By Audrey Vanderlinden

INTRODUCTION:

There are 19 known species and subspecies of the genus Uromastyx. Commonly referred to as spiny tail lizards, they are indigenous to North Africa, Egypt, Bahrain, Yemen, Sudan and some parts of India. Only in recent years, have a handful of breeders been able to successfully breed several species. Importation of some wild caught species still occurs in the pet trade. The most commonly imported is the U. maliensis. This is likely due to their higher populations in the country of origin. All species of uromastyx is listed as CITES II.

The most desirable of lizards is captive bred. There are currently seven species of uromastyx kept in captivity to date: U. maliensis, U. ocellatus ornatus, U. acanthinurus, U. aegyptius, U. benti, U. philbyi and U. hardwicki. All but U. malienis are rarely imported.

The largest of the species is the U. aeyptius, reaching maximum lengths of two to three feet. Among the smallest is the U. ocellatus ornatus and U. hardwicki, reaching lenghts of 12 to 16 inches.

Sexual dimorphism is prevalent in most species, showing more differences as they mature. Males tend to more brightly colored, especially the U.ocellatus ornatus, while females are often more subdued.

ENCLOSURES:

These are very active, heat loving lizards that thrive in a hot, dry desert environment. A vivarium set up that closely resembles their natural environment should be provided. Less is more, is a good idea as

These lizards are diggers and anything too elaborate will make for a messy habitat. Avoid any organic edibles, such as live plants, which are usually destroyed or eaten. Plastic cage decorations that resemble live plants should be also avoided, as these herbivorous lizards have been known to ingest plastic plants mistaken for food. Adequate space is necessary, especially when housing pairs or colonies of uromastyx. A good rule of thumb for most desert lizards, is to provide a habitat four times the length equivalent to an adult lizard, and then some. A maximum cage height of two feet is ideal and a cage depth minimum of 2 feet (4X2X2). This will provide adequate space for a single animal or a pair. Colonies require more space. Many keepers of this species will build custom wood or melamine enclosures. These lizards cannot get enough space, so go BIG! There are also several good ready built reptile enclosures available in specialty pet stores and hobbyist magazines. Be certain that these enclosures will suite the specific needs of this species. Ready made enclosures usually require some modification to make them uromastyx friendly.

The enclosures need good side and top ventilation for airflow. Too much humidity (70 % and over) for these desert animals can be harmful, so a well-ventilated enclosure is crucial. This is especially important when using sandy subtrates as this can create dust. A frontal view into the cage with glass or tightly screened sliding doors is desirable.

Breeders often use 55-gallon plastic tubs for isolation of males and females during breeding or times of aggression amongst colonies. These can be rigged to accommodate uromastyx for long or short term housing using the same enclosure guidelines as above. When keeping more than one animal in a single enclosure, it is a good idea to have a back up enclosure such as this, when the need arises. These are good for use as "sick" tubs in times of medical treatments when it is recommended that the animal have less contact with owners (to lessen stress) or when treatment requires that the lizard be separated from cagemates.

Sanitation and hygiene are very important as with any reptile habitat. These lizards, being more active than others, can make this even more so. If attention is paid to daily clean up of fecal matter, keeping the habitat clean requires minimal work. Remove old food debris on a daily basis. Leaving old and rotting vegetation for more than a day or two will stink and mold. Interior walls or glass can be cleaned monthly or more often if necessary, with mild soap and water. Rinse or wipe down thoroughly with wet cloths to remove any remaining cleaning product.

Diluted glass cleaners work well on glass tanks and should also be wiped off well using water after initial cleaning. Always wash your hands with a good grade antibacterial hand soap after cleaning and more often when cleaning multiple cages. It should go without mention that you should wash your hands after handling your lizards. Use clean, sanitized (bleached) food dishes for every new feeding.

HEATING, LIGHTING and PHOTOPERIODS:

Uromastyx lizards come from the driest, hottest and most barren parts of the world. They thrive under extreme conditions unsuitable for a lot of other lizard species. A good source of florescent full spectrum UVB lighting is important. These lights should be placed a maximum distance of 18 to 20 inches away from the animal. UVB lighting is crucial for vitamin D3 synthesis and fresh bulbs should be provided and replaced every year. In larger enclosures, four-foot florescent shop light fixtures can be mounted or hung inside the habitats. These fixtures will house two four-foot florescent tubes. There are several good reptile specialty bulbs available so do not neglect to purchase high quality bulbs. Full spectrum tubes come in a variety of sizes. Purchase the largest tubes possible according to the size of your enclosure. If possible, use more than one fixture. A bright and "sunny" cage is necessary for good health with this species.

For heating the enclosure, a heat element can consist of an incandescent light bulb of 100 to 150 watts, in an aluminum dome utility lamp with a porcelain socket (for high heat sources). This will be the basking site heat. The heat source should be a safe distance away from the animal yet have enough wattage to get the basking site to around 110 to 130 degrees Fahrenheit. Domes can be placed on top of secured screened tops. Some custom enclosures have sockets built inside the enclosures. Make sure your lizard cannot physically contact the light bulbs as this could result in severe burns. In larger set ups, you may need to place additional basking sites for both additional heat as well as multiple basking sites for more than one animal. These can be placed within several inches of the other spots, along with an individual flat basking rock per spot. For all sizes of enclosures, it is recommended that most of the heat be contained to 1/3 to 1/2 of the habitat to allow for a "cooler" end. This is important as it allows the animals to retreat to the cooler end when desired and for sleeping. It is a good idea to keep any caves or hide boxes near the cooler end.

You do not need to purchase high priced incandescent light bulbs, as there is some doubt as to the validity of manufacturer claims that their light bulbs provide a source of UV. Standard household incandescent bulbs work fine. The closest we can come to Mother Nature in mimicking natural sunlight is with florescent lighting. There is also further speculation as to whether a higher priced UV florescent lights are better than one that costs less as well. As long as the CRI index of the light is 90 or above, you will be providing a good source of UV.

Breeders often use a florescent "black light" placed in the enclosures in addition to the other lights. These are implemented for about two months at the start of spring. Keep in mind this is not the poster black light used in the 1970's, but rather a white light that provides a UVA source that has been known to stimulate breeding activity in adults. The standard among the breeders of desert lizards is the Sylvania 350 Magnum BL bulb. These are usually found only in lighting specialty stores.

Good digital thermometers need to be implemented in place to determine cage temperatures and fluctuations. One thermometer probe needs to be placed at the cool side of the enclosure to determine the temperature at that end. This temperature is ideal in the mid to high 80’s. The other probe needs to be placed directly under the basking site to read the temperature of the hottest part of the cage. Adult Uromastyx can safely bask with temps as high as 130 degrees, but 120 degrees is ideal. Baby uromastyx need basking temps kept slightly lower overall (110 to 115 degrees) due to the smaller body mass of the baby. Ambient temperature or overall cage temperature should be in the 90's. A night drop can dip into the 70’s, with all heat and light sources turned off. If your reptile room gets below 70 at night, you may want to supplement heat either by increasing the overall room temperature or adding night lights (low wattage red or moonlight bulbs) to the enclosures. During the hot summer months, this is usually not necessary. It is more likely needed during very cold winter months.

If you need to add night heat to the enclosure, monitor the temps carefully as it is important NOT to heat uromastyx lizards for 24 hours straight as this will not allow the necessary daily "down" time for the animal to rest and recharge it's metabolism. A cheap and practical way to regulate heat is by using a table top lamp dimmer as a rheostat to increase or decrease wattage.

A daylight period should follow our own seasonal changes. Less daylight in winter and longer daylight in the spring and summer months. During the spring and summer, 12 to 14 hours of daylight and heat is adequate. Fall and winter months find most species of uromastyx less active and eating less due to barometric changes in the environment. At this time, less heat and light, about 8 hours a day is acceptable. Brumation, the lizard's natural need to "slow down" during cooler weather is a natural occurrence, necessary for longer, healthier lives. At this time, the lizards will eat less and require less food. Brumation is also vital for breeding. Even if you have no desire to breed your uromastyx, you must allow for natural environmental changes to take place. In the wild, reptiles experience the same seasonal changes conducive to their natural environment as we do. To not allow the reptile to experience some brumation for a short period of time will likely shorten its lifespan.

SUBSTRATE AND CAGE FURNISHINGS:

There a several good cage substrates as well as some to definitely avoid. For adult animals, playsand is a good, cheap substrate. Another excellent source for all ages (except babies under a year) is compressed coconut fiber bricks (Bed a Beast), which needs to be rehydrated with hot water and then used in its completely dry state. Drying out the substrate, once it has been watered to expansion and breaking apart the large chunks, can take a few days. This has shown no impaction complications to date, whereas playsand can impact young and some adult animals. Healthy, well-nourished adults do very well on playsand. Some keepers of uromastyx use birdseed as a substrate and have proven well with this, too.

For babies and young lizards, plain paper cage liner or newspaper is best for the first year. These need to be changed weekly.

Avoid substrates that can cause impaction and even death. These include walnut shells, cellulose lizard litter, cat litter, cedar chips and other wood chips, colored calcium sand, silica sand, aquarium sand or colored pebbles. Beware of false claims in products stating that they won’t impact. These claims are often poorly researched or not researched AT ALL before they are unleashed on the public. Some products will even list the specific species that can use the product. Again, it is often sold without valid, long-term husbandry data. Marketing of these products is just that: Marketing. When in doubt, don’t buy it! For your animal's sake, talk to your vet or an experienced breeder/ keeper if you have questions.

Cage furnishings, as mentioned before, should be sparse. A hide box or rock cave should be available for the lizard. Several should be implemented for multiple lizards. Flat slate rocks or terracotta tiles can be used and placed beneath the basking spotlights. Large decorative pieces of flat slate can be purchased at garden specialty stores. Large. hollow cork bark logs can be placed for additional climbing places as well as additional places to hide. Paver bricks bought at home improvement centers are great for creating stacks, steps and caves for uromastyx.

Always make sure your cage furnishings are safe and secure. Large objects need to be placed directly on the floor of the enclosure without any substrate beneath. Any opportunity to dig under a heavy object will be taken and can often be fatal. Make sure large rocks and bricks cannot be easily toppled by the lizards and accidentally crush them to death. HEED THIS WARNING from personal experience!

FOOD:

Uromastyx lizards are primarily herbivorous. An occasional insect feeding is ok, even on a weekly basis, however the overfeeding of insects can cause severe health problems, including gout and kidney failure. Insects should be limited to well gut-loaded crickets and the occasional superworm (giant zoophoba) dusted with a calcium/vitamin supplement prior to feeding.

Young uromastyx should never be fed superworms, as these worms are extremely hard to digest and often reek havoc on the digestive tracts. Stick to a primary vegetarian diet for optimum health. Adult uromastyx can be fed every other day and babies up to one year should be fed daily.

A good varied diet should include mixtures of turnip greens, dandelion greens, romaine, endive and escarole lettuces, organic spring mixes, edible flowers, red clover and other sprouts, mustard greens, frisee and occasional collard greens. Cabbages and members of the cabbage families, including broccoli and kale should be avoided or fed sparingly, as these are high in oxalates, which can bind calcium.

Frozen, thawed and cut to bite-size mixed vegetables, such as green beans, carrots, baby lima beans and peas are especially savored, with an affinity for green peas. Vegetables can be fed every other feeding. When feeding vegetables to small lizards, chop in small baby bite-size pieces based on the size of the baby lizard. Chopped apples and firm blueberries can be an occasional treat for everyone. Other fruits and vegetables, such as cactus pears, pears, bananas, sweet potatoes and figs are often accepted, but as with all the foods mentioned, some lizards have varying tastes for personal favorite food items.

A DRY blend of seeds and legumes need to be provided in a shallow dish and refilled as needed.

This is an important source of vegetable protein. A good blend consists of red and green lentils, yellow and green split peas, millet, sesame seed, wheatberries, bee pollen granules, waste-free birdseed blend, organic grain cereal and dry15-bean soup mix. Important note: The 15-bean soup mix contains beans that are too large for your lizard to eat as is. I recommend purchasing a uros only, inexpensive COFFEE GRINDER to grind the 15-bean mix to a fine to coarse mix, which can then be added to the other seeds and legumes. Also, remove the red kidney beans, as there is some documentation that these have toxins that can be harmful to reptiles. If you are raising hatchlings or have very small animals, you can grind the entire seed blend to a powder-like mix that can be easily ingested by the smaller lizards. Do not give babies LARGE DRY pieces of ANY seed or legume until they are at least a year old. Babies can dehydrated easily if not eating enough greens and vegetation and beans and legumes that are too large can swell and cause GI tract problems.

As an additional food source, a weekly serving up of commercial iguana food is acceptable. The fruitier blends (Repcal) tend be relished by all. It can be placed in the dish with the dry seed and legume blend. This also provides a source of calcium and vitamins. I usually give the juvenile formula to everyone.

Generally, if you are providing the above-mentioned foods, your lizards are getting a good amount of calcium and other nutrients from their food sources. Other than via the food sources listed, I rarely give additional supplementation. I do, however, give females extra calcium (neo-calglucon) for several weeks prior to breeding to help build up reserves that get depleted during egg formation. This has made significant differences in egg quality for my females. Calcium supplementation can be given during gestation and post oviposition (to replace lost calcium after egg laying) as well. Any sick or compromised animal that is weak is also a candidate for extra nutrients. There is no harm in providing a weekly high quality vitamin supplement, if you so desire. This can be sprinkled lightly on foods. Make sure the product is for animals kept indoors, if you are housing indoors. Over supplementation can also be harmful.

WATER:

I do not provide water to my animals ever. The only time water is necessary is if the lizard is a newly imported, likely parasitized animal who may be suffering from dehydration due to shipping stress (lethargy, weight loss or injury) or a female who has just laid eggs. Post egg deposition females will drink gratuitously once they have laid their clutches and will usually not drink at any other time. A lizard being de-parisitized will often become dehydrated from the medications, so it is a good idea to give these animals water, too. Most uromastyx will not drink from a water dish. Keeping a water dish in the enclosures will only make a mess when the lizards run through it and you risk the incidence of high humidity. There are basically two ways to provide water to your uromastyx. One is you can soak the lizard in shallow warm water (no more than past the belly) for 10 minutes a day. The absorption through the skin will allow some water to the animal's system. This must never be done unsupervised.

Another way is by droplets of water given via a plastic irrigation syringe or eyedropper. This is done while holding the lizard and introducing a few drops at a time. Water is not the most palatable of tastes so using fruit flavored Pedialyte or other electrolyte replacement drink may entice the animal to drink. Healthy uromastyx will get all the water they need from their diet.

SOCIAL BEHAVIOR:

Uromastyx lizards are very social reptiles, both among their respective colonies and mates and with their human owners. It is very rewarding to raise a baby to an adult and experience the growth and interaction.

Reptiles are basically creatures of habit and thrive under conditions that are not in a constant flux. It is probably not a good idea to change furnishings around often or move them so they are unfamiliar to the lizard. This can cause unnecessary stress. Keep things as consistent as possible in regards to feedings, cleanings , changing enclosures or adding cagemates. Any changes to the world your lizard has come to feel safe in will cause some acclimation stress if the animal is subjected to adjust to a change. This may seem like a small thing to us, but with reptiles, it is always a major thing.

When introducing new cagemates, stress is a given. It is my opinion and recommendation that the same species of uromastyx be housed with their own. It is also important to keep captive-bred lizards separate from wild caughts. The exception is with long term (year plus) captives who have been deemed healthy and disease free AND raised by the same keeper.

Some species can be kept together. U. maliensis and U. acanthinurus were once thought to be of the same species, before the U. maliensis received separate species status. It is likely that these two species often integrated in the wild. Ideally, these should be housed separately for bloodline purity.

Raising small groups from hatchlings is always best, but not always possible given the current price for a captive bred baby, particularly the U.ocellatus ornatus or ornate spiny tail. Most keepers will purchase one or two babies and add to the collection later. This is fine as long as the keeper is willing to commit to observation and close monitoring of the new introductions for a brief period. Dominance can show up early in babies and juveniles and will often go unnoticed until there is some obvious signs of aggression such as a bite mark to the side of the belly, a missing toe or noticeable lethargy and weight loss. The subordinate animal will almost always stop eating and quickly deteriorate, as this is the ultimate sign of submission. It does not wish to compete with the dominant or alpha lizard for food and will simply give up. If this animal is not removed and isolated, it could succumb to death. If caught early, simply separating the animals and supplementing the compromised lizard with extra nutrients will save its life. This behavior is especially conducive to growing babies establishing territories. I keep all hatchlings separately after a month or so. Some early pairings, however, are the exception and remain together for life. I have found that hatchling U. acanthinurus are quite aggressive from the start and therefore they are immediately housed in separate nurseries. This is also true of U. aeyptius. U. ocellatus ornatus are generally more accepting of siblings and cagemates. Nursery set ups are basically ten gallon aquariums lined up on industrial shelving with proper heating and lighting.

Adult uromastyx usually do well in small groups of a few females and one or two males. Different species have different degrees of aggressions and this is usually based on individual personalities. It is also dependent on the season. Breeding season brings out the worst aggressions among females, towards each other as well as towards the male(s). If two males are raised together, it is usually the males that get along the best. The tendency is that there will be an alpha male (the dominant one) and a subordinate male. This is an accepted relationship that allows them to co-exist harmoniously. The alpha male is usually the larger of the two.

Often when a single male is reluctant to breed, a brief introduction of another male in the enclosure can help stir things up. This will induce territorial behavior. The intended female is part of the territory belonging to the reluctant male and copulation often results. The "intruder" male should not remain in the enclosure without constant monitoring by the keeper. Sometimes all it takes is a very brief presence. If the males become too aggressive, remove the intruder at once.

The pairing up of two potential breeders will not always result in copulation or even a successful impregnation. The females seemingly pick only desirable males to mate with, fighting off males that are not. I have witnessed this personally with several females.

Females tend to be more aggressive overall and can be so year round. Again, this is an individual's personality as some are more passive than others. Aggression is more prevalent during breeding season. I have found from keeping dozens of colonies and pairs that an aggressive female should and will be the sole queen of the colony. Some of my high strung females are kept entirely alone. If you have a proven breeder, male or female, it is my opinion that these lizards be housed singularly except briefly during breeding for a few weeks. That pairing usually turns aggressive once the female has bred and the animals will once again need to be separated.

Once it is determined that the female is gravid, she should be allowed to have a private, secure residence prior to egg laying. Gestation for most uromastyx is four to six weeks. A nesting box should be provided in the enclosure for the female to deposit her eggs. This can consist a covered 5-gallon plastic storage tub filled with semi-damp playsand and an entry hole cut out of the side for the female to enter. Gravid females will dig several laying sites the week prior to deposition. Egg laying is usually complete after several hours. It is not unusual to find an egg or two laid the next day. Depending on the species, uromastyx lizards can lay anywhere from 12 to 20 eggs.

Once having laid her eggs, females resemble deflated footballs. After oviposition, these lizards are extremely fatigued and dehydrated and water should be offered immediately. In a matter of days, these remarkable animals incredulously recover and begin gaining weight. It is my opinion that allowing one clutch per year is the best way to maintain optimum breeding health.

Babies uromastyx will hatch in 72 to 80 days with eggs incubated at a consistent temperature between 88 and 90 degrees Fahrenheit. There are a few incubation mediums used by different breeders but my preference is vermiculite and water. The ratio of vermiculite to water is approximately 70/30 by weight in grams. I have found that Hovabator styrofoam incubators work very well. There is a slight fluctuation tendency with styrofoam incubators, however I have found that keeping the incubators in a cooler area has minimized this. Digital thermometers that detect maximum high and minimum low temps are used for monitoring

Care of neonates is similar to adult uromastyx husbandry as previously mentioned, with extra care given to weak or lethargic hatchlings. Healthy baby uromastyx will be immediately active, alert and robust upon emergence from the egg. Weaker animals will have difficulty emerging from the egg and often will not have completely absorbed the yolk sacs. This is not necessarily hopeless and an experienced breeder can pay close attention to this situation and with proper neonate care can save the baby. Optimum hatchling health can be determined after about 4 months. Most health problems that can occur with hatchlings will manifest during the first 3 to 4 months of life. Eating and defecation patterns will have been established as well as the possible sex of the lizard. This is the minimum age a baby uromastyx should leave the breeders care, especially in the care of a novice hobbyist.