Uromastyx acanthinura nigriventris is a native species to the north of Africa mainly Marocco. The species of acanthinura is divided
into two subspecies acanthinura acanthinura and acanthinura nigriventris the last one mentioned is the most commonly kept. The big
difference between the subspecies is mainly the bright colours of the a. nigriventris vs the dull colours of the a. acanthinura subspecies.
These lizards are mainly found in desertareas where they roam the ground. In these environment temperatures vary between 5-60 °C. The level of
humidity is very low between 20 and 60 %. Temperatures may drop far at night. However for the hobby of keeping these lizards room-temperature is
sufficient. In their natural environment the animals live in deep burrows in the ground.
Total length of spiny tailed lizards is between 22 cm (macfadyeni) and 70 cm (aegyptica). The tail consists of the half of the total length of the animal.
The tail of a spiny tailed lizard is very unusual this tail consist of hardened skin in the shape of spikes. The tail varies in every subspecies
the subspecies of occelate have a relatively long tail where thomassi has an extremely short tail. Uromastyx hardwicki has a tail which is least
spiky of al the genus. It is hard to sex a spinytailed lizard (esspecially at a young age). The best advise is to check a few external distinctive
features males generally are more colourfull as femals (aegyptica both sexes are dull). In the mating season the males femoral pores enlarge considerably
with females this doesn’t happen. Males are build more heavily then females so a bulky animal will more often be male males also have a bigger and wider
head as a female. But it’s still hard to sex an animal but with al little experience this can be done.
Spiny tailed lizards are fairly acitve lizards therefore we recommend you keep these lizard in big enclosures approximately 10000 cm2 (1m2) or for
aegyptica 20000 cm2 (2m2). By creating an enclosure with a climable wall you can increase the effective space of an enclosure. Sand can be used as
substrate only don’t finely graded sand like silver sand use only big grained sand. You can also use lime or sand mixed with turf.
When you establish the inside of the enclosure you can use several materials like flagstones other stones etc but alsoe light materials
like bark branches and entire treetrunks. Also provide enough hiding areas (minimum 1 for every animal). Spinytails love to pinch themselves
in between rocks and feel extremely secure like this. They even use their spinytail as a way to close the way for intruders. Look out with
heavy rocks that the animals can’t burrow under the rock and the structure collapses many people lost animals to a similar event.
Uromastyx are real sun-lovers and you can never have to much light in your enclosure. For heating the enclosures I use enforced glass light
bulbs and a UVB lamp for UV. To create the rights temperature in your enclosure you need more than one lamp or you need to put the lamp next
to the middle (otherwise the temperatures will be the same allover). An average temperature of 30 °C-32°C is what you should try to achieve..
In a basking spot temperature may rise to +55°C your other basking spot shouldn’t be over 45 °C. On the cool spots and in the hiding places
temperature shouldn’t be over 25 °C to 29 °C. A night temperature of 15 °C to 20 °C is sufficient this means that you don’t need to heat the
enclosure at night. During the months in the summer I have 12- 14 hours of light and in winter this declines to 8 hours a day.
What shouldn’t miss in an enclosure is a UVB lamp. I use 100 watt Megaray lamps in my enclosures. The UVB lights makes sure that in
the body of the lizard the production of vitamin D3 is kept at a good level this is important for the health.
I feed my spinytailed lizards every day a salad of greens sometimes I skip a day. This green salad consists of mainly enidive. Also I feed:
paksoi tauge several sorts of lettuce leek alfa-alfa grated carrot hawkbit grated pumpkin etc. I also offer a mixture of seeds and red lentil.
The level of humidity is low in the enclosure. One of the hiding places I keep a little moist to help shedding. In general the animals don’t
drink from a bowl they extract the most of the needed moist out of their food. I offer water but this isn’t used many times by the animals.
At night I remove the bowl so that the humidity level doesn’t rise.
Spinytailed lizards are sexually mature after about 3 or 4 years Uromastyx macfadyeni is the only exception on this rule this subspecies
is sexually mature after 2 years. I have successfully bred two subspecies of Uromastyx once with Uromastyx geyri and once with Uromastyx
acanthinura nigriventris. I have offered the animals a winter-rest of 2 months. Gradually I decrease the light hours from approximately 12-14 to
6 each week I decrease with 2 hours. When I reach the point of rest (6 hours) I hold this point for 3 weeks and then I steadily increase the hours
of light (some to this abrupt but I have good results with this method). If the animals keep being active in the rest-period I also decrease the amount
of watts in my lighting. It helps when temperatures outside drop to so that the animals get a low night temperature.
Most times after increasing the hours of light the Uromastyx show their mating-rituals. They first start by the males spinning in circles
in the enclosure and on the female while doing this the male marks the enclosure and the female with a white substance. After this the male
start head bobbing and chasing the female. If this is successful a typical lizard mating follows with the male delivering a firm neck bite to
the female and the tails entangling. If a female isn’t prepared to mate she turns on her back the male usually stops pursuing the animal.
Uromastyx carry the eggs on an average of 6 weeks. After this time the female has increased significantly in size and you can see huge
bulges in the stomach-area. When the female lays the eggs it’s not hard to find them because she will dig viciously and remove all the
sand to the nest. She also loses significant size and weight after the laying. With Uromastyx the female sometimes offers a certain kind
of nest guarding which would suggest maternal care but I have never witnessed this. Only one female would stay in the vicinity of her nest
but didn’t react when I removed the eggs.
Incubation of the eggs
Incubation of eggs of Uromastyx isn’t hard. There is only one important rule don’t incubate to wet. Success will be reached with a mixture
of substrate and water of 2:1 (vermiculite/perlite:water). Temperature should be between 29 °C and 31 °C. The eggs will hatch after 90 to 120 days.
Remarkable is that baby uro’s are very timid when they have just hatched it takes about 4 hours before the animals start walking around. For this
reason is let the animals quite long in the incubator after hatching after 6 hours I put them in their rearing enclosure.
Juvenile Uromastyx are usually much less coloured than their parents. Other than that they behave the same as their parents and dig a lot.
The animals can be raised for the first weeks in a group. After that they will start to threaten each other and they start to fight for dominance
(not in all subspecies I witnessed this with Uromastyx acanthinura nigriventris). You can separate the dominant animals when necessary. It’s very
funny to see a juvenile spiny tail that threatens you they start to dance shacking their behind. I feed the juveniles the same as the parents only
I cut up the salad a little finer. I dust al their food with a supplement consisting of calcium and vitamins.
Spiny tailed lizards are very interesting animals to have. They have relatively simple desert-like enclosures. Uromasty are pretty active
small lizards only sometimes they can be a bit sheer. However with the right amount of space the animals will let you observe them frequently.
Spinytails are one of the most colourfull species of lizards and have very distinctive exterior features (like: colour a tortoise-like head and
a spiny tail). Conclusion: a attractive and interesting animal in the herphobby.
• Uromastyx plus other common Agamids – Jerry G Walls – isbn
1882770870 – The herpetocultural library
• Spiny-tailed Agamids: Uromastyx and Xenagama – R D Bartlett – isbn<
0764125729 – Barron’s
• Uromastyx – Thomas Wilms – isbn 3936180121 – Herpeton
• Dornschwanzagamen – Thomas Wilms – isbn 3980621472 –Herpeton
• Uromastyx and Butterfly Agamids – Jerry G Walls – isbn 079382074x –
• Basic care of Uromastyx Lizards – Philippe De Vosjoil – Advanced
• AVS Uromastyx – Jerry G Walls – Bowtie Pr
• Uromastyx verzamelnummer, 2005 – Stichting Doelgroep Groene
• Draco 31, Dornschwanzagamen – Draco
• Reptilia 16, Dorschwanze – Reptilia