Ackie monitors, also known as spiny-tailed monitors (Varanus acanthurus), are captivating reptiles native to northern Australia. Their manageable size, intelligence, and intriguing personalities make them a popular choice for reptile enthusiasts. This article provides a detailed guide to their diet and care, ensuring a long, fulfilling life for your ackie.
Introduction to Ackie Monitors
Ackie monitors are diurnal, terrestrial lizards found in arid and seasonally dry habitats. They are relatively small compared to other monitor species, typically reaching around 24 inches in length. Their bodies are slender with a tapered head, long neck, rounded belly, sharp claws, and a spiky tail. They come in various colors, including yellow- to reddish-brown, with pale rings on their back and tail.
These monitors are known for their active nature and can develop strong bonds with their owners, almost like a dog or cat. Fortunately, most ackies in the pet trade are captive-bred, reducing the risks associated with wild-caught specimens.
Housing Your Ackie Monitor
Enclosure Size and Type
As active lizards, ackie monitors require substantial space to explore. The minimum enclosure size for a single ackie is 5’L x 2.5’W x 4’H. However, providing the largest enclosure possible is always best practice. Enclosure materials should retain heat and humidity. PVC and wood are ideal, while glass is less suitable due to heat and humidity loss. Covering the sides of the enclosure can help reduce stress, especially for skittish ackies.
Enclosures can have screen tops with lights placed on top or solid tops with lights inside. Solid enclosures are better at maintaining heat and humidity. Screen-top enclosures need modifications to reduce heat and humidity loss but offer more climbing opportunities.
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Enrichment
Enrichment items are essential for an ackie's well-being. These include:
- Slaterock: Excellent for basking spots as they hold heat well.
- Climbing Branches: Provide enrichment and exercise.
- Cork Tubes: Serve as climbing structures and hiding places. Burying them in the substrate promotes burrowing behavior.
- Rock Ledges/Climbable Backgrounds: Add dimension and climbing opportunities.
- Multiple Hides: Allow the ackie to retreat when stressed.
- Water Bowl: Deep enough for soaking but heavy enough to avoid tipping.
Substrate
Ackies are fossorial, meaning they require deep substrate layers for healthy burrowing. A minimum of 12 inches of substrate is recommended, either throughout the entire enclosure or in a localized dig box. The best substrate is a mixture of organic topsoil and washed play sand. The top layer should remain dry, while the deeper layers should be moist.
This depth is crucial for maintaining humidity, as ackies get a significant portion of their hydration from humid air via pulmocutaneous exchange. Digital probe thermometers/hygrometers can monitor substrate humidity. Regularly cycling the substrate reduces the buildup of fungi and bacteria.
Bioactive Setup
Converting enclosures to bioactive setups is highly recommended. When choosing plants, ensure they are non-toxic. Grasses like Mundo grass are great additions, as long as they are not too close to basking spots. A cleanup crew (CUC) of invertebrates like Dwarf White Isopods and Springtail species is beneficial.
Temperature and Lighting
Basking Spot
Ackies require very hot basking spot temperatures, ideally providing a gradient with multiple temperature options. A Rete's stack (rock or plywood with spaces in between), slaterock, or wooden branches can achieve this. The basking spot temperature range should be between 120-150 degrees F, monitored with an infrared temperature gun.
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Monitor your ackie’s basking behaviors to ensure the appropriate thermal gradients. If the ackie basks for prolonged periods or avoids the basking spot, adjust the temperatures accordingly.
Ambient Temperatures
In their native ranges, ackies experience temperatures from 59-90 degrees F. In the enclosure, ambient temperatures should range from 80-85 degrees F, with areas near the basking spot reaching 90 degrees F. Use multiple digital thermometers/hygrometers on both sides of the enclosure to monitor thermal gradients.
UV and LED Lighting
Ultraviolet (UV) supplementation is mandatory for ackies. LED tubes, fluorescent bulbs, or mercury vapor bulbs can provide UV. LED tubes offer the best coverage. Provide areas where the ackie can escape the UV lighting. Replace UV bulbs annually to ensure optimal output.
LED bulbs are also crucial for illuminating enclosures, as heat bulbs and UV lighting alone may be insufficient. Provide a 12-hour day/night cycle to promote healthy circadian rhythms.
Humidity
While the ambient humidity in ackie habitats tends to be low, chronic exposure to low humidity levels (30% RH or less) can lead to dehydration and renal disease. Ackie burrows are areas of high humidity, and they often seek humid microclimates. Maintain humidity gradients of 50-80% RH during the day, with substrate and nighttime humidities approaching greater than 90% RH.
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Maintain humidity using a deep substrate layer, water bowls near the basking spot, live plants, substrate cycling, and occasional misting. A warm water soak once a week for 15 to 20 minutes can aid shedding and promote hydration.
Ackie Monitor Diet
Natural Diet
In the wild, ackies are primarily insectivores, frequently consuming smaller lizards. Their diet includes grasshoppers/locusts, beetles, lizards, and cockroaches.
Captive Diet
Captive diets should replicate these proportions, with the bulk of the diet consisting of grasshoppers, roaches (Dubia, Discoid, Red Runner, etc), beetles and their larvae, and other insects like crickets, black soldier fly larvae, silkworms, and hornworms. Avoid super worms and waxworms due to their high fat content; substitute them with giant mealworms.
Gut-load all insects with high-calcium diets and supplement with calcium (no D3) at every meal and a multivitamin with active Vitamin A once a week. Due to the lack of high-quality captive-bred feeder lizards, lizards should not be offered at this time.
Avoid non-invertebrate food items like scrambled egg, mice, chicks, and ground turkey, as they are high in dietary fat and can lead to obesity. If offered, these should be rare treats and heavily supplemented.
Feeding Schedule
- Hatchling Ackies: Feed daily.
- Juveniles (6 months): Feed every other day to three times a week.
- Adults (1 year onward): Feed two to three times a week.
A common incorrect feeding recommendation is to offer as much prey as the animal will take in a given period. Studies show that varanids do not have different metabolic rates compared to other lizards. Wild ackies consume around 13.2g of fresh food per kg of body weight per day. Weighing insect portions ensures appropriate food intake and reduces the risk of obesity and gout.
Insect Colonies
Starting insect colonies is an ideal and cost-effective way to provide insects. Discoid roach colonies can be maintained in butterfly cages, fed with romaine lettuce, bell peppers, and other vegetable scraps.
Supplements
Even with a varied diet, supplements are a handy way to help cover any leftover deficiencies. Wild monitors may unconsciously self-supplement by rubbing their prey through soil before eating it.
- Calcium: Essential for captive insectivores because captive-bred insects have a chronically low calcium-to-phosphorus ratio. Dust feeder insects with calcium to correct this imbalance.
- Vitamin D3: If you provide enough UVB, your ackie should make all the vitamin D3 it needs. Occasionally use a low-D3 calcium supplement or multivitamin containing D3 to top up reserves without risk of overdose. Supplementing vitamin D3 instead of using UVB lighting is not recommended.
- Vitamins: Use a reptile multivitamin powder supplement every once in a while to help cover any potential vitamin/mineral deficiencies.
Gutloading
Gutloading involves feeding nutritious food to feeder insects, directly affecting the nutrition your ackie receives. Gutload any bugs you buy for at least 24 hours before feeding them to your ackie.
Interaction and Handling
One of the best aspects of having an ackie as a pet is interaction. Trust must be established before handling, especially with babies.
Use Kevin McCurley’s “Threads of Trust” approach:
- Let your lizard know that your presence in the enclosure is natural.
- Place the enclosure in a room with moderate traffic.
- Allow the ackie to adjust for four to five days before interacting.
- Use tongs to put food in the enclosure.
- Start tong feeding and laying your hand in the enclosure.
- Slowly move your hand towards the monitor with your palm facing down, avoiding eye contact.
- Ensure the monitor is making nice, long tongue flicks, indicating curiosity.
- Keep your arm stationary and allow the monitor to wander and explore.
Eventually, the monitor will start to climb on your hand.
Common Health Issues
- Respiratory Issues: Often caused by improper humidity or low temperatures. Symptoms include wheezing, excessive mucus, open-mouth breathing, or nasal discharge.
- Parasites: Internal and external parasites, such as mites or worms, can cause significant discomfort. Symptoms include decreased appetite, lethargy, weight loss, or irregular stool.
- Metabolic Bone Disease (MBD): Often results from calcium or vitamin D3 deficiency and improper UVB lighting. Signs include swollen limbs, lethargy, soft or malformed bones, and difficulty moving.
- Dysecdysis (Improper Shedding): Can lead to retained skin around the toes or tail, restricting blood flow. Often stems from low humidity levels.
- Obesity/Malnutrition: Overfeeding can lead to obesity, while insufficient or imbalanced diets result in malnutrition. Symptoms of obesity include visible fat pads and reduced activity, while malnutrition manifests as thinness, weakness, or deformities.
- Uncharacteristic Behavior: Extreme lethargy, lack of appetite, or aggression often signals underlying health concerns.