SAN ANTONIO -- The San Antonio Zoological Society has successfully hatched three Texas blind salamanders (Eurycea rathbuni) in its lab at the Center for Conservation and Research (CCR).

  • Texas blind salamanders only live in the San Marcos pool of Edwards Aquifer
  • Have been on endangered species list since 1967
  • Salamanders are good barometer of health of water in which they live

Texas blind salamanders have been listed as an endangered species by the United States Fish and Wildlife Service since 1967 and live only in the San Marcos pool of the Edwards Aquifer. In the wild, Texas blind salamanders depend on a constant supply of clean water from the Edwards Aquifer. 

"A lot of people will come by and they'll ask why should I care about a little blind salamander that lives in the water below the city? And there are some very practical reasons for that. For example, they live in groundwater that we are entirely reliant on for our freshwater needs. So that means we're really reliant on water quality," said Dr. Danté Fenolio, vice president of Conservation & Research at San Antonio Zoo.

Texas blind salamanders are blind amphibians that are adapted to life below ground. They are also sensitive to any change in their subterranean habitats and can serve as an identifier for when contaminants possibly get into the aquifer.

"They're the first ones who are going to feel it. They live there, they don't leave the water. So, if the water gets contaminated, there's nowhere else to go. So if you are keeping tabs on how the groundwater animals are doing, how their populations are, what the individuals look like when you find them, it tells you a lot about the quality of the groundwater," Fenolio said.

This is a significant accomplishment for the CCR team, as it's the first time that viable eggs have come from breeding in the lab. Now the research shifts from how to get them to breed to pinpointing the conditions needed to get more viable eggs.​

“So rather than just come out and say ‘Oh yeah, you know twice in the 30 years we've had them they've laid eggs and we have no idea why.’ That's not what we're after. We're after exactly what conditions do you have to manipulate so that you can get them to breed predictably so that if that ever is something that wildlife officials need, they have it,” Fenolio said. "The plan is that we can mimic the cues and conditions that they would get in the wild in the lab, so that we can get a research colony breeding on command should captive bred offspring be needed at some future point for a conservation effort or for more research."

Since the Texas blind salamanders are endemic, that means they're found nowhere else in the world but in Spring Lake and a small region of the headwaters of the San Marcos River near Aquarena Springs. Miranda Wait, the deputy director of Spring Lake operations, said San Martians have a special connection to the amphibian.

"Our mascot for Texas State University should be the Texas blind salamanders. You know, they're not as vicious but they are that one of the top predators of the aquifer. They're really special to San Marcos," Wait said.

The Discovery Hall at The Meadows Center in San Marcos has the fountain darter, San Marcos salamander and the Texas blind salamander all on display to the public. That Texas blind salamander in the tank was featured in an episode of "Planet Earth" that focuses on "Troglobites," which are animal species strictly bound to underground habitats.

"They move around the aquifer in the complete darkness, moving back and forth, waiting to sense pressure changes on their sides. That's when they know that there's something that they can eat nearby," Wait said. "We don't know how many there are in the aquifer because they're really hard to study because they're underground and you can't really see them. And so there's a net where we catch salamanders and that's one way we can kind of monitor how they're doing down there, how many we’re catching."

The Texas blind has no eyes, only two small black dots under the skin. It has little skin pigment, is white in color, and has red external gills used to get oxygen from the water. Fenolio said they look other-worldly.

"They're really adapted to a very specific challenging environment. And so they don't look like the things that come from our environment," Fenolio said. "By studying animals that have evolved in and adapted to really challenging environments like an aquifer, we learn a lot about how flexible the vertebrate system is, how much adaptability it has. And also animals that live in extreme environments tend to have really cool tricks for dealing with the extreme environments, and we learn a lot about that."

The conservation team at the zoo had been working toward hatching the Texas blind salamanders in the lab for the last four years and will continue their efforts. 

“I am proud of the passionate team at the Center for Conservation & Research as they continue to find success in breeding species that are at risk of extinction,” said Tim Morrow, president & CEO of San Antonio Zoo. “They are living our vision of securing a future for wildlife, and in this case, a critically important species our very own local waterways.”

“A major initiative of the EAA is the administration of the Edwards Aquifer Habitat Conservation Plan (EAHCP), which enables the region to comply with the Federal Endangered Species Act by safeguarding habitats in the Comal and San Marcos Springs for endangered and threatened species, including the Texas blind salamander,” said EAA general manager Roland Ruiz.  “The successful breeding of the salamanders in captivity at San Antonio Zoo is another major milestone in further assuring the enduring presence of the species, and one we applaud.”

On top of hatching the Texas blind, the zoo CCR team has also successfully bred the critically endangered reticulated flatwoods salamander (Ambystoma bishopi) for the first time in the care of man. There are just two or three known populations and only one healthy breeding population in the middle of a military base, Eglin Airforce Base in Florida.