Reptiles and Amphibians

FIELD NOTES PART III: Saving our state reptile

Reptile supervisor Bradley Lawrence guest-blogs on ZooHoo!

We’ve encountered this beautiful western diamondback rattlesnake recently at RPQR Ranch!

This guest-blog is part of a series. Click to read Part I and Part II!

As much as we all love Texas Horned Lizards, I’d like to take some time this week to talk about another small part of our work at the Rolling Plains Quail Research Ranch…RATTLESNAKES!!!

We love rattlesnakes at the Dallas Zoo, and they are such a vital part of our ecosystem. Rattlesnakes were historically hunted heavily in the area around the ranch for “round ups.” These snakes were hunted indiscriminately until the current property management took over 15 years or so ago. Since then the rattlesnakes have been protected from harvest.

Rattlesnakes are the frontline defense against rodents that carry many diseases harmful to other wildlife, agriculture, and of course, humans. We need them! If you ever encounter one in the wild, leave it alone. Rattlesnakes only bite as a last resort when threatened (and they give you fair warning before doing so!)

The elusive prairie rattlesnake.

As a side project during our time at the ranch monitoring Texas horned lizard populations, we do a similar mark and recapture study for every rattlesnake we see. This allows us to get an idea of the population size, their home ranges, growth rates, and more. We’ve tagged and released about 12 rattlesnakes on the property this spring so far. When we catch one we record its location, weight, length, body condition, and environmental data as well. Most of the rattlesnakes on the property are western diamondbacks, but this week we also found an elusive prairie rattlesnake!

Although they can be dangerous if harassed, I can’t stress enough how important these predators are to the ecosystem. The Texas horned lizard, the rattlesnake and the quail all live in perfect balance at the ranch. Perhaps we could all learn something from them…

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FIELD NOTES PART II: Saving our state reptile

Reptile Supervisor Bradley Lawrence guest-blogs on ZooHoo!


A Texas horned lizard spotted at RPQR last weekend.

This guest-blog is part of a series. Click here to read Part I!

Springtime is never boring on the rolling plains of Texas. Our latest expedition to the Rolling Plains Quail Research Ranch in search of Texas horned lizards (aka “horny toads”) started a little rough. We arrived just in time to get an hour or so of searching in before we were forced to call it quits for the evening due to weather. The storms were severe enough to produce baseball-size hail and at last one tornado within 5 miles of us. We spent a little time in the much appreciated storm shelter.

The next morning was very wet, windy and a little cold – not a good combination for finding Texas horned lizards, but the afternoon finally warmed up, and the day turned out to be very nice. We’ve found that when conditions are sub-optimal, we tend to see only young lizards and old lizards that are thin, injured or less than prime specimens. My personal feeling is that the adult animals that are in good condition simply wait bad days out until a better one comes along. They can afford not to feed for a few days or even weeks at a time.

We release the lizards in the same spot we found them.

When we catch a lizard, we immediately start to log a GPS location. While this is happening, we measure the total length of the animal, weigh them, and record the surface temperature and UV index at the point where we initially spotted the lizard. A small electronic “chip” is placed in the lizard so we can track home range, growth, and population density. These and some other observations are all recorded in a handheld computer/GPS.  This whole process takes about 5 min. Then the lizard is released, no worse for wear, right where it was found.

Our lizard sightings are getting more frequent as spring turns into summer – these little lizards are doing very well here. We even found our first gravid (that means pregnant or egg-carrying in reptile-speak) lizard of the season. We love to see reproduction in the wild! A large female is able to lay 40+ eggs at a time. We will start to see this year’s hatchlings toward the end of July and into August.

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FIELD NOTES PART I: Saving our state reptile

Reptile Supervisor Bradley Lawrence guest-blogs on ZooHoo!

Dallas Zoo reptile team members went out into the field last weekend to check in on the Texas horned lizard population.

Unless you’ve been living under a rock (like our state reptile was during the winter months), you know how much we love Texas horned lizards here at the Dallas Zoo. Last weekend we began our 10th year of studying “horny toads” at the Rolling Plains Quail Research Ranch in Fisher Co, Texas.

The population in this area of Texas is very healthy, and we have been monitoring them for 9 years now. We are gathering as much data as we can to help us learn what makes a habitat like this so good for horned lizards. We hope to use what we learn to help conserve these fabulous reptiles both in the wild and in our care here at the Dallas Zoo.

Over the next several months, we’ll be providing up-to-date notes from the field to give y’all a first-hand look at what we do. I hope that you will learn more about the Texas horned lizard as well as how they fit into the bigger ecological picture here in Texas.

The team worked against the unpredictable spring weather. Check out that lightning!

The RPQRR is a 4700-acre ranch about 4 hours west of Dallas. Along with horned lizards, we get to experience a rare glimpse of wild Texas that is more and more difficult to find these days.

We start our lizard season in late April or early May, giving them a chance to wake up from their roughly 5 month hibernation. Once they’re awake they start looking for much needed food and also start to think about finding a mate.

We had a very productive first outing. We saw several very healthy looking horned lizards, even though we fought Mother Nature a bit. Spring weather in the rolling plains of Texas can be unpredictable and a little scary.

Stay tuned! We’ll give you more in a couple of weeks.

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Creating a better world for turtles

Conservation Interpreter Grayson P. guest-blogs on ZooHoo!

An endangered black-breasted leaf turtle at the Herpetarium.

With a family tree that began 300 million years ago, turtles have been around since the time of the dinosaurs. There are 356 species of turtles, and they play an essential role in maintaining our environment. Freshwater turtles keep our lakes and rivers healthy by controlling aquatic vegetation; tortoises shape habitats for animals and plants by grazing; and sea turtles’ infertile eggs fertilize coastal dunes. However, while turtles have survived multiple mass extinctions, they are facing threats like never before, and as many as one-third of turtles could be extinct in the next twenty years. The Dallas Zoo is determined to change that.  

This April, we are highlighting endangered turtles and how we can protect them through everyday actions as part of our Protecting the 12 conservation plan, and we hope you’ll join us. The Dallas Zoo has a long history of protecting turtles. We take a two-pronged approach: protecting endangered turtles in the wild and breeding them in human care. We provide funding to many turtle conservation organizations, including the Turtle Survival Center in South Carolina, home to breeding populations of thirty turtle species at the brink of extinction. And in turtle biodiversity hotspots such as Madagascar, Myanmar, and India, we facilitate boots-on-the-ground field research and conservation to protect these reptiles.

With our conservation partner, the Turtle Survival Alliance (TSA), the Dallas Zoo is ensuring no species of turtle becomes extinct in the 21st century. One of the most significant threats facing turtles is the illegal wildlife trade. In April 2018, over 10,000 endangered radiated tortoises were found in a poacher’s house in Toliara, Madagascar without access to food or water. It is believed the animals were collected for the illegal pet trade. The TSA led an unprecedented rescue mission to get these animals safe and healthy. Along with other AZA-accredited institutions, the Dallas Zoo sent emergency funds, supplies, and reptile specialists to Madagascar. Our team spent weeks soaking the surviving turtles to give them water and keep them alive. Because of this collaboration, the majority of the turtles lived and were able to be returned to the wild.   

In addition to the illegal pet trade, one of the biggest threats to turtles is plastic pollution. Every day, 8 million pieces of plastic flow through rivers, creeks, and other waterways, and end up into the ocean, threatening sea turtles who mistake it for jellyfish. As part of our movement to protect turtles, we are asking Zoo guests to make a pledge to pick up ten pieces of plastic pollution every Tuesday to keep the land and waters that turtles call home clean and safe. We hope this pledge is just a starting point and inspires our guests to reduce the amount of single-use plastic they use in order to protect turtles and other species.  

When you think of conservationists, you might picture biologists in the field. Here at the Dallas Zoo, we see our guests as conservation heroes because protecting our planet and the animals that call it home is a collaborative effort and everyone’s responsibility.

By picking up plastic pollution, making sure our reptile pets are from reputable breeders, and supporting the Turtle Survival Alliance, we can help protect turtles from extinction. We can’t do it alone and will need everyone’s help to save these magnificent animals which are essential to the wellbeing of our environment. Visit our turtle conservation station at the Galapagos tortoise habitat in ZooNorth through the end of the month to learn more about how you can help, and join us in creating a better world for turtles.

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Dallas Zoo staffers awarded nearly $70,000 in funding from National Geographic Society for conservation work

Penguin nesting project and amphibian conservation to be funded through National Geographic Society Grants

Two of our team members will join the ranks of renowned conservationists like Jane Goodall and Jacques Cousteau, as National Geographic Explorers, working on personal field conservation projects across the globe.

Dallas Zoo’s Animal Care Supervisor of Birds Kevin Graham was awarded a $50,000 grant in support of his project: “Using Artificial Nests to Improve Breeding Success of Endangered African Penguins.” Additionally, Curator of Ectotherms Ruston Hartdegen was awarded $18,955 in support of his project: “Expanding an Amphibian Rescue Center at the Dallas Zoo.”

Kevin Graham on South Africa’s Dyer Island installing the artificial nests.

“Receiving grants of this magnitude from National Geographic Society really shows the advances our team is making in the field of wildlife conservation,” said Harrison Edell, Dallas Zoo’s Executive Vice President of Animal Care and Conservation. “These are lifesaving undertakings that Kevin and Ruston have worked at length on – they had to prove successful completion of similar projects with measurable results before being awarded the grants. Now, we can make an even bigger impact for endangered African penguins and near-extinct frogs.”

Protecting penguins

In addition to caring for Dallas Zoo’s birds, Graham has worked hard to save African black-footed penguins in South Africa for the past three years as the Artificial Nest Development Project Coordinator for the Association of Zoos and Aquariums (AZA). He leads a team that studies, designs and installs artificial nests for the penguins to lay eggs in.

Over the past 100 years, the population of African penguins has declined from more than two million breeding pairs to slightly more than 20,000 breeding pairs left – that’s a more than 98-percent population decline mainly due to improper nests that fail to protect their eggs.

African penguins burrow and nest in guano (a term for their poop), but decades ago, Europeans and South Africans began removing the guano to use as fertilizer, leaving the penguins’ eggs vulnerable to predation, human activity, and the elements. There are currently only 27 natural guano nests left.

An African penguin sits on an egg inside the artificial nest.

In February 2018, Graham joined forces with AZA scientists, the Dyer Island Conservation Trust and Pan-African Association of Zoos and Aquaria (PAAZA) to install 200 artificial nests in two South African penguin colonies. After extensively testing various artificial nest prototypes, two designs were penguin-approved. At the end of the testing period, the scientists learned that approximately 96 percent of the nests in the study were utilized by the penguins, just over 80 percent had eggs laid in them, and more than 56 percent had successful chicks.

Over the next few months, the team will build 600 more nests to install, which is where the grant funding will come into play. Long-term, Graham hopes to have 6,000-7,000 nests installed in total.

“Our vision is to eventually achieve large-scale implementation that will allow thousands of penguin pairs access to suitable nesting locations, improving the current breeding success rate, and establishing population sustainability and stability,” said Graham. “There are other threats hurting African penguins – over-fishing, climate change, and marine pollution – but it feels good knowing that right now we’re taking immediate action to save them, and if nothing else, at least we gave them a place to raise kids.”

Hopping to the rescue

With one-third to one-half of all amphibian species worldwide threatened with extinction, conservation action is absolutely critical to preserving herpetological biodiversity. The Dallas Zoo is taking the next step to develop assurance populations of three threatened amphibian species – the dusky gopher frog, the Houston toad, and the Puerto Rican crested toad.

Ruston Hartdegen releases a dusky gopher froglet back into Mississippi’s DeSoto National Forest.

This past summer, we opened a behind-the-scenes Amphibian Rescue Center where our herpetologists are working to produce healthy offspring to release back into their natural environments.

We are already leading efforts to protect the dusky gopher frog, one of the most endangered amphibians in the world. In October 2018, herpetologists released new froglets from our existing dusky gopher frog population into their native habitat of Mississippi, where the frog is endemic to only three small ponds in the DeSoto National Forest.

“Without conservation efforts like our zoological breeding program, many endangered species would become extinct in the wild,” said Hartdegen. “Amphibians are critical to our environment. Known as ‘indicator species,’ they’re used to gauge the health of their ecosystems – the moment they’re in decline, we know that habitat has been compromised due to problems like, pollution, habitat destruction, or disease.”

With the help of the National Geographic Society grant, Hartdegen is expanding the Amphibian Rescue Center to accommodate two new breed-and-release programs – the Houston toad (currently only found in three Texas counties) and the Puerto Rican crested toad (the only native toad on the island) – helping a total of three species increase their numbers while protecting genetic diversity.

A dusky gopher frog at the Dallas Zoo Amphibian Rescue Center before its release.

The National Geographic Society funding marks the first time our staffers have received support from the Society in its history. Since its inception 130 years ago, the National Geographic Society has supported the work of more than 3,000 Explorers in the field.

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