Each species of reptile has gradually evolved over the course of millions of years to be very good at living in a very particular environment. As such, a reptile’s health and wellbeing is heavily dependent on the environment that it is living in. They’re not as adaptable as mammals like humans and dogs and cats. So when you’re planning to bring home a pet ackie monitor, you need to make sure that its enclosure replicates the natural conditions of its native habitat. Once a suitable enclosure has been selected, the habitat replication process starts with mimicking the effects of the Sun through your choices for ackie monitor lighting.
Sunlight is complex, but if we simplify it, we can divide it into the 3 general components that are most important for successful reptile husbandry: infrared (heat), visible light, and ultraviolet radiation. Each component plays a different role in reptile health and wellbeing, which science is just barely beginning to understand. If you are interested in learning more about the relationship between reptiles and light, “Fire — The Sun: Its Use & Replication Within Reptile Keeping” by John Courteney-Smith is a great place to start.
Day Length for Ackie Monitors
If you want to keep it simple, you can keep your ackie monitor’s lights on for 12 hours/day year-round. However, light plays an important role in hormonal cycling (Horn & Visser, 2007), and hormones play a critical role in reptile wellbeing. Instead of using a static day/night cycle, ReptiFiles recommends a dynamic day/night cycle of increasing and decreasing daylight over the course of a year according to the geographical location of a reptile’s natural habitat. This encourages more natural hormonal cycling in captivity, and hopefully, better long-term health as a result.
Here is a proposed day length schedule for ackie monitors kept in the northern hemisphere, based on day length data from Alice Springs, Northern Territory, Australia (rounded to the nearest 5 minutes):
- January — 10 hours, 40 minutes
- February — 11 hours, 0 minutes
- March – 11 hours, 40 minutes
- April – 12 hours, 20 minutes
- May – 13 hours, 0 minutes
- June – 13 hours, 30 minutes
- July – 13 hours, 30 minutes
- August — 13 hours, 10 minutes
- September — 12 hours, 30 minutes
- October – 11 hours, 50 minutes
- November — 11 hours, 15 minutes
- December — 10 hours, 45 minutes
For the southern hemisphere, that schedule needs to be flipped upside-down to match with local seasons:
- January – 13 hours, 30 minutes
- February — 13 hours, 10 minutes
- March — 12 hours, 30 minutes
- April – 11 hours, 50 minutes
- May — 11 hours, 15 minutes
- June — 10 hours, 45 minutes
- July — 10 hours, 40 minutes
- August — 11 hours, 0 minutes
- September – 11 hours, 40 minutes
- October – 12 hours, 20 minutes
- November – 13 hours, 0 minutes
- December – 13 hours, 30 minutes
The easiest way to schedule when your lights turn on/off is with a smart plug or digital outlet timer. I prefer to schedule each of my lamps and heat sources individually, so I recommend the Kasa Smart Power Strip or Zilla Digital Power Center for convenience. Aside from being better for your reptiles, using timers also makes reptile keeping that much easier!
Ackie Monitor UVB Requirements
UVB stands for “Ultraviolet-B”, and it’s one of the three types of ultraviolet radiation produced by the Sun. Many people freak out about ultraviolet because it’s strongly associated with sunburns and skin cancer when humans over-expose themselves to it. And when they hear the word “radiation,” they think about nuclear fallout and catastrophic meltdowns at nuclear power plants. But there are many different types of radiation, and while some are harmful, others can be beneficial.
UVB is a type of ultraviolet radiation that is essential to reptile health in both the wild and in captivity. One of its most well-known functions is enabling the synthesis of vitamin D within an animal’s body. But it also has many other benefits, including strengthening the immune system and stimulating the production of the feel-good hormone serotonin.
An excellent ackie monitor enclosure MUST include access to appropriate amounts of UVB. In order to meet this requirement, you will need a strong, high-quality UVB lamp, mounted at a safe distance from the basking area in a reflective, wide-angle fixture. Here are the best ackie monitor UVB lamps that ReptiFiles recommends for use with ackie monitors, categorized by vertical distance between the lamp and the ackie’s head while standing on the basking surface:
- Arcadia T5 HO Desert 12% / Zoo Med T5 HO Reptisun 10.0
- mesh: 9-11″ /23-27cm
- no mesh: 14-17″ / 35-42cm
- Arcadia T5 HO Dragon 14%
- mesh: 10-12″ /25-30cm
- no mesh: 14-18″ / 35-45cm
(These recommendations are an approximation based on the assumption of a ~45% mesh block. For more details on adjusting basking distance based on mesh obstruction, see the Facebook group Reptile Lighting > Guides > Guide 1: Using T5-HO lamps above a Mesh Screen.)
Your ackie monitor’s UVB bulb should span roughly half of the enclosure’s length, mounted over the basking area with the other basking equipment.
If you are using a Solarmeter 6.5 or 6.5R to measure your lamp’s specific UVB output at your basking area (recommended!), you will need to know that they prefer strong sunlight in their environment. According to the Arcadia Lighting Guide for Full-Sun Baskers, the maximum UVI in the basking area at the ackie’s head level should be between 4.0-6.0. UVI should be highest at the basking spot and lower in other areas of the enclosure so your monitor has options to choose from.
Due to reported unreliability in performance, ReptiFiles does not recommend ANY other brand of UVB bulb at this time. Using other brands of UVB lighting without the use of a Solarmeter 6.5 may negatively affect your ackie’s health.
Can vitamin D3 supplementation be used instead of UVB lighting?
Although it is true that monitor lizards are capable of surviving and even reproducing without UVB when they receive high quantities of dietary vitamin D3, that does not necessarily mean that this is best practice. Aside from missing out on the other benefits of UVB, attempting to provide the perfect amount of vitamin D3 through diet alone is an imprecise science at best. Physiological need for vitamin D3 fluctuates from day to day and according to an animal’s species, life stage, and size.
When reptiles have access to appropriate amounts of UVB radiation, they are able to manufacture the exact amount of vitamin D3 that their bodies need in that moment. When reptiles only have access to vitamin D3 through diet, they are limited to the amount available. If there’s not enough, physiological processes that require vitamin D will be compromised. If there’s too much, excess vitamin D will get stored in fat cells for later use, creating the potential for overdose in the future. Considering that modern science doesn’t even know exactly how much vitamin D humans need — much less ackie monitors — relying on dietary supplementation is most likely to result in under- or over-dosing the animal, both of which will negatively affect their health over the long-term.
To summarize: Rather than messing around with supplements, it’s best for your monitor’s wellbeing to simply focus on providing appropriate amounts of UVB from a high-quality lamp.
General Lighting for Ackie Monitors
Considering that ackie monitors are diurnal (day-active) and mid-day baskers, it is reasonable to assume that they prefer and are stimulated by the presence of bright light in their environment. This assumption is supported by captive observations.
Although UVB lamps and heat lamps (we’ll get to that later) do produce some visible light, they simply don’t produce enough of it to get anywhere close to replicating daytime illumination. For this reason, ReptiFiles strongly recommends adding 6400K or similar full-spectrum T5 HO fluorescent or LED lighting to further illuminate your enclosure.
Here are ReptiFiles’ favorite “daylight” lamps for a 5’ long ackie enclosure:
DO NOT use colored lights of any kind with your ackie monitor’s enclosure (red, black, blue, etc.), not even during the night. These can potentially negatively affect your lizard’s mental health by altering their perception of color in their environment. And honestly, it looks weird and unnatural.
Keep reading about ackie monitor care:
- Introduction to Ackie Monitors
- Varanus acanthurus Subspecies
- Shopping List: Supplies You Will Need
- How to Select and Buy a Pet Ackie Monitor
- Enclosure Size & Roommates
- Lighting & UVB Requirements
- Heating Requirements
- Humidity Requirements
- Substrate Options
- Environmental Enrichment: Decorating the Enclosure
- Feeding Your Ackie Monitor
- Handling Tips & Behavioral Notes
- General Health Guide
- Additional Resources