🦎 General Info

The Ackie Monitor (Varanus acanthurus) — also known as the Ridge-Tailed Monitor or Spiny-Tailed Monitor — is a small, active, and highly intelligent species native to the arid regions of northern and western Australia. Named for the rows of sharp, spiny scales along its tail, this monitor is known for its curiosity, manageable size, and bold personality.

Ackies are part of the dwarf monitor group and come in two main subspecies: the Red Ackie (V. a. acanthurus) and the Yellow Ackie (V. a. brachyurus). Adults typically reach 24–30 inches in total length, with a strong emphasis on tail length. They are diurnal (day-active), terrestrial, and burrowing, spending much of their time exploring or basking under intense heat sources.

These monitors are excellent choices for intermediate reptile keepers and make one of the most rewarding and interactive lizards to care for. With proper husbandry, Ackie Monitors can live 15–20 years in captivity.

Enclosure

  • Size:

    • Juveniles: Minimum 4 ft x 2 ft x 2 ft.

    • Adults: Minimum 4 ft x 3 ft x 3 ft, though 5–6 ft long is preferred for more space to dig and explore.

    • Material: PVC or sealed wood enclosures are ideal for retaining heat and humidity.

  • Avoid all-screen tops — they lose heat and humidity too quickly.

  • Décor: Include multiple hides, sturdy branches, flat rocks, and basking platforms, provide deep substrate (8–12 inches) for digging and thermoregulation. Add logs, tunnels, and rocks to encourage natural climbing and hunting behavior.

  • Tip: Ackies are avid burrowers — deep substrate and a secure enclosure are essential for their health and natural behavior.

Temperature & Lighting

  • Basking Spot: 120–150°F

  • Ambient Temperature: 80–90°F

  • Cool Side: 75–80°F

  • Night Temperature: 70–75°F

  • Heating:

    • Use halogen floodlights or ceramic heat emitters to create a strong basking zone. Provide a thermal gradient allowing them to move about the enclosure to regulate body temperature.

    • Avoid under-tank heaters or heat rocks (risk of burns).

    • Always use digital thermometers with probes and regulate heating with thermostats.

  • UVB Lighting: UVB lighting is essential, use a T5 HO 10–12% UVB tube spanning at least ⅔ of the enclosure. Replace UVB bulbs every 6–12 months per manufacturer instructions.

    • Supervised outdoor exposure to natural sunlight is highly beneficial when possible.

  • Tip: Ackie Monitors require very hot basking zones — proper heat gradients are critical for digestion and immune health.

Humidity & Water

  • Humidity: 40–60%, with slightly higher humidity (60–70%) inside burrows.

  • Maintaining Humidity:

    • Mist the enclosure lightly each morning.

    • Keep a moist hide or deep burrow area — the substrate should be damp several inches down.

    • Allow the enclosure to dry out a little bit between misting's to avoid swamp like conditions, allowing bacteria and mold to grow..

  • Water:

    • Provide a shallow water dish large enough for soaking.

    • Replace daily with clean, fresh water.

  • Tip: The key to success with Ackies is balance — warm and dry on the surface, humid and cool inside their burrows.

Substrate

  • Recommended Options:

    • Topsoil/play sand mix (50/50)

    • Coconut fiber mixed with organic soil

    • Bioactive substrate (for advanced keepers)

  • Depth: 8–12 inches minimum, more if space allows.

  • Maintenance:

    • Spot-clean waste daily.

    • Stir substrate weekly to prevent compaction.

    • Full replacement every 3–6 months, depending on setup.

  • Tip: Ackies naturally dig complex tunnels and chambers — deep, slightly damp substrate mimics their wild environment and helps with humidity regulation.

Diet

  • Type: Primarily Insectivorous

  • Staple Foods:

    • Crickets, dubia roaches, mealworms, superworms, silkworms, locusts, and snails.

    • Occasional treats: Hard-boiled or scrambled egg, pinky mice (rarely), or small portions of lean ground turkey.

  • Feeding Schedule:

    • Juveniles: Feed daily with a variety of gut-loaded insects.

    • Adults: Feed 4–5 times weekly; reduce frequency if overweight.

  • Supplements:

    • Calcium: 3–4 times per week.

    • Calcium with D3: Once weekly.

    • Multivitamin: Once weekly.

    • Gut-Loading: Always feed insects nutritious greens and grains before offering to your Ackie.

  • Tip: Ackies have fast metabolisms — frequent small meals are better than large, infrequent ones.

Behavior & Handling

  • Temperament: Ackies are naturally alert, inquisitive, and intelligent. When raised and handled regularly, they become very tame and interactive, often recognizing their keepers and coming to the glass when approached.

  • Handling Tips:

    • Start slow — allow your Ackie to observe and approach you.

    • Avoid grabbing from above; use gentle, calm movements.

    • Support their full body and tail during handling.

    • Regular, calm interactions build trust over time.

  • Enrichment:

    • Rearrange décor periodically to encourage exploration.

    • Offer puzzle feeding opportunities (e.g., hiding insects under rocks).

    • Include climbing structures and dig boxes for natural activity.

  • Tip: Ackies are one of the most personable monitor species — consistent, positive handling leads to a confident, curious pet.

Health & Lifespan

  • Lifespan: 15–20 years in captivity with proper husbandry.

  • Common Health Issues:

    • Obesity: Overfeeding fatty foods or too many rodents.

    • Metabolic Bone Disease (MBD): Due to lack of UVB or calcium deficiency.

    • Respiratory Infections: From overly humid or cool conditions.

    • Parasites: Possible in wild-caught individuals.

    • Shedding Problems: Caused by low humidity or dehydration.

  • Prevention:

    • Maintain accurate temperature and humidity gradients.

    • Provide strong UVB and proper supplementation.

    • Keep enclosure clean and dry on the surface.

    • Regularly monitor body condition and appetite.

  • Signs of Illness:

    • Lethargy or hiding constantly

    • Loss of appetite

    • No interest in basking

    • Wheezing or mucus

    • Retained shed

  • Veterinary Care: Annual check-ups with a reptile vet are recommended. Fecal exams are especially important for newly acquired or imported animals.


Final Thoughts: The Ackie Monitor is a favorite among reptile enthusiasts for good reason — they are intelligent, hardy, and full of personality. Despite being smaller than other monitors, they display all the fascinating behaviors of their larger cousins in a more manageable size.

They thrive with deep substrate, hot basking zones, and consistent enrichment, making them a great choice for keepers ready to provide a naturalistic and stimulating environment.

With proper care, Ackies become engaging, active, and entertaining companions that showcase the true intelligence and curiosity of the monitor family — a truly rewarding species for any dedicated reptile keeper.