Hutchins can capture them in nets.

I met them early one morning at Texas State University to see how this works. The day before, Schwartz and Hutchins, aquifer biologists, had placed a mesh net over an artesian well on campus. When I arrived it was full of tiny crustaceans. These organisms were all eyeless and transparent, with long, gangly legs and antennae. (Those appendages help them navigate and find food in the dark, Hutchins explained.)

Hutchins and Schwartz, also known as “The Bens,” aren’t looking for lost species, but they’ve found dozens of new ones — all of them small crustaceans. That’s one big draw to the study of invertebrates, they said, which might otherwise seem dull. “We can find [new species] any old day,” Hutchins told me.

Their work contributes to a much bigger scientific mission of understanding what does and does not exist in Earth’s many ecosystems. Documenting life anywhere, Hutchins told me, creates the foundation from which researchers can ask biology’s biggest questions, such as how different animals evolve and why some environments have more diversity than others.

Hunting for lost species is part of that same endeavor. Right now, we know close to nothing about the Blanco blind salamander, such as where it lives and what it contributes to the aquifer. Finding and studying this species could help answer all kinds of questions about this unique ecosystem and life in extreme environments.

If only Gluesenkamp could find one. Scientists have yet to capture the salamander in nets near springs or wells, possibly because these water sources aren’t in the right spots. The salamander is also rare, Gluesenkamp said, which means you’d have to sample huge amounts of water for an individual to appear, like looking for a hair tie in a warehouse of Olympic-sized pools by grabbing buckets of water.

But he has one other idea.

It was close to 100 degrees when Gluesenkamp and I arrived at our destination: a rusty metal pipe in the middle of a ranch on the outskirts of San Marcos.

“This is the portal,” said Gluesenkamp, who was wearing a floppy camo sunhat.

He meant that somewhat literally: The pipe is a 360-foot well that connects to the Edwards Aquifer. As he tapped the side of it, the well produced an echo that sounded like a toy laser gun firing in quick succession.

I was here to see Gluesenkamp’s most promising idea for finding the Blanco blind salamander in the wild: a sampling method called eDNA.

All animals, including us, are constantly releasing DNA into the environment, such as when they sneeze or shed dead skin and hair. This is how detectives might find a suspect from a crime scene; they’ll collect DNA and cross-reference it with a criminal database.

It’s also how scientists can find missing species. Environmental DNA, or eDNA, is an increasingly common technique for detecting bits of an animal’s genome in small samples of air, soil, or water. After collecting DNA, scientists search for a match in databases containing the DNA of known species.

Scientists have used eDNA to detect invasive species in rivers and ancient human remains in dirt. They’ve also used it to argue that the Loch Ness Monster likely doesn’t exist.

Now, Gluesenkamp, a real-life species detective, is using this approach to search for the Blanco blind salamander. This pipe is one of several dozen wells across Texas that he’s hoping to test over the next 15 months, with financial support from Re:wild.

Wearing blue surgical gloves to prevent contamination, he carefully lowered a plastic tube into the well to collect water, which he then forced through a small, circular filter designed to capture DNA. He’ll soon send that filter to a company in the UK for analysis.

The idea is pretty simple: If the missing salamander lives anywhere near this well, some of its DNA should be floating around in the water. Gluesenkamp isn’t looking for the salamander so much as he’s searching for the clues it leaves behind, which are theoretically more abundant.

“It’s a very efficient approach,” Gluesenkamp said. It’s also less intrusive than traditional sampling methods, he added. All you need is a little bit of water. (Most wells in Texas are privately owned, he said, and it’s easier to convince land owners to let you collect a small amount of water than to install and frequently check nets or traps.)

But there’s a catch. Scientists don’t actually have any DNA for the Blanco blind salamander — it deteriorated decades ago when the only known specimen was first preserved. Instead, Gluesenkamp will be looking for genes associated with the broader group of species to which the Blanco blind salamander belongs. If the analysis reveals DNA that’s similar to blind cave salamanders (but doesn’t quite match any other known species), that would signal that the Blanco blind salamander exists, he said.

DNA evidence on its own isn’t enough to prove, without a doubt, that an animal has been rediscovered, according to Re:wild. You need physical evidence. So if and when Gluesenkamp gets a hit through eDNA in a particular well or spring, he’ll lay traps to try and capture a physical specimen. Only then would he be able to say with certainty that Eurycea robusta has been found.

Lost animals are rediscovered all the time. In the last few months, for example, someone in Vermont found an orchid that hadn’t been seen for more than a century and scientists announced they discovered a type of crayfish in Alabama that was presumed extinct.

Why do we care? Because finding them can prove valuable.

In 2017, after a park ranger in Guatemala spotted a lost species of salamander on the edge of a reserve, Re:wild and other environmental groups helped expand the park’s boundaries to protect the species (which is critically endangered). Two years later, researchers rediscovered a rare rabbit-size deer in Vietnam, and have since developed a program to conserve it, including removing hunting snares in the forest.

The impact of finding the Blanco blind salamander would be a bit more complicated. It could prompt the US Fish and Wildlife Service to review the species again, Gluesenkamp said, which could, in turn, cause them to classify the salamander as federally threatened. (That might not mean much because the salamander shares habitat with other threatened species — so, in a sense, it’s already under protection.)

More than anything, finding the Blanco blind salamander would be a reason to be hopeful. The species is not only an indicator of water quality, but it’s also likely the top predator in the aquifer. “They’re the great white sharks of their ecosystem,” Gluesenkamp said. Knowing they’re alive and well would mean the aquifer — on which so many people and other species depend — is more or less healthy.

These animals are also just metal and a reminder that we share our planet with some seriously cool critters. Blanco blind salamanders might not have eyes, but they do have motion-sensing organs that help them find food. They have no pigment in their skin. And they’re experts at conserving energy, spending most of their time in complete stillness. “If you’re into salamanders, it’s the coolest of the bunch,” said Gluesenkamp.

It would be a shame to write off this species without an exhaustive search, Gluesenkamp said. While the planet is, indeed, losing dozens or even hundreds of animals to extinction each year, many of which science has yet to even document, sometimes, animals aren’t gone — they’re just missing.

Mandy Nguyen contributed reporting to this article.

Will you support Vox’s explanatory journalism?

Millions turn to Vox to understand what’s happening in the news. Our mission has never been more vital than it is in this moment: to empower through understanding. Financial contributions from our readers are a critical part of supporting our resource-intensive work and help us keep our journalism free for all. Please consider making a contribution to Vox today.