Mastering Uromastyx Husbandry and Breeding
with Kamiel Hamers
Spiny-tailed lizards are a large group of desert-dwelling reptiles from Africa and Asia. Comprised of the Uromastyx and Saara genera, they are iconic lizards and have been reasonably popular in captivity for decades. In the past, they were imported in large numbers from Africa and the Middle East. Since 1977, all are listed under CITES Appendix 2. Although some species are still exported to the USA under strict quotas, Europe and the UK have seen a decline in the availability of even the most popular Uromastyx species. Luckily, some passionate breeders are working hard to re-establish them in European herpetoculture. We caught up with one of the most well-known Uromastyx breeders in Europe, Kamiel Hamers of Hammerhead Reptiles to discuss these unique desert animals.
Uromastyx ornata
Species within the trade
Kamiel has been working with Uromastyx for around 25 years and breeding them for 15. Over that time, he has bred around nine of the thirteen different Uromastyx species and subspecies. “I started with Uromastyx ornata” explains Kamiel. “Honestly, I like all reptiles but when you have a collection of desert species it’s really difficult to keep anything else because the room is so hot.”
“For me, all thirteen species and subspecies have something cool about them. For example, the thomasi have huge round tails and beautiful colouration but behaviour-wise they’re pretty boring. Then you have the princeps, they’re not so colourful and have large spines on their tales, but they’re really active! I think it’s just a matter of what the keeper wants. Some like the colouration, some want a tame animal, and some want their lizard to be active. It’s really up to the keeper to pick what’s right for them, rather than the pick the rarest species, just because they are rare. I think people that go for the rarest animals are not keeping them for the right reasons. But then again, I’ve done it myself. I had some Egernia’s but after a few years I lost interest because they weren’t as cool to me as Uromastyx.”
Although demand for Uromastyx changes periodically, the most popular species has been the ornate Uromastyx (Uromastyx ornata). These animals are reasonably small, extremely colourful and can often become quite tame. They are also a very active species within the genus. All these factors have supported their popularity over time which means they are also readily available as captive-bred animals, particularly in Europe. Although all species are reasonably straightforward to care for providing their conditions are met, different Uromastyx “groups” require slightly different care. The nigriventris and dispar group are bigger than other species so requires bigger caging and a very hot environment during summer but can handle low temperatures during winter. The Yemenensis group are far less common in herpetoculture and can be more challenging to keep. Princeps, yemenensis, macfadyeni and a few other species will require a little more humidity and some might even drink from a water bowl, which is unusual for most species of Uromastyx. “There’s a lot of information out there” added Kamiel. “It’s quite easy to see if the species lives in more coastal or more arid regions and even get climate information on the temperatures, daylight hours and UVI readings, which can be easily found through google. This is important because some species come from areas where these temperatures don’t drop at all and others come from areas where, in the winter, temperatures drop drastically.”
Sadly, the availability of Uromastyx in the UK has dropped greatly in recent years. Kamiel added: “I think for the UK, Brexit has been pretty terrible for all species listed under CITES, not just Uromastyx. Before Brexit, friends in the UK could visit shows such as Hamm and pick up various species of juvenile Uromastyx. Back then, we could do the paperwork for them on the spot but now people have to apply for the paperwork ahead of time.”
Uromastyx nigriventris
Keeping Uromastyx
Uromastyx need exceptionally hot temperatures to thrive and should have access to a hot area that reaches up to 55°C. Not only does this require a lot of energy it also requires several different bulbs to create a hot zone that covers the entire animal, provides UVB and maintains an exceptionally bright environment. Kamiel uses a T5 for the UVB as well as two halogen lamps next to each other (of different wattages to create a gradient) and in the cold zone where they can retreat from the heat, a 6500K energy saving light to ensure the enclosure is as bright as possible. “People think my cages are really bright, but I have a lumen meter and it’s not one-tenth of what I can measure in my garden in the Netherlands and that’s not even half of what I can measure in a desert in Africa. Uromastyx enclosures need to be really bright! I think it’s strange that people use black cages for desert species because the black absorbs the light. Although my white PVC enclosures stain quite easily, I personally think it’s better to use white or light wood vivaria for desert species. The minimum size is 4 x 2 x 2 feet for one Uromastyx, but bigger is better. I see people using glass tanks that are way too small to provide a proper temperature gradient. Also, glass tanks have exposed sides which can make the Uromastyx uncomfortable easily stressed and less tame.”
Uromastyx need a cool end surface temperature of 28°C, a middle-zone surface temperature of 35-45°C and a hot spot that reaches 50-55°C. This is extremely difficult to achieve in small vivaria and requires careful consideration towards the placement and choice of lighting products. Therefore, it is important that new keepers fully understand the nuances of each individual electrical component before building their Uromastyx’s enclosure.
Although Uromastyx are expensive to keep, Kamiel is resourceful with his hobby. Firstly, he uses solar panels to provide electricity during summer. Also, by investing in a solarmeter he can see whether lamps are still giving off UVB. If they are not providing UVB, they can still be used alongside a T5 tube and a heat source to add more visible light to the enclosure. Kamiel’s collection is also comprised mostly of desert species, meaning that the room is always kept warm. For the average person who wants to keep a single Uromastyx in their home, several very high-wattage bulbs are required. However, Kamiel can reach similar temperatures with lower wattage bulbs because of the conditions within the room.
Wild Moroccan Uromastyx (U. nigriventris)
Kamiel added: “My energy bill did go up by €200 a month and I’ve heard of people who can’t sell their animals because people are scared of the costs, but most people that breed Uromastyx don’t do it for the money because it is already a very expensive animal. The lizard may only be €200 - €500 but they need a big enclosure, special lighting and a lot of heat. I think people that are into keeping Uromastyx for the right reasons, as a pet or hobbyist, won’t have such a problem with the rising energy costs as a hobby can cost a bit of money.”
Uromastyx are best housed in a naturalistic enclosure with a natural substrate. Kamiel uses a mix of granite rock, play sand and soil to achieve similar results. The use of natural substrates and décor can produce an excellent-looking cage without the need to add plants or create a bioactive setup. Although arid bioactive enclosures are reasonably easy to build for species that require lower temperatures, Uromastyx inhabit some of the most uninhabitable areas on earth and therefore, experimenting with bioactive might jeopardise the welfare of the animal.
“Bioactive should be a way to achieve a goal and the goal should be to have a healthy, thriving animal” explains Kamiel. “Going bioactive should be a way to achieve that goal, not the goal itself. In my opinion, I have not seen one good bioactive Uromastyx setup. The simple reason is that they need a very high temperature and all vivariums are too small to achieve this with a bioactive setup. If you go to their natural habitat, their basking spot is a rock that gets really, really hot. They have to travel much further to reach plants and get to their food source of plants. My largest cage is 10 feet long, three feet deep and two feet high. That’s for my loricata pair, so I can split them up. Even if I housed a much smaller species in there, it would be the only enclosure where I could maybe try to make it bioactive.”
For Uromastyx, it is much easier to create a naturalistic enclosure than a bioactive one and there are practical ways to achieve this. Uromastyx use thigmotaxis to warm up and feel secure. This is when an animal wedges itself into a tight crevice to press its body against both the top and the bottom of the hiding place. Uromastyx can even inflate their bodies and use their spiky tail as a defence mechanism, so choosing a hide that simulates this is extra important. Kamiel uses roof tiles that are angled to create a wide opening and a narrow interior so the lizards can hide amongst them. Tiles also warm up quickly and will produce an additional warm area with IR-C away from the dedicated “hot zone”.
Although ambient humidity should be kept low for most species, all should be provided with a humid hide that’s large enough for them to enter and turn around. This is most easily achieved by using a plastic box containing a layer of sand mixed with either moist vermiculite or peat moss. The additional humidity will allow the animal to hydroregulate and shed its skin much easier.
Uromastyx ocellata
Diets
Uromastyx are primarily herbivorous, although some species will eat insects occasionally. A varied diet is extremely important for most reptiles and Uromastyx are no exception. Leafy greens should make up the bulk of the lizard’s diet, but adding carotenoid-rich toppers such as shredded carrot or pumpkin can provide a nutritious treat. As most vegetation grown for commercial use is far richer than wild vegetation, Kamiel also adds hay to his reptiles’ diets. By finely chopping the hay and mixing it with more palatable leafy greens, he can mitigate the richness of shop-bought salad. The ratio of hay is also increased during winter when the Uromastyx are less active and would naturally experience food shortages in the wild. “I still feed my animals in winter, but a lot less” adds Kamiel. “I give them a few hours of UVB, so they can still eat, drink and digest their food. Some will be visible for a few hours a day, while others wont be out for a few weeks or alost all winter.”
For some herbivorous species that can be fussy about supplements, the keeper must have a good knowledge of the calcium-to-phosphorous ratios of the plants they are feeding to their animals. For example, endives, dandelions and many garden weeds will have good amounts of calcium in them. If an animal is fed a natural diet and has access to the right level of UVB, it should be able to synthesise vitamin D effectively. Uromastyx are highly adapted to the aridest places on earth so their bodies are excellent at gaining nutrients from small amounts of vegetation.
“I only really use calcium and vitamin supplements once every two weeks” added Kamiel. “For gravid females, I will add a bit more calcium. The problem is Uromastyx don’t like the taste of calcium and vitamins, so if you add it too often they won’t eat as much as they normally do. I used to add calcium one day and vitamins the next but they wouldn’t eat the food. Now, I feed them every other day so they have enough food to skip a meal when I do add calcium but it is available to them if they need it.”
“In the summer I try to provide about 50% store-bought plants and the rest is from my garden. Just about everything in my garden is edible, I also have some huge hibiscus plants, so I try to add all those things in during summer. If I only had a few lizards, I would hand-pick their food every day but because I have so many animals I do need to use some store-bought stuff as well. Luckily, the tortoise table app is really good, because you can put in the Latin name of a plant in your garden and see whether it’s good for a tortoise or not. About 90% of the time, if it’s good for a tortoise, it’s good for a Uromastyx!”
An aspect of Uromastyx care that carries some controversy is hydration. Not all Uromastyx species will drink from a water bowl, but the novice keeper should provide access to water where possible. In some countries, it is a legal requirement that all animals have access to water. However, the average pet keeper will not raise the humidity in their lizard’s enclosure too drastically by including a small shallow water bowl. “Some species will drink and some won’t. So, for novice keepers, I would recommend including a shallow water bowl. They might not drink from it, but it’s certainly not a bad thing,” explained Kamiel.
An example of the foliage in Uromastyx habitat. Seasonality plays a huge factor in food abundance.
Breeding Uromastyx
Uromastyx, like most reptiles, require seasonal fluctuations to encourage breeding. Although it may take several years to ‘cycle’ a pair of Uromastyx, the breeding process begins and temperatures in Europe start to fall. “The year starts in November” explains Kamiel. “This is when the animals go into their winter resting period. Some species are awake for an hour every day, others will be hiding for many days. Thomasi and princeps come from a climate that has higher temperatures all year round, so they barely change. Others will have a proper cooldown process, so even though they have access to a hotspot of 45°C, it’s only on for 4-6 hours a day. They are also allowed to drop to 13°C at night. I would probably tell an inexperienced keeper to not drop below 15°C, but my heater kicks in at 13°C. This prompts them to enter brumation around December time but I try to plan it around the Dutch weather as it can be unpredictable. They tend to wake up and go into breeding mode around March. This is when I’ll increase daylight by 2 hours a day until I’m back up to about 13 hours of light and the heat is usually on for nine or ten hours a day.”
Some species that are kept togehter for the biggest part of the year will start to showing some mating rituals like chasing, headbobbing , neckbiting and females turning on their backs around April. At this time, he also searches for signs of breeding behaviour in individually-housed animals. If he begins to notice the males getting restless and the females becoming more active, he will introduce the female into the male’s enclosure. Each species will be paired slightly differently. Most Uromastyx are left in pairs for between two to four weeks, while others must be removed instantly after copulation. Even individual males belonging to a docile species can become territorially aggressive towards the female after mating and females can become extremely agressive to males after breeding, especially after egglaying.
“The eggs usually start appearing in May, June, July and even August if it’s a late year. This is the best part of the year for me! When I see that a female looks thin and I can go digging in the nest box, I always find that a lot of fun. If the animals are still paired, I will remove the female to get fat and healthy again and add a water bowl to every enclosure, especially the females.”. Smaller lizards will usually produce smaller clutches, so U. thomasi, U. princeps and U. o. philbyi generally produce around six to 15 eggs whereas U. nigriventris and U. d. flavifasciata will generally lay 18 – 25 eggs. Some medium-sized species can be sporadic with their clutch sizes. For example, Uromastyx ornata can lay clutches of six to 20, but in extreme cases even 30 eggs without complications whereas phillbyi will only ever lay between six and 10 eggs at a time. This has produced interesting waves of demand for Uromastyx.
Kamiel incubates most eggs at around 32°C – 33°C and the incubation period can vary from 65 to 90 days. Hatchlings appear in September/October and after this, the cycle begins all over again. Kamiel added: “It’s very healthy for a female to skip a year, but if she skips several years I need to re-think what I’m doing. So, in winter I will analyse everything I have done and start to think about the next year. Now is also the perfect time to change bulbs over and re-do cages because all the lizards are down for winter so I can begin preparing for next year.”
A love nurtured
Uromastyx are some of the most energy-demanding of all exotic pets. They are infrequently bred in captivity and some species lay such small clutches that they will never reach the height of popularity as other desert species. However, they are perhaps some of the best pet lizards for the right type of keeper. As we are still learning a lot about them in captivity and breeders are getting better results, they will likely be more available in the near future.
Many people describe Uromastyx as tortoises without a shell. They have bulky heads, a flattened stocky body with short but strong limbs and claws that are perfect for digging. Although every species, and even every individual, is very different, some can be easily tamed, are robust and strong, feed mostly on vegetation and in some cases, are amongst the most colourful reptiles in the world. Kamiel concluded: “Although I love all reptiles, it’s the ones with the spiny tails that appeal to me most. What started out as an interest in all reptiles slowly developed into a passion, a love, for the Uromastyx and became a way of life. I cannot imagine my life without Uromastyx. They are a great and diverse genus that can adapt well to captivity. With more and more people starting to breed them there will be a good variety of captive bred Uromastyx species available in the near future. As long as their basic needs are met, the Uromastyx can be a rewarding and long-lived pet and a lifetime hobby. Just make sure you do your homework, like you need to do with every new animal!”
