Tom Harvey vividly remembers playing with horned lizards as a boy in his grandparents’ Lubbock backyard in the 1960s. He’s now the deputy director of communications at the Texas Parks and Wildlife Department, and the reptile still hasn’t lost any of its appeal.
It’s a cool little critter, Harvey said. With its flat body, many prominent horns and two central head spines, the horned lizard or “horny toad” looks much like a miniature dinosaur.
As the state reptile in Texas and school mascot at TCU, the lizard is a treasured member of the community, especially in Fort Worth. But it’s also considered at-risk.
In an effort to keep the species from becoming endangered, the Fort Worth Zoo has pioneered techniques to breed the lizards and release them into the wild, in partnership with Texas Parks and Wildlife Department and Texas Christian University. The department on Thursday will release 204 horned lizard hatchlings into the wild.
A baby horned lizard awaits being tagged. The lizard is about the size of a quarter. (Cristian ArguetaSoto | Fort Worth Report) 
A Fort Worth Zoo employee holding a baby horned lizard tag. The tag must be long in order to be picked up by trackers. (Cristian ArguetaSoto | Fort Worth Report) 
Baby horned lizards waiting to be tagged. The baby horned lizards, a few weeks old, will be released in Mason Mountain Wildlife Management Area on Sept. 16. (Cristian ArguetaSoto | Fort Worth Report) 
Horned lizard tags sitting on a table. The tags allow researchers to track and release the lizards into their natural habitats. (Cristian ArguetaSoto | Fort Worth Report) 
Seven few-week-old horned lizards sit in a petri dish waiting to be tagged. The research team will release the lizards into the wild on Sept. 16. (Cristian ArguetaSoto | Fort Worth Report) 
Diane Barber, the Fort Worth Zoo’s curator of ectotherms, preps a lizard for tagging. The horned lizard is the mascot of local college Texas Christian University who collaborates with the zoo on wildlife projects. (Cristian ArguetaSoto | Fort Worth Report) 
A baby horned lizard patiently waits to be tagged. Adhesive is used to tag the lizards. (Cristian ArguetaSoto | Fort Worth Report) 
A baby horned lizard being tagged. The tag is lightweight at less than a gram. (Cristian ArguetaSoto | Fort Worth Report) 
Diane Barber, the Fort Worth Zoo’s curator of ectotherms, tags a lizard. The lizards are native to Texas. (Cristian ArguetaSoto | Fort Worth Report) 
Diane Barber, the Fort Worth Zoo’s curator of ectotherms, holds an adult horned lizard. (Cristian ArguetaSoto | Fort Worth Report) 
An adult horned lizard at the Fort Worth Zoo. Adult horned lizards have a white line painted on their backs for camoflouge when released. (Cristian ArguetaSoto | Fort Worth Report) 
An adult horned lizard next to its feeding dish. The white line on the lizard’s back allows it to blend in with its West Texas environment. (Cristian ArguetaSoto | Fort Worth Report) 
The Fort Worth Zoo’s Curator of Ectotherms Diane Barber (right) and Wildlife Diversity Biologist with Texas Parks and Wildlife Department Nathan Rains (left) talk to media. (Cristian ArguetaSoto | Fort Worth Report) 
Deputy Director of Communications at the Texas Parks and Wildlife Department Tom Harvey speaks to media about the horned lizard project. (Cristian ArguetaSoto | Fort Worth Report)
About the program and lizard release
In 1994, the first statewide biological assessment of the lizard confirmed it had declined in east and central Texas.
Almost 30 years later, the horned lizard is considered one of more than 1,300 “species of greatest conservation need” in Texas. Basically, this means it’s not considered “endangered,” but it could be in the future, according to Harvey.
From 2011 to 2016, the Fort Worth Zoo conducted a pilot study to test ways to reintroduce lizards into wild settings, and since then, the Dallas Zoo and San Antonio Zoo have also begun horned lizard research.
While the Fort Worth Zoo breeds the lizards and cares for the hatchlings in its facilities, Texas Parks and Wildlife Department works to reintroduce the lizards back into the wild, said Nathan Rains, wildlife diversity biologist with the department. After their release, TCU graduate students do the groundwork of following up and tracking the lizards.
Diane Barber, the Fort Worth Zoo’s curator of ectotherms, said the zoo initially released horned lizards on a private property in Parker County to start studying them post-release. Since then, most of the lizards bred in captivity by the Fort Worth Zoo have been released in Mason Mountain Wildlife Management Area.
How it works
The zoo normally houses between 80 and 100 horned lizards, any number of which can be involved in the breeding program throughout the year, Barber said. Whether each lizard is selected for breeding depends on genetic conditions and other similar factors.
Caring for the lizards can be tricky as they require strict diet regulations and intense UV lighting, Barber said. Many of the lizards are kept mostly outdoors during the summer with the same environmental parameters they’d live under in the wild. During the winter, the lizards hibernate indoors.
As for breeding, the lizard eggs are kept in incubators for about two months before they hatch. Then, the hatchlings are kept for about two to four weeks before release into the wild.
When the lizards first hatch in captivity, the zoo feeds them termites because they’re too small to eat ants, and termites are better for their health. Once they’re big enough to eat other food items, the zoo feeds them fruit flies, beetles, crickets, worms and harvester ants.
Before release, the hatchlings that are large enough are tagged so the TCU graduate students can track and research them, Barber said. They found that it’s better to release large numbers of hatchlings rather than smaller numbers of adults due to predation.
The 204 lizard hatchlings will be divided and released into two different areas of land, Rains said. About half of them will be dispersed every five meters across their plot of ground, and the other half will be released in clusters.
The goal is to test different types of release to see if one is more successful and can lead to a higher survival rate than the other, Rains said.
Dangers facing horned lizards in the wild
The biggest danger and a major factor contributing to the decline of horned lizards in the wild is habitat loss, Harvey said. With buildings and roads taking over what used to be wide open green space, there’s less natural space for the lizards to thrive.
Additionally, horned lizards must face the challenge of red fire ants. While people hate them because they sting, the ants also reduce horned lizards’ prey: harvester ants. The rise and spread of red fire ants displaced more common harvester ants, eliminating much of the lizards’ diets, although they do also eat other insects.
They might not look like a desirable prey item, but Rains said horned lizards are on the menu for several native animals, including birds, mammals and other reptiles.
“Everything out there eats horned lizards; they have predators from every direction,” he said.
Horned lizards aren’t mobile enough to just leave their predators behind and migrate to another location. They can’t just fly off like quail, Rains said.
They have a few defense techniques such as camouflage, but they’re often not fast enough to escape predators.
One of the ways they’ve evolved to counter these challenges is high reproductive rates, Rains said. While many other lizard breeds only lay a few eggs at a time, horned lizards average about 30 eggs per “clutch,” or per lizard.
But of the 204 lizard hatchlings being released Thursday, 70 to 90% likely won’t survive long-term, Rains said.
However, Texas Parks and Wildlife Department biologists and TCU graduate students discovered a new milestone in August. While conducting ant surveys, they found 18 baby lizard hatchlings that appeared to be from two separate clutches at Mason Mountain Wildlife Management Area.
The research team concluded captive-raised zoo hatchlings released there in 2019 had survived long enough to begin breeding and reproducing. This was the first time to their knowledge that captive-bred horned lizards from the program have successfully reproduced in the wild.
Why should Texans care about horned lizards?
There are several reasons to care about the decline of horned lizards, but the most prominent is the environment, Harvey said.
“It’s decline is telling us that there’s something wrong on the landscape, and that could eventually affect people,” Harvey said.
The health of wildlife species like horned lizards is greatly connected to the health and quality of human life in Texas because their habitat is good for things like clean air and water and healthy, abundant soil, Harvey said.
Beyond that, they’re such a charismatic species, Rains said. Ranchers, farmers and even city folks who grew up in the country have an affinity for horned lizards because they’re so ingrained into Texas culture.
That cultural attachment is a major motivation to keep them alive and thriving, Rains said.
What’s next for Texas horned lizards?
Although Texas horned lizards aren’t saved yet, there’s hope for the future. Harvey said biologists and researchers are optimistic that continued research and restoration work will eventually lead to more self-sustaining and reproducing wild populations.
An important next step for the lizards and other at-risk species in Texas is the passage of Recovering America’s Wildlife Act. The bipartisan congressional proposal would provide necessary funding to scale up conservation and restoration models such as the Fort Worth Zoo’s program.
If the act passes, the horned lizard could be off the list of “species of greatest conservation need” in as little as five to ten years, Harvey said.
It takes various resources and much effort to successfully breed these lizards, Barber said, and the program’s biggest limitation to doing so is definitely funding. Anyone who cares to donate can visit the Fort Worth Zoo’s website.
Harvey said another way for Texans to help is to visit the Texas Wildlife Alliance website where there are various ways to get involved and advocate for the species. The alliance is a nonprofit coalition of dozens of organizations across the state that support Recovering America’s Wildlife Act.
Fort Worth Report fellow Cecilia Lenzen can be reached at cecilia.lenzen@fortworthreport.org or via Twitter. At the Fort Worth Report, news decisions are made independently of our board members and financial supporters. Read more about our editorial independence policy here.
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