Argus monitors (Varanus panoptes) are also known as yellow-spotted monitors. They are large, diurnal, terrestrial lizards primarily native to Indonesia and New Guinea. They prefer a riparian habitat close to bodies of water.
Argus monitors are lean, yet powerfully-built, lizards with a slender head, strong limbs, and a thick tail. They are typically brown to reddish in color, with rows of pale spots and markings down their body. They grow 3.5-5’ long, with males being larger than females.
Argus monitors are advanced-level pet reptiles due to their high level of activity, large size, and the potential for harming humans. However, when well cared-for, they can be engaging, entertaining, and fascinating pets.
Minimum enclosure size for argus monitors
The absolute minimum enclosure size for a single argus monitor is 8’L x 4’W x 4’H. This may seem huge, but keep in mind that these are large lizards that need access to an appropriate temperature gradient and enough room to accommodate their active lifestyle. Babies under 18” long can be temporarily housed in a 36”L x 18”W x 18”H terrarium if needed.
Of course, if you can manage it, larger is always better! Regular supervised free-roaming opportunities are also recommended.
Housing multiple argus monitors in the same enclosure is not advised.
Do argus monitors need UVB?
Yes! Although argus monitors have been proven to survive and breed without access to UVB, using UVB light in captivity is still best practice. UVB lighting helps provide a clear day/night cycle, supplies all of the vitamin D that your pet needs, supports the immune system, facilitates better digestion, and provides other benefits.
Here are the best UVB bulbs for argus monitors housed in a 8’x4’x4’ enclosure:
- Arcadia Desert 12%, 46”
- Zoo Med Reptisun T5 HO 10.0, 46”
For best results, house the UVB bulbs in a reflective fixture like the Arcadia ProT5 or Vivarium Electronics. Position the lamp on the same side of the terrarium as the heat lamp. The UVB lamp should be mounted inside the enclosure, with the basking platform placed so the monitor’s back will be 14-16” below the lamp.
Argus monitors are also likely to benefit from plant grow lights as part of their environment as well. Add a ~6500K LED or T5 HO fluorescent grow lamp to provide extra illumination, as well as help any live plants in the enclosure to thrive.
Lights should be on for 12 hours/day.
Best temperature for argus monitors
Argus monitors should have a basking surface temperature of 140-145°F, as measured by an infrared thermometer. Juvenile monitors may prefer cooler basking temperatures around 120-125°F. The cool side should be between 75-85°F, as measured by a digital probe thermometer.
Provide heat for your argus monitor with a cluster of halogen heat bulbs placed above the basking platform. You will need enough lamps to evenly heat an area at least the size of the monitor’s body. Halogen bulbs are the best way to imitate the warmth of sunlight indoors, and considered to be a superior form of reptile heating by experts. Do not use ceramic heat emitters (CHEs), red bulbs, or blue bulbs, as these are not as effective.
Heat lamps should be turned off at night. If your enclosure gets cooler than 70°F at night, provide lightless supplemental heat with a radiant heat panel connected to a thermostat.
Best humidity levels for argus monitors
Argus monitors are a tropical species, so the humidity inside their enclosure should be fairly high: 60-80% on average. Humidity should be measured via a wall-mounted digital hygrometer in the middle of the enclosure.
Increase humidity by misting your monitor’s enclosure 2x/day with a large pressure sprayer or automatic misting system. Mist in the morning and at night, preferably when the lights are off. If you need more help maintaining humidity, install a cool mist humidifier connected to a humidistat to run at night.
Argus monitors are very comfortable around the water, so it’s best to provide a pool of water that is deep and large enough for them to soak and swim around in. This means that it should be at least 12” deep, and occupy 1/2 to 1/3 of the enclosure’s floor space.
Your monitor’s pool water will need to be changed once weekly or whenever it gets spoiled. Give the pool a good scrub with disinfectant before refilling. Using a siphon (or better yet, a powerful mechanical water pump) and a hose will make maintaining your lizard’s pool faster and easier.
Best substrate for argus monitors
Providing a layer of naturalistic substrate (“bedding”) in the enclosure will help maintain correct humidity, cushion your argus monitor’s body, provide a digging medium, and also help make your enclosure more attractive!
We recommend the following substrates for argus monitors:
- Zoo Med ReptiSand
- Exo Terra Desert Sand
- Play sand
- 60/40 topsoil/sand mix
Scatter a layer of leaf litter over the substrate to further assist humidity and add enrichment value.
Substrate should be at least 12” deep (absolute minimum) and completely replaced every 3-4 months. Remove poop and urates daily, along with any contaminated substrate.
How to decorate an argus monitor enclosure
An empty enclosure makes for a bored lizard, reducing its quality of life. Keep your pet entertained and engaged with its environment with the strategic use of décor items that encourage it to exercise natural behaviors!
Here are some ideas to get your started:
- hiding places
- sturdy branches
- large hollow logs
- artificial boulders
- live or artificial foliage
Due to argus monitors’ large size, make sure that all branches are securely fastened to the sides and/or floor of the enclosure.
Training and designing enrichment activities are also good ways to help keep your monitor engaged, as well as provide a nice opportunity for bonding!
What to feed to an argus monitor
Argus monitors are carnivores. When they’re young and growing, they are likely to prefer a variety of insects, but as they get larger, they will transition to vertebrates and large insects. Here is a general feeding schedule:
- Juveniles (<3’ long) — daily
- Subadults and Adults (>3’ long) — 3-4x/week
Each meal should be roughly the same size as the monitor’s head.
Feeder insect options for argus monitors: crickets, discoid roaches, dubia roaches, earthworms, grasshoppers, hornworms, silkworms, mealworms, superworms, black soldier fly larvae, snails (captive-bred only)
Other protein options for argus monitors: mice, small rats, quail, chicks, fish, lizards, snakes, eggs (whole), organ meat
How to handle your argus monitor
Reptiles generally don’t appreciate petting and handling in the same way that dogs and cats do. But with patient and persistent training efforts, your argus monitor can become quite tame.
If you want to build a trusting relationship with your pet argus monitor, you will need to develop a firm foundation of positive interactions first. Offering food from feeding tweezers works well as an initial bribe, and it’s best to get the lizard to come to you rather than simply grabbing it.
Here are some more tips for success:
- Never grab the lizard from above. Instead, scoop from below.
- Avoid sudden movements.
- Support as much of its body as possible.
- Start with short taming sessions at first, then gradually make them longer.
- Put the lizard back in its enclosure only when it’s calm.
*This care sheet contains only very basic information. Although it’s a good introduction, please further your research with high-quality sources. The more you know, the better you will be able to care for your pet!
"Varanus panoptes (Yellow-spotted Monitor)" by Arthur Chapman is licensed under CC BY-NC-SA 2.0
