Reptiles and Amphibians

Tiny tortoise, gecko hatchlings are a big deal

_MG_1516-baby Forsten's Tortoise


_MG_1511-baby leaf geckoEvery day, people pour past the front gates of the Zoo to witness our enchanting animals. But this month, some of the most fascinating events took place behind the scenes in our herpetology department.

We’re proudly welcoming two new hatchlings that will be much-needed ambassadors for their species: a satanic leaf-tailed gecko and a Forsten’s tortoise.

If you’ve visited our Herpetarium, you may have walked right past the leaf geckos, thinking the exhibit was empty. These reptiles are masters in camouflage and often go unnoticed by an unsuspecting eye. They dwell in the lush forests of Madagascar, where their leaf-like design provides the perfect cover to hide them from predators. Satanic leaf-tailed geckos are facing a significant decline in the wild as heavy logging wreaks havoc on their habitat. Their incredible design also makes them a much-wanted pet, and they’re often captured and sold illegally.

_MG_1232-Satanic leaf-tailed gecko-CBThe Dallas Zoo is one of only two U.S. institutions to successfully reproduce satanic leaf-tailed geckos. Since this gecko can only be found in a remote region, the select institutions that are lucky enough to host the leafy lizard have a large responsibility to reproduce and study the animal. This little lizard makes baby No. 8 for the Zoo and our herpetologists are beaming with joy at the sight of another successful hatching.

Also, for the first time, the Dallas Zoo is welcoming a baby Forsten’s tortoise to our family, a major breeding success. Found only on the single island of Sulawesi in Indonesia, the Forsten’s tortoise is commonly hunted both for meat and pet trade industries, which has left this species in desperate need of help.

“Our reptile team is very excited to be working with these highly threatened animals and we’re proud of the fact that we’re making a significant contribution to the success of these species in zoological care,” said Ruston Hartdegen, Dallas Zoo’s curator of herpetology.

The arrival of these reptile hatchlings shows that with a little help from passionate people willing to fight for their survival, we can make a difference in their well-deserved comeback.

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‘Living fossils’: Meet our rare reptiles from the dinosaur eras

IMG_3681-Tuatara 4x6

What if we told you dinosaurs were living right here is Dallas? That would sound crazy, right? Well, it’s true.

While they’re not the towering, fierce giants of the Jurassic that you’re picturing, tuataras are the only surviving member of a distinct reptilian order, Sphehodontia, which lived alongside early dinosaurs 200 million years ago in the Upper Triassic period.

Māori priest blesses the tuataras during Dallas Zoo’s welcome ceremony.

Their small size and dusty brown scales may not catch the eye of many Zoo visitors, but these “living fossils” have one of the most fascinating stories of all of our residents. Don’t be fooled by their scaly skin and long tails – the tuatara isn’t your average lizard!

Tuataras are incredibly rare. They are found only in remote areas of New Zealand or in a few lucky institutions across the globe. The Dallas Zoo is one of only four U.S. zoos to receive permission to host the rare reptile. Not only does the New Zealand government have to grant approval for the export, but a tribe of native New Zealanders also must agree that the export has direct benefits to the species in the wild. When the tuataras arrived here in 1992, a Māori priest came along with them to perform a special blessing for the animals in their new home.

They may have lived through the extinction of dinosaurs, but unfortunately tuataras aren’t indestructible. Oddly enough, one of the biggest threats to their survival is small enough to fit in your hand – rats! Tuatara eggs must incubate 12 to 15 months before hatching, which gives the rats and other predators plenty of time to sneak into the den to steal a snack.

IMG_3692-tuatara-4x6Fortunately, it’s not too late to save these animals from extinction. The Dallas Zoo has donated thousands of dollars to our tuatara conservation partners in New Zealand to fund work in their natural habitat. Because tuatara eggs are so vulnerable in the wild, one of the best ways to ensure the survival of this species is through zoological breeding programs.

“We’re thrilled to be able to work with tuataras and have the opportunity to share with the public a totally unique and ancient lineage of reptile found in very few facilities across the globe,” said Ruston Hartdegen, Dallas Zoo’s curator of herpetology.

We are fortunate to have not one, but three tuataras in our care, and we hope to see that number rise soon. Unlike most reptiles, tuataras don’t breed until they’re 13 to 20 years old, and our two females and male have reached maturity. Veterinary staff recently performed a check-up and are happy to report that all three are in great health. With a little luck and a lot of patience, we hope to welcome the next much-needed generation of tuataras.


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Rat snake study the longest of its kind at Dallas Zoo


For more than 20 years, the Dallas Zoo has studied an animal that doesn’t even have a permanent home inside Texas’ largest zoo.

The Texas rat snake (P.obsoleta) slithers (and climbs!) onto the Dallas Zoo grounds every spring in search of food. These snakes, while not venomous or harmful, may alarm Zoo guests because of their large size.

Since 1989, Zoo herpetology staffers have captured, marked, examined, and released the snakes away from Zoo animals and guests. It’s the longest study of urban snakes of any kind.

Wait, releasing the snakes?!?

“They’re completely harmless, big snakes that eat a lot of rats,” Herpetology Supervisor Bradley Lawrence said.

Given that a female rat can produce hundreds upon hundreds of babies, Texas rat snakes are like Dallas Zoo junior staff members, keeping the rat population maintained. Because the Zoo sits on more than 100 acres of heartland prairie forest, rats are simply part of the ecosystem.

The snakes are tracked with digital transponders, the size of a grain of rice, inserted just below the skin. This transponder identifies the individual snake with a unique number. When a snake is found, reptile keepers scan for the transponder and note weight, length, sex, and physical description. They also add notes of what they find: “Swallowed decoy egg … Regurgitated fledgling bird.”

Texas rat snakes that find themselves with injuries or other ailments (like swallowing a decoy egg, used to encourage nesting) get an extra-long stay at Château Dallas Zoo to see our veterinarians before being released back in the wild.

Since tracking began, 20 different snakes have been caught repeatedly over four-year periods, and two snakes have lived around the Zoo for more than seven years.

The data, which has more than 1,000 captures, is teaching Zoo herpetology staff about how these urban-environment reptiles live.

“We want to learn growth rates, what they prey on, their movement pattern, and how urban spaces affect their population,” Herpetology Curator Ruston Hartdegen said.

Don’t be alarmed if you see a Texas rat snake, at the Zoo or anywhere else in Dallas. If you’re visiting us, just alert Zoo staff and we’ll happily scoop the snake up to be examined, released and tracked.

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Hopping to the rescue: Protecting the critically endangered dusky gopher frog

IMG_9168 Gopher Frog CS

For eight hours, Ruston Hartdegen drove. Through the flatlands of East Texas, then the red clay of northern Louisiana, and finally into the thick pine forests of Mississippi.

The Dallas Zoo’s curator of Herpetology was on a mission years in the making – a tadpole rescue mission.

His journey ended deep in the DeSoto National Forest, an hour north of Gulf Coast, where he gathered 188 dusky gopher frog tadpoles to bring back to the Dallas Zoo – not for exhibit, but to save them from extinction.

In 2012, the International Union for the Conservation of Nature (IUCN) named Rana (Lithobates) sevosa one of the top 100 endangered species in the world, with only 100 to 200 adults remaining.

The longleaf pine forest habitats that dusky gopher frogs call home are disappearing as paper companies harvest the trees and replace them with faster-growing loblolly and slash pine. Today, the dusky gopher frog has only a few homes in the wild remaining, including the geographically isolated Glen’s Pond.

The Zoo's biosecure facility is an asset to growing and breeding the dwindling gopher frogs.

Zoo staff are required to wear special suits and boots to enter the quarantined gopher frog facility.

The Dallas Zoo and more than a dozen other institutions are participating in a Species Survival Plan to breed and raise these 3-inch-long, dark-spotted victims of deforestation. The plan is a kind of zoo-backed insurance policy to help the species survive: Should wild populations continue to decline, the frogs raised at Dallas, Detroit, Memphis and other participating zoos could be released to bolster numbers.

“Amphibian decline is a global phenomenon,” said Hartdegen. “One out of every three species of amphibians is under serious threat. Our involvement with the gopher frog SSP allows us the opportunity make a significant difference for a critical endangered species in our backyards.”

The Dallas Zoo was invited to participate because of the unique, biosecure facility available in ZooNorth’s herpetarium.

The tadpoles, which began as eggs at Glen’s Pond, were transferred to holding tanks at Harrison Experimental Forest Station before being collected by Hartdegen. After a long drive home, they are now in an isolated quarantine space at the Dallas Zoo, being cared for by the herpetology staff.

But the efforts don’t stop there.

“Protection of habitat is crucial to saving a species,” said Matt Vaughan, the Dallas Zoo’s assistant supervisor of Herpetology.

Hoping to keep dusky gopher frogs from disappearing from the earth, the U.S. Fish and Wildlife Service has designated nearly 6,500 acres of land in Louisiana, Alabama, and Mississippi as critical habitats for them. Longleaf pine restoration efforts also are under way.

The partnership between governmental agencies and non-profit zoos will give these struggling little creatures a chance to beat the odds, and the Dallas Zoo herpetology team is proud to be on the front lines in this crucial conservation effort.

Matt Vaughan and Anna Campitelli contributed to this story.

IMG_3453 Gopher Frog Tadpoles CS

Gopher frog tadpoles are examined by a reptile keeper.

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An adult dusky gopher frog.

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License plates to save mysterious Texas water snakes

A baby Brazos water snake photographed by DFW Herpetological Society president Mark Pyle.

A young Brazos water snake photographed by DFW Herpetological Society president Mark Pyle.

With 42,000 miles of water to inhabit, you’d think the Brazos water snake would be living the dream in Texas’s longest river. But the Brazos River is ever-changing, and human influences have left few habitat options for this elusive snake that’s exclusive to its water, and only resides along its rocky stream beds and banks.

Next spring, Dallas Zoo’s herpetologists will embark on a year-long field research project to bring much-needed light to the Nerodia harteri population – commonly known as the Brazos water snake, which is one of only three snake species endemic to Texas. And it’s all thanks to Texas Parks and Wildlife Department’s conservation license plates.

The Horned Lizard License Plate program supports wildlife conservation projects across our state./Texas Parks and Wildlife

The Horned Lizard License Plate Program supports wildlife conservation projects across our state./Texas Parks and Wildlife

While driving through Texas, you’ve probably spotted a super-rad license plate featuring a Texas horned lizard, or a flying hummingbird, or possibly a rattlesnake. These specialty plates fund important field projects across our state to benefit wildlife diversity and protect native non-game species.

The Dallas Zoo’s herpetology team recently was awarded a $4,500 grant through TPWD’s license plate program to spearhead a population assessment on this threatened water snake.

In recent years, Brazos water snake population surveys have been unsuccessful after very few snakes could be found. But a recent chance discovery of a potential population in Lake Granbury, an artificial lake damming the Brazos River, has local herpetologists beaming with excitement.

“DFW Herpetological Society president Mark Pyle lives near Lake Granbury and spotted the little brown snakes that no one pays much attention to,” said Ruston Hartdegen, Dallas Zoo’s curator of herpetology. “Now that a potential population has been discovered, we have a chance to make a direct and significant impact just an hour outside the zoo.”

These small snakes average 20-30 inches long./Mark Pyle

These small snakes average 20-30 inches in length./Mark Pyle

Come April, the Dallas Zoo’s reptile team will be on the ground armed with dip nets, searching for the mysterious snakes. UT Arlington and TPWD also will join in field efforts. When the team spots one of the small serpents, they’ll note the exact location and activity: swimming, basking, feeding, or hiding. When it’s captured, they’ll record its gender, snout-to-vent length, total length and weight, then insert a passive integrated transponder (PIT) tag to identify the snake (similar to the chip inserted in cats and dogs).

“Some researchers have spent hundreds of man hours searching for these snakes and have only found a half-dozen,” Hartdegen said. “We now have an opportunity to understand one of Texas’s most rare and habitat-restricted species.”

Brazos water snakes are viviparous, meaning they give birth to live young./Mark Pyle

Brazos water snakes are viviparous, meaning they give birth to live young./Mark Pyle

It’s a conservation partnership that will help decide how these misunderstood native Texans will be protected. Stay tuned here on ZooHoo! this spring for video and photo updates from the field!

You can help, too: Buy your Texas conservation plate for only $30, and $22 of that fee goes directly to research projects like this one.

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