What to Know About Nile Monitors

Reviewed by Amy Flowers, DVM on December 07, 2022

Most large lizard lovers consider the Nile monitor a special kind of animal. This is due to their beautiful looks as well as their impressive tree-climbing and swimming abilities. Despite their interesting features, these lizards do not make good pets. They grow to be large, strong, and aggressive adults that bite, and they should only be handled by experienced reptile owners.

Nile monitors are reptiles belonging to the monitor family. Native populations of Nile monitors are found along the Nile and throughout most of Sub-Saharan Africa. Invasive populations are found in the U.S. 

They are also known by many names such as:

  • Veranus niloticus 
  • Water Leguaan

Nile monitors are large, strong, and quite hostile. They eat so much that they are often called one of Africa's most voracious predators.

Physical characteristics. Nile monitors have features in common with other monitor lizards, including a robust physique and forked tongue. Their strong claws and powerful muscular legs help them climb trees easily. They also have some distinct features that make them excellent predators, such as a bowed lower jaw, an elongated snout, and blunt but strong posterior teeth. These features allow them to easily devour hard-shelled creatures like mollusks.

Their most unique feature — which makes them easy to identify — is their long, laterally compressed tail, which is usually longer than their body. 

Juvenile Nile monitors have beautiful bright yellow and black patterns on their tough skin. As they develop into adults, their heads and backs become covered with olive-brown or greenish-brown patterns while black bars form on the pale skin of their throats and bellies.

The Nile monitor is one of the largest lizards in Africa. It usually ranges in size between 100 cm and 140 cm (tail included). It can, however, reach up to 200 cm in length. In comparison, the hatchlings are quite small, with a weight of 26 grams and a length of 30 cm.

Suitability as pets. Nile monitors usually live from 10 to 20 years in captivity, something to consider when deciding whether this reptile is a suitable pet for you.

They may live a long time, but they do not make friendly pets. Known to be hostile, Nile monitors don't hesitate to bite their owners when stressed or cornered. If you raise one from the hatchling stage, you may be able to trust them a little. But even then, they may resist your attempt to tame them and should be treated with caution. 

If you ever see them standing on their legs, hissing and flicking their tails, this means they feel threatened and are about to attack. They might also emit a foul-smelling odor to deter you or whoever they assume to be their attacker.

Nile monitors live in a variety of habitats in the wild. They can live in swamps, woodlands, evergreen thickets, mangroves, scrubs, and dry savanna. Being excellent swimmers, they like staying near water sources like pans, rivers, and lakes. But they are also great climbers, which allows them to adapt very well to living on land. 

In the wild, you may often find them lying on overhanging branches above pools and rivers during the day. At night, they usually hide or burrow so it is harder to spot them.

While taking care of your pet Nile monitor, keep in mind these points:

Handle with patience. Because of the less-than-friendly personalities of these lizards, it is hard to hold them without being bitten. It's best to start working with them while they're still young and small. If you handle them frequently with care and a lot of patience, you may gain their trust over time. 

Clean regularly. Nile monitors tend to excrete in the water dish. So, you need to clean the dish every day or whenever it's soiled. Also, make sure that the water tub is big enough that they can soak in it fully.

Create a suitable environment. Nile monitors need large, open areas — similar to their natural habitat — to thrive in captivity. Cover their floors with orchid bark or pine shavings and scatter rocks and hollow logs across the area to give the enclosure the look and feel of natural woodland.

Nile monitors need sunlight. Make sure their enclosures get unfiltered natural sunlight. Otherwise, use UV radiation/full spectrum fluorescent reptile lights. Regularly check the enclosure temperature and make sure it is in the range of 80ºF to 90°F during the day and 78ºF to 80°F at night.

Plan regular vet visits. Nile monitors can develop metabolic bone disease if they lack UV light or calcium in their diet. They can also catch infections caused by the Dracunculus sp. larvae.

They often suffer from constipation as they usually eat a lot and many different things — some of which they may not be able to digest. Since you may find it hard to detect some of these conditions in your monitor, you should regularly get them checked by a vet who specializes in lizards.

Nile monitors have huge appetites. They are one of Africa's most voracious predators. In the wild, they eat whatever is available including fish, frogs, toads, insects, rodents, beetles, crabs, spiders, slugs, earthworms caterpillars, millipedes, caterpillars, birds, and their eggs, and even other reptiles like lizards and snakes.

Because this species has adapted to eat a variety of food in the wild, if you keep one as a pet, you should ensure they get a varied and balanced diet. Some of the foods you can feed them include:

  • Fish
  • Cooked eggs 
  • Raw beef heart
  • Canned monitor or dog food
  • Insects (like well-fed crickets)
  • Pre-killed rodents like rats and mice
  • Worms (mealworms, butterworms, waxworms)

While Nile monitors eat live prey in the wild, it’s best to feed them pre-killed foods to avoid putting your pet at risk of being bitten. 

The frequency and the type of food you feed your monitor will depend on its size. For example, small, young monitors need smaller foods every day, while large adults need bigger foods a few times a week. Also, depending on what your vet suggests, you may need to give them vitamin supplements weekly and calcium supplements two times a week.

Nile monitors are known to scratch their owners' faces when agitated. So, it's best to avoid getting one as a pet if you have young kids at home. Also consider your finances, because owning such large lizards can get expensive. 

Not only do these animals need to be fed large prey several times a week, they require a custom-built enclosure with a large water source where they can swim, run, climb and grow to their adult size. You need to ensure that the enclosure is secure enough that they can't escape by burrowing or climbing out. 

If you like reptiles but don’t have experience with them, think twice before getting a monitor. They don't make friendly or obedient pets. Also, check your local legislation to find out if you’re allowed to keep exotic pets in your area. In Florida, for instance, where the Nile monitor has become an invasive species and poses a threat to native wildlife, the law prohibits keeping Nile monitors as pets.

Show Sources

Animal Diversity Web: "Varanus niloticus."
Everglades Cooperative Invasive Species Management Area: "Nile Monitor."
Melissa Kaplan's Herp Care Collection: "Handling Reptiles," "Nile Monitor."
Scientific Reports: "Susceptibility of anurans, lizards, and fish to infection with Dracunculus species larvae and implications for their roles as paratenic hosts."
South African National Biodiversity Institute: "NILE MONITOR."

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