Efforts to save horned lizards continue
Zoos, state, biologists team up in hopes of rescuing species
MASON — A dozen conservationists clad in khaki and forest green march into the Hill Country brush.
In their hands are cameras and clear deli cups, the kind used to take home leftover potato salad. Inside each are tiny lizards, about the size of a quarter and only a few weeks old.
They are the latest, greatest hope for bringing their species back from the brink.
Call them horny toads, horned frogs, Phrynosoma cornutum or the Texas horned lizard, the state reptile is in dire straits. For several decades, they’ve been vanishing from Texas landscapes for reasons researchers cannot fully explain.
Now, Texas zoos, Texas Parks & Wildlife Department officials, Texas Christian University biologists and more are working together to release hundreds of horned lizard hatchlings at Mason Mountain Wildlife Management Area about 100 miles west of Austin.
It’s an uphill battle, one that has become more and more common as species like the Texas horned lizard struggle to survive.
The horned lizard is not on the brink of extinction — yet. It is listed as “threatened” in the state, but strong populations in New Mexico and elsewhere keep it off the federal endangered species list.
Status as a state treasure helps give the lizard cultural protection, but it could easily become just another Texas legend.
“There’s a lot against us in terms of establishing these guys,” said Diane Barber. She’s the Fort Worth Zoo’s curator of ectotherms, in charge of the cold-blooded creatures there. “There’s a lot of species where people wait until the 11th hour and there’s 20 left — literally, only 20 — and people come to us. It’s far better to try to take action.”
‘For the common good’
They were once so populous, the lizards were backyard favorites across the state. Slow and docile, they were easy to catch and made for fun summertime pets. Some Texans remember keeping the lizards in a shoebox under the bed. Others remember carrying pillowcases full of lizards to trade at Boy Scout jamborees.
Then, slowly and inexplicably, they started to vanish.
Fire ants are the most oft-cited perpetrators. Human interference shoulders some of the blame as well. Urban sprawl and the spread of pesticides certainly harmed the horned lizard’s prospects.
By the time researchers noticed the horned lizard was disappearing, it was almost too late. Now, you’re unlikely to find a single lizard in the wild east of the Interstate 35 corridor. You’re more likely to find them in South and far West Texas.
About 10 years ago, TCU biology professor Dean Williams joined an effort with Parks & Wildlife and Texas zoos to study and protect the horned lizard.
Barber’s team at the Fort Worth Zoo pioneered breeding strategies, learning how to successfully raise the lizards in captivity.
“We’re all sort of working together for the common good,” said Nathan Rains, a wildlife diversity biologist with Parks & Wildlife.
Last year, Parks & Wildlife released hatchlings — just a few weeks old — in an attempt to establish a stable population. Sixtythree babies from the Fort Worth Zoo were released at Mason Mountain, a trial run. It’s unclear whether any of those have survived lizards.
At the end of last year, Parks & Wildlife and the zoos settled on a new goal: 300 hatchlings for release by September 2018. That number, they guessed, would give the lizards a greater chance to reach adulthood, breed and produce their own wild offspring.
“Nobody’s more optimistic than I am,” Rains said, “but we don’t know if it’s going to work yet.”
‘Tinder for horned lizards’
Within a few weeks of waking from hibernation in late March, the lizards at the Fort Worth Zoo are clearly ready for action. They’ve been in bachelor and bachelorette tanks, warming up and starting to move.
Each lizard’s DNA has been tested by Williams at TCU. Those DNA results go into a computer program that analyzes every individual for its best possible mating match.
The goal: Pair the male and female lizards to create the most genetically diverse offspring possible.
“It’s like Tinder for horned lizards,” said Robyn Doege, supervisor of aquatics.
It’ll be at least a month before there are any signs of eggs, and even then every nest may not be viable. Three hundred hatchlings is still the goal.
“If each of them lay 20 eggs,” Doege says after the lizards are all paired with their potential mates, “we have a shot.”
For weeks after pairing day, Doege and zookeeper Jaimie Peltier watch the sandy enclosures at the zoo.
By late June, the zookeepers have found 135 eggs, and the tiny lizards begin hatching in late July.
Each is hardly the size of a penny as they slowly climb out of the paper-thin eggs over several days.
In the first week of September, it’s time to pack up the baby lizards.
Peltier and Doege count the hatchlings and label each container with a piece of neon green painter’s FrogTape.
In all, they pack 93 baby lizards in a Styrofoam box cushioned by newspaper. That’s far under the goal of 300. Next year, they’ll have more juveniles at breeding age. More potential parents means more potential offspring. The bar is still set at 300 hatchlings for release in 2019.
Unceremonious release
On a cool and cloudy Wednesday morning, Doege and Peltier drive the lizards to Mason and carry the deli cups into the brush. They take turns placing the hatchlings carefully on the ground. And that’s it. Unceremoniously, they walk back out of the brush, leaving the little lizards behind.
“Enjoy the horned lizards,” Doege says to the Parks & Wildlife biologists. “We’ll make more next year.”
There’s just one experiment left, one that will give Parks & Wildlife a better idea if these lizards survive more than just a few days.
Ten lizards were held from the initial release group to be part of a new tracking test.
A few hours after the other lizards were released, Rains and Barber glue tiny trackers onto the hatchlings before releasing them in a clearing not far away. The antennas hang off their backs like extra-long tails.
The next morning, Rains returns to the clearing. He opens a big yellow and gray receiver, turning up the monitor to check for any sign of the lizards.
Almost immediately, the device emits a rapid beep-beep-beepbeep out of the static.
In the Hill Country brush, the horned lizard hatchlings are still there.