Nile Monitors

Natural History

These large, attractive monitors are found throughout much of the African continent, excluding the Saharan desert. Such a wide geographic range dictates that this species is highly adaptable, both in nature and in captivity, and can be found in a variety of habitats throughout their range.

Most commonly encountered near permanent bodies of water, Nile monitors are adept swimmers, often seeking refuge in water in as a means of evading both predators and the equatorial sun. They possess a laterally flattened tail which serves as both rudder and propeller for these graceful aquanauts.

While rarely toted as a good choice as an "interactive pet," the beauty and fascinating nature of Nile monitors has made them a staple of the American pet trade. Most animals available today are either bred in captivity in the United States, or more often, ranched on African farms. In either case, the specimens being offered to today’s hobbyists are much healthier and hardier than the wild caught animals of yesteryear.

Size and Longevity

Nile monitors are very big lizards, often reaching sizes of 5 to 6 feet in total length. Their size alone should be means for special consideration prior to bringing one of these animals home.

Captive life spans of properly fed and cared for Nile monitors regularly exceed 10 years. Animals living to be 15 or even 20 years old are becoming more and more common as our knowledge of these creature’s captive requirements grows.

Housing

Housing baby Nile monitors is simple. Standard glass terrariums will suffice until they begin to put on size, which will occur rapidly in well fed individuals. Larger and mature animals will require special accommodations, as will any large monitor species.

Once they reach approximately 3 feet in length, Nile monitors will require either a custom built enclosure, a very large commercially available reptile cage, or a converted room. While this may seem extravagant, one must keep in mind that a 6 foot lizard will require large amounts of space in order to properly forage, exercise, and thermoregulate.

Heating and Lighting

Nile monitors inhabit a large range, encompassing a variety of distinct habitats. Nonetheless, they thrive in captivity when provided with ambient daytime temperatures in the low 80's, and access to localized basking areas reaching between 90 and 100 degrees. Temperatures may safely drop into the mid to high 70's at night.

Larger Nile monitors can be provided with even hotter basking spots so long as continual access to cooler regions is available. This is especially applicable in spacious, room-sized enclosures where the animals can easily choose from a wide variety of temperature zones.

Heat can be provided in a number of ways, and the method(s) will be based upon the type and size of enclosure being used. Among the most common heaters are standard heat bulbs, space heaters (for walk-in enclosures), and under tank heat pads or pig blankets. Ceramic heat emitters and infrared (red) bulbs are also excellent choices, and may be used to provide heat 24 hours a day.

Enclosures for Nile monitors should be well lit during the day. A standard cycle of 12 hours of light and 12 hours of darkness is acceptable. Full spectrum lighting is highly recommended for all monitor species, especially those that are still growing. The lighting used should be designed specifically for reptile use, and should provide light in the ultraviolet B (UVB) range of the spectrum. UVB rays help diurnal reptiles synthesize vitamin D3, and aid in the metabolic processing of dietary calcium.

UVB lights are available in a few basic forms. The most common are fluorescent tubes or the more recently available compact fluorescent bulbs. Alternatively, one may utilize self-ballasted mercury vapor bulbs. These large flood lamps provide not only ample amounts of UVB, but heat as well. These bulbs, due to their significant heat output, should be reserved for larger set-ups.

Substrate and Furnishings

There are many acceptable substrate choices for Nile monitors. Reptile (orchid) bark, aspen (shredded or chipped), cypress mulch, and clean soil have all been used successfully. Ultimately, one should choose a bedding that is affordable, easy to spot clean, and not overly drying or dusty.

A fairly deep layer of substrate should be provided. This will encourage natural foraging and burrowing behavior in these active animals.

Enclosures housing smaller monitors can be decorated to the liking of the keeper with various forms and sizes of tree limbs, half-logs, cork bark slabs, and even live or plastic foliage. However, larger monitors would quickly trample such elaborate decor, and should instead be housed in simple, utilitarian enclosures.

Water and Humidity

Nile monitors are powerful swimmers, and enjoy having access to a water receptacle large enough for the animal to completely submerge in. These lizards will spend a lot of time in the water, and will frequently defecate in it as well. As a result, special attention must be paid to ensuring that the water and dish itself remain scrupulously clean.

The overall humidity within the Nile monitor cage does not need to be especially high. However, occasionally misting the enclosure with water will help with shedding, as will the inclusion of a few localized humid areas. These can be easily created by stuffing moist moss into a hide box or under a piece of wood or cork.

Nutrition

In the wild, most monitor species dine on a wide variety of vertebrate and invertebrate prey. The captive diet should closely mimic this, and should be varied and nutritionally balanced. Crickets, mealworms, and roaches should be regularly offered to Nile monitors of all ages. A mixture of lean ground turkey, eggs, and calcium/vitamins can be offered as well. Larger animals can be given rodents occasionally, but a diet heavy in mice and rats can cause health problems over a period of time.

Every attempt should be made to offer Nile monitors the widest variety of foods available. This ensures that they receive a balanced array of vitamins and minerals, as well as reducing the chance of the lizard becoming bored with a monotonous diet.

All non-living prey, as well as all insect prey, should be dusted with a high quality calcium/vitamin D3 supplement at every feeding for yong monitors, and once or twice a week for mature animals. A reptile multivitamin should be similarly used. Consult the manufacturers directions for proper dosing and frequency, as they vary from brand to brand.

Handling

Despite their popularity, Nile monitors are far from what most would consider a hands-on pet. Even with patient and consistent handling most of these lizards never become fully trusting of humans. Instead, they will hiss, whip their tails, and bite if grabbed roughly.

While some very workable Nile monitors do exist, it is best to assume that these animals will be looked at, but not touched. Instead, hobbyists should appreciate the beauty and grace of these creatures from a distance. Doing so will ultimately prove less traumatic to both the keeper and the kept.