Hundreds of Houston Zoo Houston toads go back to the wild

Toads on their way to the wild!

We have great news to share with you from the Houston toad program! Last month we successfully transferred 634 adult toads to our collaborators at Texas State University. Texas State kept the toads in a large, outdoor holding area for a few days to re-acclimate to natural conditions, then over the course of a week, they were released at a pond at Bastrop State Park.

Hooray! We are in the wild! We will save our species!

We are at the tail-end of Houston toad breeding season, so hopefully these individuals will have an opportunity to “do their thing” at the pond!

Stay tuned for more updates on our efforts to save local species from extinction!

Home Sweet Home

Inspecting a toad before weighing

Last week we were happy to announce that the Leon county toads, a group of toads that had been housed at the Houston Zoo’s toad facility since 2010, had finally been given approval for release back into the wild. On the first leg of their journey, the toads were transported from the Houston Zoo to an outdoor facility managed by Texas State University.  The facility is in the county of Bastrop, one of the few counties in Texas where Houston toads still remain in the wild.

The facility consists of ~40 large tubs filled with sand, water, and vegetation.  When the Leon county toads arrived at the Texas State facility, groups of sixty toads were placed into the tubs. Here the toads were given an opportunity to acclimate to the outdoors before actually being released into the environment.

The “release” itself was staged over the course of several evenings. Graduate student Melissa Jones from Texas State was in charge of orchestrating each of the toad releases.  Before they could be released, Melissa had to weigh, measure, photograph, and give each toad an identifying mark. We were very fortunate to have the opportunity to assist Melissa in processing the toads one of these evenings.

Documenting toad information

First, we had to find the toads hidden in either the sand or in the water of the tubs, and then take their measurements. Melissa was very patient showing us how to perform these techniques in the field – it was far more difficult than taking these same measurements in the comfort of the quarantine building at the zoo! Collecting all of this data took several hours, but it was an amazing night.  The gentle winds blowing through the pine trees kept us company and were additionally treated to the singing of several other wild amphibians.

Processing toads

After processing, the toads were transferred to smaller bins and driven out to a pond near the holding facility. We stumbled through the dark with flashlights, carefully clutching our precious cargo as we made our way through the brush. Surprisingly, we did not disperse our charges at the pond’s edge; instead, under Melissa’s direction, we circled the pond and placed toads in small holes that we dug in the soil with our hands. We made holes under trees or other brush, placing two or three toads in each. By spreading out and hiding the toads in this way, we were ensuring that we were not making a “toad buffet” for hungry predators.

Slowly but surely, some of the little toads dug themselves out of their holes and made their way to the pond. Like any good “toad mom,” I got a little teary eyed watching these animals that I have taken care of for so long take their first few hops into  this strange new place, but I take comfort knowing that they have finally made it back where they belong. This is what wildlife conservation is all about. Thanks to everyone who has supported the Houston toad program and conservation programs everywhere!

The Houston Zoo is Sending Animals Back to the Wild!

The Houston Zoo cares deeply for Texas wildlife.   We are committed to ensuring the recovery and protection of local species and habitats.  We take great pride in our efforts to rehabilitate/assist wild animals and reintroduce zoo-born animals to the wild.   This blog series will keep you up-to-date on our 3 local recovery projects:

The Attwater’s prairie chicken is the rarest native Texas bird. It is estimated that less than 100 of these birds are left in the wild.   The Houston Zoo manages the captive breeding programs for the Attwater’s prairie chicken.  We have breeding facilities both behind the scenes at the Zoo and at NASA’s Johnson Space Center.  When the birds hatch and grow large enough, they are slowly introduced and then released into the wild, where they will support the already existing populations.

There are 5 species of sea turtles inhabiting the Gulf of Mexico, all of which are considered to be either threatened or endangered. They include the Kemp’s ridley, Green, Leatherback, Atlantic hawksbill, and Loggerhead sea turtles. Some of the threats these sea turtles face in the Gulf are drowning in shrimp nets, getting caught in hook and line, vehicle traffic, development of beaches, ocean and light pollution.  The Houston Zoo has treated over 100 sea turtles since 2010 in our vet clinic. The turtles are then brought to the sea turtle barn in Galveston to prepare for reintroduction. You may also catch a glimpse of a recovering sea turtle at the Zoo in the Kipp Aquarium.

The Houston Toad disappeared from Houston in the 1960s following extensive drought and urban expansion.  Today, less than 100 of this Texas amphibian resides in Bastrop, Austin, and Colorado Counties.

Th Houston toad program began in 2007 when the only known egg strands laid by Houston toads that year were delivered to the Zoo for “head starting” – a way to start the toad’s life in captivity and release them when they reach a certain maturity. Since then, we have been building a population at the Zoo to be sure that the toads will not go extinct, as well as releasing toads into the wild to build the population there. So far, we have released more than 20,000 toads! We also monitor and survey existing populations of toads in the wild.

 Stay tuned this spring as we update you on these local efforts to put species back into their homes in the Texas wild!


Free at Last!

We have fantastic news from the Houston toad program! On the morning of Friday, April 12th, we got the call from the US Fish and Wildlife Service that we had been crossing our fingers for – the “go for release” of our Leon county toads! Finally, three years after being collected from the wild as eggs, Red and her friends were finally going home.

This event is the first ever release of adult Houston toads from the Houston Zoo. Animals head-started in the facility are generally only kept a few weeks after metamorphosis and are thereby released as juveniles.  In the case of the Leon county toads, several unfortunate events prevented this particular group from being released after they were reared here at the facility.

The initial phone call from USFWS set off a flurry of events in the toad facility. It is no easy matter to pack up and ship out 600+ adult Houston toads!! With a rain event predicted mid-week, we were scrambling to get the toads out in enough time to give them a chance to acclimate to their new environment. In the world of the toad, rain means breeding, and getting more Houston toads to breed in the wild is one of our leading priorities!

With the help of our Houston toad interns and volunteers, we were able to pack up all of the Leon county toads Saturday afternoon. Dr. Lauren Howard of the Zoo’s veterinary team visually inspected every single toad being shipped out. Wow! I bet the doctors as the medical center can’t say that they’ve seen that many clients in a day!

After their health check-up, the toads were carefully loaded and transported to an outdoor facility outside of Bastrop State Park that is managed by our collaborators at Texas State University. We met up with graduate student Melissa Jones, to move the toads into several large, outdoor tubs where the toads would be allowed to acclimate to outdoor conditions for several days before being released. Melissa will be monitoring the released toads as part of her PhD dissertation work.

Loaded up and ready to go!

As soon as we placed the Leon county toads into these large holding tubs, which were deigned to be half water and half sandy shore (aka perfect toad habitat!) the male toads immediately started to call.  The sound was deafening in the quiet of the evening and honestly brought tears to my eyes. Though I know they were just “doing what toads do,” I would kind of like to think that they were saying “thank you…”

Goodbye and good luck!


Moving the Leon county toads to the Texas State facility was just the first stage of the release. To find out about the next step in their journey home, please check out the blog next week!

Houston Toads: What Are Those Bumps?!

One of our Leon county toads, Red, paused chasing crickets for moment for a quick photo op. She is quite the photogenic toad!

Have you noticed in our Houston toad photos the large, lump-like structure behind the eyes? This structure is not a lump or a wart; it is in fact a specialized gland called the parotid gland. This gland is responsible for producing toxins that protect the toad against predators. Different toads produce different toxins of various “strengths.” In general, these toxins are not dangerous to humans; however, the cane toad (Bufo marinus) produces a toxin that can cause some skin irritation. Has your dog ever picked up a toad, then started foaming at the mouth? It is a reaction to these chemicals that the toad hopes will distract the unlucky pup so it will have a chance to get away!

The size and location of the parotoid gland can also be used to tell the difference between different species of toad. A good resource can be found here: Know Your Toads.

Did you know several compounds made by the skin of amphibians, specifically frogs, are currently the focus of a great deal of biomedical research? Several studies have found that many of these compounds have anti-microbial properties which have led some researchers to believe that they might be used to make the next generation of antibiotics. Additionally, a compound produced by the skin of the green-eyed tree frog (Litoria genimaculata) may be able to stop infection by the HIV virus, the virus that causes AIDS.

It is estimated that ~32% of all amphibian species are threatened with extinction.  Who knows what amazing medical breakthrough is waiting to be discovered on the back of a frog or toad? Now more than ever it is critical that we join together to help save these amazing creatures!


For more reading:

Houston Toad Update

Last week we introduced everyone to Red, one of the many Houston toads that we are caring for here at the Houston Zoo. Red is a member of a group of toads that we refer to as the Leon county toads, which were collected and head-started from an egg strand that was found in Leon County, Texas (for an explanation of what head-starting is, please see the previous blog post).  Unfortunately, we were unable to release this group of toads the year they were collected and they have been with us at the zoo ever since. Now, 3 years after the eggs were originally found, these toads may finally have an opportunity to be released back into the wild!

One of the reasons it has taken so long to get Red and her siblings back out into the Texas landscape is because the Houston toad is considered a habitat specialist.  What is a habitat specialist? A habitat specialist requires a very specific environment in which to live. Houston toads require deep, sandy soil as well as an over story, which is a fancy term for “tree cover.” During the hot summer months, Houston toads actually bury themselves in the sand (called estivation) under the shade of trees and logs to escape the heat. The Houston toad also needs water in the form of lakes, ponds, or ditches in the early spring for reproduction.

Have you ever found a toad underneath an outdoor trashcan or within the coils of your garden hose? Most likely you have discovered the daytime hiding place for a Gulf Coast toad, the toad that most folks see in their yards.  The Gulf Coast toad is considered a habitat “generalist” in that it can make a home almost anywhere without the necessity of sand or other specific environmental features.  Because they are not picky about where they live, the Gulf Coast toad has adapted much better to living with humans, whereas the Houston toad has not.  Gulf Coast toads still require water for hydration and breeding, which is why you might catch one sitting in your dog’s water bowl on summer nights!

It took several years to locate land with the right environmental requirements where the Leon county toad “refugees” could be released. (But we’ve finally found a great place – yay!) Most of the land in Texas is privately owned, so are relying heavily on collaborations with local landowners to help us bring this species back. Thanks to everyone out there that is involved in the program!

Though Houston toads prefer sandy soil, we don’t actually keep them on sand in the facility. Want to know why not? We’ll tell you all about in our toad husbandry post next week!


Meet "Red" the Houston Toad!

This post written by Cassidy Johnson

The Houston toad staff would like to introduce everyone to Red, a 2-year old female Houston toad. Red is a little smaller than some of her female tank mates; however, what she lacks in size she makes up in spunk!

Red is a member of strand 25, which is a group of toads that were collected from Leon County, Texas. Why do we call groups of toads in our facility strands?  Unlike many species of frogs that lay their eggs in large clumps called egg masses, many toads lay their eggs in linear strings, or strands.  Each strand represents the offspring of a single mating event, so all of the toads in a strand can be considered brothers and sisters.

The Houston toad facility at the zoo raises toads from egg strands that are either laid in captivity or from partially collected wild egg strands. Why don’t we collect and raise the entire wild egg strand?  Just like other amphibian eggs, the Houston toad eggs are an important part of the ecosystem and it is important that we leave some behind. Additionally, in the off chance that something happens to the eggs that are taken to the facility, there will still be offspring produced from the eggs left behind.

Once they reach a certain size, the toads raised in the facility are released back where they were collected.  This process of raising toads from eggs in captivity is called head-starting, and continued release of animals back into the environment using this method will hopefully increase the wild population over time.

Back in 2010, several partial egg strands were collected from a site in Leon County; unfortunately, due to unforeseen circumstances, the toads head-started from these strands could not be released back at the collection site.  It has taken several years and lots of work by our partners at U.S. Fish and Wildlife, Texas Parks and Wildlife, and Texas State University, but a new, suitable release may have finally been located!

Why was finding a suitable location so difficult? Check out the blog again next week to find out!

A Prelude to Spring…

This post written by Cassidy Johnson

Spring is upon us, and for lots of folks that means that it is time to get in the garden, grease up the bicycle chains, or clean out the closets; however, for the dedicated staff at the Houston Zoo, spring time is “toad time” – Houston toad time that is!

The Houston toad (Anaxyrus [Bufo] houstonensis), which is only found in southeastern Texas, is one of the most critically endangered amphibians in North America. Though it once called Houston home, only a few, isolated populations remain in Bastrop, Austin, Burleson, Leon, and Lavaca counties. In an effort to save the toad from extinction, the Houston Zoo has partnered with the U.S. Fish and Wildlife Service, Texas Parks and Wildlife, and Texas State University to manage a Houston toad captive assurance colony and head start program at the zoo.

Sure this sounds good, but what the heck are a “captive assurance colony” and a “head start” program you ask? A captive assurance colony functions like an ark by housing animals in captivity to ensure that if the remaining wild population disappears that the animals don’t go entirely extinct.  Head starting refers to the practice of raising animals to a point where they have a better chance of survival in the wild. In the case of the Houston toad, both wild-collected and captive bred Houston toad eggs are reared through metamorphosis in the facility before being released into the wild. There are a large number of predators that love feeding on toad eggs and tadpoles, therefore raising them in safe environment during these developmental stages will hopefully increase the number of toads that reach adulthood.

Since the Houston Zoo’s toad facility was finalized in 2007, around 20,000 juvenile toads have been released back into the wild. Unfortunately, the extreme drought and the Bastrop complex wildfires of 2011 prevented any releases from taking place during the last two years; however, this year looks like it is shaping up much differently! Though many people are bummed out by gloomy, rainy days, this is exactly what we need to get toads back out in the wild!  So cross your fingers and hope for rain!

In addition to the release of head started toads, this spring we will also be releasing a group of adult toads that have been in our facility for over two years. Why have they been at the zoo for so long and what’s so special about this group? Stay tuned for our next post to find out!

Rhythm of Conservation


In 1968, a small amphibian landed a spot on the list of “Rare and Endangered Fish and Wildlife of the United States.” Five years later, the Houston toad was included in the passing of the Endangered Species Act, one of the first amphibian species in the United States and maybe even the world to be recognized as declining.  Today the Houston toad is no longer found in its namesake city, and fewer than 300 individuals remain in the wild, largely due to habitat loss.  The Houston Zoo is working with the US Fish and Wildlife Service, Texas Parks and Wildlife Department, Texas State University, and the Environmental Defense Fund to ensure the toad’s survival by caring for them in captivity in their early stages of life.  It is estimated that one out of every 1000 toad eggs will make it to be an adult toad. Because tadpoles are food for just about everything in the pond, The Houston Zoo collects the eggs from the wild, lets them hatch and grow from tadpole to toad, and then releases them back into the wild.  The Zoo also works with private landowners to restore habitat and monitor populations in Houston toad counties.

For more information about how you can help The Houston Toad, visit our own Houston Toad website.


Learning about endangered species is the first step in helping to protect them. According to, there are 5,689 known endangered species and 10,002 known vulnerable species on the planet. Can you imagine how different our Earth was before the populations for these species began dwindling?   The Houston Toad is just one of the many species you can learn about. Knowledge is power. The more you know, the more we can help protect the habitats of these precious creatures.


To learn about a new endangered species each day, visit the Rhythm of Conservation website. The Association of Zoos and Aquariums has teamed up with K12 to bring you information on seventy-five different endangered species as well as fun activities for the kids! The best part is you can enter their sweepstakes daily, up to seventy-five days, for a chance to win a trip to Walt Disney World! As always, you can visit our Conservation Blog for information about endangered species and what we can do to help!


Bastrop State Park Volunteer Work Parties to Save the Houston Toad, By Dale Martin

As most people in Texas know, early September 2011 brought a devastating wildfire to the Bastrop state Park.  A few park structures built by the CCC (Civilian Conservation Corps) in the 1930’s were damaged, thousands of trees burned along with acres and acres of underbrush. An endangered species resident of the Park became even more endangered: The Houston Toad. 

From December 2011 thru February 2012, Texas Parks & Wildlife Department led six volunteer work parties to restore the banks around the known Houston toad ponds in Bastrop State Park.  Though people were hoping the toads made it okay, surveys of the area have resulted in no Houston Toad calls being heard at some of the ponds. 

Friday, January 27, I drove up to Bastrop State Park from Houston and set up camp in the Deer Run campground for a two-night stay.  A few weeks prior, I had signed up for the January 28 volunteer work party.

Saturday morning, at 8:30am, I and 62 other volunteers gathered at The Refectory, checked in, received our hard hats and instructions from TPWD Park Interpreter/Volunteer Coordinator Katie Raney.  She, her team of TPWD staffers, and the 63 volunteers were going to caravan out to pond #2 to put down mulch along the pond and drainage banks. 

The ground cover had been burned off leaving nothing in the way of cover for any Houston Toads who may emerge from their underground burrows to call to females or hear and respond to male calls.  Providing 50% coverage of mulch provides some camouflage for the toads while they are on the surface and provides something they can hide under to avoid predators. The mulch is also important for promoting plant growth and helping to attract insects…just what the toads need.  

We arrived at and parked on the shoulder of the roadway near some big piles of mulch–about 10 or 20 cubic yards or more.  Katie walked us out to the pond about 200-300 yards from the road and showed us what she wanted in the way of mulch coverage.  Six of us stayed at the pond as the rest of the group strung themselves along the route back to the road

Volunteers began shoveling mulch into the tall, orange,  Home Depot buckets.  The buckets were passed from person to person down to the pond area where six of us took the incoming buckets as they arrived and shook out mulch between the high-water mark and the tree line. 

As we worked our way towards the road, the line got more compressed and became more like an actual bucket brigade where a bucket (or buckets) was passed hand-to-hand without any steps being taken by the passers. 

Once the mulch distributors reached the road, Katie declared it was time for a lunch break.  We had mulched the north side of the pond and the north bank of the pond drainage to the roadway. 

After lunch, as we again formed a bucket brigade line to feed the mulch distributors, I opted to be part of the line. 

Apparently, we were either so fired up from lunch or we had all gotten much better at passing buckets because we finished mulching the south side of the pond and its drainage banks in half the time it took us to do the north bank in the morning.  Once we put our equipment away–shovels, rakes, buckets, hard hats, etc–Katie thanked us and everyone left for home. 

Early Saturday morning, February 11, I drove up to Bastrop State Park to again participate in the last volunteer work party of the season–it is close to toad breeding season and Park staff don’t want to disrupt the toads’ activities.

This time, we went to toad pond #8, a pond which toad specialists had heard Houston toads calling earlier in the week.  Just like the work party a couple of weeks ago, we set up a bucket-brigade line between the mulch pile and the pond, and a mulch distribution team at the pond.  The first buckets started down the line about 10:00am.

Unknown to us down at the pond or along much of the bucket-brigade line, there was some unexpected excitement at the mulch pile: Someone uncovered a coral snake that had been hunkered down in the pile, likely staying warm during the 30-degree temperatures that night and morning. A TPWD staffer was posted to guard the snake from curious volunteers who wanted to look at it. 

By about noon, we finished putting down a 50%-coverage of mulch on the banks of the pond. Katie declared our work complete and led us through the Park back to our cars.

Dale Martin is a wonderful long time devoted volunteer at the Houston Zoo.  He assists our staff photographer and the web team.  

If you want to hear more about how the Houston Toads are doing after the Bastrop fires join us at the Zoo for our Wildlife Speaker Series  event on Friday, March 9 at 7:00 p.m.  Get up close and personal with a live Houston Toad and get an update on the wild Toads from our Amphibian Conservation Manager, Paul Crump.  Dr. Michael Lannoo of Indiana University School of Medicine will give a presentation titled: A Window into the Global Amphibian Crisis: Discovering the Biology of North America’s Most Secretive Frog, the Crawfish frog, as it Approaches Extinction.  Buy your tickets HERE.

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