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The Uromastyx genus

also known as Spiny Tailed Agamas or Dab Lizards

Uromastyx in captivity

As I have already stated, the basic information for keeping these fascinating animals can be found in my Uromastyx caresheet. There are areas of special concern, or which can be expanded upon, that I document below.

I must repeat that long term survival of these species as with many others) in captivity depends on attention to their habitat and behaviour in the wild and maintaining Uromastyx in captivity in the long term still remains a challenge. They are NOT an animal for someone new to keeping lizards.

Accommodation

My Care sheet sets out the basic concept. This can, however, be improved for the benefit of the animals and visually.

Expanded polystyrene can be used to represent the shapes of rocks and rock faces. This will need overlaying with several coats of PVA adhesive mixed with sand. This is both visually attractive and will protect the polystyrene which the animals would rapidly shred otherwise. One can also use various resins with sand sprinkled on them before they set. In this case the polystyrene must first be protected by a few coats of PVA as the resin might attack it. This is a job best carried out in the open air and a mask is recommended. Obviously the animals should not be placed in the vivarium until this is thoroughly dried and odour free.

A sprinkling of silver sand over the floor of the cage will allow the easy removal of dried faecal material and dried up food remnants with the aid of a fine sieve (such as a kitchen flour sieve – but get your own – the household authorities might be upset if you use theirs!)

There is little to add to my caresheet comments regarding heating and lighting. The critical factors mentioned therein are both UV and broad spectrum (daylight) lighting, a basking hot spot and a good temperature gradient.

Diurnal and Annual cycles.

There are a great many misapprehensions about the desert environment in which these animals live. It is certainly hot, very hot; but temperatures can drop dramatically at night and there are significant seasonal differences. Our job is to emulate this as closely as is practical.

Once again, these cycles are covered in my care sheet but their importance cannot be over-stated. These natural rhythms are essential to the long term well-being of the animals and equally important the brumation period, brief as it might be, is critical to egg and sperm formation and, indeed, to the triggering of breeding behaviour in the spring.

Breeding

Mating is preceded by the typical Agamid “press-ups”. The male will then circle round in front of his potential mate clearly showing off what a splendid specimen he is. An unreceptive female may hiss and puff at the male and if he persists she may attack him. Others might simply try to run away and the male will pursue her. Occasionally a female will flip over onto her back to avoid being mated although it is unclear if this is a submissive gesture or simply selecting a posture in which mating is impossible.

Sooner or later mating will probably take place in typical lizard fashion with the male placing his tail beneath the female’s with their cloaca opposed to each other.

With a single pair sometimes there will be no attempt at mating at all. The temporary introduction of another male to induce rivalry will often address this. This must always be supervised very closely. Normally, after mutual display, puffing and hissing one male will run way with little more than a parting nip of the tail. He should however be removed immediately and the remaining male will almost certainly be inspired to mate.

Once the female has been mated, she in turn will tend to become more belligerent. She will resist further mating attempts but is also likely to defend the potential egg-laying site. This is the period during which females might well inflict wounds on the male and other females. The gravid female will become fatter and fatter until she is distinctly pear-shaped.

Silver sand, as with most lizards, makes an ideal egg-laying medium although it need not be as damp as with most other lizard species. Neither, however, should it be bone dry. The depth of sand required varies largely according to the species size. Animals such as U. flavifasciata need about a foot while little more than 6 inches is fine for U. geyrii.

Eggs are laid at some point between May and July. With some individuals there will be some exploratory digging in the few days immediately preceding egg-laying, others give no clue at all. It will, in either case, be obvious when the female has laid as she will appear thin and dehydrated and certainly exhausted. At this time plenty of moist leafy, calcium enriched food must be provided. A few extra super-giant mealworms seem beneficial both before and after laying.

The eggs should be removed for incubation. Once again, the incubating medium should not be as damp as with most lizards. If using vermiculite then 1 part of water to two parts vermiculite by weight is about right. (For most other lizards the ratio is 1:1). Temperatures should be about 31C but a small variation in either direction won’t matter. Typical incubation periods are around 90 days.

Infertile or poorly developed eggs may occur in small numbers in an otherwise good clutch and could be attributable to almost any factor – but most are down to husbandry. Entire clutches of such eggs are of more concern. While it is possible that either the male or female are infertile it is far more likely to once again be a husbandry issue – although in such cases it is more serious and probably detrimental to the health of the animal as well.

Rearing young

As hatchlings and for the first few months of their lives, Uromastyx can be kept in quite large groups of 12-15 animals. They should be closely observed to ensure that bullying and/or excessive domination doesn’t take place. Even if this is not seen taking place there will be other clues such as animals hiding away, bite marks appearing or some individuals lagging well behind in growth rates. Once again, separation is the solution.

Young can be accommodated in a suitable, well ventilated vivarium with a UV tube. A basking area is essential to ensure a temperature gradient together with suitable hiding places. Feeding is much the same as the adults but on a smaller scale.

Injuries and general health concerns

Like many Agamids, fights between individuals of the same sex can occur. Occasionally females may pick on a male but rarely vice-versa. As a general rule two males should not be kept together. Two or more females alone, or with a male, seldom produce problems but females can become aggressive towards one another and even the male when they are gravid or do not wish to be mated. Needless to say, whatever sex mix you may have it is important to keep an eye open for aggressive interaction and, if necessary, separate the animals as necessary. Probably the ideal is to keep them only in pairs and even then to have suitable accommodation to allow their separation if need be.

Even with the best endeavours, however, injuries can occur. Mating behaviour, which should not be confused with aggression, may leave females with substantial scar tissue. Even these should be checked to determine if treatment is necessary. Particular attention should be paid to any wounds which produce swelling, especially on the limbs where wounds are almost certainly the sign of aggression rather than mating. Any such swelling almost certainly indicates that some form of infection has taken hold.

In such cases, a specialist veterinarian should be consulted. X-rays may be necessary and a swab to establish the type of bacteria to establish the most appropriate antibiotics.

On occasion animals can become stressed and this can lead to loss of appetite and condition. This also can arise from aggression, but factors such as their accommodation, heating, lighting and food may also be relevant. Even if everything appears fine and yet an animal starts to lose weight, especially if you see the upper limbs becoming emaciated (a healthy Uro will always have plump thighs!) and stops feeding properly then these are clear indications that something is seriously wrong and the vet should again be consulted.

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