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Spiny Lizards

Biology

Spiny lizards are all lizards from the family known as Iguanids. They are mainly small to medium sized lizards that come from the New World. The tail is about half the total length. They are often attractively coloured with shades of grey, brown and green predominating. Some of the males also have patches of blue to make them even more handsome.

Housing

Spiny Lizards are best housed in as large a cage as possible. Because of their rapid rate of growth and the heating and lighting equipment they need, purpose made vivaria are probably the most appropriate. The types with sliding glass doors to the front being especially resistant to escape. Another often-used cage is a converted aquarium. A special adapting lid is used to contain the reptiles and attach the heating and lighting equipment that may be used. As a guide, the cage recommended should be a minimum 60 cm x 30 cm x 30 cm for a pair of small specimens but 100 cm x 45 cm x 45 cm for an adult pair of the larger type like Desert Spiny Lizards. Of course, the cage could be larger as this would allow the animal room to grow and make it easier for the owner to manage the environment. The cage should be set up in a manner similar to the diagram over leaf. It will be necessary to provide a local hot spot near 40ºC, while the coolest part of the cage should be nearer 28ºC. The hot spot can easily be arranged by installing a Basking Spot Lamp. To ensure the cage does not overheat, the lamp is best controlled with a HabiStat Dimming Thermostat. White and UV light, from a lamp like a Reptile D3 tube, will be needed and should be present for a similar period as the hot spot; about sixteen hours per day in summer dropping to eight in winter. Much of the success achieved in keeping Spiny Lizards will come from the skilful manipulation of ventilation. The lizards require lowish humidity and cannot stand stagnant air conditions. Fresh air moving into the cage is essential. Use the upward draughts caused by heated air rising to flush out the cage and drag fresh air in. A light occasional misting with a hand sprayer will provide any moisture required.

Husbandry

Spiny Lizards may be kept singly or in groups. Of course the more lizards kept in each cage, the larger the cage should be. Males will tend to fight as they reach maturity and no more than one should be present in the cage. In any case, there should be plenty of retreats and visual screens. Watch out for bullying, particularly among juveniles. These lizards may become quite tame but do not really like being handled. Some individuals are a little nervous and will not hesitate to bite if restrained. The bite, whilst not as dangerous as that of a pet dog or cat, can be a hefty pinch. The teeth are, however, tiny and will not inflict anything more than a superficial wound. The lizards will wriggle if held and try to escape. The tail is easily shed and should not be grasped. Once shed, however, a new tail will grow in time. So to sum up; only handle the lizard if absolutely necessary and always hold the head and body, not the tail. As a last caution, watch out for the nails, which may be sharp and inclined to scratch. In time the cage will begin to look scruffy as faeces and debris builds up. As everything recommended for the cage is washable or disposable, a good clean out is easily done. Eight to ten weeks would be about as long as the cage could be left before being completely cleaned. The cage set up advised in this leaflet is practicable and can be made to look pleasing to the eye. If a more natural set up is envisaged, it may be best to wait until some experience is gained. In any case, some of the very informative books on Lizards in general and Spiny Lizards in particular could be investigated.

Food & Feeding

Insects like crickets and locusts form the staple diet in captivity. Mealworms can also be fed. Insects should be dusted with Repton. Alternatively, the live food can be fed Cricket Diet Plus and Mealworm Diet Plus respectively to 'load' the insect with vitamins and minerals but do not dust and gut load! Other insects that are eaten include Waxworms but these are best given only occasionally as a treat. Another occasional meal that is accepted by the larger specimens are the commercially prepared, fresh meat reptile diets or a frozen rodent pup that has been thoroughly thawed. With all food it is important to balance the nutrients. These lizards grow very rapidly, so any dietary deficiency will quickly result in deformity. Calcium and the associated vitamin D3 being particularly important. Live food is only eaten if it is seen to move and will usually be jumped upon and grabbed with the mouth. One lizard may eat up to ten or more insects at one meal; it will depend upon their size. Feed the lizards every other day with just enough to be completely eaten in fifteen minutes. Try not to leave an excess of uneaten insects in the cage. In addition to live food a portion of sweet fruit, leafy vegetable or salad could be offered occasionally. A small water dish kept full of fresh water should always be available. The lizards may drink from this but should not be allowed to bathe in it. The more usual method of gaining moisture is to lick water droplets from dew off the scales. This can be replicated by giving a fine misting from a hand sprayer. Make sure the lizard and any of the cage dampened, dries out within about half an hour. Good ventilation and adequate heat will keep the cage dry.

Reproduction

Spiny Lizards are proportionately larger than the females and they have broader heads. The males have brighter colours, especially blue and have a different pattern to the females. Other characteristics include a more bulbous base to the tail and pronounced femoral pores. For precise information, look up the details of the species being kept. A period of courtship proceeds mating and during this time much activity can be expected. Eggs are laid after mating and they may take several weeks to hatch. A few species, like Yarrow's Spiny Lizard are livebearers. To grow to adult in captivity may take as short a time as twelve months but in the wild, two to five years may elapse. A cooler winter period will be needed to condition the lizards for breeding in the following season.

Health & Disease

Spiny Lizards live for a few years in the wild but seem to live even longer in captivity. They do not suffer from many diseases and veterinary attention is rarely needed. An environment and diet as described in this leaflet will preclude most problems. The most often encountered disease will be a metabolic bone disorder caused by insufficient vitamin D3 or calcium. Good practice, hygiene and first aid will probably deal with rest. If real disease is discovered, a vet must of course, be consulted. Pet lizards do not pose a real threat to human health. All the normal hygiene precautions regarding humans and animals should, however, be observed.