The Uromastyx acanthinurus.

This article is split in to two main sections with each part dealing with
separate issues. The first part is more about the identification of
U.acanthinurus and how it has adapted to life in the arid desert. I believe
this is an important aspect when trying to provide the correct captive
conditions for uromastyx lizards. The second section is somewhat larger and
deals with the captive care requirements of this magnificent lizard.

Introduction.

The sun rises slowly over the Moroccan desert and a gentle wind blows the sand
across the arid terrain. Mid morning comes and the air temperature rises to an
almost unbearable heat for anyone hiking. This is when the uromastyx
acanthinurus emerges from his burrow where he has spent the last evening
buffered from the extreme cold of the North African Desert.

This scene is played out by the North African uromastyx every day of the year
except for the cold African winter when the temperature is too cold for the
lizard and it must hibernate. The uromastyx acanthinurus has lived in this
manor for thousands of years now and has developed many exclusive methods of
survival.

GENERAL DESCRIPTION AND IDENTIFICATION.

The North African Spiny-Tail is a very beautiful and in most cases very
colourful lizard that can reach a total of up to 16 to 18 inches in length
(although most will only reach the length of just over 12 inches). The tail is
by far the most prominent and distinguishing feature of any Uromastyx and
accounts for just under half of the total body length. When the lizards are
very young it is very difficult to tell the difference between males and
females, as they get older it becomes a little bit more apparent. For example
females are not usually as long as the males and have a somewhat narrower
head. The best way to sex them is looking at the adult's pre anal pores. Males
will have small dots running down the inside of the leg starting at the pelvis
and ending at the knee. During the breeding season the pores will be enlarged
and secreting a brown waxy substance. Females also have these pores. However,
they are smaller and are only situated around the pelvis area.

Uromastyx are constantly digging and shuffling the substrate around and as a
result of this have strong claws and legs (especially the rear legs, which
also have large spines on the thighs). If you look at the animal from the top
you will notice that the body is quite depressed and has strong wrinkles on
the sides and around the neck.

The coloration of this lizard has a great deal of variety and is therefore
very difficult to generalise. The colour of any U.acanthinurus may differ
depending on a number of factors such as: -

Age, Temperature, The amount of Ultra Violet light available and even mood.

A healthy, warm specimen usually has bright pastel colours such as yellow,
orange and green. A common adult pattern is black legs and head while the body
remains bright with one of the above colour's mentioned. The lizards also
sometimes have patterns such as stripes (bars across the back) and spots. The
pattern and colours are always over the back, while the underside remains
quite dull. Males are brighter than the females and often show red heads when
ready to breed.

Very young Spiny-Tails do not have bright colours and tend to just be a kind
of light brown colour, as they get older they will develop dark mesh work
across the back and quite often will have darks markings around the eye
connecting to the jaw. I think that the most appealing feature to me must be
the very strong eyebrows and short snout that make the North African Spiny-
Tail look very majestic in nature.

The uromastyx acanthinurus lizards are found over much of the deserts and arid
wastelands of North Africa. Because of this fact, the lizards have adapted to
a wide range of environments and dietary needs. The most important feature
that U.acanthinurus has developed is the ability to remove salt from the water
in the blood stream through a small gland found just above the nostrils, (on
extremely hot days salt crystals form around the nostrils).  By doing this,
the water that is consumed is used much more effectively. This is an important
consideration when you think of how little water is present in the desert. In
fact U.acanthinurus gets most of, if not all of the water it needs from the
plant mater it consumes. Some additional water is also collected by the
lizards from due and condensation forming in the burrow of the animal. There
is some evidence that suggests that uromastyx lizards have channels between
the scales that direct due and droplets of water to the mouth.

The tail of a uromastyx is where the lizards get their common name. Uromastyx
lizards have developed this club like tail for the main reason of defence.
Because the lizard stores most of its precious fat and water reserves in the
tail, they will not shed it even if held by the tail. (Like so many lizards
do!) In fact some uromastyx that have lost their tail in fights with their own
kind or other reasons often die of shock a short time later.

The North African Spiny Tail's large stocky limbs and stout fingers with large
claws make it the perfect digging machine, which is a must in the desert. With
out burrows in the desert all reptile life would almost certainly die due to
the harsh condition there. The burrow serves as a shelter against the cold of
the night, the extreme heat of the day, a warm damp place for the female to
lay her eggs and a protection against predators and even protection against
others of their own kind! Male U.acanthinurus are highly territorial and will
kill any other males in their terrain.

The last thing that U.acanthinurus has developed are large eyes that can
detect movement from a great distance. It is guarantied that a uromastyx will
see you, long before you see him.

North African uromastyx are primarily vegetarian which is another thing
believed to have been adapted. U.acanthinurus will also eat insect material
when available. Many people believe that uromastyx are not vegetarian by
choice but have become that way to aid survival, I tend to agree.

In the wild uromastyx are solitary animals and probably only come together
when mating, however, a lot of uromastyx do tend to share certain parts of the
deserts. This is probably more to do with the conditions in the area, more
than sociability. For example, there could be a source of food or water
readily available. The lizards are only active above ground during extreme
heat and only for a small part of the day, from about 10 / 11 a.m. to 5 / 6
p.m.

BASIC CARE

The most important aspects to consider when keeping any "herp" (Reptile or
Amphibian) are: -

Enclosure (including ventilation)
Temperature (including Humidity)
Diet

Selecting an enclosure

North African Spiny-Tail's come from desert regions where little water may be
present, because of this the vivarium must be keep extremely HOT and DRY.
There are lots of different enclosures on the market at the moment, and with
all the different options it may be hard to pick the right one. For starters
all plastic enclosures are out of the question because Plastic will never be
able to withstand the high temperatures and the lizards scratching. All Glass
tanks should also be avoided because they have bad insulation and unless you
keep the lizards in a very warm room you will need more that one bulb to keep
the enclosure warm thus raising your electricity bill. In my opinion the best
Uromastyx enclosures are made of wood with a sliding glass door for access and
viewing.

Enclosure size

When keeping any uromastyx lizard you must take into account that when fully
grown, they will need a lot of surface room to run around because all
uromastyx are very active lizards. When the lizards are young you should not
keep them in an enclosure that is too big. I know that you may want to give
you lizard as much room as possible, but if the vivarium is too big the
occupants may become insecure and refuse to bask. This will result in a loss
of appetite and the lizard will quickly demise. A good size enclosure for a
baby acanthinurus is about 2 ft by 1.5ft by 1 ft. If you do not want to buy
two tanks you can buy the adult size tank and keep the young lizard inside an
extra large plastic critter cage (like the ones used to keep large spiders,
your pet store will sell them) inside the full size vivarium. The length of
the adult enclosure should be at least 4-5 times the total length of the
animal, and the width should no less than 2 times the total length of the
animal. The tank does not need to be very tall because uromastyx do not climb
very well (although they will clamber over any rock piles that are put on the
surface). This is an advantage when fixing the UV (Ultra Violet) lights
because if the lights are too far away the lizards will not benefit from the
vital rays (see lighting).

Ventilation

Because all reptiles breathe oxygen just like people it is necessary that you
have good ventilation for your uro's cage. Ventilation should be provided by a
hole running the length of the vivarium, the hole should be covered with a
ventilation grill to prevent the lizards or insect pray from escaping.

Decor

The first thing that you will need to put in your uro's cage is Substrate.
There are many different substrates to use and listed below are just of a few
of them: -

1.             Wood Chips (Not Cedar, as this has fumes that can irritate your
uro)
2.               Alfalfa Pellets (Will not wear down the lizards nails and if
the nails are not cut on a regular basis they  may
                  become too long and twist causing infected fingers)
3.               Sand (May cause impactation in younger animals leading to
death, but is safe for adults)
4.               Bird Seed

All of the above are acceptable substrates but a like to use ESU's "Lizard
Litter, desert blend", I use this substrate because it is free from all
bacteria and parasites, safe for the uro's to eat, easy to clean and it looks
good. The only draw back of using this litter is that the uro's can not dig
burrows in it (that is if you're letting your uro dig it's own burrow. Most
don't, including myself).

Now that you have laid out the substrate you will need a place for your lizard
to hide. Hiding places are very important to all reptiles because they provide
shelter from heat, light and inter specific aggression (if you keep more than
one uro in the same cage). The hiding place should be dark, long and slightly
humid if possible (this may help them shed their skins and provide some needed
moisture). For my hides I use Cork Bark, PVC Pipes and toilet roll tubes for
hatchlings. I would put the hiding place in the cool end of the cage as long
as it gets to 80F or so (see temperature). It may also be a good idea to put a
hiding place at both ends of the cage, as the lizards should not have to
choose between warmth and security.

How to create a dark, warm, damp-hiding place: -

1. Take an old margarine tub (one that the uro can fit inside and have room to
turn around in)
2. Cut a hole in the side that you can fit a PVC pipe into (or a kitchen roll
tube if you have a smaller sized uro).
3. Then make sure that you tape up around the connection area so that it is
not lose.
4. Punch a few holes in the lid for air.
5. Half fill the tub with moist sand or vermiculite (Not wet).
6. Half bury the new hide in the substrate and cover with cork bark and you
have a new slightly damp burrow for your uro, which will also provide the
lizard with some much needed moisture.
7. Make sure the burrow is warm day and night because you don't want you
lizard to get ill from cold/wet conditions (about 85/89 in the day and 70/75
at night.)

The last piece of decor that you will need is a large flat rock to place under
the basking spot. This will soak up the heat to reach the kind of temperature
that the lizards are used to. Beware - set up the rock so that the lizard can
not dig under it because it may fall on the animal or trap them until he/she
cooks to death!

Temperature

I have found that there is a great deal of difference in opinion when it comes
to the best temperature to keep U.acanthinurus, with some as low as 80F in the
cool end and some as high as 90F. However I have found that is best to have an
overall temperature of around 85F - 88F in the cool end with a basking spot
that reaches 110F-130F. If the lizards are too hot they may lay in the basking
area and pant. At night time you should let your tank drop to 68F-75F (I know
someone who has kept his night time temperature's as high as 80F with no
apparent ill effects, however I don't recommend it. For younger uromastyx the
basking site should only be 110 - 118 and the night-time temp should not fall
bellow 75. Now you know the best temperature to keep you uro how do you obtain
and maintain the high temperatures? Well I'm going to tell you!

First you should have a wooden construction vivarium as this will insulate a
lot of heat, if you do not have an all wooden tank you can reach the correct
temperatures be adding additional spot bulbs in the cool end.

When you purchased your vivarium or your lizard you may have noticed that the
store sold infra red under tank heating pads made for reptiles. You will need
to buy one. You do not have to use a thermostat with the heat mats as they
provide gentle heat (however, always read the products safety leaflet). The
pad should be placed inside the tank but under the substrate, it should also
not cover more than 1/2 of the floor space and be placed in the middle/hot end
of the tank to provide a "thermal gradient". I'm sure you already know what a
thermal gradient is but I'm gonna tell you anyway! A thermal gradient just
means that you have a hot end and a cooler end of the enclosure so that if the
animal gets too hot or cold it can move to a different temperature zone. Do
not place the basking rock directly on the heat mat as it could tear the mat
and/or make the rock temperature too hot! You can place a small hand/face wash
cloth over the heat mat or just move the heat mat to the middle of the
enclosure. The heating pad will provide you with a good background heat but
you will need incandescent spot light bulbs to provide you with the hot
basking zone. You CAN just experiment with different wattage bulbs until you
find one that gives you the correct temperature but I find it better and
easier to use a "dimming thermostat".

A dimming thermostat can be used with incandescent lights and has a probe that
you should put in the middle of the tank and the temperature dial set to read
around 88F-92F. This will keep the tank at a constant temperature by turning
up or down the light in small amounts (if you check the temperature under the
basking zone I think that you find that it reaches the required temperature).

Lighting

The incandescent spot bulb will provide you with all the "daylight" that you
will need in the tank, however you will need a full spectrum ultra violet
light (UV). By far the best UV light to use is the Zoo Med "Reptisun 5.0",
when you are using an ultra violet light you must remember that the tubes
should be replaced at least every year and more often if you can afford it.
The bulb should be placed not more that 10 - 12" away from the basking area or
the animal will not be able to soak up the UV light. The day length should be
12-14 hours in the summer and 10-12 hours in the winter. It is best if you buy
a timer switch for this just in case you don't come home for the night!

Humidity

When keeping any uromastyx it is a good idea to keep the air humidity down and
under 50%. I would say that a good air humidity level is about 20% - 40%, any
lower and the uro may have problems shedding, any higher than 60% the uro will
become sick and die.

Diet

The diet for these animals is just as important as all the above issues
because with the correct diet they can have a healthy and extended life (maybe
even years).

First off ALL uromastyx lizards are primary vegetarian so should not be given
too much animal protein as it may lead to kidney problems, however immature
uromastyx should be fed insects 2-3 times a week. Crickets are the best live
food but wax worms can be very useful for fattening up thin animals and will
be relished. However wax worms are full of fat and are very rich therefore
should not be feed more than twice a week and only a couple at a time (if too
many are feed the uro may get runny stools). Insects should be coated with a
calcium and mineral supplement at every feeding.

The best way to provide a good diet is variety, try and give your lizard as
bigger choice as you can. Bellow is just some of the foods that provide good
nutrition and are liked by the uro's: -

Endive, Kale, Spinach (not too much as it can block some of the uptake of
calcium in the body), Hibiscus leaves and flowers (If available), Mustard
Greens, Peas (frozen and dried split), Carrots, Apple, Banana and Dandelion
flowers. Birdseed and dried split pea's can be offered once a week.

Its is also very important that you supplement the food given to the lizards
on a regular basis as this will help the lizards grow strong and prevent done
disease. With immature uro's you should supplement every other feeding with a
calcium and mineral mix (approx. 4 parts calcium 1 part multi vitamin). Adult
uro's should only be supplemented 1-2 times a week.

Water

Uromastyx lizards need very little water and most will get the needed water
from the greens that they eat. To make sure that the uro gets all the water
that it needs you can spray the food with water and keep a SMALL water dish in
the cold end of the tank so not to raise the humidity level.
 

By Adam B. Cheal
 
 

I would like to thank the following people for husbandry advice, natural
behaviour information and support: -

Rob Crunden
Simon Crunden
Randy Gray
And the Uromastyx mailing group

For details on how to subscribe to the Uromastyx mailing list see the front
page of the Uromastyx home page.