Herpetoculturists have diverse opinions about how large a terrarium should be for any reptile. Many recommend an enclosure based on the special needs of an adult lizard. They say the young monitor will grow into a familiar place from the onset. Some keepers suggest the terrarium be about twice as long as the adult on all planes. That would be at least 6 feet for every cage dimension. Others, pointing out that young monitors are arboreal and spend much of their time in trees, recommend a terrarium 8 or 9 feet tall.
I favor keeping young savannah monitors in terraria measuring about 36 inches long, 24 inches wide and 15 to 20 inches tall. This provides a confined space that allows you to closely examine the lizard, so you can make sure it is eating and look for early signs of ill health. Once the lizard reaches a length of 14 to 16 inches, transfer it to an adult-sized enclosure.
Savannah Monitor Checklist
Thinking of taking the plunge? Keepers of savannah monitors need the following materials to increase their chances for success:
- Terrarium with side ventilation ports.
- Water dish big enough for the monitor to soak.
- Heat lamp for the hotspot.
- Incandescent or full-spectrum fluorescent light for viewing.
- Laser temperature gun and standard thermometer.
- Large rock (not a heat rock) for a basking site.
- Hollow trees, boxes or other hiding places.
- Branches and climbing material for young lizards.
- Enough moist soil for the monitor to dig.
- Good sources for live insects, and live or frozen rodents.
- Books and other husbandry reference materials.
- Calcium, phosphorus and vitamin D3 supplements.
- The name of a good, local herp veterinarian.
2. Climate Control
How to ventilate, heat and light the terrarium should be your next concern. Proper ventilation is important. Avoid aquaria; they have ventilation only at the top. Warm air and humidity will rise up and out of the enclosure. A properly ventilated terrarium allows natural airflow parallel to the substrate. An unventilated roof makes it easier to control the terrarium’s thermal gradient. Specialty suppliers offer such terraria, or you can have one custom built.
Reptiles typically derive their internal body temperatures from the substrate and sunlight. A reptile retreats from heat when it needs to cool down and finds heat when it needs it. This is why a thermal gradient is important.
A terrarium needs a basking spot heated to the high end of what the monitor can tolerate. Reptilekeepers generally employ high-wattage or special heat lamps focused on the basking site. For savannah monitors, the air temperature under the basking spot should be between 105 and 110 degrees Fahrenheit. The material under the hotspot, usually a rock, may reach a surface temperature of 135 to 145 degrees, and this is fine. However, avoid using heat rocks because they may burn the reptile’s skin.
There has been much debate lately about the proper temperatures to keep a monitor. Many keepers have discussed hotspot temperatures exceeding 130 degrees. This would be lethal if they meant the air temperature. However, what they mean is that the basking site substrate should be allowed to reach those extreme temperatures. The lizards will move to a cooler spot when they have warmed sufficiently. Air temperature for a single pet monitor should never be allowed to exceed 120 degrees. The maximum surface temperature of the substrate, provided there is at least 2 feet of substrate, should be 130 degrees.