Captive husbandry of Varanus acanthurus, aka The Ackie.
Ackies are a member of the monitor family (varanus) and are classed as a dwarf monitor (odatria).
They rarely exceed 24 inches in length and make good and rewarding captives if provided with good husbandry during their lives. I would like to address what constitutes good husbandry here, and would like this to become a place to discuss our experiences and success with these amazing lizards as they seem to be growing in popularity recently. I must stress that I am not a fan of care sheets and that here I am merely trying to point people in the right direction.
Enclosure
I feel the minimum size enclosure for a single, or group of ackies is a 5x3x2. They are active lizards and appreciate a decent sized enclosure. The 3 feet of height is recommended as you need to provide at least a foot of substrate. Ackies like to burrow and will also nest in deep substrate. The enclosure can be made from wood but it is important to reinforce the bottom plinth section as a deep substrate puts a lot of pressure on the sides of the enclosure and the reinforcement is needed to prevent the wood from bowing and warping under such pressure.
It is also very important to seal the inside of the enclosure to protect the wood from the damp substrate and high humidity levels from within. I have used melamine in the past and have not had a single enclosure last more than 18 months before taking on water and blowing out. I have found plywood to be much better when coated with something like yacht varnish (minimum of 7 coats), a 2 part epoxy resin such as garage floor paint or a boat builder’s epoxy and I know people who have had success with blagdons V8 pond sealer.
Heating
Before going into how to heat the enclosure I’ll take a look at how ackies use temperatures and what they need to be successful.
Ackies, like all monitors require very high basking temperatures to be able to metabolise properly. A good basking site should have a minimum surface temperature of 135F. Personally I have used temperatures of up to 160F but slightly lower is recommended, especially to newcomers to monitors. It is important to recognise the difference between surface temperatures and ambient temperatures. Ambients are the temperature of the surrounding air, and surface temperatures are the temp of the actual objects surface. When an ackie basks it flattens and spreads its whole body on the basking site to soak up as much heat as possible. Therefore it is these surface temperatures that are important to us. A lot more important than the ambient temps. So it is essential to be able to accurately take readings of these surface temps and the best thing to do this with is an infra-red temperature gun. This is the single most important piece of equipment that a monitor keeper can own. They are quite cheap and readily available from ebay or maplins electronics stores. I don’t use any thermometers in my enclosures, however I take readings from my temp gun daily.
The best type of bulbs to use for the basking site are par38 halogen floodlights. These create a really wide beam of light which is important as the basking spot should at the very minimum be the SVL of the ackie. Ideally you are aiming for the total length of the monitor, and it is usually necessary to use 2 smaller wattage bulbs side by side rather than one higher wattage bulb. I should state that these bulbs are not run on a thermostat so you must choose wattages that will not overheat the enclosure. The best way to make fine adjustments to the basking site temperatures is by using a porcelain bulb holder hung by a chain from the top of the enclosure. You can then lower or raise the bulb to the basking site until you reach your desired temperatures.
There must be a gradient of temperatures within the enclosure and again I use the infra-red temperature gun to take readings, although thermometers are sufficient for this purpose. What you are aiming for in any monitor enclosure is a good range. You need to be able to offer the ackie multiple choices of temperatures so it can pick one to suit it’s needs. Ambient temps between 95F and 75F are ideal. While on the subject of choices, an ideal basking site for ackies is a “Retes Stack”. This is a stack of plywood boards or slate tiles that offer many layers of tight spaces under the basking spot. Each layer on the stack gets cooler the further away from basking lamp and this gives the ackies choices of many different temperatures to bask at.
Additional heating can be provided by a ceramic heat bulb or ceramic tube via a pulse stat. I do not use any additional heating as I keep my basking lights on 24/7 and choose bulbs that maintain the desired temperatures throughout the enclosure. I’ll discuss the advantages of 24/7 basking further on.
Lighting and UV
Lighting the enclosure can be done via fluorescent tubes or compact fluorescent bulbs. I have used both and prefer the tubes as they are less bulky and give a better spread of light. I have recently switched over to the new T5 type tubes which have a much higher light output for the same wattage than the conventional T8 tubes. Ambient lighting is provided via a 16/8 day/night cycle.
I do not use any form of UV in my enclosures. Monitors simply do not need it to thrive. I have raised babies I have hatched to healthy egg laying adults without it. I have maintained older reproducing adults without it. There are some minor benefits to using UV such as it increasing the colours of your ackies and enabling them to see a greater range of colours but they do not require it for a healthy life. I know this is a heated topic and I am not recommending you to not add it to your enclosure. The choice is yours but they will do fine with or without it.
Deep Substrate
A deep substrate is an absolute must for ackies. They are a burrowing species and enjoy a minimum of a foot of substrate to create their burrows and tunnels in. Females will also nest their eggs in the substrate. A mix of sterilised topsoil and playsand can work well as can a sandy loam type dirt if you can find anywhere to go dig it up. Ackies come from areas that contain a Xeric soil. That is a soil that contains little to no decaying plant matter. Whatever substrate you use, you must dampen it down enough so that it will form a burrow well without collapsing.
Humidity
Another advantage of deep substrate is it holds a good humidity in the enclosure without the need to regularly mist. I never mist my ackies enclosures and just simply add water to the dirt if it looks like it is drying out. It is important to keep a relatively high humidity in the enclosure and I do not use vents at all in any of mine. I simply do not see the point of going to all the trouble of heating and humidifying the cage just to let it all out again. The gap between the glass along with the daily opening of the doors for maintenance is more than adequate for fresh air exchange. I also do not use hygrometers. As long as I can feel the heat and humidity hit me in the face when I open the doors then I’m happy. Kind of like when you step off a plane into a hot tropical country and the heat and humidity is almost overwhelming.
Diet
Ackies have voracious appetites and will consume a wide variety of prey. A diet made mostly of invertebrates is recommended, with crickets, locusts and cockroaches all making a good staple feeder item. Ackies eat a lot and it is well worth maintaining a cockroach colony to save on feeding costs. Mice can be given once a week as can chopped up day old chicks. I am personally not a fan of supplementing the diet with items such as egg or turkey mince. I feel it is important that every meal should consist of whole prey food items. That way the monitor gets a good range and ratio of nutrients. In the wild ackies will always consume whole prey apart from the odd chances they get to feed on carrion. Whole prey contains a range of nutrients, amino acids, soluble and insoluble fibers that are present in a ratio that the lizards have evolved to digest and thrive upon. In single item foods such as turkey mince that range is substantially less and the bioavailability of the nutrients offered is reduced. For those reasons I feel whole prey is superior and I believe it should be given for every feed.
I feed my ackies as much as they can eat every day. A few smaller feedings several times a day is much better than one large daily feeding. With good temperatures and humidity your ackies will not get fat. Hatchlings and juveniles will put all energy into growth, and sexually mature monitors will put all energy into reproduction. Please bear in mind that I am a breeder, and if I were keeping a solitary animal as a pet then such a high feeding regime would not be needed and a feed every two days would probably suffice although I must admit I have never kept a lone ackie.
2 days a week I add Nutrobal to their feedings with all the other feedings dusted in 100% pure calcium carbonate.
Ackies rarely drink but a small water bowl with fresh water changed daily should be present in the enclosure at all times.
Ackies are a member of the monitor family (varanus) and are classed as a dwarf monitor (odatria).
They rarely exceed 24 inches in length and make good and rewarding captives if provided with good husbandry during their lives. I would like to address what constitutes good husbandry here, and would like this to become a place to discuss our experiences and success with these amazing lizards as they seem to be growing in popularity recently. I must stress that I am not a fan of care sheets and that here I am merely trying to point people in the right direction.
Enclosure
I feel the minimum size enclosure for a single, or group of ackies is a 5x3x2. They are active lizards and appreciate a decent sized enclosure. The 3 feet of height is recommended as you need to provide at least a foot of substrate. Ackies like to burrow and will also nest in deep substrate. The enclosure can be made from wood but it is important to reinforce the bottom plinth section as a deep substrate puts a lot of pressure on the sides of the enclosure and the reinforcement is needed to prevent the wood from bowing and warping under such pressure.
It is also very important to seal the inside of the enclosure to protect the wood from the damp substrate and high humidity levels from within. I have used melamine in the past and have not had a single enclosure last more than 18 months before taking on water and blowing out. I have found plywood to be much better when coated with something like yacht varnish (minimum of 7 coats), a 2 part epoxy resin such as garage floor paint or a boat builder’s epoxy and I know people who have had success with blagdons V8 pond sealer.
Heating
Before going into how to heat the enclosure I’ll take a look at how ackies use temperatures and what they need to be successful.
Ackies, like all monitors require very high basking temperatures to be able to metabolise properly. A good basking site should have a minimum surface temperature of 135F. Personally I have used temperatures of up to 160F but slightly lower is recommended, especially to newcomers to monitors. It is important to recognise the difference between surface temperatures and ambient temperatures. Ambients are the temperature of the surrounding air, and surface temperatures are the temp of the actual objects surface. When an ackie basks it flattens and spreads its whole body on the basking site to soak up as much heat as possible. Therefore it is these surface temperatures that are important to us. A lot more important than the ambient temps. So it is essential to be able to accurately take readings of these surface temps and the best thing to do this with is an infra-red temperature gun. This is the single most important piece of equipment that a monitor keeper can own. They are quite cheap and readily available from ebay or maplins electronics stores. I don’t use any thermometers in my enclosures, however I take readings from my temp gun daily.
The best type of bulbs to use for the basking site are par38 halogen floodlights. These create a really wide beam of light which is important as the basking spot should at the very minimum be the SVL of the ackie. Ideally you are aiming for the total length of the monitor, and it is usually necessary to use 2 smaller wattage bulbs side by side rather than one higher wattage bulb. I should state that these bulbs are not run on a thermostat so you must choose wattages that will not overheat the enclosure. The best way to make fine adjustments to the basking site temperatures is by using a porcelain bulb holder hung by a chain from the top of the enclosure. You can then lower or raise the bulb to the basking site until you reach your desired temperatures.
There must be a gradient of temperatures within the enclosure and again I use the infra-red temperature gun to take readings, although thermometers are sufficient for this purpose. What you are aiming for in any monitor enclosure is a good range. You need to be able to offer the ackie multiple choices of temperatures so it can pick one to suit it’s needs. Ambient temps between 95F and 75F are ideal. While on the subject of choices, an ideal basking site for ackies is a “Retes Stack”. This is a stack of plywood boards or slate tiles that offer many layers of tight spaces under the basking spot. Each layer on the stack gets cooler the further away from basking lamp and this gives the ackies choices of many different temperatures to bask at.
Additional heating can be provided by a ceramic heat bulb or ceramic tube via a pulse stat. I do not use any additional heating as I keep my basking lights on 24/7 and choose bulbs that maintain the desired temperatures throughout the enclosure. I’ll discuss the advantages of 24/7 basking further on.
Lighting and UV
Lighting the enclosure can be done via fluorescent tubes or compact fluorescent bulbs. I have used both and prefer the tubes as they are less bulky and give a better spread of light. I have recently switched over to the new T5 type tubes which have a much higher light output for the same wattage than the conventional T8 tubes. Ambient lighting is provided via a 16/8 day/night cycle.
I do not use any form of UV in my enclosures. Monitors simply do not need it to thrive. I have raised babies I have hatched to healthy egg laying adults without it. I have maintained older reproducing adults without it. There are some minor benefits to using UV such as it increasing the colours of your ackies and enabling them to see a greater range of colours but they do not require it for a healthy life. I know this is a heated topic and I am not recommending you to not add it to your enclosure. The choice is yours but they will do fine with or without it.
Deep Substrate
A deep substrate is an absolute must for ackies. They are a burrowing species and enjoy a minimum of a foot of substrate to create their burrows and tunnels in. Females will also nest their eggs in the substrate. A mix of sterilised topsoil and playsand can work well as can a sandy loam type dirt if you can find anywhere to go dig it up. Ackies come from areas that contain a Xeric soil. That is a soil that contains little to no decaying plant matter. Whatever substrate you use, you must dampen it down enough so that it will form a burrow well without collapsing.
Humidity
Another advantage of deep substrate is it holds a good humidity in the enclosure without the need to regularly mist. I never mist my ackies enclosures and just simply add water to the dirt if it looks like it is drying out. It is important to keep a relatively high humidity in the enclosure and I do not use vents at all in any of mine. I simply do not see the point of going to all the trouble of heating and humidifying the cage just to let it all out again. The gap between the glass along with the daily opening of the doors for maintenance is more than adequate for fresh air exchange. I also do not use hygrometers. As long as I can feel the heat and humidity hit me in the face when I open the doors then I’m happy. Kind of like when you step off a plane into a hot tropical country and the heat and humidity is almost overwhelming.
Diet
Ackies have voracious appetites and will consume a wide variety of prey. A diet made mostly of invertebrates is recommended, with crickets, locusts and cockroaches all making a good staple feeder item. Ackies eat a lot and it is well worth maintaining a cockroach colony to save on feeding costs. Mice can be given once a week as can chopped up day old chicks. I am personally not a fan of supplementing the diet with items such as egg or turkey mince. I feel it is important that every meal should consist of whole prey food items. That way the monitor gets a good range and ratio of nutrients. In the wild ackies will always consume whole prey apart from the odd chances they get to feed on carrion. Whole prey contains a range of nutrients, amino acids, soluble and insoluble fibers that are present in a ratio that the lizards have evolved to digest and thrive upon. In single item foods such as turkey mince that range is substantially less and the bioavailability of the nutrients offered is reduced. For those reasons I feel whole prey is superior and I believe it should be given for every feed.
I feed my ackies as much as they can eat every day. A few smaller feedings several times a day is much better than one large daily feeding. With good temperatures and humidity your ackies will not get fat. Hatchlings and juveniles will put all energy into growth, and sexually mature monitors will put all energy into reproduction. Please bear in mind that I am a breeder, and if I were keeping a solitary animal as a pet then such a high feeding regime would not be needed and a feed every two days would probably suffice although I must admit I have never kept a lone ackie.
2 days a week I add Nutrobal to their feedings with all the other feedings dusted in 100% pure calcium carbonate.
Ackies rarely drink but a small water bowl with fresh water changed daily should be present in the enclosure at all times.
