I see reptiles on a regular and ongoing basis in my small animal veterinary practice and am often confronted by the lack of concise and clear information on general reptile husbandry. The most frequent problems I find can be traced back to poor cage conditions and in an effort to correct this, I am going to go through the points to be considered when setting up a cage for a reptile. I am not including reptiles with special needs, like aquatic/marine specimens as this is a specialized subject requiring facilities out of the range of the average reptile hobbyist.

One cannot reasonably expect your local veterinarian to have detailed knowledge of all the nuances for every possible reptile found in the pet market. It is imperative that the hobbyist inform themselves adequately before purchasing a specimen. It is impossible to give a fully detailed explanation for all the points made in this discussion. I hope to touch on some of these in greater detail at a later stage.

1. Construction

In order to keep the environment clean and limit the build-up of parasites and pathogens, the surfaces of the enclosure/cage should be non-absorbant i.e. impervious to water and easily cleaned. Wood, cork and bark do not make good surfaces.

2. Space

This can be quite perplexing for the herpetologist when commencing this hobby. A rough guide is that the cage should be 1.5x the length of the adult reptile. In some cases this is difficult e.g. large Boids (6m+) may then require an enclosure 9m long, this would be impractical. On the other hand, a fully grown Leopard Gecko should only require a cage roughly 30cm long, again this is silly.

Smaller reptiles usually require somewhat more space and large reptiles a little less space. The reason for smaller herps needing more space will become evident when I discuss temperature control. Larger reptiles are housed in proportionally smaller habitats due to the constraints of economics and available space.

The environment should ideally then be half the length wide and half the length high. As an example, consider the cage used to house an adult Corn Snake. Assuming the snake is 60cm long, the cage would measure 90cmx45cmx45cm.

Using the expected adult length of the reptile, gives one an ideal cage size. If you are unsure, go bigger. You want an enclosure which is long enough and has sufficient volume to allow you to create a temperature gradient.

3. Light

This is a poorly understood and often neglected part of reptile husbandry. Many lizard keepers are aware of the problems associated wtih Metabolic Bone Disease (Chronic Hypocalcinaemia). Unfortunately the cause of the problem is not fully appreciated. Suffice to say that an effective UVB light source should be available.

I have encountered some articles discussing the necessity of UVB in snakes and nocturnal species like Leopard Geckos. I am of the definite opinion that UVB provision is necessary in all reptiles housed independently of full sunlight.

Consider that glass absorbs a good deal of UVB and sunlight through glass should not be considered a substitute for UVB provision.

The quality of visible light should also be considered wrt reptile behaviour. We are dealing with relatively primitive species which take many of their metabolic signals directly from the intensity and length of exposure to natural light. Consider photoperiods i.e. daylength and adjust your cage suitably.

4. Temperature

The preferred optimum temperature for your keep should be carefully researched. I prefer an enclosure large enough to create a temp gradient i.e. a range extending from the warm basking area to something close to room temp. The basking area would ideally be 28-32C (82-90F). The room temp would be in the vicinity of 20C (68F). How do you achieve such fine temp control? Create a thermal barrier around the cage. Control the temp in the room in which the enclosure is kept and fine tune the temp in the cage.

Where I live, winter temp can vary from -5C to 30C. It would be naive to think that the small heating element in a reptile enclosure would be able to cope with such temp extremes. Use the cage heater to fine tune the temp provided by the room.

The heat source should also be carefully considered. In a small enclosure, avoid excessive radiant heat sources (incandescent globes, infra-red light, porcelain heaters) as these push the temp up very quickly and may heat the entire volume of the cage very quickly, drying the air out and thermally stressing the reptile. It also poses a very real burn hazard.

I recommend an under tank heater UTH. These are not fool-proof and usually require some form of covering to spread the heat out (thin cermaic tile is adequate). You should be able to comfortably place your hand onto the covering object without ever needing to pull away from the heat.

It is essential that a maximum/minimum thermometer be placed at the basking area. If you cannot measure it, you cannot control it.

5. Water

Clean water should be provided in a spill proof bowl. The water should be readily available to the specimen i.e. not too high, restricting access in smaller individuals or too deep to present a drowning hazard. I would place the water source on the cool side of the enclosure to limit any evaporation which may create a hygiene hazard with the resultant condensation.

6. Humidity

Do not attempt to closely control the humidity in an enclosure. Too little moisture can quickly be corrected by providing large water bowls and frequent mistings. Dysecdysis (shedding abnormalities) may be circumvented by soaking specimens prior to shedding taking place.

Too much moisture will place your reptiles at risk of developing 'Blister Skin Disease' (Bacterial Necrotising Dermatitis).

7. Substrate & Furniture

These items are considered together because similar circumstances apply. Limit the surface area inside of the tank to facilitate cleaning and hygiene. Avoid sand, corn-cob pellets, vermiculite and similar substrates. They are breeding grounds for mites as well as a host of other pathogens. I spent a long time working for a reptile zoo and the simulate natural environments were a continuous source of frustration when attempting to control and eradicate mites. If you attempt a natural setting, use artificial, non porous decorations and substrates that can be readily cleaned.

Always provide a reptile with an escape option. Try to limit exposure to handling and movement which contribute to the specimen's level of stress. Consider where you place your enclosure. Always put some sort of hide, preferably more than one, to give the reptile the opportunity to hide from any potential source of threat.

8. Sanitation

I will devote an entire article to this in the future. It is essential to limit the build-up of pathogens in a captive environment. I advise cleaning the cage evry 2 weeks (mite life-cylce is 3 weeks). Begin with a detergent (dish-washing soap) followed by sterilization using a branded substance of proven effect. Finally use an insecticidal/acaricidal preparation. Sterilization and insecticide/acaricide treatments may very well require some form of controlled exposure time and you would be well-advised to pay attention to this.

In closing, keeping reptiles should be a selfish past-time. Limit contact between your specimens and anyone else. Try to keep specimens in individual cages and keep those cages clean.