Hello, Frank Indiviglio here.  In 1705, a painting of a Pink-toed Tarantula consuming a hummingbird, published in Maria S. Merian’s book on the insects of Suriname, aroused so much attention (and horror!) that all New World tarantulas are commonly termed “bird-eating spiders” to this day.  It seems now that amphibian fanciers have their own dramatic bird-eater – Limnonectes megastomias, an aquatic frog recently described from 3 locations in Thailand. 

An Aquatic Ambush Predator

The newly discovered frog is largely aquatic, and apparently catches birds that come to the water’s edge to drink – quite a unique feeding strategy for a frog (I once saw a surprising film of African Side-necked Turtles catching doves in this manner). 

It is assisted in hunting by large (to 2 inch) “fangs” and a head that is disproportionately large for the body.  The fangs are not true teeth but rather extensions of the jawbone, known as odontoid processes.  The African Bullfrog and the South American Horned Frogs, known also for consuming vertebrates (and biting the hand that feeds them!), also sport odontoid processes.  Insects and other frogs have also been recorded as prey.

Same Bodies, Larger Heads – Sexual Dimorphism

Interestingly, the heads and “teeth” of male Bird-eating Frogs grow much larger than those of females, despite similar body sizes.  In certain other creatures (i.e. Barbour’s Map Turtles) this strategy allows the sexes to consume different diets and, it is theorized, avoid competition.  Researchers also believe that the enlarged teeth are used in combat, as many males carry scars.

So Much to Discover

There are over 50 species classified in the genus Limnonectes- the new “bird-eater” appears most closely related to the Kuhl’s or Large-Headed Frog, L. Kuhlii, but little is known of its natural history (the photo attached is of a Kuhl’s frog).  

This new species was first observed at the Sakaerat Environmental Research Station, an area that has been extensively studied for 40 years.  The fact that such a large and unique frog was able to remain undiscovered in this area illustrates the untold opportunities open to those who wish to get out and look around in just about any habitat – recently a new centipede was discovered in NYC’s Central Park!

Further Reading

Another toothed amphibian behemoth, the African Bullfrog, also takes quite large prey…to read about a most unusual frog meal, please see my article An Appetite for Cobras.

Please write in with your questions and comments. 

Thanks, until next time,

Frank Indiviglio

Limnonectes kuhlii image referenced from wikipedia and originally posted by W. Djatmiko

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Hello, Frank Indiviglio here.  Please see Part I of this article for background information on these snake-keepers’ favorites.  Garter Snakes and the closely related ribbon and water snakes usually make hardy captives, yet there are very few records of individuals surviving over 10 years.  I believe this may have to do with some of their unique environmental and dietary needs (I’ll cover temperature, light and diet in Part III of this article).

Natural vs. Captive Habitats

Nearly all garter and ribbon snakes favor swamps, wet meadows, pond edges and other moist habitats.  Oddly, however, they are very susceptible to skin infections (“blister disease”) when kept on damp substrates – even more so than snakes native to dry environments.  This holds true even for those that spend a great deal of time in the water, such as the Aquatic Garter Snake (Thamnophis couchi), the Ribbon Snake (T. sauritus) and the True Water Snakes (Nerodia sp.).

While all should be given water in which to soak, the substrate must remain dry.  The aforementioned species may be kept in semi-aquatic terrariums that allow for swimming, but they must have access to warm, dry basking sites (branches over water work well).  Shy specimens that will not bask should be moved into terrestrial situations with just a bowl of water available. 

Curing Blister Disease

A Northern Water Snake (Nerodia  sipedon) that I kept decades ago developed skin blisters after only 2 weeks of a largely aquatic existence.  I wrote to famed reptile man Wayne King, then curator of reptiles at the Bronx Zoo.  His advice to move the animal to a dry terrarium and provide a warm but sheltered basking site worked like a charm, and the snake’s skin condition cleared within 10 days.

Further Reading

An excellent article on the unique Aquatic Garter Snake, including habitat photos, is posted here.

Please write in with your questions and comments. 

Thanks, until next time,

Frank Indiviglio

Thamnophis proximus rubrilineatus image referenced from wikipedia and originally posted by Dawson

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Hello, Frank Indiviglio here.  Please see Part I of this article for general information concerning pet turtle shelters.  Today we’ll look at meeting the needs of a few specialists.

Aquatic Bottom Dwellers

Mata Mata Turtles (Chelus fimbriatus), Snapping Turtles (Chelydra serpentina), Alligator Snapping Turtles (Macroclemmys temmincki) and some other aquatic species prefer to burrow under plants or mud, and rarely use caves.  These turtles can easily be accommodated with Hagen Suction Cup-Equipped Plants.  By positioning the suction cups so that the plant just touches the bottom of the aquarium, you can create a naturalistic shelter …several plants used in together can accommodate quite large specimens.

Shallow Water/Swamp Dwellers

Bog Turtles (Clemmys muhlenbergi) and other retiring, shallow water species are usually most comfortable in heavily planted terrariums, with plenty of dead wood and moss available for hiding (please see photo).  These will readily utilize artificial plants as well.

Large Tortoises

That 150 pound Spurred Tortoise you’ve raised will need a custom built “house”, but for most large terrestrial turtles, you can also use the Hagen plants described above.  This actually suits tortoises quite well – in the wild most shelter within brush and under leaves, and not in “caves” per se.

Softshell Turtles

Softshell Turtles of all species are specialists, and do best when provided with fine sand in which to burrow.  Although excellent swimmers, they prefer to shelter below sand in shallow water, so that they can breathe by merely extending their necks to the surface.  Although sand complicates cleaning, most softshells fare poorly without it.

A Hundred Year Old Home

You can also create your own shelters…broken clay flower pots are an old standby.  The Common Musk Turtle (Sternotherus odoratus) pictured here has been with me for 40 years.  It is posing before its very unique cave – a 100 year old tile from the roof of the Bronx Zoo’s Reptile House!

Further Reading

The Eastern Spiny Softshell Turtle (Apalone spinifera spinifera) has specific habitat requirements in both captivity (please see above) and the wild, and is threatened throughout much of its range.  A comprehensive recovery plan containing interesting natural history notes is posted here.

Please write in with your questions and comments. 

Thanks, until next time,

Frank Indiviglio

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Hello, Frank Indiviglio here.  As autumn approaches I invariably receive questions from reptile owners whose pets have lost interest in food.  This most commonly occurs among Red Eared Sliders, Box and Painted Turtles, and other North American species, but may show up in lizards and snakes as well. 

Amphibians in general, and reptiles from regions without a seasonal change, are largely immune.  Bear in mind, however, that many species native to warm climates do experience a cool season – Bearded Dragons are a prime example, with certain populations hibernating in the wild.

Internal Controls on Behavior

It is common for native reptiles to slow down or stop feeding as the seasons change; often circadian rhythms (“internal clocks”) control this, and they will not feed even if kept warm. As long as the animals are otherwise in good health, they will be fine.  We are learning that reptiles have amazing abilities to alter their metabolisms to suit local conditions (please see article below).  Gharials (fish eating crocodilians) that I kept for 17 years at the Bronx Zoo went off feed annually, right in sync with wintertime in their native Pakistan.  Despite being kept at 86-92 F, and moving about daily, they lost almost no weight over their 3 month fasting period.

Keeping Turtles in Winter

Sliders, Snapping Turtles and others that refuse to feed as fall approaches can be kept in water that is at average room temperature (65-68F) or a bit higher over the winter.  Leave their UVB and basking lights on during the day, as they will continue to bask and move about.  You can offer food 1-2x per week, but they will likely not eat much.  Sick or stressed animals are another matter…please write in if you need advice.
Actually putting reptiles into true hibernation by lowering temperatures significantly is tricky, although often an important breeding stimulus.  Please write in if you need further information.

Future Research -Your Observations Needed

One thing I’ve noticed, and which I’d like to research further, is that wild-caught turtles, even if taken into captivity on the day of hatching, usually stop feeding in the winter, while captive-hatched animals of the same species feed throughout the year.  I would be very interested to hear from readers with similar or different experiences, thanks.

Further Reading

Please see Hibernation in Captive Bearded Dragons for specific information on these popular pets.

There is some amazing new information coming to light on snake metabolisms.  Please check out How Snakes Grow During Times of Food Deprivation.

Please write in with your questions and comments. 

Thanks, until next time,

Frank Indiviglio

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Hello, Frank Indiviglio here.  Classified within the family Iguanidae we find some of the most the world’s most popularly kept lizards, such as the Green Iguana (Iguana iguana) and the Chuckwalla (Sauromalus obesus).  As we will see, this diverse group is also populated by a number of oddities as well - rare island dwellers and lizards that dive into icy ocean waters to munch on seaweed, for example.

Species Diversity

The family Iguanidae originally contained over 700 species.  Recent work by taxonomists at the American Museum of Natural History has left the family with 36 species.

The 36 family members range from the United States south through Central America to Paraguay, and also inhabit the Galapagos Islands, West Indies and Fiji. 

Habitats

Most are terrestrial but a number are habitat specialists – i.e. the rock-dwelling Chuckwallas, the arboreal Green Iguana and the ocean-dwelling Marine Iguana (Amblyrhnchus cristatus).

All are diurnal, oviparous (egg-laying) and largely herbivorous, although some invertebrate prey is taken, especially by young animals.  Iguanids range in size from the 6 inch Desert Iguana to the 6.5 foot Green Iguana.

A Seagoing Iguana

The Marine Iguana must surely be the strangest lizard in the family, if not the world.  Indigenous to Ecuador’s Galapagos Islands, it feeds entirely on submerged marine algae (“seaweed”). 

The water surrounding these tropical islands is very cold, arising as it does from the Humboldt Current.  Under normal circumstances, a lizard entering such water would be rendered immobile within minutes. The Marine Iguana, however, slows its heart’s action to ½ of the normal rate when diving for food, thus limiting the amount of blood that circulates to its outer surfaces (where it would cool rapidly). 

After feeding, Marine Iguanas increase their heart rate and bask in the sun to warm up.  Other adaptations to a marine existence include nasal glands that expel seawater, partially webbed feet and a laterally compressed tail. 

The unique ticks that parasitize these ocean-going iguanas are hunted by brilliantly-colored crabs that clamber over the lizards’ bodies as they bask – one can only imagine what the first people to view such a scene might have thought!

Endangered Island Dwellers

All 8 species of Rhinoceros Iguana (Cyclura spp.) are limited to specific islands in the Caribbean, such as Cuba, Hispaniola, Jamaica, the Caymans and the Bahamas, and all are critically endangered.  Threats include hunting, habitat loss due to development and the grazing of feral goats, and predation by introduced dogs, cats and rats.  A number of zoos and governments are working on breeding, predator removal and reintroduction programs.

Several species of Rhinoceros Iguanas are also being bred in the pet trade, a fortunate circumstance which has helped to remove collecting pressure on wild populations.  Large and highly intelligent, captive Rhinoceros Iguanas require room-sized enclosures or outdoor aviary-type pens.

Feral, Pet and Food Trade Iguanas

The Green Iguana, long a pet trade staple despite its large size, is also an important food animal and is farmed throughout Latin America.  Escaped and released pets have established large breeding populations in southern Florida and on the Florida Keys. 

Native to Central and South America, several of the 14 species of Spiny-tailed Iguanas (Ctenosaura spp.)are common in the pet trade.  Escapees have established breeding populations in southern Florida and on several of the Florida Keys.

Further Reading

Information about each member of the family Iguanidae is posted at here.

In the future I’ll write about the captive care of individual Iguanids, including my favorites, the chuckwalla and desert iguana. Please write in with your questions and comments. 

Thanks,

Frank Indiviglio

Iguana in Mexico image referenced from wikipedia and originally posted by Keith Pomakis
Marine Iguanas image referenced from wikipedia and originally posted by Aquaimages

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Hello, Frank Indiviglio here.  Many amphibian websites tend to focus only on popularly kept species. Today I’ve compiled a list that addresses both common species and less well-known topics, such as amphibian health care and caecilian husbandry.

Salamanders and Newts

Caudata.org

This is the most comprehensive salamander-oriented website available.  I’m very impressed by the depth of interest and expertise evidenced by many of the members, who are always eager to help less-experienced hobbyists.  The forum discussions are always interesting and often break new ground, and the posted articles and care sheets are top notch.

Frogs and Toads

FrogForum.net

This informative website focuses on frogs other than the “attention-grabbing” poison frogs, although discussions concerning these are welcome.  It’s very refreshing to see that North American frogs and other under-represented groups are given the spotlight here.  Popular pet trade species such as White’s treefrogs, horned frogs and African bullfrogs, are also well covered.

The discussion forums show great promise, and the care sheets and natural history information supplied are of excellent quality.

Toadily Toads

I’ve never understood why toads have always been given so little attention by amphibian enthusiasts.  They exhibit an amazing diversity of forms and lifestyles and, on the whole, make much hardier and more responsive pets than do frogs.  The folks at ToadilyToads have taken great strides in remedying this unfortunate situation.

This website deals with all aspects of toad keeping and conservation, and provides some enjoyable activities as well.  I was especially happy to see that a good deal of attention is given to encouraging local species through backyard and similar habitat improvements.

Dart Den

This site is a great resource for those who keep or are interested in learning more about the ever-popular poison frogs and their relatives (“dart frogs”, Mantella spp., Dendrobates spp., etc.).  The discussion forums are quite active, and quality care and natural history information is available.

Caecilians

Gymnophiona.org

A real find for those interested in this little-studied but fascinating amphibian order, this site posts some of the most well-researched caecilian natural history information available.  The captive care details provided are a rare and valuable resource. 

Those interested in caecilian husbandry are well-situated to uncover volumes of new information on these unusual creatures; this website would serve well as a vehicle to publish such and to interact with others working with caecilians.

Health Care

Arizona Exotic Animal Hospital

I’ve long relied upon Dr. Kevin Wright, founder of the Arizona Exotic Animal Hospital, for answers to my most difficult pet and zoo animal health and husbandry questions. 

One of the world’s foremost exotic animal veterinarians and coauthor of the classic Amphibian Medicine and Captive Husbandry, Dr. Wright has posted a variety of much-needed amphibian care sheets on the hospital’s website.  Covering topics ranging from general emergencies to parasites, the information contained therein is an invaluable resource to the amphibian keeper.  Hobbyists whose interests extend beyond amphibians will find a wealth of information on the care of invertebrates, fishes, reptiles, birds and mammals as well…a real treasure trove!  For information on phone and email consultations with Dr. Wright, please click here.

Conservation

Amphibian Ark

Amphibian Ark was formed in response to the wave of amphibian extinctions occurring worldwide.  The organization coordinates both field and captive-management conservation programs in association with zoos, museums and researchers worldwide.

The Amphibian Ark Newsletter, posted monthly, is the internet’s most comprehensive collection of articles dealing with amphibian research, conservation and natural history.

Please write in with your questions and comments. 

Thanks, until next time,

 Frank Indiviglio

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Hello, Frank Indiviglio here.  Garter Snakes (Thamnophis ssp.) have long introduced aspiring herpetologists to snake-keeping and remain popular today.  A number of North America’s 30+ species are regularly available in the pet trade, and they remain the most commonly encountered free-living snakes in most areas.  Although often thought of as “beginner’s snakes”, I maintain that garters possess a unique combination of characteristics that render them fascinating additions to any private or public collection…they certainly have been a source of many of my most interesting observations.

Range

Garter Snakes of one or another species range from southern Canada to Central America, and reach their greatest diversity in the United States.

Those best suited to captivity are classified in the genus Thamnophis.  Along with ribbon and water snakes, this genus is placed within the subfamily Natricinae and the family Colubridae. 

Diet

Frogs, tadpoles, earthworms, salamanders, fishes and insects comprise the diets of most species.  Several are immune to the virulent skin toxins of amphibians such as California newts, which have caused human fatalities when ingested, and toxin-protected American toads are the primary food of plains garter snakes (T. radix) and others.  Some, such as the giant garter snake (T. couchi gigs), take rodents on occasion.

Attractive Attributes

A preference for fishes and earthworms, and a willingness to accept nonliving food items (garters sometimes consume road-killed frogs) greatly simplifies garter snake husbandry, and suits them well to those who prefer not to keep rodent-eating snakes. 

All bear live young and, when properly maintained, are likely to breed.  Although wild-caught snakes will bite and release musk when handled, they tame down readily…the most frequently kept species, the common garter snake (T. sirtalis), is especially docile. 

Eliciting Natural Behavior

What I especially favor about garter snakes is that they can be kept in planted, naturalistic terrariums – a difficult prospect where most other snakes are concerned. 

When kept so they reveal a great many of their natural behaviors – far more than is the case for large snakes maintained in bare enclosures.  A pair of garter snakes in a terrarium stocked with plants, branches, hideaways and a pool will provide you with insights into snake behavior that are not easy to come by otherwise.

A Wide Spectrum of Colors

While not subject to the intensive captive breeding efforts applied to other species, garter snakes are being kept by several breeders interested in developing unique color morphs.  Already, some spectacular results have been achieved, and more can be expected.  

This is not to say that selective breeding is necessary where garter snake colors are involved.  All are interestingly marked, and a great many species sport bright colors.  In fact, a subspecies of the common garter, known as the San Francisco garter snake (T. sirtalis tetrataenia), is one of the most beautiful snakes to be found anywhere.  Unfortunately, it is highly endangered and may not be kept in the USA, but by all means try to see it in zoo collection if possible. 

Individual variation among animals of the same species is the rule when it comes to garter snakes, so all sorts of interesting surprises await those who seek out these most fascinating reptiles.

Further Reading

Please see my article Keeping Snakes in Naturalistic Terrariums for some ideas concerning planted habitats for garter snakes.

To read about captive breeding and in situ conservation programs for the San Francisco garter snake, please see here.

Next time we’ll cover the basics of garter snake keeping, and look at a few interesting species in detail. 

Until then, please write in with your questions and comments. 

Thanks,

Frank Indiviglio

Texas Garter Snake image referenced from wikipedia and originally posted by Dawson

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Hello, Frank Indiviglio here.  Today’s update, while concerning an animal not suited as a pet (the American Alligator, Alligator mississippiensis) will I’m sure will be of interest to all who keep or study reptiles.  Scientists from the Savannah River Ecology Lab, working with alligators in Louisiana’s Rockefeller Wildlife Refuge, were surprised to find a high degree of mate fidelity in their study population.

Remaining Faithful Despite Choices

Writing in the October, 2009 issue of Molecular Ecology, the researchers explained that 70% of the female alligators they studied over a 10 year period mated with the same male each year.  This is the first time such behavior has been documented in any Crocodilian, and is rendered even more interesting by the fact that the refuge supports a very dense population of alligators, and females freely move through the territories of a great many males.

A Look Back in Time

Crocodilians are the sole surviving reptiles classified as Archosaurs, a group that includes the dinosaurs and which gave rise to the birds (some taxonomists argue that alligators are closely related to birds, and should be removed from the Class Reptilia).  It is hoped that this newly discovered alligator mating behavior will reveal something about the mating strategies of dinosaurs and the ancestors of modern day birds.

Working With Crocodilians

Crocodilians make poor pets, but, as you see from the accompanying photos, they can be exciting to work with in zoos (please be in touch if you’re considering a career in herpetology). 

A pair of Cuban crocodiles (Crocodylus rhombifer) under my care at the Bronx Zoo produced young together over a period spanning 40 years (the photo shows some of the “little ones” rushing to a meal) – but, unlike the Louisiana gators, they were housed together, without others of their kind, and so had little choice!

Further Reading

To read about how other research with alligators is granting us a peek at how dinosaurs may have lived, please see this piece.

Please write in with your questions and comments. 

Thanks, until next time,

Frank Indiviglio

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Hello, Frank Indiviglio here. Male Great Crested Newts undergo an amazing change in appearance during the breeding season.  In Part I of this article I introduced the natural history of this most beautiful newt, and discussed how to bring it into breeding condition.  I’ll cover breeding details and raising the larvae here.

Courtship and Egg Deposition

Breeding male newts tend to fight and, although severe damage is rarely inflicted, less dominant animals may become stressed and cease feeding. Courting males position themselves near females and appear to direct pheromones towards them with their tails. Females thus stimulated follow the males, push against their tails, and eventually pick up the spermatophore that the male has dropped.

Several hundred eggs are laid, each being individually attached to an aquatic plant. Females use their rear legs to bend a plant leaf around each egg – quite an ordeal, and well-worth watching!

Adults may consume eggs and so should be removed from the aquarium after egg-laying has been completed.  If prevented from returning to land after breeding, adult crested newts usually become quite stressed, thrashing about wildly.  Some subspecies, however, can be habituated to a more-or-less permanent aquatic existence.

Raising the Larvae

Crested Newt larvae generally hatch within a month and transform into the terrestrial phase within 3 months, at which point they average 2.4 inches in length. 

The larvae can be raised on chopped live blackworms, brine shrimp, daphnia and similar foods; new metamorphs can be offered 10 day old crickets, blackworms, termites and tiny sow bugs.  Sexual maturity occurs in approximately two years, at which time they will re-enter water to breed.

An Even More Flamboyant Relative

A close relative, Triturus vittatus ophryticus develops an incredibly high crest that starts at the nose area and ends at the tail. This species is now showing up in the pet trade, and can be bred in a similar manner to the Crested Newt.

Further Reading

Please see a book I’ve written, Newts and Salamanders, for more on the care and natural history of Crested Newts and their relatives.

You can learn more about the natural history of each newt in the genus Triturus here.

Please write in with your questions and comments. 

Thanks, until next time,

Frank Indiviglio

Larval Crested Newt image referenced from wikipedia and originally posted by Piet Spaans

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Hello, Frank Indiviglio here.  One of the most over-looked aspects of proper turtle care is the provision of a secure place to hide.  It makes sense that a hiding place would seem unnecessary – after all, turtles can simply withdraw into their shells when threatened.  However, it’s not that simple (as usual!).

Shelter Use in Nature and Captivity

Even though their shells are often hard, and offer excellent camouflage – imagine a box turtle on a forest floor or a leopard tortoise among brush – most turtles become quite stressed if denied a secure place to hide.  Even bold, long-term captives prefer a shelter, at least for sleeping. 

Particularly retiring species, such as mata mata, bog and Malayan snail-eating turtles, will often fail to thrive if kept in bare surroundings. Hatchlings, even of common snapping turtles and other aggressive species, are consumed by predators ranging from giant water bugs to herons…most are always “on guard” and will refuse to eat unless given ample cover.

Note: at 80+ pounds, the Common Snapper Pictured here is among the heaviest ever recorded. He is on exhibit at The Cold Spring Harbor Fish Hatchery, which houses an extensive collection of native reptiles and amphibians.

Useful Shelters for Terrestrial and Aquatic Turtles

The Zoo Med Turtle Hut, available in 5 sizes, suits nearly all land-dwelling turtles.  R Zilla Rock Dens sink, and so can be used on land or underwater (check that aquatic turtles cannot lodge themselves inside too tightly, and provide larger shelters as they grow).

The Zoo Med Turtle Dock can be set up to serve both as a basking platform and hideaway for aquatic turtles.  When used in shallow water, the sloping side, top of the platform and tank’s wall form a nice underwater cave readily used by young painted, spotted, mud and other turtles.

Next time we’ll take a look at a few species that have special needs, and I’ll add a note about an old turtle of mine that hides within a unique, very old “cave”.  Please write in with your questions and comments. 

Further Reading

For an interesting report on Eastern box turtle natural history, including the use of shelters in the wild, please look here.

Thanks, until next time,

Frank Indiviglio

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