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

Reptile and amphibian keepers are fortunate to have at our disposal a huge array of substrates, many of which are formulated for specific animals (burrowing frogs, large snakes).  However, there are still a few situations, usually involving especially sensitive species, where we may need to improvise.  Today I’d like to relate my experiences using “alternative” substrates for desert-dwelling reptiles and hatchling tortoises.  I have long used both while working with animals in zoos, but have noticed that neither is well-known in the pet trade.

The Immune Systems of Desert Dwellers  

Reptiles hailing from desert and semi-desert habitats are often very sensitive to molds and fungi.  Having evolved in unique, relatively pathogen-free environments, their immune systems are usually unable to adapt to attack by microorganisms commonly encountered in captivity.

Potential Problems with Sand

Many of the substrates traditionally used for such creatures, including most types of sand, harbor molds and fungi when damp.  Although not a problem (in limited-contact situations) for all desert animals, some are especially sensitive and quickly succumb to skin and respiratory infections.

Chief among these in my experience are Egyptian tortoises (Testudo kleimanni), padloper tortoises (Homopus signatus, the world’s smallest tortoise) and several of the whip-tailed lizards (Cnemidophorus spp.).

Using Oyster Shell

Oyster shell (available at garden and poultry supply stores) does not support the growth of fungi or mold, is benign when swallowed in small amounts, and can be easily spot-cleaned and discarded when fouled.  I cannot recall any skin or respiratory problems in desert-dwelling reptiles maintained on oyster shell.

 

Further Reading

You can read more about fungal and other respiratory ailments in tortoises at: http://www.azeah.com/Care-Sheets.asp?id=125

Tortoise photo referenced from Wikipedia and originally posted by Stefano Alcini.

Having been chased by a Kodiak bear, confronted by an escaped king cobra and otherwise molested by scores of formidable animals, I felt relatively secure in accepting responsibility for a group of arboreal South American millipedes entrusted to me by colleague about to travel abroad. A primatologist, she had observed capuchin monkeys to rub millipedes over their bodies, and was investigating the situation (I, on the other hand, have always been far more interested in millipedes than monkeys!).

Deadly Millipedes?

A week after her departure, another coworker phoned me at 4 AM, frantically speaking in the rapid fire Spanish typical of her native Venezuela…and which I have great difficulty in grasping at 4 PM, much less 4 AM! Eventually I learned that 3 elderly millipede researchers had passed away recently, and that preliminary evidence indicated that cyanide poisoning, courtesy of the millipedes’ defensive chemicals, was suspected. I was warned against handling the millipedes (which I had been doing for weeks!) or putting them near my face (which I do not do with any creature).

The deaths turned out to be coincidental and unrelated to millipedes, but the incident led to a good deal of research into the defensive chemicals produced by these popular terrarium pets. It seems that millipede toxins are a very unique and complicated group of compounds.

Exploiting Millipede Toxins

Interestingly, a number of species of frogs and monkeys harness these chemical weapons for their own use. Although lagging behind such creatures by a few million years, humans are also getting into the act, and we may soon be putting millipede secretions to medicinal use.

An Amazing Coincidence!!!

The incident I related above, concerning myself and the millipedes, transpired approximately 8-10 years ago. I’m not sure why I decided to write about it today, but I’ve had millipede articles on my mind for some time, and thought this would make a nice introduction to the topic.

After writing this article I searched for a reference to add, for those readers who wished to learn more. You can imagine my shock when I discovered that today’s NY Times (28 June 2009) carries an article about the very same monkeys, people and millipedes involved in my story!!!

To read the entire article, please go to http://www.nytimes.com/2000/12/05/science/05MONK.html?pagewanted=print.

Next time I’ll explore the nature of these defensive weapons and the uses that monkeys, frogs and people are finding for them. Following that we’ll take a look at keeping and breeding millipedes in captivity.

Image referenced from Wikipedia and originally posted by Prashanthns.

 

I received my first “Uncle Milton’s Ant Farm” at about age 6, and instantly realized that therein lay the keys to a world previously closed to me (incidentally, Uncle Milton’s Ant Farms are still on the market, complete with decorative green plastic farmhouses and a coupon for live ants!).  My interest in subterranean creatures soared, and I soon had farms stocked not only ants but also earthworms, beetle grubs and even mole crickets.

From Ants to Gerbils

My introduction to using ant-farm type enclosures for other animals came a few years later.  Mongolian gerbils had just entered the US pet trade, and I became fascinated with these social, burrowing rodents.

In preparation for receiving my first pair of gerbils, I read all that I could get my hands on.  This amounted to a single care pamphlet – but within its pages I read about a burrow system designed by the author.  By inverting one aquarium (bottom side up) inside a larger tank, the author encouraged the rodents to burrow along the front glass.  When they emerged, the active little fellows had use of the entire large enclosure, since the bottom of the inverted tank, covered with soil, served as a substrate.

Fossorial Herps and Invertebrates

Starting with my own collection and refining the system while working at the Bronx and Staten Island Zoos, I found the basic premise widely applicable to fossorial (burrowing) creatures of all types.  The burrows are essentially sandwiched between 2 panes of glass, allowing for easy viewing through one side.

I especially like this set-up for eastern spadefoot toads, marbled salamanders, Australian water-holding frogs and fossorial tarantulas, scorpions and centipedes.  In the terrariums and zoo exhibits typically used for such creatures we are fortunate to get an occasional glimpse of anything approaching natural behavior.  However, displayed as described above, they reveal a great deal about their fascinating life histories.

Refinements

Tarantulas often line terrarium glass with silk, thwarting our efforts to observe them.  However, they are less likely to do this if you cover the outside of the glass (that portion that fronts along the burrow) with black paper or cardboard, hinged at the top with tape.  If you lift this gently, the spider may remain on view.

This technique is also useful for other high-strung creatures.  At Tokyo’s Ueno Zoo, I noticed that fossorial voles were very nicely displayed in an ant-farm type enclosure.  A hinged wooden door was used in place of the black paper described above, allowing visitors a peek at the rodents going about their business below-ground.  I have also successfully used the tank-within-a-tank system in zoo exhibits for dune mole rats and African pygmy mice.

Useful Products

Many burrowing animals are not only shy but nocturnal as well.  A night-viewing bulb  will help in observing them.

Substrate composition will vary, depending upon the species that you keep.  Two very useful products for burrowing animals are R Zilla Coconut Husk  and Zoo Med Repti Sand. Experiment with moisture levels until you have a composition that supports permanent burrow systems.

Further Reading

Some years ago I acquired a group of Australian water-holding frogs (Cyclorana platycephala) and found them to be among the amphibian world’s most accomplished burrowers.  To learn more about these amazing creatures, please see http://animals.jrank.org/pages/181/Amero-Australian-Treefrogs-Hylidae-WATER-HOLDING-FROG-Cyclorana-platycephala-SPECIES-ACCOUNTS.html.

 

Water holding Frog image referenced from Wikipedia and originally posted by Haplochromis

Tortoises are among the most highly-desired of reptile pets, but their care is fraught with difficulties, and captive death rates remain surprisingly high.  The plucky Russian, Horsefield’s or Central Asian tortoise (Testudo horsfieldi) is often promulgated as an ideal “first tortoise”.

A Cold Hearty Tortoise?

In many regards this is true.  Unlike most of its relatives, the little Russian tortoise is quite cold hearty.  Its range (three subspecies) extends from the southeastern coast of the Caspian Sea through Kazakhstan to western China and south to Iran, and encompasses some very cold regions.  Tortoises living in the north may be active for a mere three months each year.

Living on Little

The Russian tortoise’s adaptation to a Spartan diet also suits it to captivity. Generally, it subsists upon dry grasses, with only limited access to flowers, herbaceous plants and fruits.   Individuals in some populations rarely encounter standing water.

Size

Size also recommends the Russian tortoise as a pet…it tops out at 8.8 inches, and many are considerably smaller.

Nearly round in profile, the Russian tortoise is pleasantly colored in light to yellowish brown, and patterned with dark blotches.

Some Cautions

For all of the above reasons, it is a Russian tortoise that is often taken home by those new to tortoise-keeping.  Unfortunately, thousands perish each year, often because their owners were initially supplied with misleading advice.

Space and Cage Style

Despite their small size, Russian tortoises are far more active than other reptiles…even the largest of glass aquariums is inadequate.  You must think in terms of a 4-6’ x 4-6’ enclosure.

Glass aquariums, unless ventilated via fan, also do not provide sufficient air flow.  As humidity rises, respiratory problems are a near certainty.

Ideally, these tortoises should be housed outdoors throughout the warmer months.  Outdoor bird aviaries work well, although you may need to install an opaque, plastic barrier along the lower wall edge to prevent climbing. If you must keep your tortoise indoors, a custom-build enclosure is needed (please write in for details).

Environmental Conditions

Indoors or out, Russian tortoises require deep, dry substrates – grass and moist soil will not do.  A mix of sandy soil and oyster shell is ideal.  If unable to construct nighttime sleeping pallets (excavations), Russian tortoises become stressed and subject to dehydration-related disorders.

Pros and Cons

With proper care, the Russian tortoise can indeed be a most responsive and long-lived pet.  However, they are by no means animals to be purchased lightly.  Please consider your abilities carefully, and write in if you have any questions whatsoever.

I hesitate to discourage responsible people from keeping these fine animals…tortoises ranging from the tiny South African padloper to the massive giants of Aldabra and the Galapagos Islands have provided me with some of my most memorable herp-keeping experiences.  Yet I hesitate to paint too rosy a picture.  Please write in regarding your specific situation, and I’ll do my best to advise you appropriately.

The Russian tortoise owner must also take into consideration those other factors critical to the care of all tortoises – diet, UVA/UVB exposure, humidity levels, etc.. We’ll take a look at these and other subjects in future articles.

Further Reading

Please check out A Complete Guide to Russian Tortoises  in our Reptile Books Department.

An interesting article detailing the natural history of Russian tortoises in a harsh environment is published in the journal Ecography at

http://www.bio.usyd.edu.au/Shinelab/staff/xavier/ecography2003.pdf

Please see Part I of this article for more on bent-toed geckos (Genus Cyrtodactylus; C. louisiadensis and C. irianjayaensis).

UVB and Calcium
Although nocturnal, assume that bent-toed geckos require UVB radiation (others in the genus seem prone to metabolic bone disease). As these lizards generally do not bask at very high temperatures, a fluorescent bulb is preferable. Among florescent models, the Zoo Med 10.0 Bulb  has been shown to consistently deliver the highest UVB output.

To cover all bases until we learn more, I suggest adding extra calcium (along with Vitamin D3) to all food offered. A high calcium supplement can easily be fashioned by mixing Reptivite and Zoo Med Repti Calcium  together in a 1:1 ratio. While this step has not specifically been proven necessary, it has served me well in similar situations.

Snails as a Calcium Source
Many arboreal geckos, Cyrtodactylus included, relish snails, and these seem to be an important source of calcium in the wild.

You can use small garden or aquarium snails, or smaller individuals of those species typically sold for human consumption (i.e. the grapevine snail, Helix pomatia). All can be rather easily reared at home, with the aquatic species being, in general, more prolific.

If you would like to raise your own snails, I suggest the large freshwater snails commonly sold as apple snails in pet stores. They are quite interesting in their own right, so don’t be surprised if you wind up paying them quite a bit of attention! Apple snails lay orange egg cases just above the water line; these are produced year-round, with more being laid as food intake increases. Apple snails feed ravenously, and do well on a diet of Spirulina disks and kale, romaine and other greens. They should also be provided with a piece of cuttlebone  (discard the metal holder provided for use with cage birds) as a calcium source. The young fall into the water upon hatching and grow rapidly.

Any of the small aquatic snails commonly found among aquarium plants can be bred and used as a food source as well.

Most terrestrial snails do not breed quite as rapidly as do apple snails, and temperate species need a cool period (a refrigerator works well) of 2-4 weeks at 38-40 F if they are to reproduce. Most feed readily upon tropical fish flakes, fruit, vegetables and cuttlebone.

Diet
Roaches stimulate most geckos to feed; many also respond with enthusiasm to moths, beetles and other wild caught insects. Please see my article on Raising Orange-Spotted Roaches  for more information.

I believe it to be very important to offer a variety of invertebrates to bent-toed geckos. If at all possible, try to collect local insects…the Zoo Med Bug Napper is very useful to have on hand.

Leave food in the terrarium overnight, and offer grubs, mealworms, wax worms and the like in cups suspended above ground as opposed to releasing them in the terrarium.

Further Reading
Providing reptiles with a varied diet is always important, but never more so than when dealing with bent-toed geckos and other little-studied species. Please see my article Collecting Live food for Reptiles and Amphibians for some tips on providing your lizard with wild-caught invertebrates.

Image referenced from Wikipedia and originally posted by W.A. Djatmiko. Image is NOT the Giant Bent-toed Gecko, but a related species, Cyrtodactylus marmoratus.