Monitor Lizards

That Pet Place


9/25/2019 3:28 pm
Monitors are highly intelligent lizards found in many areas of the tropics. While they are well-known for the gigantic Komodo dragon, this family of lizards is surprisingly diverse in size, appearance, and behavior. While some species are too large and potentially dangerous for average households, many smaller ones make unique and interesting captives. The following information can be applied to most species of monitor lizards commonly available.




In and around water sources

Average Size


Life Span

Average 12 years

Natural History

Sixty-eight species of monitors range across Asia, Africa, and Australia. Nile Monitors, introduced to south Florida, are a major environmental concern. Lace Monitors, Komodo Dragons, and other massive species are the dominant predators in their habitats.

Depending upon the species, monitors take prey ranging in size from termites to deer. The Komodo Dragon has on occasion attacked humans, while three species from the Philippines are unique in consuming fruit.


Monitors are very alert lizards and easily startled by noises and sudden movements. They vary greatly in personality both by species and individual specimens. Some may become quite docile, while others remain wary of people. All are very responsive and quickly learn to anticipate regular feeding times.

Even 2 to 3 foot long monitors can inflict severe bites and scratches that could require medical attention. Monitors of this size and larger must be restrained when handling. The mouth, tail, and claws should never be allowed near one's face.


Setting up the Terrarium

Hatchlings may be housed in 20-55 gallon aquariums. Monitors in the 3 to 4 foot range are best kept custom build enclosures, preferably made from wood/plywood, plexiglass/glass front facing doors and all lights in the interior. A formula for choosing a minimum enclosure size is" 2 x the animal's total width, snout to tip of tail, by 2 x the animal's TL deep, and 1.5x the animal's TL tall. A 4 foot monitor lizard should be, at minimum, in an enclosure of 8' x 4' x 6' tall. Note that these are minimum dimensions. It is always better to go bigger! 

Height is an important consideration for arboreal species. Monitors 6 feet or longer require room-sized enclosures with drainable pools.

Stout branches, wooden shelves, and secure hide boxes should be arranged according to each species' needs. A water bowl large enough for bathing must always be available, while aquatic monitors should be provided with a larger swimming area that is easy to clean. Allowing your monitor to roam in a safe escape-proof room for short periods of time will make a large difference in its health and quality of life.

Sand is suitable for monitors occurring in arid environments. Cypress mulch or fir bark can be used for forest dwellers. The largest species should be kept on easily-cleaned rubber mats or in custom rooms/cages equipped with floor drains.

Light, Heat and Humidity

Monitors should be given daily exposure to UVB radiation in the form of UVB fluorescent bulb or mercury vapor bulb. The functionality of these bulbs and their positioning in relation to the basking site vary depending on the strength and type of bulb used. UVB radiation allows reptiles to synthesize Vitamin D3 in their skin. This essential vitamin can also be given in the form of powdered supplements.

Most monitors require basking temperatures of 90-100°F, but must be able to move to cooler areas of 75-88°F as well. A ceramic heater, under tank heating mat, or red/black night bulb can be used for supplemental heat after dark.

Species from arid climates will develop health problems in damp enclosures while those found in tropical forests need access to both damp and dry areas.


Males will fight and cannot be housed together. Females may also battle for dominance. Juveniles may be housed together on a case by case basis, but must be watched carefully.


Strict attention to diet is essential for all monitors. Nutritional deficiencies can develop quickly and are difficult to treat. High calcium intake and access to Vitamin D3 and/or UVB radiation is especially important for juveniles.

Species that feed mostly on invertebrates, including Savanna monitors, should be fed a varied diet comprised of roaches, crickets, waxworms, hornworms, superworms, wild caught insects, canned snails and grasshoppers, wild-collected insects, and occasional nestling mice. Larger species that prey upon whole vertebrates and carrion can be fed mice, rats, hard cooked eggs, and fish.

Invertebrate prey should be coated with a calcium powder regularly and a separate multivitamin supplement and mineral supplement should be used less frequently.

Depending on the type of food items, adult monitors can be fed daily, every other day, or twice per week. Smaller species and juveniles should be fed at more frequent intervals.

Daily Care and Maintenance

Check monitors daily for signs of injury and disease, such as swollen limbs, wheezing, mites, broken toes, rubbed noses, and unshed skin. Daily care includes misting, changing water, removing waste and uneaten food, and feeding.

Health Considerations

Large monitor lizards are potentially dangerous animals and can inflict serious wounds. It cannot be stressed enough that extreme caution needs to be taken when dealing with these specimens, and that they are unsuitable for all but the most experienced hobbyists and professionals. Smaller monitors can also cause nasty lacerations with their teeth and claws. Monitors are wild animals and must be treated with respect and proper precautions

Salmonella bacteria, commonly present in reptile and amphibian digestive tracts, can cause severe illnesses in people. Handling an animal will not cause an infection, as the bacteria must be ingested. Salmonella infections are easy to avoid via the use of proper hygiene. Wash your hands with warm, soapy water before and after handling any animal. Please speak with your family doctor or veterinarian for more tips on preventing Salmonella, or please read our care guide Cleaning and Disinfecting Recommendations for additional instructions.

When it comes to your new pet, knowledge is the best way to choose an appropriate addition to your family. Learn as much as you can about your new friend before you bring him home to ensure your pet enjoys a long, healthy life.

If you have any questions or concerns, please contact our reptile room at 717-299-5691 ext. 1246 or