A Houston Toad Success Story!

The past three weeks in the Houston toad facility have been a whirlwind of activity. Keepers, veterinary staff, and toads have all been racing the clock to get everything prepared to try to squeeze in a breeding event before the end of Houston toad’s normal breeding season. We are happy to announce that in all we were able to produce ~36,000 Houston toad eggs that have now been released in and around Bastrop State Park.

This marks the first release of eggs from the Houston toad facility. Generally, the survivorship of eggs in the wild is quite low, around 0.01%! However, our collaborators at Texas State University placed the egg strands inside wire cages, termed “predator excluder devices,” to protect the eggs from getting eaten by birds, fish, aquatic invertebrates, and even other amphibians! The eggs will develop and hatch inside the protective wall of these cages. Eventually, the resulting larvae and tadpoles will swim through the wire mesh; however, the cage will be left in the water so the tadpoles can continue to use it as a hiding place.

A graduate researcher from Texas State University is currently monitoring the developing eggs. She has recently observed very large Houston tadpoles hanging around one of the excluder devices from the first batch of eggs released, indicating that they are working and the tadpoles are surviving!

We kept a few of the eggs in the Houston Zoo’s toad facility to grow up to “toadhood” so they can be a part of our captive assurance colony.  These little toads are the offspring of some of our oldest and most “genetically precious” toads that we have here in the facility. Two of the females and three of the males that laid eggs last week are members of the very first group of toads that were brought into the toad program in 2007. We’re so happy that these toads are getting their offspring back into the wild!

Fingers crosses that the egg strands will produce lots of little toadlets that will be chorusing at the Bastrop ponds next year!

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!

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!


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Houston Toads: Caring for 2,000+ Houston Toads

Interested in finding out what it is like taking care of 2,000+ Houston toads? In this week’s blog post we are going to take you through a typical day here in the Houston toad facility.

Like most of the animal departments here at the zoo, our day starts at 7AM sharp. The first order of business is to clean all 144 tanks in the quarantine building – that’s a lot of tanks! Each tank is divided into two sections: a dry portion that has a deep layer of moss for burrowing, and pool area, where toads can soak and drink. After the water from the previous day is drained from each tank, the tank is sprayed down and any leftover food or fecal matter is removed. After cleaning, the tank is filled up again with clean, reverse osmosis water (just like the fancy bottled water you pay big bucks for!)

Remember that in the last post we mentioned that toads prefer living in sandy soil. There are several reasons that we don’t keep our toads in sand in captivity. The first reason is that the sand is very difficult to clean; therefore waste products quickly build up in the tank which could potentially make the toads sick. Also, have you ever tried to move a wheelbarrow of wet sand? It’s heavy! A tank full of sand is very difficult to move, which would overly complicate our daily cleaning regime.  Sand is also somewhat pricy, so for as often as we disinfect each tank, it would get very expensive to continue to buy new sand.

Instead of sand we use a moss from New Zealand that is collected from an area where no amphibians are found. This is important because it reduces the possibility that this moss could have an amphibian disease that could be transmitted to our toads. This moss is also slightly alkaline (basic) which reduces bacterial growth.  The moss is light weight very easy to use. We make sure each tank has a deep layer of moss so that the toads can burrow down into it just like they would in sand in the wild.

In conjunction with cleaning and refilling each tank, we also collect fecal specimens to be submitted to the veterinary clinic.  This routine health screening ensures that our captive colony toads are free of parasites.  After the morning husbandry is done, we then spend time feeding the toads.  Feeding occurs on a regulated schedule, because like most captive animals, we don’t want to feed them too much to maintain their health! We mainly feed the adult toads large crickets, but we also supplement this cricket diet with waxworms and mealworms. The younger toads eat smaller crickets, fruit flies, and bean beetles.

After the toads are fed, the remainder of the day is spent taking care of the bugs that we use for food (we grow the small crickets, flies, and beetles ourselves), building new or fixing old tanks, performing medical treatments, or working on our own research projects or the helping out with the projects of our collaborators. Occasionally we get out for a Houston toad keeper chat, so check the zoo website in the next few weeks if you are visiting the zoo and want to catch us!

Like all conservation programs, teamwork is absolutely required for its success. Not only do we rely on our external partners including the U.S. Fish and Wildlife Service, Texas Parks and Wildlife, and Texas State University, we also get tremendous support internally from the zoo. The aquarium provides us with most of our water, the vet staff gives us an incredible amount of medical support (it’s a lot of work to keep 2,000 toads healthy!), and keepers from Herpetology and the Children’s Zoo regularly lend us a helping hand with the day-to-day husbandry. We have also had a fantastic group of interns and volunteers whose enthusiasm and hard work continues to inspire us to make our program better. Thanks to everyone who has lent us a helping hand, we couldn’t do it without you! Stay tuned next week for a “guest blog” from one of our current interns, Jacquelyne Brauneis!

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!


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