Nile monitors (Varanus niloticus) are giant, diurnal, semi-aquatic lizards native to wet areas of sub-Saharan Africa. They prefer habitats close to water, such as swamps, mangroves, rivers, lakes, and pans.
Nile monitors have powerfully-built bodies, with long necks and long, vertically-flattened tails. Their base color is black or gray, with white to yellow spotting. Like other monitors, they have a long, forked, purplish tongue.
Nile monitors are not easy animals to keep as pets, which is why you mostly see them in zoos. They’re huge, temperamental, and very capable of inflicting moderate to severe injuries on humans. These are a pet only for the most serious of reptile keepers. With good care, they can live up to 20 years in captivity.
Minimum enclosure size for Nile monitors
The absolute minimum enclosure size for a single Nile monitor is 12’L x 12’W x 8’H. In other words, you need at least a small room in order to house a Nile monitor adequately. This may seem huge, but keep in mind that these are very large, active lizards that need opportunities for both climbing and swimming within their enclosure. If you can manage it, larger is always better! If your climate allows, it is generally best to house Nile monitors outdoors.
Housing multiple Nile monitors in the same enclosure is not recommended.
Do Nile monitors need UVB?
Yes! Nile monitors require UVB lighting for their survival. UVB lighting helps provide a clear day/night cycle, provides all of the vitamin D that your pet needs, strengthens the immune system, facilitates better digestion, and provides other benefits. Here are the best UVB bulbs for Nile monitors housed in a 12’x12’x8’ enclosure:
- Arcadia Desert 14%, 34” (x4)
For best results, house the UVB bulbs in a reflective fixture in a 2x2 array. Position the UVB on the same side of the terrarium as the heat lamps. You will need a Solarmeter 6.5 to help position the UVB array correctly so you achieve a UVI of 3.0-4.0 at the height of the monitor’s back in the basking area.
You will also need plant grow lights as part of the environment to supply additional illumination and simulate daylight. Add several ~6500K LED or T5 HO fluorescent grow lamps to provide extra illumination, as well as help any live plants in the enclosure to thrive.
Lights should be set to turn on with sunrise and turn off with sunset in your area, which replicates seasonal changes in day length and helps encourage healthier hormonal rhythms. All lamps should be turned off at night.
If your Nile monitor is housed outdoors in an appropriate climate, with access to direct sunlight, artificial lighting of any kind should not be necessary.
Best temperature for Nile monitors
Nile monitors should have a basking surface temperature of 110-130°F, as measured by an infrared thermometer. The air temperature around the basking area should be between 88-92°F, and between 70-80°F on the cool side, as measured by a wall-mounted digital thermometer.
Provide heat for your Nile monitor with a cluster of halogen heat bulbs placed above the basking surface. You will need enough lamps to evenly heat an area at least the size of the monitor’s body. Halogen bulbs are the best way to imitate the warmth of sunlight indoors, and considered to be a superior form of reptile heating by experts. Do not use ceramic heat emitters (CHEs), red bulbs, or blue bulbs, as these are not as effective. However, radiant heat paneling is helpful for maintaining appropriate nighttime temps if the enclosure tends to get cold at night.
If your Nile monitor is housed outdoors in an appropriate climate, artificial heating should not be necessary.
Best humidity levels for Nile monitors
Nile monitors are a tropical species, so the humidity inside their enclosure should be moderately high: 50-75%. Humidity should be measured via at least one wall-mounted digital hygrometer.
Increase humidity by misting the enclosure 1-2x/day with an automatic misting system. Mist first thing in the morning and then again at night if needed. If you need more help maintaining humidity, install a cool mist humidifier connected to a humidistat to run during the night.
Nile monitors are semi-aquatic, so they need more than just humidity to meet their water needs — they also require a pool of water at least 12” deep, and large enough for the monitor’s entire body. Ideally, it should be deep and large enough to allow for swimming.
Your Nile monitor’s pool water will need to be changed once weekly or whenever it gets soiled. Give the pool a good scrub with animal-safe disinfectant before refilling. Using a siphon (or better yet, a powerful mechanical water pump) and a hose will make maintaining your lizard’s pool faster and easier. If possible, install a drain in the bottom of the pool and connect it to your property’s plumbing.
Best substrate for Nile monitors
Providing a layer of naturalistic substrate (“bedding”) in your Nile monitor’s enclosure will help maintain correct humidity, cushion your lizard’s body, encourage good posture, provide a digging medium, and also help make your enclosure more attractive!
We recommend the following substrates for Nile monitors:
Alternatively, you can use a deep layer of soil and/or play sand. Layering clean, chemical-free leaf litter on top of the substrate can help with humidity as well as add enrichment value.
Substrate should be at least 12” deep and completely replaced every 3-4 months. Remove poop and urates daily, along with any contaminated substrate.
How to decorate a Nile monitor enclosure
An empty enclosure makes for a bored Nile monitor, reducing its quality of life. Keep your pet entertained and engaged with its environment with the strategic use of décor items that encourage it to exercise natural behaviors!
Here are some ideas:
- more branches
- live or artificial foliage
All climbing branches should be securely anchored into the walls/floor of the enclosure to prevent collapse.
Training and designing enrichment activities are also good ways to help keep your Nile monitor engaged, as well as provide a nice opportunity for bonding!
What to feed to a Nile monitor
Nile monitors are carnivorous, which means that they require a whole animal-based diet to get the nutrition that they need. Offer food every 1-2 days, and beware of feeding too much or too often, as this leads to obesity. Each meal should be slightly smaller than the lizard’s skull.
When they’re young and small, they primarily eat insects like:
- dubia roaches
- discoid roaches
- hissing cockroaches
When they’re older and larger, they switch to a vertebrate-based diet, although they also eat whole mollusks like large captive-bred snails. Here are some ideas to maintain variety:
- guinea pigs
- whole fish (tilapia, salmon, pollock)
You will also need calcium and vitamin supplements to help keep your Nile monitor healthy. When it’s young, we recommend Repashy Calcium Plus LoD, lightly dusted on insects. When it’s older, reduce the dusting schedule to just occasionally.
How to handle your Nile monitor
Reptiles generally don’t appreciate petting and handling in the same way that dogs and cats do. It’s important to remember that, although they can be personable and fairly handleable as babies, mature Nile monitors are generally defensive and prefer to be left alone. Given that Nile monitors are very capable of injuring humans, it’s important to learn and respect their body language.
If you want to build a trusting relationship with your pet Nile monitor, you will need to develop a foundation of positive interactions. Offering food from feeding tweezers works well as an initial bribe. NEVER grab the monitor — instead, entice it to come to you.
*This care sheet contains only very basic information. Although it’s a good introduction, please further your research with high-quality sources. The more you know, the better you will be able to care for your pet!
"Nile Monitor" by skuarua is licensed under CC BY-NC-ND 2.0