FAQ - Monitors

Monitors are generally large, carnivorous reptiles although three species never seen in the pet trade have been known to eat fruit. Of the 70 known species, the three monitors most commonly seen in the pet trade are the Savanna Monitor (Varanus exanthematicus) or Bosc’s Monitor, the Nile Monitor (Varanus niloticus) and the Water Monitor (Varanus salvator). Other species are kept in captivity but generally require special permits not available to the general public.

Savanna Monitor (Varanus exanthematicus)

Also known as the Bosc’s Monitor, after Louis Bosc the French scientist who first described the species, is a heavy bodied carnivore native to the grasslands of Sub-Saharan Africa. Growing to between 4 and 5 feet, the Savanna monitor is a uniform gray to pale yellow with short powerful legs and a box-like head. Primarily a ground dweller, it will use bushes and low growing trees as cover.

Nile Monitor (Varanus niloticus)

Native to the sub-Saharan regions of Africa, this species prefers to live near permanent water sources. One of the larger species of monitor, Nile Monitors can grow over 5 feet in length with some individuals reported as being over 9 feet. This species is not recommended for inexperienced monitor owners due to its large size, extensive space requirements and temperament. Nile monitors are highly adaptable and are considered an invasive species in parts of the United States. Life span in captivity has been reported as being between 10 and 20 years.

Water Monitor (Varanus salvator)

Not to be confused with the Crocodile Monitor (Varanus s alvadorii), there are 5 subspecies of water monitor. Found along the banks of rivers and lakes of Southern Asia, India, Indo-Australian Islands and the Philippines, this monitor is a water dependent species. Classified as an extreme carnivore, water monitors will eat anything they can catch and have been known to scavenge graveyards, raid chicken coops, and attack pets in its native environment. Water monitors can grow to a length of 9 feet, but most individuals are around 5 feet fully grown.

Diet

 Monitors are carnivorous reptiles. The diet recommended includes the animal items listed below.

Never offer scorpions or lightning bugs

Avoid food items such as beef heart and stew meat, as they are not nutritionally complete. When feeding live insects only provide as many insects as the animal can eat in a few hours. Vitamin supplements are unnecessary, and in fact are often harmful. Clean water should be available at all times in a bowl large enough for the animal to soak in.

Temperature and Lighting

Daytime ambient temperature (everywhere in the enclosure) should be maintained around 80-90 degrees F. Monitors also require warmer basking area during the day. Use an incandescent light bulb to heat one spot in the cage (such as a rock) to around 100 degrees F. Night time ambient temperature should be maintained in the mid 70’s.

Monitors require a good source of UVB light for 10-12 hours every day. Fluorescent lamps with a strong UVB output, such as the Repti-sun 8.0 (ZooMed) or ReptiGlo 8.0 (Exoterra) are appropriate. A mercury vapor lamp, such as Power Sun by ZooMed or Mega Ray at www.reptileUV.com provides both heat and UVB. Fluorescent tubes are preferred and should be within 18 inches of the animal's body, with no glass or plastic between them.

Housing

As solitary and territorial creatures, Monitors are best housed individually, as fighting with cage mates can occur between all combinations of sexes. Monitors require a large cage where they can be physically active. Some individuals will require custom built enclosures at their adult length. Provide multiple hiding places and branches for climbing.

Some of the most common medical issues we see in monitors are related to obesity. Over feeding and lack of activity result in obese monitors. Hiding food in their cage so they must search for it and getting them out of their cage to exercise are additional ways to increase their physical activity. Monitors may be housed outdoors in Southern Arizona during the summerto provide natural sunlight, temperatures and activities, but this setup should be done with caution and only by experienced owners as some monitors may revert to wild behavior patterns.

Recommended cage substrates include coarse gravel, dry orchid bark, forest mulch, pine shavings (never cedar), and folded paper. The majority of intestinal impactions occur due to sand (including Calci-Sand), crushed walnut shell, or other substrates composed of small, equal-sized particles and therefore these are not recommended. Indoor-outdoor carpeting is also not recommended due to the possibility of carpet threads constricting toes or being ingested.

Gut-Loading

Gut-loading is the practice of feeding insects a diet high in calcium, protein, and other nutrients prior to offering the insects to reptiles and amphibians.  Domestic crickets and meal worms should be fed a diet consisting of four parts chicken or turkey starter mash and one part calcium carbonate, or a commercial, grain-based calcium enriched product such as those made by Flukers or ZooMed, for two or three days before offering the crickets to your pet. Also, offer the crickets water in a shallow dish or wet sponge.  Gut-loading beyond 2-3 days is not beneficial, and can actually decrease the life expectancy of the insects.

© Sonora Veterinary Group, 2011  Free for distribution with proper citation.