Lace Monitor (Varanus varius) Care Sheet
The Lace Monitor is a very large, highly intelligent and active Australian monitor lizard. Also known as the Tree Goanna, it is an accomplished climber but also spends substantial time travelling and foraging on the ground.
Lace Monitors require purpose-built, walk-in accommodation, powerful heating and lighting systems, extensive climbing structures, deep substrate and a high level of behavioural enrichment.
They are not conventional pet lizards and should only be considered by highly experienced keepers capable of safely accommodating an adult monitor for several decades.
QUICK REFERENCE
Scientific Name: Varanus varius
Common Names: Lace Monitor, Tree Goanna
Family: Varanidae
Origin: Eastern and southeastern Australia
Adult Size: Commonly approximately 1.5–2 m (5–6.5 ft), with exceptionally large animals around 2 m or more
Adult Weight: Large males can exceed 10 kg, with exceptional animals substantially heavier
Lifespan: Potentially 20–40+ years
Activity: Diurnal
Lifestyle: Terrestrial and arboreal
Diet: Carnivorous
Care Level: Expert / Specialist
IMPORTANT COMMITMENT WARNING
A Lace Monitor is a major long-term commitment.
Adults are:
- Very large
- Extremely strong
- Highly intelligent
- Powerful climbers
- Capable diggers
- Fast when motivated
- Equipped with sharp teeth and claws
Before acquiring one, consider:
- Adult enclosure construction
- Heating and electricity costs
- UVB and visible lighting
- Food costs
- Deep substrate
- Structural reinforcement
- Safe keeper access
- Veterinary availability
- Long-term care if circumstances change
The enclosure should be planned around the adult animal, not the juvenile being purchased.
NATURAL HISTORY
Lace Monitors occur across much of eastern Australia.
They inhabit a wide range of environments including:
- Dry forest
- Wet forest
- Woodland
- Grassland
- Coastal regions
- Rural environments
They are both terrestrial and highly capable climbers.
Wild animals can travel over large areas while searching for food and may climb considerable distances into trees to:
- Rest
- Escape threats
- Search for prey
- Raid nests
- Thermoregulate
They frequently shelter within:
- Tree hollows
- Fallen timber
- Rock crevices
- Dense vegetation
- Other secure retreats
A captive enclosure should therefore provide substantial horizontal and vertical space rather than treating the species as either purely terrestrial or purely arboreal.
ADULT SIZE
Adult Lace Monitors are among the largest monitor lizards kept privately.
Large males can approach:
2 m (6.5 ft) total length
with a substantial proportion of this consisting of the long tail.
Females are generally smaller.
Body size varies considerably between individuals and geographical populations.
Their long body, powerful limbs and muscular tail mean that enclosure requirements should not be based solely on total length.
They require room to:
- Walk
- Turn
- Climb
- Dig
- Bask
- Explore
- Retreat completely from view
ENCLOSURE
Adult Lace Monitors require a custom-built walk-in enclosure.
There is no single dimension that automatically guarantees appropriate housing.
As a practical starting point, an adult enclosure should be at least approximately:
3.6 m long × 1.8 m deep × 2.4 m high
(12 × 6 × 8 ft)
but larger is strongly encouraged.
For a large adult male, significantly more space can be justified.
The enclosure should provide:
- Extensive floor area
- Substantial climbing height
- Multiple basking levels
- Deep substrate
- Numerous secure retreats
- Strong visual barriers
- Environmental complexity
Where possible, a dedicated reptile room or indoor/outdoor facility can provide substantially better long-term accommodation than a conventional vivarium.
SECURITY
The enclosure must be exceptionally strong and secure.
Lace Monitors can:
- Push against doors
- Climb enclosure walls
- Dig
- Damage lightweight furnishings
- Manipulate loose objects
- Exploit small gaps
Doors should have reliable locks.
Ventilation panels, light guards and access points should be robust enough to withstand repeated contact from a large monitor.
Where practical, enclosure design should allow the keeper to perform routine maintenance without needing to physically restrain the animal.
CLIMBING STRUCTURE
Climbing opportunities are essential.
Provide numerous:
- Large branches
- Tree trunks
- Logs
- Platforms
- Shelves
- Cork structures
- Elevated hides
Branches should be thick enough to comfortably support the entire animal.
Horizontal, diagonal and vertical routes should be provided.
The monitor should be able to move between:
- Ground level
- Intermediate levels
- Elevated retreats
- Basking positions
without needing to climb enclosure walls or heating fixtures.
All structures must be exceptionally secure.
HIDES & RETREATS
Multiple secure hiding locations should be provided.
Useful options include:
- Large hollow logs
- Artificial tree hollows
- Ground-level caves
- Elevated hide boxes
- Covered platforms
- Deep substrate retreats
A large monitor should still be able to completely conceal itself.
Hides should be distributed across different temperature zones.
The animal should never need to choose between feeling secure and maintaining an appropriate body temperature.
SUBSTRATE
Lace Monitors should be provided with a deep, naturalistic substrate.
Ten or twenty centimetres is unlikely to provide meaningful digging opportunities for a large adult.
Where enclosure construction allows, aim for approximately:
30–60 cm (12–24 in)
over substantial portions of the enclosure, with deeper areas where practical.
Suitable mixtures can include:
- Organic topsoil
- Washed sand
- Clay-containing components
- Leaf litter
The substrate should:
- Permit digging
- Hold burrows or depressions
- Provide moisture gradients
- Remain structurally safe
- Drain appropriately
Large buried rocks or structures must rest securely on the enclosure base rather than loose substrate so that excavation cannot cause collapse.
BASKING & HEATING
Lace Monitors are active diurnal baskers.
The primary basking system should provide both intense visible light and broad radiant heat.
A bank of halogen or appropriate incandescent flood lamps works well because it creates a broad basking zone rather than one dangerous concentrated hot spot.
The basking area should be large enough to warm the animal’s entire body simultaneously.
Deep Heat Projectors or Ceramic Heat Emitters may have roles as supplementary or non-visible ambient heat sources, but they should not automatically replace bright daytime basking lamps.
BASKING TEMPERATURE
Aim for a basking surface temperature of approximately:
45–55°C (113–131°F)
across a broad accessible area.
Some individuals may utilise surfaces towards the upper end of this range.
The important point is that the monitor must have:
- A broad hot zone
- Cooler adjacent surfaces
- Extensive cooler retreat areas
rather than a single intensely heated point.
Monitor basking temperatures with a reliable infrared temperature gun.
AMBIENT TEMPERATURE
A suitable daytime gradient can include:
Warm Side
Approximately:
28–32°C (82–90°F)
Cool Side
Approximately:
22–27°C (72–81°F)
Large enclosures should contain multiple thermal zones.
The monitor should be able to completely leave the basking area and cool down.
NIGHT TEMPERATURE
A natural nighttime reduction is appropriate.
Healthy established adults can generally experience temperatures around:
18–22°C (64–72°F)
overnight.
There is no requirement to maintain the entire enclosure above 21°C at all times if the animal is healthy and can warm normally the following day.
Young animals may require somewhat more conservative nighttime conditions.
Supplementary non-light-emitting heat can be used where room temperatures become excessively cold.
HEATING SAFETY
Large monitors readily climb towards heat sources.
All lamps and heaters must therefore be:
- Securely mounted
- Protected from direct contact
- Positioned beyond reach where possible
Burns can occur rapidly when a monitor climbs directly against an unprotected lamp.
Heating systems should be appropriately controlled and independently monitored.
Use:
- Thermostats where appropriate
- Digital thermometers
- Infrared temperature gun
A thermostat controls the heater — it does not replace temperature measurement.
UVB
Lace Monitors are diurnal sun-exposed lizards and should have access to appropriate UVB.
Use high-quality linear T5 UVB systems positioned around the principal basking zone.
For an animal of this size, several lamps may be required to create a sufficiently broad irradiated area.
Rather than choosing a lamp simply because it says 12% or 14%, measure the actual UV exposure reaching the animal.
Aim for approximately:
UVI 4–6 in the principal exposed basking area
with a gradient towards:
UVI 0 in full shade
The animal must be able to completely withdraw from UV exposure.
A suitable UV meter is strongly recommended for a specialist enclosure of this scale.
VISIBLE LIGHT
Lace Monitors naturally experience extremely bright daylight.
UVB and heat lamps alone may still leave a large indoor enclosure unnaturally dim.
High-output daylight LEDs can therefore be used to create strong general illumination.
The brightest part of the enclosure should generally correspond with the:
- Warmest area
- Highest UV exposure
- Main basking location
This creates a more natural association between:
Light + heat + UV
while extensive shaded areas remain available elsewhere.
PHOTOPERIOD
Provide a clear day/night cycle.
Approximately:
11–13 hours of daylight
provides a useful general range.
Seasonal variation can be used to reproduce Australian annual cycles.
All visible lighting and UVB should be switched off overnight.
Do not use red, blue or purple night bulbs.
HUMIDITY
Lace Monitors occupy a broad range of eastern Australian habitats, so one fixed humidity percentage should not be treated as mandatory.
A general ambient range of approximately:
40–70% relative humidity
is suitable when accompanied by environmental gradients.
More important than maintaining one exact number is providing:
- Dry basking surfaces
- Moist deeper substrate
- Humid retreats
- Fresh water
- Good ventilation
Humidity can naturally rise overnight and within deep substrate.
The entire enclosure should not remain warm and saturated.
WATER
Fresh drinking water should always be available.
Provide a large, sturdy container that:
- Cannot easily be tipped over
- Is easy to enter and leave
- Can be cleaned thoroughly
- Contains sufficient water for the animal to drink freely
A container large enough for partial or full immersion can also be provided where space permits.
However, soaking should not be treated as a substitute for correct hydration, humidity or substrate moisture.
Lace Monitors may defecate in water, so the container should be checked frequently.
DIET
Lace Monitors are opportunistic carnivores.
Wild diets can include:
- Small mammals
- Birds
- Reptiles
- Eggs
- Carrion
- Invertebrates
Captive diets should be varied and should avoid excessive calories.
A monitor should not be deliberately maintained in an obese condition.
WHOLE PREY
Whole prey provides:
- Muscle
- Bone
- Organs
- Connective tissue
- Fur or feathers
Suitable foods can include appropriately sized:
- Mice
- Rats
- Quail
- Chicks
- Other responsibly sourced whole vertebrate prey
Whole prey should form an important part of the diet.
INVERTEBRATES
Invertebrates are particularly useful for:
- Young monitors
- Smaller meals
- Enrichment
- Encouraging active hunting
Suitable options include:
- Locusts
- Dubia roaches
- Other large roaches
- Crickets
- Appropriate beetle larvae
- Other suitable captive-bred invertebrates
Large adult monitors can still benefit from insect feeding because catching numerous smaller prey items encourages active foraging.
EGGS & OTHER FOODS
Eggs may be offered as part of dietary variety.
Whole poultry eggs should not become the primary food.
Boneless meat such as:
- Chicken breast
- Minced turkey
- Beef
should not form the staple diet because plain muscle meat is nutritionally incomplete.
Fish may occasionally be included where appropriate, but variety remains important.
FEEDING FREQUENCY
Feeding should be determined by:
- Age
- Size
- Meal size
- Activity
- Reproductive status
- Body condition
Juveniles
Young growing monitors require more frequent meals.
Small meals can be offered most days or every other day, depending on prey size and growth.
Adults
Adults generally do better with smaller, controlled feeding rather than infrequent enormous meals.
Approximately:
2–4 feeding opportunities per week
can be suitable when meals are appropriately sized.
There is no requirement to feed one huge meal only every 7–10 days.
A feeding programme based around varied smaller meals can provide more behavioural enrichment and make body condition easier to manage.
OBESITY
Obesity is a significant concern in captive monitor lizards.
Warning signs can include:
- Excessive fat around the base of the tail
- Thickening around the neck
- Reduced mobility
- Persistent abdominal enlargement
- Poor stamina
A healthy Lace Monitor should be muscular and powerful without appearing excessively heavy.
Overfeeding large quantities of:
- Rodents
- Chicks
- Eggs
- High-fat foods
can produce rapid weight gain.
Monitor body condition and adjust food accordingly.
SUPPLEMENTATION
Whole vertebrate prey generally provides substantial natural calcium and minerals.
Appropriately gut-loaded insects should be dusted according to the supplement being used.
Supplementation depends on:
- Diet
- Age
- Feeding frequency
- UVB exposure
- Product formulation
Do not routinely cover complete whole vertebrate prey with large quantities of calcium and multivitamin powder.
Over-supplementation can also create health problems.
FEEDING SAFETY
Lace Monitors can become intensely food motivated.
Use long feeding tongs or other appropriate equipment.
Avoid:
- Hand feeding
- Encouraging the animal to attack hands
- Associating enclosure entry exclusively with feeding
A predictable feeding protocol can help reduce accidental food-response bites.
Large monitors should be taught to respond to keeper cues and movement rather than being encouraged to rush the keeper whenever the enclosure opens.
INTELLIGENCE & ENRICHMENT
Monitor lizards are exceptionally intelligent reptiles.
A Lace Monitor enclosure should therefore provide far more than heat, food and shelter.
Useful enrichment includes:
- Climbing
- Digging
- Scent trails
- Hidden food
- Suspended food
- Puzzle feeding
- Different substrates
- Large logs
- Rotating safe furnishings
- Novel scents
- Multiple feeding locations
Food can be hidden within:
- Logs
- Leaf litter
- Substrate
- Secure containers designed for enrichment
The objective is to encourage:
- Searching
- Investigation
- Climbing
- Digging
- Problem solving
rather than allowing the animal to spend most of its life waiting beside a feeding door.
TRAINING
Positive-reinforcement and target-based training can be extremely useful with large monitors.
Training may help with:
- Moving the animal between enclosure areas
- Weighing
- Veterinary preparation
- Routine inspection
- Reducing stress during maintenance
Training should be based on reward and voluntary participation rather than punishment or forced domination.
A large monitor that willingly moves to a designated location can be considerably safer to manage than one that must be physically restrained.
HANDLING
Lace Monitors should not be regarded as conventional handling pets.
Some captive animals become calm and highly tolerant of their keepers, but this does not remove their physical capability.
An adult has:
- Powerful jaws
- Sharp teeth
- Long claws
- Strong limbs
- Muscular tail
Unnecessary restraint should be avoided.
Interaction should focus on:
- Calm routine
- Training
- Voluntary approach
- Enrichment
rather than repeatedly picking the animal up.
SAFETY
Even a well-socialised monitor can cause serious injury.
Potential injuries include:
- Deep bites
- Lacerations
- Claw injuries
- Tail strikes
Keepers should always remain aware of the animal’s position during enclosure maintenance.
Visitors and children should never have unrestricted access to a large monitor enclosure.
Doors should remain securely locked.
Never rely on an animal’s previous calm behaviour as proof that a bite cannot occur.
SOCIAL HOUSING
Lace Monitors are generally best housed individually.
Wild animals are territorial and largely solitary.
Cohabitation can result in:
- Aggression
- Competition
- Feeding injuries
- Basking exclusion
- Chronic stress
- Unplanned breeding
Adult males should not be housed together.
Experienced breeding facilities may temporarily or selectively manage compatible animals together in exceptionally large accommodation, but this should not be regarded as standard pet husbandry.
SHEDDING
Lace Monitors shed their skin in patches rather than as one complete piece.
Appropriate:
- Hydration
- Humidity gradients
- Deep substrate
- Rough climbing surfaces
help facilitate normal shedding.
Retained skin should be monitored around:
- Toes
- Tail tip
- Limbs
Do not routinely pull attached skin from the animal.
Persistent shedding difficulty can indicate inadequate environmental conditions or health problems.
CLEANING & HYGIENE
Large monitor enclosures produce substantial waste.
Remove:
- Faeces
- Urates
- Uneaten food
- Contaminated substrate
promptly.
A deep naturalistic enclosure does not necessarily require frequent complete substrate replacement.
Instead, well-designed systems can use:
- Regular spot cleaning
- Partial substrate replacement
- Deep-cleaning when necessary
rather than repeatedly stripping hundreds of litres of substrate.
Water containers should be cleaned whenever contaminated.
Always wash hands thoroughly after handling reptiles, waste, prey or enclosure equipment.
Reptiles can carry Salmonella without appearing ill.
QUARANTINE
New monitors should undergo an appropriate quarantine period away from established reptiles.
During quarantine monitor:
- Appetite
- Weight
- Faeces
- Skin
- Respiratory function
- Mobility
- General behaviour
Veterinary examination and faecal parasite testing may be appropriate.
Specialist veterinary arrangements should ideally be made before acquiring a large monitor.
HEALTH
Potential warning signs include:
- Persistent refusal to feed
- Unexplained weight loss
- Excessive weight gain
- Weakness
- Difficulty climbing
- Limping
- Swollen limbs
- Soft or abnormal jaw
- Tremors
- Skin lesions
- Persistent retained shed
- Eye problems
- Regurgitation
- Abnormal faeces
- Wheezing
- Nasal/oral discharge
- Open-mouth breathing unrelated to basking
- Significant behavioural change
Metabolic Bone Disease
Inadequate:
- UVB
- Calcium
- Vitamin D3
- Appropriate diet
can contribute to metabolic bone disease.
Possible signs include:
- Weakness
- Tremors
- Skeletal deformity
- Swollen limbs
- Difficulty climbing
- Softened jaw
Correct UVB, diet and heating are fundamental to prevention.
LONG-TERM CONSIDERATIONS
A Lace Monitor may live for several decades.
Long-term costs can include:
- Walk-in enclosure construction
- Structural reinforcement
- Multiple basking lamps
- UVB systems
- Bright LED lighting
- Electricity
- Deep substrate
- Whole prey
- Invertebrates
- Enrichment
- Veterinary treatment
- Repairs to enclosure furnishings
These animals are highly intelligent, active and physically powerful.
A Lace Monitor should only be acquired when the keeper can provide a genuine large-scale, behaviourally complex environment for the adult animal.
IMPORTANT INFORMATION
This care sheet provides general husbandry guidance and does not replace species-specific research, professional experience or veterinary advice. Individual requirements may vary.
Lace Monitors are large, powerful reptiles capable of causing serious injury. Appropriate enclosure security, keeper experience and safe management procedures are essential.
Keepers should also check all applicable legal requirements before acquisition, transport, breeding or sale.
If you have concerns about an animal’s health or care, consult a suitably experienced exotic or reptile veterinarian.
Information correct at the date of publication.
ReptileCommunity.com | Revised: August 2026