Bosc Monitor Caresheet

Bosc Monitor - Varanus exanthematicus

If you are new to keeping reptiles,
please read our introductory care sheet :
Reptile Keeping for Beginners.

Please read the following information below very carefully as a basic guide to caring for your Bosc Monitor. Any new owner would be wise to purchase a more in depth book.

Bosc Monitors are a large lizard, though moderate size for a monitor, from West Africa. Their large size and relatively good nature has made them popular pets.

6 foot Vivarium or larger
Beech Chips/HerbiSoil
Shallow, Heavy Dishes
Rocks/Logs/Branches/Artificial Plants
Crickets Locusts, Eggs, Rodents
Calcium D3 and multivitamin supplements
Spot Bulb, Thermostat, Spot Guard

Bosc Monitors can grow up to 5 feet (4 foot is more common) long and one adult will require at least a 6 foot Vivarium. Many people prefer to use a small spare room in their house. Provide several hiding places throughout the cage so your Bosc Monitor will feel secure. Rocks and logs add interest and make good resting areas. Water must always be available in a heavy shallow dish.

All reptiles are cold blooded and so they can not control their body temperature independent to their environment like we do. The only way they can have some control over their body temperature is to move from warm areas to cool areas and vice versa. So we need to provide a temperature gradient. This is done by heating only one side of the vivarium to create a hot spot and leaving the other side relatively cool. The temperatures necessary on the hot spot and the cool end will vary from species to species.

One of the most popular heating method for Bosc Monitors is with an incandescent bulb controlled by a dimming thermostat.

Another alternative is a Ceramic Bulb that emits only infra red and no visible light. The temperature of ceramic bulbs can be controlled with either a dimming or pulse proportional thermostat.

Whether using an incandescent or ceramic bulb, it is crucial that there is a guard around the heating element to prevent your bosc burning themselves on the hot surface.

Yet another alternative is the use of a mercury vapour UVB spot bulb, like those manufactured by Arcadia, though other brands are available. These bulbs emit a great deal of both heat and UVB and are the closest artificial equivalent to natural daylight. These type of bulbs can not by controlled by a thermostat so should not be used in an enclosed vivarium, but are suitable for use in an open enclosure. If using one of these bulbs, additional UVB lighting will not be required.

The temperature during the day should be maintained between 95F on the hot side and 72F at the cool end with a basking spot at 110F. Locate the tank out of direct sunlight to avoid overheating.

NB With all heating equipment, please be sure to follow the manufacturer’s instructions.

All day-active reptiles require specialist lighting. This is usually provided using fluorescent strip or compact bulbs designed specifically for reptiles that emit a form of ultraviolet light called UVB, the most popular brand in the UK being Exo Terra's Repti Glos though other brands are available. It is very important because day active reptiles synthesize a vitamin called D3 using UVB light. Vitamin D3 is an essential vitamin that allows reptiles to metabolize the calcium in their food. Without it, they can not metabolize the calcium regardless how much is in their diet and so they will suffer from a crippling condition known as Metabolic Bone Disease (MBD) which can result in severe skeletal deformities and in worse case scenarios, death.

Normal fluorescent lights do not emit UVB and nor do common ultraviolet lights like "black lights." Always use a light that is designed to be used for reptiles. These bulbs also emit visible light, however they will only emit UVB for a period of around 9 to 12 months so regardless of whether the bulb is still emitting visible light after this time it will need replacing.

For maximum effect, the bulb should ideally be no more than six inches away from the reptile so try to position the bulb and arrange the vivarium so that your reptile will spend a large part of the day close to the bulb.

There are several types of UVB emitting fluorescent bulb. Repti Glos come in three types: 2%, 5%, and 10%. The percentage refers to how much of the light's spectrum is in the UVB range. 5% and 10% are the most popular though are suited for different types of reptiles. 5% bulbs are usually used with Rainforest and European species since the intensity of the sunlight in these areas is relatively low. 10% bulbs are usually used for desert species that spend a large part of their lives in direct sunlight.

Bosc Monitors require a minimum of 10% UVB.

As mentioned in the heating section, some prefer to use UVB emitting mercury vapour bulbs for both their heating and UVB requirements, though these bulbs should only be used in an open enclosure.

There are a variety of substrates that can be used. Beech chips are one of the most popular substrates, though may cause problems if your monitor accidentally ingests it. Herbi Veg or Repti Maize are a safer alternative since they can be "passed through" if ingestion occurs.

Some people prefer to use Reptile Carpet, which is a coarse, felt-like, material which eliminates any ingestion problems though is not a very natural substrate and makes it impossible for your monitor to burrow into the substrate.

Your Bosc Monitor should thrive on a diet of insects, mainly crickets or locusts (of appropriate size) though you can occasionally feed them mice (appropriately sized), Snails or Eggs for variety. All foods should be supplemented with a pure calcium supplement like Calypso and once a week with Nutrobal (a calcium supplement with added D3), also, fresh water should be available at all times.

Bosc Monitors are one of the tamer monitors but do require work to get them tame.

They may be a bit nervous when young and may be a bit bitey. In the first few weeks of getting your monitor do not handle it at all. Let it get used to your hand entering the vivarium to change its water and for general viv maintenance. At first, your monitor may run and hide but after a while they will learn that you are not a threat and will stay out in the open.

At this point you can try patting your monitor on the back and see his reaction. He may run off or take on a defensive stance. Again, do this daily. Eventually he should be calm and at ease with your presence. At this point it should be fine to start handling your monitor.

Check the vivarium daily and remove faeces and dead food immediately. Wash out the water and food dishes daily. Place the Bosc Monitor in an escape proof container while cleaning the vivarium. The vivarium should be washed monthly in hot water and the substrate changed. Use a Reptile Safe disinfectant to sterilise the tank such as BEA Reptile Disinfectant. Rinse well with hot water and dry thoroughly.

Extra Info
Due to their large size these lizards are not recommended for beginners.

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