First Texas horned lizards bred in captivity could save declining species
Texas horned lizards are being tagged to track their movements and longevity. Scientists use the data to help determine the best habitats for release and repopulation. Courtesy photo
Awaiting the warmth of spring, about 30 baby Texas horned lizards with radio tags glued to their backs are burrowed in for the winter 2-4 inches underground in Mason County. At least, that’s what researchers with the Texas Parks and Wildlife Department, the Fort Worth Zoo, and Texas Christian University are counting on.
“We hope a bunch of them will be out there come spring,” said Jim Gallagher, a natural resource specialist at the Mason Mountain Wildlife Management Area, a TPWD property. “The problem with these itty-bitty guys is that they grow so fast. They shed their skin every two to three weeks and tend to lose their tags.”
Researchers are using a recently upgraded harmonic radar system to track the lizards. The summer of 2018 was the first time captive-hatched lizards were tagged and released into the wild. About 130 were released and, of those, around 30 were tagged. A second, larger group was released in September 2019. Antenna strips that can be tracked with small, handheld receivers were glued onto the backs of a select group of lizards.
Gallagher keeps a careful watch over the release zone at the 5,301-acre wildlife management area, sometimes finding tags and lizards just a few feet apart. Horned lizards are notoriously easy to catch, which gives Gallagher an opportunity to retag them.
On one scouting day last September, he found a yearling that he believes survived from the release the year before.
“That was the first time to our knowledge that a captive-reared hatchling survived over the winter,” he said. “It’s encouraging. Now, we have to figure out how to get a couple of hundred of those to survive, and we’ll be over the top. They can take care of themselves.”
That might be a bit optimistic as these Texas cultural icons have a high annual mortality rate.
“Everything in the world eats a horned toad, despite their looks,” said Nathan Rains, a TPWD wildlife diversity biologist.
Add in their specialty diet of large red harvester ants, which also have done a disappearing act thanks to invasive fire ants, and Texas horned lizards have basically vanished in East, Central, and South Texas. They are still plentiful in the Panhandle and West Texas, where fire ants are scarce and don’t compete for the horned lizard’s main food source.
CITIZEN-SCIENTISTS ON HORNED LIZARD WATCH
The disappearing reptiles are special to Texans of a certain age who remember them in abundance in their childhood.
The official Texas state reptile is “so ugly it’s cute,” Rains said. Its name is derived from the two prominent horns at the rear and center of its skull. The lizards grow to 3½-6 inches long and have wide, flattened bodies. When threatened, they puff up like balloons and spit blood from their eyes. They also try to stick their captors with their tiny horns.
Rains calls them horny toads. They are also called horned toads and, in the case of the TCU mascot, the horned frog. Rains clarified the creature is a lizard, not a toad or a frog. Whatever they are called, Texans have a passion for the species.
“It’s a high-profile, charismatic species,” he said.
The program to bring back the Texas horned lizard began about 12 years ago in a restaurant. TCU representatives agreed to research the diet and genetics of the species in different parts of the state. Based their findings, the Texas Parks and Wildlife Department would determine where to catch them and release them.
The group first caught adults and released them into areas where they might thrive. They were tagged and tracked for data.
“We got a pretty good data set on what those adults did,” Rains said. “We found out how far they dispersed, what habitats they select for, how often they reproduce, gain weight, etcetera.”
The data was good, but the news was not. Horned lizards have a high mortality rate. However, they make up for their lack of longevity by laying 20-40 eggs per female, which is high for a lizard species.
“We asked ourselves, ‘What if we take our captive-bred adults and release their babies?'” Rains said. “Instead of catching fifty in the wild, we could hatch five hundred in captivity and release them.”
The Fort Worth and Dallas zoos began the breeding program. The San Antonio Zoo also breeds captive horned lizards but releases them in a different area.
The goal is to eventually release thousands of baby horned lizards, giving them a better chance to develop a sustaining population.
“This is all new to us,” Rains said. “We had never bred in captivity before. We had a pretty steep learning curve.”
Both Rains and Gallagher think positively when it comes to re-establishing the Texas horned lizard in its native land.
“If I see one, that means there are ten others out there I can’t see,” Gallagher said. “If I’ve got three, then there’s another thirty wandering around out there somewhere. Come the first warm, sunny day in April, I’m going to be out there looking for them.”