Nile monitors are occasionally seen in the pet trade but are not recommended due to their large size and agility. But regardless of what kind of a pet they make, Nile monitors are popular with the large lizard lovers because of their swimming and tree climbing abilities and sheer beauty.
These monitors can thrive in captivity but aren't always the friendliest. If raised from a very young age and handled regularly you may be able to trust your monitor a little bit, but more often than not they aren't very tame. These reptiles are strong, can be aggressive, and are large. From the "Little Book of Monitor Lizards" in 1995,
"There are few of these lizards less suited to life in captivity than the Nile monitor. Buffrenil (1992) considered that, when fighting for its life, a Nile Monitor was a more dangerous adversary than a crocodile of a similar size. Their care presents particular problems on account of the lizards' enormous size and lively dispositions. Very few of the people who buy brightly-coloured baby Nile Monitors can be aware that, within a couple of years, their purchase will have turned into an enormous, ferocious carnivore, quite capable of breaking the family cat's neck with a single snap and swallowing it whole."
(Bennett, D. 1995. Little Book of Monitor Lizards, Viper Press, Aberdeen, UK) Need I say more?
Feeding Nile Monitors
Nile monitor lizards have a voracious appetite. In the wild they feed on a variety of prey items including fish, eggs, insects, rodents, birds, and even other reptiles such as snakes. As pets, Nile monitors are usually fed insects like crickets when young and rodents like mice and rats as they get larger (although wild Nile monitors eat live prey items, it is not recommended to feed live mice or rats to a pet Nile monitor to prevent the risk of the prey biting your lizard).
Gut loading crickets and dusting with calcium powder before feeding your monitor is vital for a growing reptile but if feeding whole mice or rats it is not necessary to add anything to the prey items.
Juveniles should be fed daily and adults should be offered food a few times a week. Obesity can be an issue in adults who don't get enough exercise therefore be careful you are not overfeeding your monitor. When considering how much an adult monitor eats a week (several large rats) you can see how expensive owning a Nile monitor will get.
Of course bigger is always better when it comes to reptile housing - especially for a monitor that likes to climb, swim, run, and can grow to be nine feet long. At the bare minimum, your enclosure should be twice as long as your full grown lizard is. This means your six foot monitor has an enclosure that is 12 feet long. It also needs to be secure enough to prevent your pet from escaping by burrowing under a fence or climbing out. A large water source, preferably one that he can actually swim around in is required, as is something to climb on and hide in.
An entire bedroom in a house is often used or secure, custom made, outdoor enclosures are great seasonally to provide natural sunlight.
Heating and Lighting
Nile monitors are native to Africa (although an invasive population is thriving in Florida) where the weather is hot. A basking spot temperature should reach 120 degrees Fahrenheit with a temperature gradient down to the 80's during the day and not dropping below 80 at night.
A Nile monitor also requires UVB lighting. This light should be on a 12 hour cycle and the bulb should be replaced every 6 months, even if it doesn't burn out (unless the manufacturer guarantees it to last longer). The invisible UVB rays eventually run out and you are left with nothing more than a fluorescent bulb emitting light.
Overall, a Nile monitor is a beautiful, large, strong, and aggressive reptile. They do not make good pets but are hardy nonetheless. If you are considering getting a pet Nile monitor please ensure a large and safe enclosure, make sure you have the regular funding to pay for all the food it will eat over the next 20 years, and check to see if it is legal where you live and if a vet near you will treat it.