Lizard Learning
Captive-breeding program offers hope for the Texas horned lizard.
By Mary O. Parker
John Ward, an assistant curator at the Fort Worth Zoo, is facing his annual challenge: coercing the Texas horned lizards under his care to hibernate. The yearly task is just one of the difficulties he encounters as director of the zoo's Texas horned lizard captive-breeding program.
"I enjoy a challenge and Texas horned lizard husbandry is quite challenging from their need to hibernate, and for us to do this artificially, to finding natural food items for hatchlings, juveniles, all the way up to adults," he says.
After years of effort, the program, part of the zoo's ectotherm department, had its first captive-breeding success of Texas' state reptile in 2005.
In large part, the program's accomplishments have been a collaborative effort. "Other institutions' lack of success has been helpful to us in that we know what hasn't worked and can concentrate on new ideas," says Ward. He adds that one aspect he enjoys most about overseeing the project is how it helps others develop similar programs.
Since 1977 Texas horned lizards have been classified as a threatened species by the state, meaning that they cannot be captured, possessed, transported or sold within Texas without a special permit. However, even with such status, their numbers have continued to decrease. While recent surveys show that they can still be found in about 60 percent of Texas' 254 counties, 90 percent of those interviewed by Texas Horned Lizard Watch volunteers say they no longer see the reptile in abundance as they once did.
Biologists are not exactly sure of the reason for the decline. Ward notes, "It is suspected that habitat alteration, fragmentation and lack of food source are the culprits." Their traditional food source, harvester ants, may have declined due to habitat changes, the abundant use of pesticides intended for the invasive fire ant, and the effects of fire ants themselves.
Lee Ann Linam, president of the Horned Lizard Conservation Society and the TPWD biologist who oversees the Texas Horned Lizard Watch Program, is encouraged by the zoo's success, noting that the challenges in maintaining a captive population have made it so that "we've learned much through the Fort Worth Zoo experience."
"Ultimately," she says, "there is interest in seeing whether captive-reared horned lizards could be reintroduced into the wild and survive." She cautions that this step is still several years away.
Ward is also cautiously optimistic. "The timeline only extends so far as to having some students from TCU taking part in site surveys at the Fort Worth Nature Center to attempt to determine whether or not there is suitable habitat and food sources at the nature center," he says.
Texans are nostalgic for their beloved "horny toads," and Linam reports that she is contacted often by those eager to have horned lizards released on their property. While such enthusiasm is appreciated, she notes that the difficulties in transplantation are much trickier than might be imagined. She does, however, encourage participation in the "Texas Horned Lizard Watch, which relies on volunteers to help look for and monitor the general well being of the popular reptile.
