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

The value of UVB light to heliothermic (basking) reptiles has long been known.  Less well understood is the role of UVA light and how, in our attempts to provide reptile pets with light and heat, we often wind up affecting another of their critical needs: adequate air flow.

Today I’d like to provide some suggestions as to how we might effectively manage these three elements to provide our reptiles with healthy environments.

Ultraviolet B Light (UVB)

By basking under UVB light rays with a wavelength of 290-315 nanometers, many lizards, turtles and crocodilians synthesize Vitamin D3 in their skin.  Vitamin D3 allows these animals to utilize dietary calcium.  Without D3, dietary calcium is not metabolized and metabolic bone disease soon sets in.  Snakes, aquatic turtles and certain others can make use of dietary Vitamin D, but most species that bask must synthesize it in their skin.

While mercury vapor bulbs , the Zoo med 10.0 bulb and some others provide useful levels of UVB, nothing can replace natural sunlight. Measurements taken outdoors in the tropics (northern Australia) yield UVB readings of 450 microwatts/sq. centimeter…most florescent bulbs emit 13-35 mw/sq. cm.

Recent research indicates that chameleons and perhaps other reptiles can sense UVB levels (please see article below) and so may bask longer in captivity, but it is essential that we use a UVB meter to measure our bulbs’ output.

Ultraviolet A Light (UVA)

Recent research has shown that UVA radiation (wavelength 320-400 nanometers) promotes natural behavior, reproduction and the establishment of circadian rhythms (internal “clocks”).  UVA also affects how and what reptiles see.   Female desert iguanas, for example, cannot see the chemical trails laid down by males in the absence of UVA, and hence rarely reproduce unless exposed to it.

UVA bulbs are available, but we know little of the actual needs of most reptiles.

Air Circulation

Indoor glass terrariums with screen tops serve well in rendering heat and UV radiation readily available.  However, air circulation in such situations is restricted, creating an unhealthy situation for many animals.

Amphibians, chameleons and arboreal snakes from humid environments (i.e. green tree pythons and emerald tree boas) present special challenges.  The humidity they require can be supplied by foggers or via misting, but severe health issues arise if air flow is limited.  I still have a letter written to me in 1967 by famed herpetologist Wayne King, regarding blister disease in a northern watersnake.  Despite being highly aquatic, my pet needed air circulation and a dry basking site in order to remain healthy.

Screen Cages and Terrarium Top Enclosures

Screen cages  provide an ideal way to address each of the aforementioned concerns.  While glass and plastic filter out beneficial UV radiation, screen cages allow UVB and UVA to enter.  Being well-ventilated, they also offer excellent air circulation.

Screen cages can, if protected from predators, be utilized as permanent outdoor enclosures.  Even the largest models are very light in weight, and may be carried outdoors to provide periodic sunning opportunities.  In some cases, the cages can even be positioned in an open window…my friend does this for his water dragon, which is often seen perched in the sun 14 floors above West 23^rd Street in Manhattan!

Screen terrarium top enclosures  added onto glass terrariums present a unique solution to those with limited space.

Further Reading

Please see my article Chameleon Behavior is Affected by Vitamin D3 Needs  for insights into emerging research on reptile basking behaviors.

Image referenced from Wikipedia and originally posted by JialiangGao

Southeast Asia’s bizarre tentacled snake (Erpeton tentaculatum) is a long-time favorite of mine and I’ve kept and bred a great many in zoo collections over the years.  Despite watching them intently for so long, I’ve never quite been able to figure out how they manage to so effectively catch fast-moving fishes while striking out in a direction that seems designed to insure that they miss the intended target.

A Unique Escape Strategy

Recently published (Vanderbilt University, Tennessee: June, 2009) research has provided the answer.  Many fishes, it seems, utilize an escape maneuver known as the C-Start.  Upon sensing danger, the body contorts into a “C” shape, the tail is flicked and the fish, in a millisecond, darts away.

Exploiting the Defensive Maneuver

Tentacled snakes, anchored to submerged objects by their tails and resembling water-logged roots, lie in wait for passing fishes.  The snake always holds itself in a very distinctive “J” shaped position.  As a fish approaches, the snake “feints” with its body by sending a ripple of water towards the fish.  This incites the C-Start reaction and propels the fish directly toward the snake’s jaws.

Once initiated, the C-Start maneuver cannot be altered, so the hapless fish is doomed.  The snake’s “J” position allows it to strike not at the fish but rather where the fish will be once it flees.  What’s more, the strike nearly always catches the fish in the head region, assisting the snake in swallowing its slippery prey.

Further Reading

To learn more about the natural history and captive care of tentacled snakes, please see my article The Tentacled Snake, an Unusual Pet Serpent .

Among the world’s 10,000 or so millipede species we find a number of common as well as extremely specialized creatures, many of which make interesting terrarium subjects. The commonly available giant African millipede (Achispirospreptus gigas) is, at nearly 11 inches long, a very impressive beast that may reach 10 years of age and reproduce in captivity.  A number of other species appear in the trade from time to time as well…while the largest hail from the tropics, several millipedes native to the USA, such as Narceus americanus, are also quite large, and some are brilliantly colored.

The following information applies mainly to the African giant millipede, but also holds true for many of the other large African and Southeast Asian species that enter the trade.

A Simple but Effective Feeding Technique

Judging from the questions I’ve received from millipede enthusiasts over the years, a poor diet is the main reason that these creatures sometimes fail to thrive in captivity.

One trick that I have found particularly useful is to add a handful of a reptile calcium supplement, such as Reptocal to the substrate in a millipede terrarium.  Millipedes consume a good deal of leaf litter and, in some cases, rotting wood, and will ingest calcium mixed into the litter as well.  They seem to require quite a bit of calcium, especially when molting and forming a new exoskeleton, so I powder their other food with it also.

Leaf Litter and Wood

In order to provide as much dietary variety as possible, I always keep millipedes in a substrate comprised of at least 50% leaf litter (oak, ash and other native species) and well-rotted (soft and crumbly) wood collected locally.  This is replaced periodically as the millipedes tunnel through and consume the nutrients therein.

The balance of the substrate consists of coconut husk  and top soil.  Millipedes need to burrow, especially when laying eggs and molting, so keep at least 4-6 inches of substrate available to them.  A layer of gravel at the terrarium’s bottom will assist in drainage.

Dietary Variety

As we know little about the actual nutritional needs of any millipedes, I strive to provide as much variety as possible.  This seems a useful technique, as I’ve been able to breed several tropical and native species over the years, and have kept individual millipedes for over a decade.  Please check out Part II of this article for salad recipes and other foods that have served me well over the years when keeping millipedes.

Further Reading

Please see my article Millipede Emergency for a unique twist to millipede keeping.

Since their arrival in the US in the early 1980’s, White’s treefrogs (Litoria caerulea) have become one of the most popularly kept of all frogs.  Although longevities of 25 years are known, captive breeding remains surprisingly uncommon.  The white-lipped treefrog (Litoria infrafrenata), a large, attractive relative, is also infrequently bred by hobbyists.  Considering how little we know about amphibian reproduction, and the precarious state of many species, I suggest that interested frog-keepers hone their breeding skills on the relatively robust White’s treefrog.

Distinguishing the Sexes

White’s treefrogs reach sexual maturity by age 2.  Mature males are smaller than females, have loose, slightly dark skin about their throats and, when in breeding condition, sport thickened nuptial pads (used to grasp females during amplexus) on their thumbs.  Only the males call.

The Dormancy Period

A cooling off period, preferably in late winter, is critical to breeding success. Cease feeding the frogs 7-10 days prior to the cooling period and place them into an aquarium furnished with a substrate of moist sphagnum moss and cork bark shelters.

Gradually reduce the temperature to 65 F during the night (a basement is ideal) and 68 F during the day (use a small incandescent bulb to raise the temperature) and maintain this schedule for 4 weeks.  Thereafter, hold the temperature at 65 F round-the-clock for an additional 2 weeks.  The terrarium should be kept in the dark throughout this time, and the frogs should not be fed.

Preparing the Frogs for Breeding

After the 6 week “winter”, warm the frogs to 80 F over a 2 week period, and feed them heavily for 3-4 weeks.  Novel prey animals, such as wild-caught or canned insects, should be offered at this time.

Thereafter, move the frogs into an aquarium filled with 4 inches water and provisioned with live floating plants (i.e. water hyacinth, water lettuce, pothos) and basking platforms.  Use an aquarium heater  to warm the water to 82-85F, and add a florescent bulb to encourage plant and algae growth.  I recommend the Reptisun 2.0  bulb, as its UVB output is ideal for amphibians and plants…avoid strong reptile UVB bulbs.

Using a small submersible water pump, create artificial rain by pumping water into a perforated plastic container or PVC tube placed on the terrarium’s screen cover.  Allow the “rain” to fall for 6-8 hours nightly, beginning at dusk.  This step is vital in inducing spawning, and will usually result in reproduction within a week or so.

The Eggs

If all goes well, you will one morning find yourself in possession of thousands of eggs.  It is wise to plan ahead and arrange for friends or nature centers to take some of the eggs, as crowded conditions can cause the loss of the entire clutch.  Remove the adults and install an air pump driven sponge filter that provides mild water circulation.

In contrast to what is commonly recommended for some other frogs, I suggest raising White’s treefrog tadpoles in plant and algae filled aquariums as opposed to bare, sterile containers.  I have even added green pond water to several tanks with good results.

Further Reading

You can read about White’s treefrog breeding in the wild, and hear recordings of the males’ calls, at http://magneticisland.s4space.com.au/L.caerulea.html.

Please see Parts I and II of this article for information on growing terrestrial and aquatic food plants for reptiles and amphibians.

Aquatic Invertebrates

A startling variety of aquatic invertebrates will likely establish themselves in almost any body of standing water, be it a backyard pond or a container of water on a fire escape in the heart of a busy city (the adults of most aquatic insects are winged, and quickly locate new breeding sites).  Ranging in size from tiny Daphnia to quite large dragonfly nymphs, all are fine food items for insectivorous herps, and make wonderful aquarium subjects as well.

You can also use an outdoor pond to breed snails, guppies, crayfish and other useful food animals.

Terrestrial Invertebrates

Your reptile garden will, in addition, attract numerous terrestrial insects.  All are interesting to observe and many can be collected to feed to your collection (a Bug Napper Insect Trap situated near a garden will provide a great nightly haul).

Flowering gardens are also important as feeding sites for pollinating insects, many of which are in serious decline.  Over 80% of the world’s plants and 90% of US food crops rely upon insect pollinators.

A Bonus…Observing Garden Visitors

You are sure to come across some interesting finds, as invertebrate diversity, even in temperate areas, is astounding.

An acre of Pennsylvania soil, for example, can host 425 million individual invertebrates (including 2 million tasty earthworms!) and New York State is home to 4,125 species of beetles.  Over 11,000 different types of moths may be found in the USA, and new species are constantly being uncovered in the most unlikely of places…be sure to check those captured in your Bug Napper carefully before popping them into a terrarium!

Further Reading

The leaf fall that gathers below your plants and trees will quickly become populated by an unbelievable assortment of millipedes, springtails, sow bugs, beetles and other creatures.  Many of these, especially the smaller invertebrates, are vital foods for tiny poison frogs and other small herps.  For information on collecting and using this free food source, please see my article on Leaf Litter Invertebrates.

Image referenced from Wikipedia and originally posted by Alvesgaspar