That Reptile Blog – Reptile, Amphibian and Exotic Pet Care and Information

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.

 

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.

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

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.

 

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.

 

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

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.