Spiny-Tailed Lizards Captive Care of the Genus UROMASTYX
By Randall L. Gray
Spiny-Tailed lizards have become popular in the pet trade during the last few years. They are commonly known as Uromastyx, but are also called “dabb lizards” or “mastigures,” depending on the part of the world from which they originate. For the purposes of this article, we will consider them all “spiny-tailed lizards.”
These unusual and interesting lizards make exciting additions to the desert vivarium; however, they can be difficult to maintain in captivity. Large numbers die during importation, and many of those that survive are very stressed and difficult for even the experienced herpetoculturists to get established. Once established, though, they can prove hardy and live for many years.
Species Information
Spiny-tailed lizards are members of the genus Uromastyx, which belongs to the Old World lizard family known as Agamide. Scientific names allow scientists from all over the world to communicate correctly about the species in which they are interested, whereas common names can vary. There are approximately 13 species of Uromastyx distributed throughout arid regions of northwest India, southwestern Asia, the Arabian Peninsula and the Sahara of northern Africa. Even though only a few species are imported into the United States, the number of species available has increased in recent years.
The most commonly available spiny-tailed lizards are Egyptian spiny tail (Uromastyxaegyptis), the ornate spiny tail (U. ocellatus ornatus) and the ocellate spiny tail (U. ocellatus). (Many taxonomists consider the ornate spiny-tailed lizard to be a sub-species of the ocellate.)
Occasionally, Moroccan spiny-tailed lizards (U. acanthinurus; this is the species that's sometimes called a “dabb lizard”), Indian spiny tails (U. hardwickii) and Bent’s spiny tails (U. benti) are available. In 1995, a new species from Mali, Africa, was imported into the United States. It resembles the Moroccan spiny-tailed lizard, and some taxonomists have classified it as such. (However, as this writing, Dr. Ulrich Jogger of Germany plans to publish a paper later this year proposing a new scientific name for the species.) Males are generally yellow backed with black heads, legs , and tails and females are generally yellow-tan in color.
The Egyptian spiny-tailed lizard is the largest member of the genus, reaching lengths of more than 30 inches and weighing several pounds. The Moroccan and Mali spiny tails are the next largest members of the genus, with about 16 inches of total length and weight approximately 1 pound. Most of the other species that are imported into the United States
usually attain 12-inch lengths or less, and weigh only 100 to 200 grams .
All Uromastyx possess well-armored tails that are used as defensive weapons; a spiny-tailed lizard deters predators by blocking its burrow or crevice with its massive spiny tail.
Each species of spiny-tailed lizard behaves differently in captivity. Generally, ornate spiny tails become the most tame; however, individuals of any species may adapt well to the presence of people. Unfortunately, on the other hand, many will run for a hide spot whenever someone approaches their cage (this is especially true for the wild-caught animals).
Before acquiring any spiny-tailed lizard, be sure you understand the basic requirements for this group of lizards as outlined below.
Acquiring a Healthy Spiny Tail
When choosing a spiny-tailed lizard, always try to obtain a captive born animal whenever possible. This can be difficult, however, because there are very few captive-born spiny-tailed lizards available. I only know of one private breeder, Matt Moyle, who consistently reproduces the Moroccan spiny-tailed lizard each year. Except on a few rare occasions, none of the other species are consistently, if at all, produced in captivity; therefore, the vast majority of the young spiny-tails available in the pet trade are wild caught.
When selecting an animal, look for an active and robust individual. The eyes should be bright and alert, the base of the tail should be thick and round, and the lizard should be active and responsive to any attempts to pick it up. Pick the animal up and look for sores, blisters or broken appendages. An experienced herpetoculturist can determine if the animals weight is healthy just by lifting it up. Do not buy a sick animal with the hope you will be able to nurse it back to health you will be disappointed.
Spiny-tailed lizards are listed in Appendix II of the Convention for the International Trade of Endangered Species (CITES); therefore, they are afforded international protection. Only a few countries allow the exportation of spiny-tailed lizards. Some species, such as the Moroccan spiny tail, are probably smuggled out of their country of origin, and then legally imported into the United States through a third country by claiming the animals as captive born. When acquiring an spiny tail, make sure you keep a receipt and have the seller document in writing that the animal was legally imported or captive born in the United States. This documentation could help protect you. As mentioned whenever possible, insist upon captive-born animals, both to discourage large-scale importation and to ensure that your animal adapts to captivity with less trouble.
Sexing Uromastyx
Determining the sex of an individual spiny-tailed lizard can be a challenge. Some species, such as the ornate spiny tail or the Mali spiny tail, are sexually dichromatic, which means you can see differences in color between males and females. As mentioned previously, male Mali spiny-tailed lizards have black heads and yellow backs, and the females are a more uniform yellow-tan; however, after the females lays her eggs, she takes on the darker coloration of the male. Ornate spiny-tailed males are spectacularly colored. They can be green, blue, lime, reddish, or any combination of colors, whereas the females are usually tan with only a little additional color evident.
Moroccan spiny-tailed lizards can be difficult to sex. The males and females are both colorful, and very similar in appearance. Adult males usually have larger femoral pores along the underside of the rear legs, as well as slightly larger heads with larger jowls. In addition, males appear to have cloacal openings that are a little larger than females’.
All of the preceding sexual characteristics are relative, and you will usually need several animals to compare. Then, just when you think you have them sexed, chances are you'll encounter another animal that is somewhere in between! Adult males are easier to distinguish in the spring, when hemipenal bulges appear along both sides of the lower base of the tail.
Other spiny tails are less difficult to sex than the Moroccans, but most are still not as easy to determine as ornate spiny-tailed lizards. In all cases, you should look at the head shapes, size of femoral pores, and the presence of hemipenal bulges. Probing spiny-tailed lizards-Moroccan spiny-tailed lizards, anyway does not seem to work.
Over time, while observing your animals, you may notice behavioral differences that can help determine sex. Of course, a clutch of eggs can prove you right or wrong!
Social Interaction
Uromastyx lizards are territorial, which means that in the wild they will actively defend a piece of ground against other members of their species, especially those of the same sex. Males will often actively patrol an area and keep out all other adult males. Females will behave similarly toward other females, and even males.
In captivity, the ability of an individual to flee a dominant animal is restricted because of the confines of the cage; therefore, you must watch for signs of stress in submissive individuals. In most cases, it is best to keep only one male per enclosure. I have observed female Moroccan and ornate spiny-tailed lizards exhibit aggressive behavior toward individuals of the same sex, causing the submissive animal's health to rapidly decline. Be sure to watch for signs of aggressive behavior, evident by bytes on a lizards body particularly along the sides of the animal. If you see this, separate the submissive animal.
Mali and Moroccan spiny-tailed lizards exhibit interesting behavior characteristics: Females will occasionally roll over onto their backs when approached by a male. Whether this behavior is exhibited by submissive females, females that are receptive to breeding, or perhaps even submissive males is unknown. Hopefully, herpetoculturists will document behavioral observations so we can increase our knowledge about this species, which should also help us to more easily sex the animals and give us a better idea as to when they are reproductively receptive. (Unfortunately, some observers often jump to unwarranted conclusions about observations, and perpetuate misinformation.)
Behavioral interactions are part of the animals environment and should be encouraged when possible. For example, some herpetoculturists will temporarily introduce a second male into a breeding cage to stimulate the resident male to breed with the female. In this case , short-term aggressive behavior may be beneficial.
Housing
Caging for the spiny-tailed lizards can be simplistic or complicated, depending upon the personal preferences of a lizard's owner. The main criteria determining cage design should be ease of cleaning and temperature control, safety, and aesthetic taste of the keeper.
Spiny-tailed lizards can be set up in aquariums, metal livestock watering tanks or plastic tubs, all of which come in a variety of sizes. You may even choose to build your own cage out of wood and glass. If climate permits, spiny-tailed lizards can be kept outdoors in large natural cages.
Screened and washed plat sand makes an attractive and natural substrate. Although some lizard species can ingest sand, which can lead to health problems, I have not had this problem with spiny-tailed lizards. Dirty sand can be easily removed when cleaning fecal mater from the cage.
All of the larger spiny-tailed lizards, as well as hardwickii, dig burrows. The ocellate and ornate spiny tails, on the other hand, often live in rocky crevices or under exfoliating slabs of rocks. A retreat can be provided by using a small plastic box with a short tube leading into a hole cut in the side , or a large plastic plant saucer with a hole cut on the edge and then placed upside down in the cage. For smaller species, stacked cinderblocks with narrow openings recreate natural crevices. Be creative and design your own rocky outcrops or burrows, but make sure they are secure. Spiny-tailed lizards will burrow under them and can either become trapped or die if the rocks topple down on them.
Heating and Lighting
Spiny-tailed lizards live in desert environments; therefore, you should try to simulate these conditions in captivity. Deserts are areas of low rainfall and high temperatures. Moroccan spiny-tailed lizards are most active during the hottest part of the day, when many other reptiles have retreated to cool burrows. Cages should allow an animal to choose the temperature it requires. Providing a heat source at one end of the cage allows the animal to retreat to a cooler spot at the other end of the cage if it becomes overheated.
An excellent source of heat is an incandescent spotlight, such as a halogen bulb. The concentrated light can heat a basking spot to an extremely hot temperature, depending upon the elevation of the light and the wattage of the bulb (make sure that nothing flammable is located near the light).
Heating pads or other subsurface heating units can help control temperatures in different parts of the cage. During the early spring of late fall I place heating pads under my lizards sleeping areas to maintain somewhat higher temperatures during the night. When cooling the animals down for the winter, the heating pads are turned off.
Natural sunlight provides a wide spectrum of light bands. Certain ultra-violet light (i.e., UVB) is important for producing vitamin D3 in an animal which is necessary for calcium absorption. There is some controversy as to whether vitamin D3 can be properly supplemented by diet, so most herpetoculturists try to provide natural sunlight or use full spectrum fluorescent lights. Several of the reptile-specific full-spectrum bulbs now on the market generate ultraviolet light specifically UVB and UVA. However there is no scientific evidence these lights are necessary. In fact many herpetoculturists have had great success breeding many species of lizards without using them. I still prefer to use full-spectrum bulbs, though, primarily to play it safe concerning the need for ultraviolet light, and because my animals’ colors are more vivid under full-spectrum bulbs.
Diet, Nutrition and Water
Spiny-tailed lizards are omnivorous which means they eat both plant and animal matter. There have been very few field studies on the uromastyx genus, but we can glean from the literature that they eat primarily plants and will take insects when available.
The foundation of a good spiny-tail diet should be a salad made from a variety of nutritious fruits and vegetables. A mixture of collard, mustard and turnip greens, with peas, corn, lentils, green beans, alfalfa pellets and strawberries will provide the basis of the salad. It should be supplemented with a variety of beans, birdseed and other vegetables. When available, dandelion greens and flowers are eagerly consumed, as well. Once a week, a multivitamin/mineral supplement should be added to your lizard's salad.
Spiny-tailed lizards will eat crickets, wax worms and super worms. Individual lizards may show changing preferences for these food items, however, so vary the diet if yours seems to shun a specific food. Some Uromastyx, such as the Mali and ornate, show greater interest in insect food than others. Younger animals may consume insects more readily than adults, but as they mature, they usually slow down on eating animal foods. The young lizards’ preference for insects may be related to protein needs for growth. There is some debate as to the amount of protein that spiny-tailed lizards should be feed, although I have not had any adverse reactions feeding insects three to four times per week
Prior to being offered to your lizards, all insect food should be fed the same nutritious salad as the spiny tails to increase their nutritive value. In addition, insects can occasionally be coated with vitamins prior to feeding them to the lizards.
I do not provide standing water to my spiny-tailed lizards; they get all their moisture from their diet. If you provide a water bowl, make sure it cannot overturn and raise the cage's humidity.
Conclusion
Spiny-tailed lizards are beautiful and interesting lizards. Unfortunately many die during importation or soon after entering the pet trade. You must select healthy animals and provide good husbandry. As previously mentioned, spiny-tailed lizards need hot and dry cage environments that offer secure places into which they retreat. A varied and nutritious diet is important to ensure good health and longevity. And even though few spiny-tailed lizards are currently being captive bred, we should work toward this end, both to ensure healthy animals for pets and to decrease the number of wild-caught lizards that are imported into the United States.
by: Michael L. Fagre
with the help of: Randall L. Gray, Philippe de Vosjoli,
Matthew Moyle, and the readers of The Uromastyx Home Page.
Q: Approximately how long, on a consistent diet, does it take for a Uromastyx to reach full grown size? How fast do they usually grow? At what age does a Uromastyx reach sexual maturity?
A: Currently there is no way to determine how long it takes for a Uromastyx to reach full size. The only difference I have seen in ages (besides size) is the amount of sleep they get. A juvenile may play all day long, whereas an adult may only come out to play a few hours a day, stopping to take naps every so often. As for age of sexual maturity, this depends on species: ornates 2 years, aegyptius 3-5 years, acanthinurus 2-3 years.
Q: When my Uromastyx reaches full size, do we get him a new terrarium, or just keep him in the one he has right now?
A: This depends on how big the terrarium is to begin with. If the lizard is 2' long and 6" wide then the cage should be about 8' by 2'. That is 4 times its length and width. Of course you can always give them a bigger terrarium (which they appreciate), especially if you have more than one lizard.
Q: How do you tell how old they are and what is their life span????
A: Currently there is no way to determine exactly how old a Uromastyx is. It can be guessed by their size but this isn't accurate because they grow at different rates. This also hinders us in knowing how long they can live. It is known that they can live at least 10 to 15 years but it has been guessed that they can live up to 35 years with proper nutrition and care.
Q: I have seen lots of different temp ranges for Uromastyx - which ones are correct?
A: Here are the ranges I have seen most often, and this is what I go by:
Night: 60 to 82 F (general temp inside cage)
Basking: 110 to 130 F (measured at their daytime basking site)
Retreat: 80 to 90 F (measured at the opposite side of the cage)
Q: Is it important to vary their temperature at night and on a regular basis?
A: Yes, it's very important. If a Uromastyx is kept too warm and active during the winter months, it can develop a goiter-like enlargement in the thyroid area which can gradually worsen over several years. To prevent this problem you should drop the temperature of their cage at night. You should also vary your light schedule in the winter, trying to keep it as close to the natural day length as possible.
Q: How important are heat lamps? Can I use a hot rock and fluorescent bulbs instead?
A: Without proper lighting Uromastyx, like other reptiles, won't be able to extract the nutrients they need from their food. The difference between adequate lighting and proper lighting is the difference between a skinny, OK lizard and a fat healthy lizard. Simply put, if a Uromastyx has a high concentrated UVA/UVB light and a hot desert like cage (with cooler night temps), the only reason it wouldn't gain weight is probably because of internal parasites.
Q: My Uromastyx ornatus has been getting lump formations on his body. Why does this happen and is it dangerous?
A: Lump formations on ornatus is a condition caused by the animal trying to save calcium in a very efficient manner until it has enough vitamin D to metabolize it properly. These lumps don't kill the lizard but a lack of available calcium does. Even with a body full of calcium, without vitamin D they can't metabolize it. These lizards come from a desert that is lacking in calcium, they have evolved techniques to store any calcium as it is ingested. In nature there is plenty of vitamin D, so there is no metabolism problem. In captivity they need very little calcium and a great amount of vitamin D.
Q: My adult Uromastyx will not accept any protein like crickets, meal worms, tofu or cheese. Is a strictly vegetarian diet OK?
A: Many of the Uromastyx (specifically ornates and acanthinurus) eat a lot of insects in the wild and without this source of protein they will not grow properly. Uromastyx aegyptius is the only species that generally does not eat crickets or worms. A good way to get a finicky Uromastyx to eat protein is to trick it: if you chop tofu into very small pieces and mix it with their favorite greens, they will eat at least some of it by accident. With any luck they might develop a taste for it.
Q: My Uromastyx is eating about three times more than it used to and also appears to be 'shedding' some skin. Could the two be related?
A: Yes, and it is a good sign. This means that your Uromastyx is getting what it needs out of it's diet to grow. The only thing that could be a problem is the amount it was eating before. If it went from eating one cup to four cups of food, I would say that this is too much and you should bring it to the Vet. It could be a sign of internal parasites.
Q: When we got our Uromastyx, he was pretty dark and didn't move or eat much. Now he is very light in color and active (mostly at night), and eats a big handful of salad a day. We keep him at a constant 90 degrees. Is this OK?
A: It sounds like he is healthy, but you're not letting the temperature vary as it should. This is apparent by him being active mostly at night. If you give them higher temps during the day and cooler temps at night, he should start playing during the day.
Q: Though I was told my Uromastyx was healthy, he appears dehydrated and has runny stools later in evening. What should I do?
A: This may be sign of parasites - take him to Vet immediately!
Q: I heard that feeding live waxworms or superworms could hurt my lizard. Is this true?
A: I don't believe you should be too concerned about the superworm hurting your lizard - they chew them pretty good. Besides, you would be hard pressed to get your Uromastyx to eat a dead superworm.
Q: My Uromastyx seem to be as big as the description of aegyptius in the texts, but they are colorful and change colors with temperature. It doesn't say in the texts whether this species does this. The male is usually brown and becomes bright yellow when warm, and the female is black and becomes white. Do you know if my Uromastyx are really aegyptius or not?
A: Yes they are. I agree that I have never seen this observation about color changes in any documentation.
Q: Some mornings when my Uromastyx wakes up there is white around his nostril or nostrils, and after a little while it goes away. Someone said that it could be shedding but it happens often. Can you help?
A: This is common and occurs as a natural way for the lizard to get rid of extra salt. Humans also release excess salt. We do it most noticeably when we sweat, which usually leaves a white line or ring. Consider this lizard sweat.
Q: How can you sex a Uromastyx?
A: The simplest answer to this question is that males usually have wider jowls, a wider tail base, and have more pronounced femoral pores (found on the inside of the upper thigh). This may not help you much if you don't have anything to compare it to. I would recommend looking at the pictures in Philippe de Vosjoli's book "Basic Care of Uromastyx".
Q: We haven't given our Uromastyx any water per se, but he does get some in his food, and is a voracious eater, so we feel that he might be getting enough moister in his diet. I was wondering if there is any merit in soaking him occasionally. We have read in several publications that soaking him once a month is helpful, but aren't sure if we should adopt this practice. What do you think?
A: If you think that it gets enough water in its food, then no I would not bother soaking it. If you should see signs of dehydration or if the lizard is having trouble shedding, then go ahead and soak it. Things that may lead to dehydration are eating a lot of rabbit pellets, bird seed, or dried fruit. Another way to give them water is to always rinse their vegetables and feed it to them without shaking the water off.
Q: I heard that misting is a good way to replicate the dew that Uromastyx get in their natural habitat. Is this correct, and if so, how do I do it?
A: No one really knows how much water these lizards get in their natural habitat. Also one species may require no water whereas another may require it daily. Unfortunately, this question still remains unanswered. If I had a dehydrated Uromastyx, I would generally soak it instead of misting it. If you think that misting is the best way then try using a fine mist spray and spraying the water above them instead of at them. Never do this on any substrate other than rocks or sand.
Q: The store that sold me my Uromastyx said they dewormed him. How can I tell if they did or not?
A: They might have wormed the lizard but it takes three or four treatments with panacure and/or Flagyl. If you suspect that your lizard might have worms, take a fecal sample to your veterinarian and have him check it.
Q: What type of foods should a Uromastyx eat?
A: I would feed them a variety of: turnip/collard greens (calcium & protein), kale, mustard greens, Euryops petals (perennial daisy), dandelion greens, cilantro, parsley, peas, corn, lentils, broccoli, lettuce (not iceberg), lollo rosso, tango, tat soi, red oak, mizuna, raddichio, escarole, endive, wheat, garbanzo and alfalfa (rabbit pellet). But you can also try: squash (summer and winter), red peppers, banana peels, iceplant flowers, carrots, sweet potatoes, large bird seed, iguana food, chopped dried fruits (apricots, raisins, cranberries, etc.) and nuts (walnut, filberts, almond, sunflower).
Q: Our Uromastyx is still not too fond of us picking him up, and I'm not sure if this is going to get any better or not. Also, I tried to take him outside on a leash and he started hissing and whipping his tail at me. Is this normal?
A: Your animal is showing typical behavior common to a lot of Uromastyx. These are not tame creatures. Some have very docile personalities whereas others seem aggressive. Even a docile animal placed outside in natural sunlight can become very defensive and aggressive. Also, these lizards are not as easily tamed as an Iguana.
Q: I try to feed my Uromastyx bird seed but they end up scattering it in their substrate before eating it. Is there anything I can do about this?
A: I have found that Uromastyx like dried fruit, nuts, and seeds, but do tend to make a mess with them. An easy solution to this problem is to buy Parrot or Cockatiel "treat sticks". They usually have a combination of large bird seed, dried fruits, and supplements in honey base on a stick. I use EightInOne's Fruit or Honey Sticks ($2.00 at Kmart) because it easy to remove the twist tie before putting it in the Uromastyx cage.