Savannah monitors are robust, hardy lizards that have relatively simple care requirements
Intelligent and appealing, the savannah monitor (Varanus exanthematicus) is a rewarding captive for the experienced lizardkeeper who has the time and patience to tame this large lizard. Adults measure a little more than 3 feet long, which means they need a substantial enclosure with plenty of room to move around. Also, in nature these lizards inhabit sparse grasslands and seasonally dry, desolate places in Senegal east to lower Sudan and western Kenya, so their captive environments need to mimic these conditions.
There are several approaches you can take in keeping a savannah monitor, and each reflects your intent for the lizard. The absolute minimum required to provide a healthy home include the following five topics.
1. Savannah Monitor Enclosures Must Be Huge With Room To Roam
Even if you plan to get a 5-inch-long hatchling, house it in the largest terrarium you can afford. The lizard’s growth rate largely depends on what and how often you feed it, but a hatchling can easily double in length in just four months and reach adult length in less than three years. Most commercially available aquariums will not meet the space requirements of an adult monitor. Of course, you can start by keeping the young lizard in a small terrarium and move it into larger enclosures as it grows, but small spaces present critical problems with controlling and regulating temperature.
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. Savannah Monitor Climate Control Tips
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.
The basking site and its substrate represent the high end of the thermal gradient, so the opposite end of the enclosure must provide lower temperatures. Daytime lows for savannah monitors should range between 78 and 88 degrees. The terrarium must be large enough to offer this thermal gradient. The heat from the basking site must not permeate the entire enclosure.
Provide 12 to 14 hours of daylight. At night, temperatures should range between 72 and 80 degrees. Some lizardkeepers have kept monitors in nighttime temperatures as low as 44 degrees with no ill effects, but this regimen was provided only one month per year, and daytime temperatures were around 95 to 100 degrees.
The terrarium should have a conventional thermometer for checking air temperature, and serious keepers also obtain a laser temperature gun, which projects a thin beam of light onto a surface, such as soil or a rock, and displays the temperature on a screen. A savannah monitor also requires a variety of hides that conceal its entire body and allow it to turn around when inside. A water dish in which the monitor can fully soak is also essential. Keep it in the cooler portion of the terrarium.
3. Savannah Monitors Require Deep Soil
Unless you’re housing very young lizards, the number one substrate is soil. All monitors dig, and savannah monitors dig long, deep, often complex tunnel systems. Fine or beach sand won’t work. The soil must hold enough moisture to support the monitor’s engineering efforts. Whether you use potting soil, a clay-based mixture or good old dirt, the substrate needs to be deep and packed tightly so it has maximum firmness. A depth of 15 to 20 inches is fine for general keeping needs. Keep it moist with periodic sprayings, but avoid making puddles.
You can skip the deep soil with young lizards because you want to be able to observe them easily. They will do fine on a thin layer of soil. Smooth gravel or paper towels are easy to clean, but they are not the best choices. Provide young monitors with small live trees, branches or other objects that offer climbing opportunities.
4. What Do You Feed A Savannah Monitor?
Wild savannah monitors are highly opportunistic carnivores, a bit like vultures. These lizards eat carrion, but like most monitors, their diet is largely made up of large invertebrates. These include orthopteran insects (grasshoppers, crickets and their kin), millipedes, slugs, beetles and scorpions. According to Daniel Bennett, one of the leading authorities on wild savannah monitors, orthopterans make up as much as 60 percent of a hatchling’s diet, about 70 percent of a juvenile’s diet and 9 percent of an adult’s diet.
In captivity, all young and subadult monitors should be fed gut-loaded live insects daily. Large orthopterans can be locally collected during the warm months, and they can supplement a regular diet of giant roaches and gut-loaded crickets.
Gut-loaded insects should be thought of, in part, as vitamin and mineral supplements. Feed the insects leafy vegetables dusted with calcium, phosphorus and vitamin D3 powders. All three of these minerals are essential in the formation, repair and health of lizard bones.
Savannah monitors undergo a considerable dietary shift when they become adults. Half of a wild lizard’s diet consists of millipedes followed by beetles, insect larvae and orthopterans. Captive monitors should be given a primary diet of whole-animal foods, such as mice, small rats and large roaches. The rodents provide natural calcium via their bones and cartilage. Females require a higher dose of calcium and vitamin D3 during egg production.
5. Does the Savannah Monitor Require UV or Not?
There are mixed opinions regarding whether savannah monitors need ultraviolet light. Lizards exposed to UV under experimental conditions had higher blood-calcium levels than lizards kept under standard lighting, but there is no substantive evidence that such extra-high calcium levels are actually needed. Ravi Thakoordyal, a veteran savannah monitor breeder, has written that he has successfully maintained and repeatedly bred lizards without using UV.
A good diet tends to provide adequate calcium without the need for ultraviolet light. UV is more important for animals with slightly poor diets. If you do opt to provide UV for your monitors, choose a full-spectrum fluorescent bulb that was manufactured to provide UVB for reptiles.
Worth the Effort
Savannah monitors are robust, hardy lizards that have relatively simple care requirements. They thrive within a fairly large temperature and humidity range, have a broad diet, and many lizardkeepers can provide for their terrarium needs. Most available in the pet trade are wild-caught, but even imported lizards can thrive as long as their keepers provide the right environment and care. If you can locate someone breeding them, please buy a captive-bred animal.
These monitors also become quite tame with very little handling, which is helpful when cleaning the cage or showing the animal to other people. An adult savannah is neither so large as to require extraordinary space nor so small as to remain comparatively fragile when handled.
Of course, the prospective keeper should remember that a 3-foot-long lizard is still fairly substantial. When the animal messes the terrarium, the smell can be unpleasant, and the cage must be cleaned immediately. They require feedings daily or every other day, so the cost of food must be considered. I am also aware of at least two verified cases where savannah monitors nipped off sizeable bits of dogs’ ears, so give these lizards the respect they deserve.
Robert Sprackland earned his Ph.D. at the University of London. Director of the nonprofit Virtual Museum of Natural History (curator.org), he has been a herpetologist for more than 40 years with interests in lizard evolution, zoogeography and neurophysiology. He has been a regular contributor to REPTILES since its first year.