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

Panther chameleons (Furcifer pardalis) carefully regulate exposure to sunlight in accordance with their Vitamin D3 levels, states an article published in the May/June issue of Physiological and Biochemical Zoology.

Nutrient Levels Affect Behavior

Chameleons with high Vitamin D3 levels (achieved through a diet of vitamin-supplemented crickets) limited their exposure to the sun, while those maintained on a vitamin-poor diet maximized basking time.  Further analysis showed that, as regarded individual Vitamin D3 levels, the lizards were “…as effective as mathematically possible” in achieving optimal sun exposure.  Vitamin D3 receptors in the brain are believed responsible for accessing vitamin needs and controlling basking behavior.

Basking or Diet?

I was most interested in this article because, although this point was not specifically addressed, it established that panther chameleons can be provided with adequate Vitamin D3 (at least in the short term) through dietary means.  I have long questioned my observations that certain reptiles, typically thought to be entirely dependent upon UVB radiation (basking) for Vitamin D synthesis, are none-the-less sometimes able to obtain sufficient Vitamin D3 from their diets (please see the article referenced below).

Some Cautions

Information of the type established by this research has a way of taking on a life of its own once spread via the internet, so a few words of caution are in order.

Please bear in mind that the Vitamin D and UVB needs of reptiles vary widely from species to species, and perhaps even within populations of the same species.  This research applies to a single species housed outdoors with access to full sunlight, and should not be used as other than a baseline for further experiments as regards other animals.

For now, it remains important to provide the heliothermic (basking) reptiles that you keep with an appropriate UVB bulb  (or natural sunlight) and to use vitamin/mineral supplements  judiciously.  This is a quite important topic, and one fraught with misinformation…please write with questions concerning individual reptiles.

Further Reading

For information on an outstanding UVB bulb and recent tests concerning its output, please see my article on Zoo Med UVB Lamps.

I have written about related experiences with day geckos and red-eared sliders… please see my article Has Anyone Observed This?  for further details.
Image referenced from Wikipedia and originally posted by Tom Junek.

Surinam toads are well known for their bizarre reproductive strategy (please see article below), unusual appearance, large size and unique habitats.  They make very interesting pets but, as most in the trade are wild-caught, present a few problems when first introduced into the aquarium.  Last time we took a look at establishing the new Surinam toad and helping it to make the adjustment to captive life (Surinam Toads (Pipa pipa) as Pets: Acclimating New Animals and Special Considerations).  Today I’ll take a look at their dietary needs.

A Live Food Specialist
Surinam toads will take live food (or food moved before them as if alive) only.  Their favorites are earthworms, blackworms and small fishes such as guppies, platys, swordtails, mollies, minnows and shiners.  Use goldfish no more than once each month, and vary the species fed as much as is possible.

Feeding Techniques and Cautions

You can leave fishes in with the frog, as it will likely feed only at night until it has acclimated.  Be sure to adjust the fishes to your aquarium’s water temperature (float bag for 20 minutes) so that the frogs do not contract Ick or other diseases that might be transmitted from stressed fishes (also, fishes are more likely to be consumed if they swim about normally).

When using earthworms, introduce them to the tank at night (foe newly acquired frogs).  Worms usually survive for 8 hours or so underwater, but add only 1 at first and make sure to remove it in the AM if uneaten.

As mentioned in Part I of this article, Surinam toads often swallow gravel while feeding and are best kept in bare-bottomed aquariums.  This is a special concern when using earthworms, which are taken right off the substrate, and blackworms, which burrow into it.  If you use substrate, avoid feeding blackworms and offer earthworms from a plastic feeding tong.

Introducing Canned Shrimp and Snails

Well-habituated Surinam toads will consume prawn and other non-living food items that are dropped so as to land directly in front of their mouths.  Start your frog off with live food, but after awhile try using canned shrimp and snails to provide dietary variety.

Composition of the Diet

I have kept and bred Surinam toads for a number of years using a diet comprised of approximately 75% fish (platys, guppies, mollies, minnows, shiners and occasional goldfish) and earthworms, with the balance of their food intake consisting of blackworms and shrimp.

Further Reading
Please see Breeding A Skin-Brooding Amphibian: the Surinam Toad (Pipa pipa)  to read about captive reproduction of this fascinating animal.

You can learn about the other aquatic species in the family to which this frog belongs (Pipidae) at

http://research.amnh.org/herpetology/amphibia/names.php?taxon=&family=pipidae&subfamily=&genus=&commname=&authority=&year=&geo=0&dist=&comment=.

Intestinal blockages and impactions (and related digestive ailments) most often occur when a pet reptile or amphibian ingests substrate along with food, although sometimes an inappropriate diet (i.e. one consisting largely of mealworms) is to blame.  My most unusual “blockage memory” involves a Cuban crocodile (Crocodylus rhombifer) under my care at the Bronx Zoo – the cause of her distress was found to be a large toy kangaroo that someone had thoughtlessly tossed into the exhibit!

Today I would like to present a few housing options for those species that seem particularly prone to consuming substrate (and anything else that gets in their way!).

“Does this happen in the wild”?

I am often questioned as to why animals do not suffer impactions in the wild, where they live on sand, moss and other materials that sometimes cause problems in captivity.  I believe the answer may lie in the slight differences that exist even between apparently similar substrates, the nature of the actual act of feeding, and differences in temperature, water, food intake and other factors that may affect the digestive system.

Overly-Enthusiastic Anacondas

Of course, animals may suffer impaction related injuries and death in the wild as well, but such goes largely unnoticed.  Although not impactions per se, I well recall finding a wild anaconda with a mouth injury suffered while trying to swallow a side-necked turtle (Podocnemis vogli), another that had a white-tailed deer, antlers and all, stuck in its throat, and a 5’10” yellow rat snake that tried to down a deer fawn on St. Catherine’s Island, off Georgia.

Substrates – Terrestrial Species

Among terrestrial species, we most commonly encounter impaction problems in African bullfrogs, horned frogs, tiger salamanders, lizards and tortoises.  Washable brown or green terrarium liners are an ideal choice for many such species.

Rabbit pellets have long been used by zoos as a substrate for tortoises and herbivorous lizards such as iguanas and chuckwallas.  Alfalfa based, they are fine if ingested along with food, and allow for the easy removal of feces.  Young tortoises that are kept on hard surfaces frequently become splay-legged, but such does not occur when pellets are used.

Further Reading

Please see our line of pet care books  for detailed information concerning substrates and diets for the animals that you keep.

A meal consisting of 17 young cobras would seem destined to cause an obstruction in any amphibian, even the massive African bullfrog…for the gut-busting details, please see my article An Appetite for Cobras.

Snakes are well known for their abilities to survive long fasts – up to 2 years in some cases – without ill effect.  Working with ball pythons, diamondback rattlesnakes and various rat snakes, researchers at the University of Arkansas have recently shown that fasting snakes slow their metabolisms by up to 80%, and yet continue to grow even when food is withheld for 6 months.

Ball Pythons, the Champion Fasters

The reduced rate of metabolism may explain why many snakes lose little weight when fasting.  Keyed by circadian rhythms (“internal clocks”), ball pythons are notoriously worrisome to pet keepers in this regard.  Most refuse food for long periods of time each year, yet remain in good condition…in fact, the longest-lived captive snake is believed to be a ball python that attained approximately 51 years of age at the Philadelphia Zoo.

Growing Without Eating

The fact that fasting snakes continue to grow suggests that large size confers important survival advantages.  If it did not, precious fat reserves would not be allocated to growth during food emergencies.

Evidence from Zoo Animals – the Gharial

Other reptiles and amphibians seem possessed of similar abilities, although confirmation is lacking.  Fish-eating crocodilians known as Indian gharials (Gavialis gangeticus) are one example.  A group of 8 at the Bronx Zoo ceased feeding in tune with the cool season in their native Pakistan each year for the nearly 20 years that they were under my care.  They fasted for 3 months, but continued to move about and bask, and lost little of their 400-600 pound bulk during that time.

Other Reptile Pets

Bearded dragons and temperate zone reptiles, such as box and Eastern painted turtles, often stop feeding during the winter, even if kept warm.  Bearded dragons usually become largely inactive, but turtles often move about normally.  Despite this apparent use of energy, they lose little if any weight.

Interestingly, at least for turtles, individuals born in captivity usually remain active during the winter if kept warm, while wild-caught specimens typically go off feed for 2-6 months.

Know Your Pets’ Needs

Providing your pet with proper care and a healthful diet is vital if it is to survive seasonal fasts.  Be sure to research the species that you keep carefully.  Please consult our reptile and amphibian care books, and don’t hesitate to write in with any questions you may have.

Further Reading

To learn more about hibernation and fasting periods, please see my article Hibernation in Bearded Dragons and other Reptiles and Amphibians.

In both captivity and nature, chameleons (Family Chamaeleonidae) stand alone – unique in so many ways, they are truly marvelous creatures to know and care for.  Today I would like to highlight a few unusual facts about these favored reptile pets.

Cultural Significance

Chameleons have long drawn our attention…in fact, their fossilized remains have been found alongside proto-human skeletons in Tanzania’s Olduvai Gorge.  Throughout Africa and Madagascar, they were regarded as somewhat mystical creatures, spying on people with their oddly-shaped eyes and reporting back to the deities about our (many!) shortcomings.

Fortunately, most of these beliefs also prohibited people from harming chameleons, and even today there are those who will risk a car accident rather than run one over.

Diversity

To date, 178 chameleon species have been described.  The smallest (pygmy leaf chameleons, Genus Brookesia), barely reach 1.5 inches in length while the family’s giant, Oustalet’s chameleon (Furcifer oustaleti) may be 30 inches or more from nose to tail tip.

Range and Habitats

Chameleons reach their greatest diversity in Madagascar.  They are also found in coastal North Africa, Africa south of the Sahara, along the western edge of the Middle East and the northern shores of the Mediterranean and in India and Sri Lanka.  Two species have been introduced to Mexico and the USA.

Often regarded as rainforest animals, chameleons have also adapted to dry forests, deserts, mountainous areas (where they endure snow) and city parks.

Moving About

Chameleons walk with a peculiar rocking motion, designed to help them blend in with swaying leaves and branches…indeed, some species are reluctant to move unless a slight breeze is blowing.

In most species, the tail may be held straight out for balance, curled around a branch as a “fifth hand” or coiled tightly during dominance displays.  Chameleons in free-fall have been observed to latch onto branches with the tail, halting their descent!

The Amazing Tongue

I could go on for a long time about chameleon tongues (fear not, I’ll contain myself!), as the surprise of first seeing one in action some 3 decades ago is still fresh in my mind.  It is certainly one of nature’s most spectacular food-gathering innovations, and completely unique to this magnificent group of lizards.

The tongue is hollow and fits over a cartilaginous (bone-like) tube known as the hyoid spike.  Depending upon the species, it may be slightly shorter than or greatly exceed the chameleon’s body in length.

The tongue is projected out towards prey by powerful accelerator muscles, and tendons attaching its base to the hyoid spike cushion the shock of impact.  Once the tongue is on its way, the chameleon can only control the length of the strike…aiming is done beforehand.

Surprisingly, the tongue’s tip is not only sticky but also very abrasive…both qualities, along with a skin flap that flips over the hapless victim, assure that few meals escape.

Retractor muscles pull the tongue back into place.  These are quite powerful, allowing the lizard to reel in prey weighing half as much as itself.  Armed in this manner, large chameleons take quite large insects, and even small birds and rodents on occasion.

Further Reading

Chameleon reproductive behavior is among the lizard-world’s most complex.  The abstract of an interesting research project is posted at http://cat.inist.fr/?aModele=afficheN&cpsidt=13694591.