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

In the past 20 or so years, the Crested Gecko (Correlophus/Rhacodactylus ciliatus), has gone from “presumed extinct” to being such a common pet that it may actually rival the Leopard Gecko in popularity! In addition to their interesting ways, innate “charm”, and extreme hardiness, these New Caledonian natives are also proving extremely easy to breed in captivity. Yet as I receive questions and review related articles and internet forums, it seems that some confusion exists on this topic. As Crested Geckos can provide a wonderful introduction to lizard breeding, today I’d like to review how best to get started. Also, since even un-mated females can produce eggs, and may suffer fatal impactions if not properly cared for when gravid, it is important for all owners to understand the basic principles of Crested Gecko reproduction.

 

Do I Have a Pair?

Crested Geckos show sexual dimorphism earlier than do many other lizards. By age 6 months or so, males will exhibit two easily-seen bulges near the cloaca, evidence of the internal male sex organs, or hemipenes. Small femoral and pre-anal pores may be visible even earlier. However, these may not be evident to folks who have not seen a good many mature males of this or related gecko species.

 

Unlike many lizards, Crested Gecko pairs may be housed together year-round. However, females that are not in breeding condition may be injured by males during unsuccessful copulation attempts. A bit of biting is normal at this time, but in small terrariums, or those lacking cover in the form of logs, plants, etc., injuries may occur.

 

Reproductive Age

Captive reptiles of many species often reach adult size faster than they might in the wild, but this does not always mean that breeding is possible or advisable.

 

Female Crested Geckos may become sexually mature by age 8 months or so, but it is best to forestall breeding until they are at least 1 – 1½ years old. Most successful long-term breeders use 40 grams as a safe weight for first-time breeding females. Males may be bred at the same or a slightly younger age, and are generally a bit lighter in weight than females.

 

Stimulating Reproduction

There doesn’t seem to be much in the way of detailed field studies of Crested Gecko reproduction. Judging from the temperature profile of their habitat, they most likely breed throughout New Caledonia’s warm season (November to April), when temperatures average 74-85 F.

 

Pets kept in temperate regions are usually stimulated to breed by local seasonal changes, beginning as the weather warms in spring and ceasing in autumn. In tropical and semi-tropical regions, well-fed females may continue to deposit eggs throughout the year. This can deplete calcium stores and otherwise impact long-term health. Cooling geckos to 68 F by day and 65 F by night, and reducing the daytime period to 10 hours, has been useful in stopping reproduction (however, this must be done gradually…please post below if you need further information).

 

Egg Deposition

Female Crested Geckos deposit clutches of 2 eggs. They usually produce multiple clutches, separated by approximately 30 days (but this number varies widely), each breeding season. Three to 5 clutches are generally considered as being typical for well-fed pets, but up to 10 have been reported.

 

In naturalistic terrariums, eggs may be secreted beneath the substrate at the base of plants, cork bark, or other cover. Gravid females are sometimes seen digging in several spots before deciding on a nest site.

 

Even if nesting sites are available in the terrarium, boxes or caves provisioned with a mix of moist sphagnum moss and soil should always be provided. This will simplify egg retrieval (if they are used, of course!) and will assure that there will always be a suitable nest site. Female geckos that cannot find a site to their liking may retain their eggs, which will eventually lead to a fatal infection (egg peritonitis).

 

Also, bear in mind that female Crested Geckos are able to store sperm. Those purchased as adults, or separated from a male, may still produce fertile eggs. As mentioned above, females that have not mated may also develop eggs, which must be deposited.

 

Stay alert for signs that a female may be egg-bound – lethargy, swollen abdomen, straining – and see a veterinarian if this occurs.

 

Egg Incubation

Crested Gecko eggs have been successfully incubated under a wide range of conditions. Here again they vary from many reptiles, as the eggs are extremely resilient and develop well at unusually-low (by lizard standards) temperatures.

 

As with most eggs, I favor course vermiculite or pearlite as an incubation medium. A water: substrate mix of 1:1 by weight works well.  The eggs may be incubated in an room with an appropriate temperature range, or a commercial reptile egg incubator.  Please see the article linked below for information on a simple method of calculating and tracking water content.

 

I haven’t found anything definitive concerning the effect of incubation temperatures on hatchling sex, but several anecdotal notes report that females predominate at temperatures of 77-80 F, males at 82 F, and mixed sexes at 70-76 F (the range most favored by experienced breeders). Incubation temperatures exceeding 84 F are said to kill the embryos.

 

Incubation periods range from 65-120 days, depending upon temperature and, in all likelihood, humidity levels and other factors.

 

Please post below for information on rearing young Crested Geckos.

 

Further Reading

Crested Gecko Substrates: Avoiding Impactions

New Caledonia Giant Gecko Care

It wasn’t so long ago that one had to search through many books to find a photo of a Crested Gecko (Correlophus ciliatus), and seeing a live individual in a zoo was impossible. In fact, the species was presumed extinct in the early 1990’s! Today, these bizarre New Caledonian natives are captive bred in huge numbers, and are popular with reptile keepers worldwide. However, while their husbandry needs are well-understood, and rather easy to meet, substrate choice can be problematic. Judging by questions I’ve received lately and feedback from my zookeeper colleagues, intestinal blockages (“impactions”) caused by substrate ingestion are an important concern.

 

Coconut Husk: Good and Bad Points

Coconut husk, the most commonly recommended Crested Gecko substrate, has a down side. I’ve had great success using this product at home and in zoo exhibits housing tarantulas, centipedes, millipedes, land crabs, beetles and other invertebrates. However, it is commonly swallowed by reptiles and amphibians during the course of feeding – more often, it seems, than occurs with other substrates. Coconut husk has been implicated in most of the Crested Gecko impactions I’ve recently been informed of.

 

As is the case for other sometimes troublesome substrates, many keepers use coconut husk for Crested Geckos without incident. How do we explain this? Through discussions with veterinarian colleagues at the Bronx Zoo, I’ve learned that there are many variables which affect the passage of foreign materials through the body. The nature of the diet (and, of course, the swallowed material), hydration levels, calcium intake (calcium assists in muscle contractions, which may be needed to expel ingested substrate), general health and vigor and many other factors are involved. It seems best to err on the side of caution.

 

My Top Pick for Naturalistic Terrariums

I favor a mix of topsoil and sphagnum moss as a substrate for Crested Geckos and for many other species as well. Perhaps because of the size or consistency of the moss strands, sphagnum seems rarely to be ingested. I’ve successfully kept a great many amphibians and some reptiles on sphagnum moss alone. Moss that is taken into the mouth is, in the incidents I’ve observed, easily expelled.

 

Soil seems like it “should be” troublesome, but that has not been my experience…I hope to look into the reasons for this in the future. I use soil collected from wooded, pesticide free areas, but you can also purchase bagged “organic” or “chemical-free” soil. Be sure to avoid products that contain white Styrofoam-like spacing material.

 

By using roughly 2 parts soil to 1 part sphagnum moss, you can achieve a mix that holds moisture well and does not easily become compacted. This also serves as an ideal planting medium for many live plants…and Crested Geckos truly come into their own in complex, well-planted terrariums.

 

I often establish colonies of sowbugs, millipedes, springtails and other leaf-litter invertebrates in terrariums with moist substrates; earthworms can also be used if temperatures are not too high. In addition to aerating the soil and consuming feces, dead leaves, and shed skin, sowbugs and others make healthful additions to the diets of many herps.

 

The Base Layer

Zoo Med Hydroballs, preferably but not necessarily covered by a layer of plastic screening, should be used as the base layer of your Crested Gecko terrarium. They are a bit more effective than the broken clay flower pots favored by us dinosaurs in assisting with drainage, preventing soil impaction, and maintaining high humidity levels.

 

Washable Terrarium Liners

Those seeking an extra measure of safety may wish to consider terrarium liners. Potted plants camouflaged with rocks or sphagnum moss can be used to create a naturalistic effect.

 

I’ll address the specifics of Crested Gecko care and breeding in the future; until then, please post any questions or observations below.

Hi, my name is Frank Indiviglio. I’m a herpetologist, zoologist, and book author, recently retired from a career spent at several zoos, aquariums, and museums, including over 20 years with the Bronx Zoo.

Please check out my posts on Twitter and Facebook.   Each day, I highlight breaking research, conservation news and interesting stories concerning just about every type of animal imaginable. I look forward to hearing about your interests and experiences as well, and will use them in articles when possible.

 

Please also post your questions and comments below…I’ll be sure to respond quickly. Thanks, until next time, Frank.

 

Further Reading

New Caledonian Giant Gecko Care

Choosing the Best Substrates for Reptiles and Amphibians

Leopard Geckos and Bearded Dragons have stellar reputations among lizard enthusiasts. In fact, they come as close to being perfect pets as any reptile can. However, there are major differences in their habits, activity levels and care needs, and it’s important to be aware of these when choosing a pet. When an animal is active, how much its care will cost, the space it needs and other factors will affect your pet-keeping experience and your new lizard’s quality of life. In the following article I’ll compare Leopard Geckos and Bearded Dragons in all relevant areas. Detailed care information is provided in the articles linked under “Further Reading”; as always, please also post any questions or observations you may have.

Reptile Handling
Most lizards are best considered as “hands-off” pets, but both Leopard Geckos and Bearded Dragons break this rule. Although individual personalities vary, both adapt well to gentle handling, and are not stressed by human contact.

Activity Levels
Neither is overly active, but both have fascinating behaviors that are well-worth watching for. Bearded Dragons are out and about by day, at which time they bask (their most common “activity”!), feed, and display to tank-mates.

Leopard Geckos, being nocturnal, are ideal for owners who are “night owls”. They will become active in a dimly lit room, or you can equip the terrarium with a black or red reptile night bulb (lizards do not sense the light produced by these bulbs). Leopard Geckos sometimes emerge during the day as well, especially if food is offered.

Life Span
A Leopard Gecko in the St. Louis Zoo’s collection lived for a record 28.6 years. The published longevity for a Bearded Dragon is 15 years, but there are unofficial reports of individuals approaching age 20.

Lizard Reproduction
Both species breed reliably, and a wide variety of color morphs are available. Please see the articles linked below for detailed information.

Cost
Bearded Dragons require larger terrariums and higher temperatures than do Leopard Geckos, and must be provided with a source of UVB radiation (Leopard Geckos and other nocturnal lizards get along fine without UVB bulbs). Therefore, Leopard Geckos are the less-expensive pet, in terms of supplies and electricity use.

Terrarium Size (single adult)
Leopard Gecko: 10-20 gallon (larger is preferable)
Bearded Dragon: 30 gallon

Temperature
Leopard Gecko: 72-85 F, with a basking site of 88 F
Bearded Dragon: 75-88 F, with a basking site of 95-110 F

Lizard Diet
Leopard Geckos are carnivorous. Young Bearded Dragons feed largely upon insects, adding plants to the diet as they mature.

Both require highly varied diets comprised of vitamin/mineral supplemented roaches, silkworms, crickets and other invertebrates. Bearded Dragons also need various greens and, perhaps, a high quality commercial food.  Mealworms and crickets alone, even if sprinkled with supplements, are not an adequate diet for either lizard. Please see the articles linked below for more information on diet.

Health Concerns (Pet and Pet Owner)
Intestinal impactions that result from the ingestion of sand and gravel are perhaps the most commonly-encountered health concern (both species). This can be avoided by the use of cage liners, or by feeding your lizards in large bowls, via tongs, or in a separate, bare-bottomed enclosure. Young lizards, being clumsy hunters, are more likely to swallow substrate than are adults.

Diseases related to poor nutrition are common among lizards maintained on crickets and mealworms alone, and in Bearded Dragons that do not receive adequate UVB exposure (Vitamin D3 is manufactured in the skin, in the presence of UVB). Both species sometimes refuse food in the winter, even if kept warm (please see this article for further information).

If a moist shelter is not available, Leopard Geckos sometimes retain the eyelid lining after shedding. Please see this article.

Atadenovirus infections are becoming increasingly common among Bearded Dragons. Unfortunately, the resulting “Wasting Disease” or “Star Gazing” is incurable. Please see this article for further information.

Salmonella bacteria, commonly present in reptile and amphibian digestive tracts, can cause severe illnesses in people. Handling an animal will not cause an infection, as the bacteria must be ingested. Salmonella infections are easy to avoid via the use of proper hygiene. Please speak with your family doctor concerning details, and feel free to post below if you would like links to useful resources.

 

Further Reading

Complete Guide to Bearded Dragon Care

Complete Guide to Leopard Gecko Care

Breeding Leopard Geckos

 

 

Among the world’s 52 species of neon-hued day geckos we find some of the most desirable of all lizard pets.  It’s not easy to stand out among such a spectacular group, but one species does so admirably – the magnificent Giant Day Gecko (Phelsuma grandis).  Although rarely seen outside of its native Madagascar until the mid-1980’s, this largest of all day geckos is now the hands-down favorite of many lizard enthusiasts.  I’m still asked to design zoo and museum exhibits for Giant Day Geckos, despite the fact that public institutions tend to avoid “pet trade species” – their beauty simply cannot be ignored.  The following information can also be applied to the care of 3 other large relatives that were once considered Giant Day Gecko subspecies – the Boehm’s Giant Day Gecko (P. madagascariensis boehmi), the Madagascar Day Gecko (P. m. madagascariensis) and Koch’s Giant Day Gecko (P. kochi).

 

Description

This stoutly-built lizard averages 9-10 inches in length, with large males reaching 12 inches.  Clad in brilliant green and bearing maroon to red head and orange dorsal markings, Giant Day Geckos must be seen to be truly appreciated.  Hobbyists have also developed an array of breath-taking color morphs.

 

Captive Gecko Behavior

All day geckos are best considered as animals to observe rather than handle.  Fast and alert, they will watch as you open the terrarium and may flee if possible; keep a net nearby to catch escapees.  Their tails snap off with the slightest provocation, and the delicate skin tears easily.  Although well-habituated individuals may accept food from tongs, these high-strung beauties are not for those seeking a hands-on pet.  However, the careful keeper will be rewarded with a range of interesting behaviors, regular reproduction and pets that may live into their 20’s.

 

Range and Habitat of the Giant Day

The Giant Day Gecko occurs across much of northern Madagascar, and on several small offshore islands.  Introduced populations are established on several of the Florida Keys (Little Torch, Plantation, Plantation and Big Pine).  It has also been sporadically reported in Florida’s Dade, Lee and Broward Counties, and on Hawaii.

 

Giant Day Geckos evolved in rainforests, but adapt well to some degree of human presence.  In both their native and introduced ranges, they can be seen on building walls and in well-vegetated gardens.

 

The Terrarium

Giant Day Geckos are highly arboreal and must have climbing opportunities.    A 30-55 gallon “high-style” tank will accommodate a pair or trio.  Always opt for the largest enclosure possible.

 

By virtue of their habits and need for security, all day geckos are ideally suited to life in terrariums provisioned with live plants; they will not thrive in bare enclosures.  Plants such as Pothos, Snake Plants and Philodendron will provide visual barriers and a sense of security.  Rolled cork bark and hollow bamboo sections make ideal hideaways and basking, perching, and egg-deposition sites; these should be arranged both horizontally and vertically.

 

Be sure to establish plenty of basking sites near heat and UVB bulbs, as dominant individuals may exclude others from these important areas.

 

Substrate

A mix of potting soil, cypress mulch and sphagnum moss is ideal.

 

Light

Giant Day Geckos should be provided with a source of Ultra-Violet B light.  Natural sunlight is best, but be aware that glass and plastic filter out UVB rays, and that fatal overheating can occur very quickly.  A daytime period of 12-14 hours should be maintained.

 

It appears that at least certain species can utilize dietary D3, and do well without access to UVB.  I’m familiar with one exhibit in which Giant and Standing’s Day Geckos have bred over several generations in the absence of UVB (please see photo of female Standing’s Day Gecko with well-developed calcium reserves, or “chalk sacs”).  However, there are a number of variables to consider…please see the article linked below for further information.

 

Heat

Ambient temperatures of 82-85 F, with a basking spot of 88-90 F, are ideal.  Nighttime temperatures can dip to 76-80 F.

 

Large enclosures will allow for the establishment of a thermal gradient (areas of different temperatures).  Thermal gradients, critical to good health, allow lizards to regulate their body temperature by moving between hot and cooler areas.

 

Incandescent bulbs should be used to maintain temperatures.  A ceramic heater or reptile night bulb can be employed after dark.

 

Humidity

These rainforest-adapted lizards do best when humidity levels range from 50-75%.  Their terrarium should be misted at least twice daily; a mister and hygrometer can be used to increase and monitor humidity if need be.

 

Gecko Companions

Males will fight savagely and should never be housed together. Females are also territorial, and must be watched carefully.  Pairs, trios (1 male, 2 females) and youngsters may co-exist in large enclosures, but be sure to check that all are able to feed and bask.

 

Feeding

A highly-varied diet is essential if you are to have success in keeping any day gecko species.  Crickets and mealworms alone, even if powdered with supplements, are not an adequate diet.

 

The diet should consist of roaches, sow bugs, crickets, butterworms, waxworms, cultured houseflies, silkworms and other commercially available invertebrates.  Feeders should be provided a healthful diet for several days prior to use.

 

If possible, also offer wild-caught insects (avoid pesticide-sprayed areas, and learn to identify stinging and toxic species; please see the articles linked below).  Moths, beetles, grasshoppers, tree crickets, earwigs, “smooth” caterpillars and a variety of others will be accepted. Your pets will definitely show greater enthusiasm towards novel foods!  The Bug Napper Insect Trap will simplify insect collection.

 

The natural diet also includes nectar, ripe fruit, pollen and sap. A mixture of fruit-based baby food, honey or molasses, liquid reptile vitamins, and ReptiCalcium with D3, mixed with enough water to achieve a syrupy consistency, should be offered 3 times weekly.  Experiment with the ingredients, and add a bit of over-ripe papaya, mango and banana on occasion.  Your geckos will prefer to take nectar from cups suspended above-ground.  Please see the article linked below for further information.

 

Important food supplements include Zoo Med ReptiCalcium with D3 or a similar product (most meals) and a vitamin supplement (i.e. ReptiVite) 2-3 times weekly.

 

Day Geckos rarely drink from bowls but will lap water that is sprayed onto foliage.

 

Further Reading

 

Keeping Day Geckos Without UVB Access

 

Collecting Insects for use as Reptile Food

 

Feeding Day Geckos

 

 

 

 

When cared for properly, Leopard Geckos are among the most hardy and long-lived of all reptile pets.  But apparently-healthy geckos sometimes refuse to feed, or cut back on their intake, and there is still much confusion as to why this occurs.  My work with Leopard Geckos and hundreds of other species in zoos and at home has (I hope!) provided me with some useful insights into this problem.  Some involve areas that any good reptile keeper would investigate – environment, stress levels, disease – while others, such as the effects of circadian rhythms (“internal clocks”), are less obvious.

 

Winter’s Arrival and Internal Rhythms Regulate Eating

Leopard Geckos are native to southeastern Afghanistan, western India, Pakistan, Iraq, and Iran, where they inhabit desert fringes and arid grasslands.  In some parts of this range, temperatures rise to 100+ F in summer and drop below 32 F during the winter.  Wild Leopard Geckos living in environments that experience severe winters become dormant for several months each year, while those in milder regions may remain active (please see the article linked below to read more about their natural history).

 

While your pet is, no doubt, many generations removed from the wild, internal circadian rhythms may cause it to become lethargic and refuse food during the winter.  This can happen even if your gecko is kept warm and given a photo-period of 12-14 hours.  To confuse matters further, some reptiles enter dormancy when winter arrives in their native habitats…even if it happens to be summertime in their present home!  I’ve seen this among Indian Gharials (fish-eating crocodiles) 15 years removed from the wild, and in many others.  Captive Bearded Dragons also exhibit this type of behavior on occasion; please see this article.

 

Unfortunately, it’s not often possible to be certain that a pet has stopped feeding due to the effects of an internal rhythm, so be sure to check the other possibilities discussed below.

 

Next I’ll mention other things that should be checked if your gecko stops feeding, including husbandry (tank set-up, temperatures, diet, etc.), stress, and disease.  I’ve written on each of these in further detail in the linked articles.

 

Your Gecko’s Environment

As Leopard Geckos are nocturnal, it’s important to monitor nighttime temperatures, especially during the winter, when most people lower their home thermostats.  The ambient air temperature should range from 78-84 F, which can be maintained by a ceramic heater or red/black reptile “night bulb”; a below-tank heat mat should be positioned so that one corner of the tank is warmer (88 F) than the rest.  Be sure also to establish a thermal gradient (areas of different temperatures) so that your gecko can regulate its body temperature as needed.

 

While Leopard Geckos often adapt to smaller enclosures than do other lizards, individuals vary in their response to crowding.  Moving your pet to a larger terrarium may help, and this will also make it easier for you to establish a thermal gradient (small terrariums tend to remain at the temperature of the basking site).

 

And, no matter how well-adjusted or bold your pet may be, it’s important to provide a dark, secure cave or other shelter.  Geckos forced to remain exposed often cease feeding.

 

Diet

Wild Leopard Geckos feed upon a huge array of invertebrates, while pets are often limited to 2-3 food items.  Dietary variety is important for health reasons.  But providing different types of insects can also incite new interest in feeding.  We see this most commonly in chameleons, but the enthusiasm your Leopard Geckos will show for novel foods will leave you with no doubt as to their value.  Please see this article to read more about adding silkworms, house flies, sow bugs, wild-caught insects and other important foods to your pet’s diet.

 

Stress Can Affect Eating

Geckos may be stressed by the mere presence of a dominant cage-mate, even absent fighting.  If you suspect aggression, observe your geckos after dark, when they will be most active (a red/black reptile bulb will prove useful).  Appetite-suppressing aggression is especially common among young geckos that are being raised in groups.

 

Locating the terrarium in a noisy part of the house, or where there are vibrations from machinery, may also depress appetites and contribute to other health concerns.

 

Disease and other Health Issues

Impactions from substrate swallowed with meals and Metabolic Bone Disease are two of the more common reasons that geckos cease feeding.

 

Other health concerns that have been identified include Hyperthyroidism, Eyelid Lining Retention (following shedding) and Cryptosporidiosis.  Internal or external parasites, and a host of other less common ailments, should also be investigated if your pet stops eating.  Please post below if you need help in locating a reptile experienced veterinarian.

 

 

Further Reading

The Leopard Gecko in the Wild

 

The Ideal Leopard Gecko Terrarium