Fellow Creatures
Pet match quiz
Ackie Monitor
Reptiles

Ackie Monitor

Varanus acanthurus

Intelligent, active dwarf monitorAdvanced

Lifespan
15-20 years
Size
24-30 in
Social needs
Best kept singly; pairs only in a much larger enclosure
Time
High - daily feeding, enrichment
Cost
High
Diet
Insectivore/carnivore - insects, rodents

Overview

What is this animal?

  • Ackie monitors, or spiny-tailed monitors, are small Australian dwarf monitors valued for their intelligence and activity.
  • Though small for a monitor, they are demanding lizards that need far more than typical reptile husbandry.
  • They are alert, fast, and curious, displaying complex behaviours such as digging, climbing, and problem-solving.
  • They suit dedicated, experienced keepers able to provide a large, high-heat, enrichment-rich enclosure.

Temperament

  • Ackies are intelligent and can become tame and interactive with consistent, patient handling, often recognising their keeper.
  • However, they are fast, strong for their size, and can scratch or bite if stressed.
Show 3 more
  • They are best regarded as active, engaging display animals that may accept handling rather than as cuddly pets.
  • Their inquisitive nature rewards enrichment and routine, but they need an experienced, committed keeper.
  • Ackies are not particularly social and do not need company, so one per enclosure is the sensible default; experienced keepers do keep pairs, but only in a much larger enclosure with spare basking spots and hides.

A good fit for

  • Experienced, dedicated reptile keepers
  • Those able to build a large high-heat setup
  • Keepers wanting an intelligent, active monitor
  • People committed to daily enrichment

Common mistakes to avoid

  • Needs very high basking surface temps (149-172°F)
  • Deep burrowing substrate is essential
  • Large enclosure and high cost often underestimated
  • Not a beginner reptile despite small size

Enclosure

Minimum 17 sq ft of floor · 6 x 3 x 4 ft

Usually kept alone. Best kept singly; pairs only in a much larger enclosure

  • Ackies need a large enclosure, at least 6 x 3 x 4 ft and ideally bigger, with a deep substrate of around 12-24 in of a moisture-holding sand-soil mix that holds burrows.
  • The height has to hold that substrate and still leave room to climb and to hang the basking lamps, and floor space and burrow depth are critical.
  • They require an intense basking spot with a surface temperature of about 149-172°F, measured with a temperature gun (specialist care sheets range from about 140°F to 172°F), under focused basking lamps, with a cool retreat around 75-82°F, plus strong UVB.
  • This high-energy thermoregulation is essential to their digestion and health.

Check your enclosure

Supplies

Setup

  • Enclosure, 6 x 3 x 4 ft or larger
  • Heating and thermostat
  • UVB fixture and bulb
  • Thermometers and hygrometer
  • Bulk soil, sand and clay for a 12-24 in burrowing layer
  • Hides and decor

Ongoing

  • Live dubia roaches, crickets and locusts in bulk
  • Frozen rodents for occasional feeding
  • Plain calcium powder without D3
  • Calcium with D3 and a reptile multivitamin
  • Feeder gut-load and a large ventilated feeder tub
Show 3 more
  • Long blunt-tipped feeding tongs
  • Heavy, tip-proof water dish
  • Digital scale for tracking body weight

Safe substrate: Topsoil and play sand mix, packed 12 in deep or more

Work out the cost

Care routine

Daily

  • Check the basking surface temperature
  • Fresh water bowl
  • Look the animal over
  • Spot-clean waste and uneaten food

Every few days

  • Feed a varied, portion-controlled dietevery 2 days
  • Short handling sessionevery 3 days

Weekly

  • Check the substrate holds a burrow
Show 5 more

Every few weeks

  • Weigh-inevery 2 weeks

Monthly

  • Deep-clean decor, glass and bowls
  • Test thermostats, lamps and guards

Less often

  • Refresh the substrateevery 3 months
  • Check the UVB lamp's age and replace it if due (if one is fitted)every 6 months

Vet: Annual exam and faecal check, every 12 months (every 6 months from 10 years old)

Tools

Is your enclosure big enough?Check your measurements against the recommended sizeWhat will it cost?Setup, monthly and over its whole life, itemisedCan it eat that?Search 27 foods, from everyday to never

Care in depth

Diet

Insectivore/carnivore - insects, rodents
  • Ackies are insectivores and carnivores fed a varied diet of appropriately sized insects such as roaches, crickets, and locusts, with the occasional whole rodent or egg.
  • Gut-load and dust insects with calcium and vitamins.
  • Juveniles eat daily and grow fast; adults are fed several times a week.
  • They are prone to obesity on fatty prey, so monitor body condition and favour lean, varied invertebrates over frequent rodents.

Health

Signs of good health, and the common problems
  • Ackies suffer when kept too cool or without high enough basking temperatures, leading to poor digestion and obesity.
  • Inadequate UVB and calcium cause metabolic bone disease, and shallow, dry substrate prevents natural burrowing and thermoregulation.
  • Provide intense heat, strong UVB, deep moisture-holding substrate, and a varied diet.
  • Their high metabolism and activity demand careful temperature and weight management, with support from a monitor-experienced vet.

Is this urgent?

8 warning signs and how fast to act, 5 of them right away

Most reptile emergencies are husbandry emergencies first. Before you panic, check the temperatures, but check them with a thermometer, not a hand.

Go now

Gasping or open-mouth breathing away from the basking spot, or bubbles and mucus at the nose or mouth (a mouth held open while basking is normal cooling behaviour in many lizards)Go now. Raise the warm end to the top of the species range in transit. Respiratory infection in a reptile is usually already established by the time it is visible, and it advances fast at the wrong temperature.
Now
Prolapse: any tissue protruding from the ventGo now. Keep the tissue moist with clean lukewarm water. Do not push it back in. Exposed tissue dries and dies quickly, and the window for a simple repair is short.
Now
Unable to right itself when gently turned overGo now. Loss of the righting reflex signals a neurological or metabolic crisis.
Now
A burn, or a blackened patch on the belly or sideGo now, and unplug the heat source before you leave. Contact burns from an unregulated mat or an unguarded lamp are among the most common injuries in captive reptiles.
Now
Tremors, twitching, jerky limbs, or a rubbery jawGo now. Note your UVB bulb type and when it was last replaced. Almost always a calcium and D3 problem, and almost always a UVB problem underneath that.
Now

Today

Retained shed over the eyes, or a ring of stuck shed on the tail or a toeRaise humidity and offer a damp hide, then call if it is not clear within a day. A constricting ring cuts off circulation and the digit or tail tip is lost.
Today
Sudden weight loss, or a visibly sunken or triangular body shapeCall today, with the weight history. A reptile that has lost condition has usually been unwell for a while.
Today

Soon

Refusing food beyond the species' normal fastCheck what a normal fast looks like for this species before worrying: for several snakes it is weeks, not days. Then log it and book if the fast is unusual for this animal. Feeding anxiety drives more unnecessary vet visits than any other reptile question, and also masks the fasts that genuinely matter.
Check the guide first

Before any non-emergency call, write down the four numbers a vet will ask for: the thermostat probe reading, the warm-end air temperature, the cool-end air temperature, and the hottest accessible surface. Surface temperature can run well above the air above it.

This is general guidance for a healthy adult, not a diagnosis. An exotics vet who knows your animal always overrides it, and the time to find one is before you need one.

Bedding and substrate

1 safe, 2 with a caveat, 4 to avoid

An ackie lives underground as much as on top: the substrate is packed, damp-enough soil it can tunnel through, and depth is the point.

Safe

Topsoil and play sand mix, packed 12 in deep or morePlain topsoil and play sand at roughly two to one, with no more than a fifth clay if you add any, moistened until it clumps so the burrows hold. ReptiFiles gives 12 in as the minimum for males, 18 in for females and about 24 in as ideal.
safe

With a caveat

Play sand aloneWorks in a pinch, but it holds burrows less well than a soil mix.
with a caveat
Paper towelQuarantine and the short term only: an ackie that cannot dig cannot rest or regulate its temperature properly.
with a caveat

Never

Coco fibre, bark, wood shavings or mulch as the main substrateThey do not hold a tunnel the way packed, damp soil does.
never
Calcium or vitamin sandSold as digestible, which encourages eating it. Implicated in impaction.
never
Crushed nut shell, gravel or reptile carpetNothing to dig in, and nut shell and gravel are swallowed.
never
Uncovered heat mats and unguarded ceramic emittersNot a substrate, but the most common cause of contact burns. Every heat source needs a thermostat, and every emitter needs a guard.
never

If the tunnels collapse, the mix is too dry: dampen the lower layers rather than the surface.

Top resources for more info

Independent creators and organisations we would send a friend to. We have no affiliation with any of them, and nothing here is sponsored. Links checked 2026-10-22.

YouTubers

Reptiles and ResearchEvidence-led husbandry: enclosure size, UVB, thermal gradients, enrichmentClint's ReptilesWhich reptile suits you, with honest care and handling verdictsGoHerpingBeginner reptile care, setup mistakes and welfare basics

Sites

Keep going

Other Reptiles worth knowing

Same axes, same care guides: the honest way to compare them.

Browse all Reptiles →Compare with other animals

More Reptiles guides

Tokay Gecko
Gekko gecko
Advanced

Large, vocal, defensive display gecko

10-20 yearsRead guide →
Sulcata Tortoise
Centrochelys sulcata
Advanced

Tiny hatchling, enormous lifelong commitment

70+ yearsRead guide →
Red-eared Slider
Trachemys scripta elegans
Advanced

Common aquatic turtle needing a large tank

20-30+ yearsRead guide →
Veiled Chameleon
Chamaeleo calyptratus
Advanced

Arboreal lizard for advanced keepers

5-8 years (females shorter)Read guide →
Panther Chameleon
Furcifer pardalis
Advanced

Madagascar's painted showpiece for meticulous keepers

Males 5-7 years (up to 8); females often only 2-4 with repeated egg-layingRead guide →
Chinese Water Dragon
Physignathus cocincinus
Advanced

Semi-aquatic emerald climber with room-sized needs

10-15 years, up to 20 with great careRead guide →

Is your enclosure big enough?

These are the smallest sizes that give good conditions, not legal minimums. More room is always better.

Minimum 17 sq ft of floor · 6 x 3 x 4 ft

Every figure, and where it comes from

The 47 in of height has to hold 12-24 in of substrate and still leave room to climb and for the lamps.

Minimum floor area17 sq ft of continuous, unbroken floor
As dimensions6 x 3 x 4 ft
Height47 in minimum. This species climbs, so height is not optional.
CompanyUsually kept alone. Best kept singly; pairs only in a much larger enclosure
The recognised standards do not agree on this one
Bask & Burrow, ackie monitor enclosure guide: 6 x 3 x 2 ft or larger recommended for one adult; 4 x 2 x 2 ft a bare minimum only. The floor area this site uses. Checked 2026-10-23.
ReptiFiles: 5 x 2.5 x 4 ft for one adult, and larger is always better. Its minimum. The height this site uses: 47 in holds a deep substrate layer and still leaves room to climb. Checked 2026-10-23.
The Bio Dude: No smaller than 5 x 2.5 x 4 ft, including a 12-24 in substrate lip, and larger is strongly advised. The same minimum as ReptiFiles. Checked 2026-10-23.

What it really costs

Setup, monthly, first year and across a whole life, itemised and with the electricity worked out from the actual wattage. Published figures for the same animal disagree by a factor of four, so the calculator shows ranges rather than picking one.

Can an Ackie Monitor eat that?

Ackies are insect-eaters first: lean, varied invertebrates as the backbone, with whole prey only now and then.

The full list: 27 foods

Never (17)

AlcoholNo safe amount at any body weight on this site.
never
AvocadoPersin. Toxic to birds and many mammals; it has not been studied in reptiles, so treat it as unsafe.
never
CaffeineCoffee, tea and energy drinks. Cardiac and neurological toxicity at tiny doses for an animal this size.
never
ChocolateTheobromine and caffeine. Small mammals and reptiles cannot clear either.
never
CitrusAcidic enough to upset the gut, and sugary. Not worth the risk.
never
Dog or cat foodFormulated for a mammal, and not food for an insect-eater.
never
FirefliesLucibufagins. A single firefly has killed adult lizards. This is the most dangerous item on any reptile list and it is the one keepers do not know about.
never
FruitSugar an insect-eater has no use for, and it fills the animal up in place of insects.
never
GarlicSame allium toxicity as onion, and more concentrated by weight.
never
Insects larger than the gap between the eyesOversized prey risks impaction and is often refused. Size the feeder to the animal, every time.
never
Leafy greensNot food for an insect-eater: it will not eat it, and it does it no good. Use greens to gut-load its feeders instead.
never
LeekAllium family. Same mechanism as onion and garlic.
never
OnionOrganosulphur compounds damage red blood cells. The whole allium family is out.
never
RhubarbOxalate load high enough to cause acute kidney injury.
never
Salty or seasoned human foodSalt, oil and seasoning. Crisps, chips, seasoned leftovers and processed meat are all out.
never
VegetablesNot food for an insect-eater: it will not eat it, and it does it no good. Use greens to gut-load its feeders instead.
never
Wild-caught insectsPesticide residue and parasites, and the identification risk. Captive-bred feeders only.
never

Rare treats (3)

SuperwormsFatty. An occasional extra for a larger lizard, not part of the rotation. One or two, rarely.
rare treat
WaxwormsVery fatty. Useful for an underweight animal or for medicating, addictive otherwise. One or two, rarely.
rare treat
Whole prey and eggThe occasional whole rodent or egg is useful variety for an ackie, but a supplement to the insect diet rather than its centre: monitors put on fat quickly on rodents. Now and then, not as routine.
rare treat

Occasional (2)

HornwormsHigh in water; useful for hydration and variety. One or two, in rotation.
occasional
MealwormsHard chitin shell and a poor calcium ratio. Fine as part of a varied feed, poor as the whole diet. A few, alongside better feeders.
occasional

Everyday foods (5)

Black soldier fly larvaeUnusually high in calcium; one of the few feeders that does not need dusting. Several per feed.
everyday food
CricketsA standard feeder. Gut-load them for 24 hours before offering, or you are feeding an empty shell. Sized no wider than the space between the animal's eyes.
everyday food
Dubia roachesBetter calcium ratio and more meat per insect than crickets, and they cannot climb glass. Sized to the animal.
everyday food
LocustsA meaty feeder that climbs and draws a strong hunting response. Sized no wider than the space between the animal's eyes.
everyday food
SilkwormsSoft-bodied, lower in fat than most worms, and readily taken. A few per feed, in rotation.
everyday food

That food is not on our list. An insect-eater's diet is live, gut-loaded insects, so if it is not a captive-bred feeder of the right size, leave it out and check the species guide.

Dust feeders with plain calcium at most feedings and with D3 and a multivitamin on the schedule in the species guide; too little and too much both cause harm.