Metamorphosis – What Is It?

Metamorphosis is a fun word, but what does it mean? The word comes from meta ,meaning change, and morphe, meaning form, so it literally means to change shape or transform. Though our topic is amphibians, I must point out that most insects do this as well and go through even crazier changes.

While some have what is called direct development where a miniature adult hatches from an egg, the majority (except for most caecilians) have a larval stage between egg and adult. The time from the egg hatching to the adult animal can take anywhere from 2 weeks (toads that breed in very temporary puddles basically) to up to 4 years for some spring salamanders. The time is dependent on species and/or environmental conditions. There are even some salamanders, like the axolotl, which never do it all the way, they stay forever in the water with gills, even becoming sexually mature and reproducing.

Because the transformation is more extreme for frogs and toads, the following is geared toward them. Depending on the species, eggs are laid in a variety of places, including in the water, attached or not to vegetation, on leaves overhanging water, and even in water filled tree holes. What hatches out of the eggs usually looks something like this:

In this stage, they are fully aquatic and get oxygen via gills. They have sucker type mouths and most feed on vegetation by filter feeding or scraping algae off of rocks and things; however, some  are carnivorous!

Tadpoles go through tremendous change. Not only is the outside of their bodies drastically changing but the inside as well. They switch from gills in the water to lungs on land, skeletal changes occur (some things that were cartilage change to bone), eyes, skin, mouth parts, digestive system, all of this has to change.

Usually the back legs emerge first, starting as little nubs.

By contrast, the front legs appear first for salamanders and newts. The back legs grow and eventually the front legs pop out too. Often at this time, tadpoles will start coming partway out of the water. The time switching to lungs differs a lot between species and the type of habitat the tadpoles are from. At this point, they look something like this:

The tail is then absorbed (it would be a waste for it to just fall off) and the frog or toad is a bona fide, air breathing, land dwelling critter. There are frogs and toads that are semi or even wholly aquatic (they still breathe air) and there are some frogs that spend all of their time in trees, even breeding and hatching young without coming to the ground.

Here is a salamander larva.  Some of them have stunningly beautiful feathery gills.

Amphibians are an incredibly diverse and fascinating group of animals. If you’d like to learn more, there are a lot of great resources out there. Check out: , ,,

Endangered Keeled Box Turtle Babies

Hatching in time for Halloween is a keeled box turtle, an endangered Asian turtle. The Houston Zoo is one of only a few institutions to breed this species and we are very excited to welcome three new babies!


Keeled box turtles have a wide range, but their numbers are very low. They are endangered due to over-collection for consumption and habitat destruction, problems that also face many other Asian turtles.

baby-turtle-2They live in rocky forests and eat plants, fruits, and invertebrates like worms and snails. Interested in learning more? Visit our website to learn how the Houston Zoo is saving animals in the wild and check out these great sites with loads of turtle info: and


What Exactly is an Amphibian?

amazon milk frog
Amazon Milk Frog

Before we get to that, let me throw this out there.  There are five taxonomic classes of vertebrate (having an internal skeleton) animals.  These are fish, amphibians, reptiles, birds, and mammals.  Historically, amphibians and reptiles have been grouped together, often resulting in confusion as to what each group contains.  Amphibians include frogs and toads, newts and salamanders, and caecilians.  Crocodilians, lizards, snakes, turtles, and tortoises are reptiles.

Houston Toad
Houston Toad

The words “frog” and “toad” are not strict definitions.  In general, frogs have smooth skin and are more likely to stay close to water, while toads usually have dry bumpy skin and can be found further from water.  Also, frogs jump and toads do cute little hops.  Same deal with “newt” and “salamander.”  Newts are a kind of subgroup of salamanders and are usually aquatic as adults.  The third kind of amphibian that you’ve probably never heard of is the caecilian.  These look basically like large earthworms and most are burrowers so aren’t seen very often.  Some are quite colorful and one can even grow to almost 5 feet!

Photo credit: Dante Fenolio
Caecilia species Loreto Peru. Photo credit: Dante Fenolio

So that is what amphibians are.  Stay tuned over the next few weeks of “Amphibian Month” to learn some interesting, and some downright weird things about them.

Malaysian Giant Pond Turtle Babies!

Baby Malayan Giant Black Pond Turtle-0005-6434The Malaysian giant pond turtle, Orlitia borneensis, is a large turtle found in the rivers and lakes of the Malay Peninsula, Borneo, and Sumatra.  Adults can reach almost three feet in length and can weigh over 100 pounds. Its diet consists mostly of fish, vegetation, and fruits. Listed as Endangered by the IUCN, the Giant pond turtle has been heavily exploited for its meat, and populations are in decline throughout the native habitat.


Because of the large size and nature of giant pond turtles, this species is rarely seen in zoos. Captive reproduction is very rare. The Houston Zoo was fortunate to acquire a group of these animals as juveniles and has been displaying them since 2002. The turtles have now reached maturity and we are proud to report that this summer, the Houston Zoo successfully hatched four adorable babies! Getting out of a shell can be tough work. Baby turtles have something called an egg tooth. The egg tooth or caruncle is a temporary structure that is used to cut through the egg membrane and break through the shell.  Once there is a hole in the egg, the turtle can break out. Although the hatchlings are currently not on display, you can see the adults in the orangutan moat; though you may have to be patient as they are a very secretive species!

Baby Malayan Giant Black Pond Turtle-0012-6886

Not Your Usual Box Turtle

Photograph © National Geographic/George Grall

There is a turtle in the state of Coahuila, Mexico that doesn’t act like a regular box turtle.  This turtle is semi- aquatic.  It has the handy dandy hinges so that it can close itself up for protection but it spends at least as much time in the water as it does on land.  This turtle only lives in the Cuatro Cienegas Basin in Coahuila and inhabits permanent and seasonal wetlands.

An animal with a very restricted range is already more susceptible to extinction; add to that the fragmentation of their habitat due to manmade canals and wells and exotic invasive plants, and you have a recipe for disaster.  So as you can imagine, the Coahuilan box turtle is endangered.  We are happy to have them here at our zoo and after 65 days of incubation and weighing in at a whopping 4.8 grams, we are especially happy to announce the hatching of our newest baby-a Coahuilan box turtle!

baby turtle

Springtime and Snakes

Hello, and welcome to spring.  With the warm weather, your odds of encountering a snake go way up, and Texas has lots of snakes.   From 7 foot rat snakes, to the diminutive earth snake, Harris County snakes are quite variable.  Most are harmless, but we do have a few venomous species.  On Saturday, May 31, the Herpetology  ( reptiles and amphibians) Department will be hosting a Save our Species event focusing on local area snakes.
Copperhead snake
Unless you know them well, snakes can be very difficult to identify.  We will have 8 of the most common snakes of Harris County out of their exhibits and in aquariums so you can get a good and safe close up look at them.  We’ll have lots of information and photos, some fun things for the kids, and staff on hand to answer any questions you may have.  We hope to inform, educate, alleviate fears, have some fun, and hopefully save some snake lives.  Please join us!

New Zoo Baby: Fantastic Leaf Tailed Gecko

Leaf tailed geckos are a group of super cool lizards who are masters of camouflage.  They mimic dead leaves and twigs.  Their little legs look like tiny branches and their tails look just like dead leaves, all the way down to having veins and raggedy edges.  We are often hard pressed to find them in their enclosure.  Sometimes, you’re looking right at them and don’t even know it.

This species is called the Fantastic, or alternately, the Satanic leaf tailed gecko due to its pointy raised “brow ridges”.

Leaf-tailed geckos are found only on Madagascar.  They really should have had a leaf-tailed gecko as a character in the movie, that would have been awesome.  Populations are decreasing due mainly to habitat loss (sound familiar?) caused by logging, agriculture, and cattle grazing.  They are active at night and eat mostly insects.  Females lay 2 eggs at a time and the hatchlings look like this!

Baby fantastic leaf-tailed gecko
Baby fantastic leaf-tailed gecko

How adorable is that?  No offense to other geckos but I think this one is my favorite.  This little cutie hatched here at the zoo on February 17.

Thank You Spider, for Killing the Bugs That Bug Us

Image courtesy of Runt of the Web

Poor spiders! They seem to be at or near the top of most folks’ list of creepy crawly icky things that they don’t want anywhere near them. They usually make the sides of pest control vans too, even though they’re practically the opposite of a pest. Spiders never infest your food supplies, but they eat some of the things that do, they don’t bite you without a good reason, and some of them construct super cool webs.

Argiope aurantia, Black and Yellow Garden Spider

According to National Geographic, the average spider eats about 2,000 insects a year, so spiders are good to have around the home.

Of the more than nine hundred species of spider in Texas, only two are potentially dangerous (barring an allergic reaction similar to how some people react to bee stings); the black widow and brown recluse. Both of these are quite shy, choosing to stay hidden and let food come to them.

The red spot is on the belly of the black widow. Image courtesy of wikipedia
Brown recluses aren’t much bigger than a penny. Image courtesy of Wikipedia

Spiders are an incredibly diverse and fascinating group of animals. There are small ones, big ones, fuzzy ones; some burrow, some make huge webs way up high, some use silk as a lasso, some take care of their babies for a time, some dive under water taking along a bubble of air. There is even one that spits a combination of glue and venom at its prey-how cool is that? Some are just downright cute.

Phidippus regius female jumping spider. Photo by Thomas Shahan via flickr
Phidippus regius female jumping spider. Photo by Thomas Shahan via flickr

As with other venomous creatures, many people tend to be overly concerned about them. Bites do happen on occasion, though almost always from accidental contact. We come close to many more spiders than we will ever know because of their usual small size and reclusive habits. This Halloween, let’s give spiders some credit and think of them as natural pest control instead of pests themselves!

Comb-clawed spider chomping down on some pesky ants
Comb-clawed spider chomping down on some pesky ants

Find out more cool stuff about spiders – check out Spider Facts on the Discovery Channel website

Wolf spider mom carrying dozens of babies on her back.
Wolf spider mom carrying dozens of babies on her back.




What Do You Know About Coral Snakes?

Back again this week, and for a few weeks more, with the next in a series on snakes that’s being written for you by The Houston Zoo’s Herpetology Department Supervisor, Judith Bryja. Our Herp Department knows their stuff, and since we get so much interest in snakes, Judith is writing this informative blog series each week just for you!  If you’d like to read the series from the beginning, click here.

The Texas coral snake is our only native elapid. Rattlesnakes, copperheads, and cottonmouths are all pit vipers. The main differences are venom composition and fang structure. While the fangs of pit vipers fold up under the roof of the mouth, elapids have short fixed fangs. Elapid venom tends to have a lot of neurotoxins compared to most pitvipers.  There is nothing simple or black or white about venom so we won’t go there.  The coral snake is also the only venomous snake here that lays eggs instead of having live babies. 

Texas coral snake (Micrurus fulvius tener)

The coral snake has bands along its entire glossy body of red, yellow, and black.  Narrow yellow bands are between the alternating red and black rings.  The red rings are mottled with black.  The head and tail are black and yellow only.  The head is small and indistinct from the body.  The eyes are so dark you can hardly see them against the black head.  This is a small slender snake, averaging about 2 feet as an adult and about as big around as a pencil.
Coral snakes like mixed hardwood and pine forests.  They are very shy and secretive and usually stay hidden in leaf litter, rotten logs, etc.  If escape does not work, a coral snake will often suddenly push part of its body against the threat.  It may also flatten the last part of the body and raise and wave the tail along with hiding its head within its coils.

Coral snakes may be active at any time of day depending on temperature and other conditions.  3-8 elongated white eggs are laid in the summer and hatch about 2 months later.  Babies are about 6 inches long and look the same as adults.

The main prey of the coral snake is other snakes including a lot of earth snakes and Dekay’s snakes (covered in blogs #1 and #2 of this series).  They will also eat slender lizards such as ground skinks.
There is another native snake with the same colors as the coral snake though they look quite different. The old rhyme of “Red and yellow, kill a fellow; red and black, venom lack” works well to tell apart the coral snake and the Louisiana milk snake (below).

Louisiana milk snake (Lampropeltis triangulum amaura)

This snakes gets much larger, is dull compared to the coral snake, has light white/beige mottling on its snout, and the red and black bands on the body are the ones that touch.  While that rhyme works well here at home, do not try to use it south of the border-it doesn’t work there.  There are many other kinds of coral snakes that look completely different.  While the venom of the coral snake is potentially quite dangerous, these snakes are in general very shy and inoffensive. Almost all bites occur when someone grabs one or tries to kill it, meaning it usually takes some personal effort to be bitten by one.  If you leave them alone they will leave you alone.

See you right back here next week for another installment in this great Snake Series!

For more information on Texassnakes, Judith has reccomended these two resources: and  The Field Guide to TX Snakes written by James Dixon and former Houston Zoo director John Werler.

Meet The Cottonmouth Snake

This is the next in a series on snakes that’s being written for you by The Houston Zoo’s Herpetology Department Supervisor, Judith Bryja. Our Herp Department knows their stuff, and since we get so much interest in snakes, Judith is writing this informative blog series each week just for you!  If you’d like to read the series from the beginning, click here.

Our featured snake for this week is the water moccasin a.k.a. the cottonmouth. 

This is the most notorious venomous snake in this area. They are venomous pitvipers just like copperheads and rattlesnakes.  They are variable in color and pattern and many other species of snake are mistaken for them.  Black, brown, or olive with or without markings describe this snake.  Babies have distinct markings (and a bright yellow tail tip just like the copperhead) but these fade with age so that some old animals don’t show any pattern at all. 

Western cottonmouth (Agkistrodon piscivorus leucostoma)


These are stout bodied snakes; the body is thick and they have short tails (the body hardly tapers and then all of a sudden there’s the tail).  The belly is dark brown or black.  Usually visible is a dark cheek stripe.  And we can’t leave out the reason for the moniker of cottonmouth.  The inside of the mouth is white and they don’t hesitate to show it to you when you come across one. 

Average adult size of this snake is 24-36 inches despite the stories you’ve probably heard.  The biggest one ever recorded was right about 5 feet. 

Cottonmouths can be found near just about any kind of aquatic habitat such as swamps, marshes, and streams.  When swimming, much of the body is visible above the water line and the head is held up high.  They are opportunistic and not super picky eaters.  The bulk of their diet is frogs, fish, and salamanders though they are also known to take mammals and birds.  Mating takes place in the spring and live babies are born in the fall.   

A very light uniformly colored cottonmouth (Agkistrodon piscivorus leucostoma)

If they have a convenient escape route when approached, these snakes will usually take it.  If not however, these guys get quite intimidating.  They will look up at you and strike a pose as in the first photo in this blog, the tail is twitched back and forth like a cat or rapidly vibrated against the ground, and the mouth is held wide open showing off the brilliant white interior.  They are also happy to strike if you get too close.   A western cottonmouth can be seen on display in the Reptile/Amphibian building.

Juvenile cottonmouth (Agkistrodon piscivorus leucostoma)

 Are you coming back for another installment in this cool Snake Series? Yep, we hope you are!

For more information on Texassnakes, Judith has reccomended these two resources: and  The Field Guide to TX Snakes written by James Dixon and former Houston Zoo director John Werler.

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