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Roughneck Monitor

Roughneck Monitor (Varanus rudicollis) Care Sheet

(Varanus rudicollis)

  • Kingdom:
  • Animalia
  • Phylum:
  • Chordata
  • Class:
  • Reptilia
  • Order:
  • Squamata
  • Family:
  • Varanidae
  • Genus:
  • Varanus
  • Species:
  • rudicollis

Roughneck Monitor
(Varanus rudicollis)

Roughneck Monitor (Varanus rudicollis)


The Roughneck monitor inhabits the rainforest of southern Thailand and Myanmar (Burma), Peninsular Malaysia, the islands of the Riau Archipelago, Borneo, Sumatra and Bangka. In the wild, the Roughneck Monitor is shy, but during the rainy season their activity level increases, making them more visible.

Varanus rudicollis has been found all the way into what is considered Northern Thailand, specifically the Umphang District, Tak Province. Although they have been found in rainforest and even oil palm plantations, they are most closely associated with primary forests (rainforests included but there are many forest types in the tropics- rainforests being just one type) and peat swamps, where they have been found most often.

Roughneck Monitor (Varanus rudicollis)


There is no visible difference between the male and female Roughneck Monitors, which makes sexing them very difficult. Hatchling Roughnecks have bands of yellow and orange. These bands disappear with age. Adult Roughnecks will be darker in color with recognizable pointed scales on the backs of their necks. Adults from Thailand and Malaysia are often almost completely black, but adults from Borneo and Sumatra may be brighter in color.


In the wild, Roughnecks show a healthy dislike of humans. Because of this, they are rarely seen and poorly studied. They are a very shy species in captivity as well, but when handled daily, they have been known to calm down and become fairly tame and social. It is believed when roughnecks are kept in pairs or groups, they are less shy and feel more secure.

"Roughnecks, both Varanus rudicollis and Varanus dumerilii do not show a ‘healthy dislike of humans’; they are much rarer than their presence in the pet trade suggests and they are cryptic (secretive). Daily handling serves more to stress out a Varanus rudicollis much more than calm them down. I have handled my rudicollis twice (in order to move it from enclosure to enclosure). He now feeds readily off of tongs (could feed him with my fingers, but I am not reckless with any of my reptiles, no matter how docile they are), I can touch him without eliciting a defensive response and I can even come face to face with him." --- Michael_C


The Roughneck is considered to be a medium to large monitor. Reaching an average adult size of 3-4 feet although there have been some reports of the breed reaching lengths of 5 feet. Hatchlings are normally 9-10 inches (25 cm) in length and weigh from 20-25 grams.

The size given for hatchlings (25cm) is twice the size of hatchlings of Varanus rudicollis, which is between 10.0-12+cm (slightly over in mm). -- Source: Dale McGinnty personal comments


Roughnecks can live 10 to 20 years in captivity, if properly cared for.


Roughnecks are both a terrestrial (ground dwellers) and arboreal (tree dwellers) species. They hunt for food on the ground but spend most of their time in the canopy of trees so you need to provide both areas in your enclosure. When designing your canopy, make sure you include heavy foliage. Make sure you include many different spots for hiding in your foliage. Adding different levels in your enclosure can also do this.

Hatchings can be housed in a 29-gallon enclosure.
Remember taller is preferred. A juvenile can be housed in a 55-gallon enclosure. Due to their fast growth rate, adults should be housed in a larger enclosure, the bigger the better. The minimum size for an adult should be 6' x 4' x 3 1/2'. Remember to make sure you have a secure top on the enclosure at all times, to prevent escapes.

Roughneck Monitors enjoy swimming, so it is recommended that a pond or large area be provided for swimming. This area should be easy to clean, as Roughneck's have been known to defecate in their swimming area. The swimming or soak is an excellent way to assist your monitor with hydration. Water temperature should be heated to around 85 degrees.


A variety of substrates can be used in the bottom of your enclosure including: peat moss, cypress mulch, coconut bark and topsoil. Cypress mulch or coconut bark is recommended as they hold moisture and will help to maintain your humidity level. Please note when using a loose substrate such as mulch, bark, moss or topsoil; consider feeding your roughneck in a separate container to prevent ingestion of the substrate. *** Ingestion of substrate is not a concern in a well hydrated specimen.


Roughnecks require an ambient temperature of 85-90 degrees Fahrenheit with a basking spot of 90-130 degrees Fahrenheit. Night temperatures can drop to 72 degrees Fahrenheit. To maintain a constant temperatures, use of an under tank heater (UTH) or heating pad is recommended.


A twelve-hour cycle (12 hours of light and 12 hours of dark) is recommended. Even though monitors do not require UVB lighting, UVB has been found helpful in digestion of food.


Roughnecks require high humidity levels between 70 and 90%. The use of a water source that is big enough for the monitor to lie in will assist in keeping the humidity at the proper requirements.


Access to a water bowl that is large enough for the roughneck to soak in is suggested. Misting the enclosure 3-4 times daily is also recommended.


Roughneck's diet consists of mostly insects, but they will also feed on small prey. Insects can include: Crickets, mealworms, wax worms, silkworms, super worms, roaches and butter worms. Whole prey can consist of appropriate sized rodents, quail, fresh water crabs and shrimp, frogs and ground turkey with egg.


Feed hatchlings every other day on a diet of 70% insects and 30% whole prey. Adults can be fed every 3 days on a diet of 60% insects and 40% whole prey.


Roughnecks will breed in captivity, though there could be difficulty. As of 2006, there have only been 21 documented clutches in captivity ever, with Tracy Caron and Dale McGinnty (Tennessee Zoo) being the only ones to have had great success. (Source: M. K. Bayless unpublished manuscript. A Survey and Checklist of the Roughneck Monitor, Varanus rudicollis Gray, 1845 (Sauria: Varanidae) of Indo-Malaysia and Thailand)

Egg Incubation

Females will lay 1-3 clutches a year with 2-14 eggs per clutch. Eggs should be incubated in vermiculite; humidity needs to be kept at 100%. Temperatures in the incubator need to be between 80-91 degrees Fahrenheit. Hatching will take place 90-166 days after laying.


Author: Savannah Munday & Michael Cota
Roughneck Monitor Images - © Jobiensis