Ackie Monitor

Overview

The ackie, or spiny-tailed monitor, is a small monitor whose shape is often likened to a miniature Komodo dragon ². Adults are 24 to 30 inches long, with females slightly smaller, and they live about ten to fifteen years in human care ². Ackies have real monitor personalities. Socialized animals can bond strongly with their owners, and the ones in the pet trade are captive bred ¹. They are still demanding: a deep, humid dig layer, extreme basking temperatures and careful portion control all matter ¹.

Natural history

Ackies live across northern Australia, most often in rocky ranges and outcrops, but also in spinifex grass and shrubland ²³. They shelter in rock crevices and burrows, and they plug the burrow entrance with their spiny tail, which they can also swing like a club ¹². They are active by day ². Their burrows can be more than a foot deep, and the air in them can exceed 90% humidity even when the surface is dry ¹. In the wild they eat grasshoppers, beetles, roaches, spiders, snails and smaller lizards, and they get most of their water from food ¹².

Enclosure

• Size. Recommended minimums range from 4 × 2 × 2 ft to 5 × 2.5 × 3 ft. Give the largest enclosure you can ¹.
• Materials. PVC or treated wood hold heat and humidity better than glass, and covered sides help a skittish ackie settle ¹.
• Furniture. Slate rock for basking, climbing branches, cork tubes (partly buried to encourage burrowing), rock ledges and several hides ¹.
• Water. A heavy, hard-to-tip bowl deep enough to soak in ¹.

Temperature & lighting

Build the basking area as a stack of slate or rock with gaps, so the ackie can choose its own temperature, and measure it with an infrared thermometer ¹. Ackies bask in short bursts. If yours basks for very long stretches, the spot may be too cool; if it avoids the spot, it may be too hot ¹.

UVB is mandatory. A 10.0 linear tube across part of the enclosure, leaving shaded areas, works well. Replace UV bulbs every year ¹. Add bright LED lighting and run a 12-hour day–night cycle ¹.

Humidity

Surface air can be fairly dry, but chronically low humidity (30% or less) can lead to dehydration and kidney disease ¹. Aim for about 50 to 80% by day, with the deep substrate and night-time air above 90% ¹. Help it along with deep, moist substrate, a water bowl near the heat, live plants and occasional misting. A shallow 15 to 20 minute warm soak once a week helps with shedding ¹.

Substrate

Ackies dig, so give at least 12 inches of a topsoil and washed play-sand mix that holds a burrow, either throughout or in a large dig box ¹. Keep the top dry and the deeper layers moist. A bioactive setup with non-toxic plants and a cleanup crew of isopods and springtails works well ¹.

Diet & supplementation

Ackies are insect-eaters ¹².

• Staples. Mostly grasshoppers or locusts and roaches (dubia, discoid, red runner), plus beetles and larvae, crickets, black soldier fly larvae, silkworms and hornworms ¹.
• Limit. Superworms and waxworms are too fatty. Mice, chicks, egg and ground turkey cause obesity and should be rare treats at most ¹.
• Supplements. Calcium without D3 at every meal, plus a multivitamin with preformed vitamin A once a week ¹.
• How often. Hatchlings daily, juveniles every other day to three times a week, adults (1 year+) two to three times a week ¹.
• How much. Do not feed "as much as it will eat." Monitors do not have unusually high metabolisms, and overfeeding causes obesity and gout. Weighing portions is the safest approach ¹.

Handling & temperament

Ackies are intelligent and must learn to trust you, especially as babies ¹:

• Let a new ackie settle for four or five days.
• Tong-feed it, then rest a hand in the enclosure, palm down, and let it come to you.
• Long, slow tongue flicks mean curiosity.

Some ackies tame quickly and some never fully do ¹. Even a small ackie bites hard and may hang on. Don't wiggle your fingers or snatch them away ¹. Wash your hands afterwards: reptiles can carry Salmonella ⁵.

Health

Common issues ¹

• Obesity and gout from overfeeding and fatty foods.
• Dehydration and kidney disease from chronically dry setups.
• Retained shed at low humidity.
• Metabolic bone disease without UVB and calcium.

When to see a vet

Before you buy, ask the breeder to have the ackie examined by a reptile vet if they can ¹. Afterwards, see an exotic-animal vet for appetite loss lasting more than a week, noisy breathing or stuck shed. Burns also need a vet. Open-mouth breathing, limp or oddly angled limbs, large open wounds or an unresponsive animal are emergencies ⁶.

Breeding overview

Ackies mature at about one year old ². Females dig nests and lay clutches of five to fifteen eggs ².

Genetics & morphs

Regional forms differ in color, with some reds and some yellows ¹.

Legal & ethics

Varanus acanthurus is listed on CITES Appendix II ⁴. Buy captive-bred from a reputable breeder, and see the animal in person or on video before buying ¹.

Sources

1. Ackie Monitor Husbandry (Reptile Rounds) · Reptile Rounds, wpvet.com veterinary practice, Winter Park, FL
2. Spiny-tailed monitor · Smithsonian's National Zoo and Conservation Biology Institute
3. Varanus acanthurus · The Reptile Database
4. CITES listing: Varanus acanthurus · Species+ (UNEP-WCMC and CITES Secretariat)
5. Salmonella, Feeder Rodents, and Pet Reptiles and Amphibians · U.S. Food and Drug Administration
6. When Should My Reptile See a Veterinarian? · Tree of Life Exotic Pet Medical Center

Last reviewed 2026-10-24 by Novel Fauna. This guide is general husbandry information, not veterinary advice. When an animal is sick, see a veterinarian experienced with exotic animals.

Revision history

1. 2026-10-24 Library: 50 cited care guides, /library/[slug] route, coming-soon cards, SLUGS.txt synced to species.guide_slug 228ce54
2. 2026-10-24 WIP: library guides (lizards) 478b100

Evidence grades: Novel Fauna editorial: source classification, not yet expert-reviewed, 2026-10-25. What the grades mean.

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