If you love something, sometimes you have to set it free. That’s even true if it’s a Texas horned lizard, bred in captivity to one day be released into the wild.
After three years of work in their lizard breeding facility, staff of the San Antonio Zoo joined with supporters to release 84 lizards onto a private ranch in Blanco County with around 1,000 acres of prime horned lizard habitat. Friday marked the zoo’s first horned lizard release and the first-ever reintroduction of captive-bred horned lizards south of the Colorado River in Texas.
Andy Gluesenkamp, director of the zoo’s Center for Conservation and Research and former Texas state herpetologist, said the moment made him feel “a little terrified.”
“They’re just really precious to us because they’re the first ones we’ve raised up in captivity,” Gluesenkamp said. “All of my staff have invested a tremendous amount of time and emotional bandwidth in getting us to this point.”
Painstaking effort, funded by the Texas Parks and Wildlife Department and other grants and donations, had allowed Gluesenkamp’s staff to develop what they called a “lizard factory” in converted shipping containers at the zoo. There, they followed in the footsteps of other zoos in Fort Worth and Dallas in building up a population large enough to set free.
“I think it’s fantastic,” center manager Bekky Muscher-Hodges said. “I mean, obviously, we’ve got an emotional attachment to them, from raising them for so long … It’s definitely a work of passion, and I’m super excited to be a part of it.”
Take the lizards’ food bill alone. The zoo spends more than $100 a week to ship in a steady supply of harvester ants, the lizards’ main food source, Gluesenkamp said. They tried to defray costs for a while by creating massive indoor ant colonies in plastic buckets, but it still wasn’t enough. Supporters now pitch in by using shop vacuums to suck ants off of local mounds and offer them to the zoo as lizard food, Gluesenkamp said.
Harvester ants were a key factor in choosing the Blanco County property for their first reintroduction site. Gluesenkamp observed the property using satellite images to verify that it had enough harvester ant mounds.
Before the release, he and other team members had also made a sweep through the ranch to kill invasive fire ants, which can swarm and overwhelm the lizards. They used a trailer-mounted system with a custom-made stainless-steel wand to blast hot, high-pressure water into fire ant nests.
“I’m driving it three feet underground and I’m cooking ‘em,” Gluesenkamp said, explaining that the fire ant-killing method involves no toxic chemicals. Even the soap they use is biodegradable.
All this is necessary to return a once-familiar lizard to its former range. Loss of habitat, fire ants, and a decline in harvester ants have driven the lizard’s disappearance from most of its former territory east of Interstate 35, according to Gluesenkamp.
Texas horned lizard habitat happens to match the habitat of bobwhite quail, a species that also has seen a reduction in Texas. There’s a saying among conservation experts that if you can roll a golf ball through vegetation with your foot, it means the grasses and forbs are thin enough to allow the movement of quail chicks.
Horned lizards need the same kind of sparse ground vegetation to move around, Gluesenkamp said. Such an environment allows the lizards to hunt for ants and other insects but still gives them cover from predators.
On Friday, zoo staff and volunteers pulled the lizards out of marked plastic containers. They flipped each one upside-down and snapped pictures of its light-colored belly speckled with a unique pattern markings used to identify each lizard.
Then, they gingerly set the lizards down near a clump of grass or some brush, not far from a path of harvester ants. Some lizards scrambled for cover; others remained motionless, relying on their remarkable camouflage.
“If I didn’t know it was there, I wouldn’t see it,” Gluesenkamp said of a newly released lizard. “And that’s really their magic trick. That’s why there are still horned lizards on this earth.”
The lizards released Friday were three years to three months old and ranged in diameter from silver dollars to drink coasters. Biologists didn’t want to release brand-new hatchlings, fresh out of their eggs. Gluesenkamp described the tiniest lizards as “nature’s popcorn,” vulnerable to any predator, even large spiders.
“A baby horned lizard is absolutely the cutest animal in the entire world,” said Leslie Nossaman, president of the Horned Lizard Conservation Society, adding that it looks like a “little miniature dinosaur.”
Nossaman said her organization has been growing in recent years, drawing members from all over North America. Texas horned lizards are only one of 22 species and subspecies of horned lizards native to the continent. Texas is also home to two other species, the round-tailed horned lizard and the greater short-horned lizard.
The big question now is whether the zoo’s lizards can survive under the Texas sky all on their own. Other releases of Texas horned lizards in North Texas have ended with all or most of the captive-bred lizards presumed dead. It can also be difficult for biologists to track lizards using transmitters and sensors.
The San Antonio Zoo has a plan for finding them more easily. They’ve partnered with dog handlers to train lizard-sniffing canines who can point out live lizards, scat, or shed skin. They hope to return next week and sniff out some of those they released on Friday.
“If I don’t see them, it doesn’t mean something happened to them,” Gluesenkamp said. “But I really hope I see them again.”