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Researchers track Texas horny toads to help bolster lizards

December 21, 2018

DALLAS (AP) — In a welcome surprise to researchers fighting to protect the state reptile, signs are good that a number of Texas horned lizard hatchlings released this fall have survived into hibernation.

The Dallas Morning News reports the hatchlings were born at the Fort Worth Zoo this summer, part of an ambitious program to bring the lizard back to Texas landscapes. The partnership between Texas zoos, the Texas Parks and Wildlife Department and Texas Christian University has worked to study and protect the iconic critter, but success has been slow and hard to measure.

However, new tracking technology and a refocused effort to release hatchlings could be the latest, greatest hope to bring the species back from the brink.

Once backyard favorites across the state, the Texas horned lizard — or horny toad, or horned frog, or whatever you call them — has vanished from most parts of the state for reasons researchers can’t fully explain.

For the past decade, biologists, zookeepers, Texas Parks & Wildlife Department officials and others have worked together to try to reintroduce the lizards in some pockets of the state. They’ve tried moving adult lizards from South Texas to Central Texas. They’ve tried breeding lizards in zoos and releasing captive-bred adults.

Recently, the effort pivoted to releasing hatchlings born at Texas zoos, including those in Dallas and Fort Worth. The baby lizards, some hardly the size of a quarter, were too small for radio transmitters. Officials had to simply release the lizards and hope for the best without tracking them.

This year, however, 10 of the 139 hatchlings released at Mason Mountain Wildlife Management Area in September were fixed with tiny harmonic tracking devices that can be used on smaller reptiles, amphibians and insects.

In the past, it appeared that most if not all of the hatchlings released here died within a few months. Even in good conditions, horned lizards have a high mortality rate, so efforts have focused on releasing hundreds of hatchlings at once to establish a stable population.

Thanks to the new harmonic tracking technology, however, researchers were able to follow the 10 hatchlings through the fall.

A month into the project, five were still trackable. In early November, one lizard had buried itself for hibernation, three had lost their tags by shedding their skin, and one was still above ground and trackable. Despite a few hard freezes in November, that last lizard was still up and moving as late as last week.

On Dec. 4, researchers saw the lizard digging, and by Dec. 13 it was fully buried for the winter.

Diane Barber, curator of ectotherms at the Fort Worth Zoo, said the project’s success means they are purchasing more tracking equipment to continue studying survivorship and microhabitats of the juvenile lizards.


Information from: The Dallas Morning News, http://www.dallasnews.com

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