HVR&R Reptile Heating and Lighting Guide

Necessity of Species-Appropriate Temperatures

Unlike humans, almost all reptiles are completely dependent on their environment to manage their body temperature. The reason different species need to be kept in different temperatures is because their bodies are adapted to varying temperatures. Reptiles do not have a way to heat or cool themselves outside of their environment (with the fascinating exception of some Tegu species during certain parts of the year!) and are completely reliant on their keeper to provide appropriate temperatures for them. 

An often overlooked necessity for reptiles is a thermogradient in their enclosures - meaning one side of the enclosure is warmer than other. This will allow your reptile to move as needed from warm to cool areas to regulate their body temperature. Having your reptile in an environment that is one temperature, even if that temperature is within their range, will not allow your pet to regulate its body temperature appropriately. There are numerous reasons an appropriate temperature is so imperative:

• Regulating their metabolism

• Supporting digestive health

• Supporting the immune system to fight infections

• Managing dormant parasite levels (almost all reptiles have them)

• Maintaining their circadian rhythm

• For females - incubating their offspring

This is not a complete list but covers a lot of the important points. 

All reptiles should be kept on a consistent 12 hour light cycle - meaning the light is on for 12 hours, then off for 12 hours. This 12 hour rule applies to diurnal (awake during the day,) nocturnal (awake during the night,) and crepuscular (awake at dawn and again at dusk) animals. 

Some people are led to believe that a nocturnal animal should never have a light source. But, how would you, as a diurnal human, feel if you had light 24/7? It would disrupt your circadian rhythm and havoc would ensue! We do not want havoc. No chaos here! All reptiles need a 12hr on/12hr off cycle to sustain their natural circadian rhythm. 

A common item marketed to reptile keepers are red or blue “night lights.” These lights offer no benefits to your reptile and actually harm them! It disrupts their day/night cycle by having lights on at night, and the colors can damage their eyes. Rule of thumb; avoid colored lights.

The Importance and Controversy of Providing UVB Light

Ultraviolet light comes in the form of UVA, UVB, and UVC. UVA is the lowest energy, longest wavelength ultraviolet. UVA light is visible to reptiles, it’s a color that humans cannot see. It promotes breeding behavior and encourages diurnal movement. UVC is the shortest wavelength, highest energy ultraviolet wavelength that is not required by reptiles but does have antibacterial properties. The main concern here for reptiles is UVB.

At its core, UVB, a form of ultraviolet light,  allows for the production of vitamin D3 in a reptiles' body. When combined with heat vitamin D is converted to vitamin D3, which is a primary mechanism for metabolizing calcium. Calcium is an essential component of bone health, among other bodily necessities. 

The level of necessity to provide UVB for reptiles varies from absolutely required to simply beneficial. This is where the controversy lies. We at Hudson Valley Reptile & Rescue are of the belief that all reptiles benefit from UVB light, but it is not imperative for all species to do well in captivity. We do believe in providing the absolute best lives possible for our captive reptilian friends, however, and do promote UVB for species even where it is not strictly necessary.

With regards to UVB for reptiles - the question should not be “why?”. It should be “why not?”.

Metabolic Bone Disease

Let’s get into why UVB is undeniably required for certain reptiles. Animals such as bearded dragons, savannah monitors, chuckwallas, red-eared sliders, uromastyx, and many others will develop Metabolic Bone Disease - MBD - without appropriate UVB lighting. Metabolic Bone Disease is a permanent and irreversible condition caused by calcium and Vitamin D deficiencies. It causes skeletal deformities that vary in severity based on the extensiveness of the condition. Reptiles affected by MBD may have misshapen skulls, legs, spines, and more. Reptiles who suffer from this condition often have trouble with mobility, struggle to eat, and have difficulty live enriched lives. It is also a notably painful condition.

Please note - the absence of appropriate UVB exposure is not the only cause for MBD, but it is the most prevalent.

Benefits of UVB For All Species

There has been extensive research that indicates all reptiles benefit from UVB exposure. Vitamin D production is promoted by UVB exposure and is an essential vitamin for metabolizing calcium. Although snakes are not typically thought to benefit from UVB because they have adapted to getting the vitamin D they need from their food, studies have shown that snakes that were provided UVB had higher levels of vitamin D in their blood. Vitamin D plays an essential part in brain, circulatory, digestive, excretory, and immune systems. Vitamin D also promotes healthy beta-Endorphin systems, which involve behavioral stability, bodily stress, and more. Ongoing research has shown that UVB exposure also benefits the eyesight, breeding, and overall mental wellbeing of reptiles. 

UVB For Nocturnal Species

There are people who push the idea of nocturnal species not benefiting from UVB light in any way. However, there are numerous sources that indicate reptiles will cryptic bask. Cryptic basking is when an animal will hide most of its body, but leave an appendage - usually a tail - exposed to sunlight to absorb UVB. An important distinction is that nocturnal animals may be more active at night, but they are not photophobic. Nocturnal animals can be active during the day at times, or cryptic bask.

A quick but important note:

Some animals with certain color mutations (morphs) are more sensitive to UVB exposure. Think of it like the Irish person you know who gets sunburned way too easily. Morphs that are especially sensitive to UVB may include albino, their derivatives, and more. Please research your specific animal’s morph when making the decision on how much UVB to provide.

Heat and Infrared Light

Infrared light is invisible to the human, and reptile, eye. The importance of infrared light in the reptile context lies in its association with heat. Although heat seems very straightforward, and to an extent it is, let’s deep dive into the types of infrared heat so you can give your reptile the best life you can!

What Heat Bulb Should You Buy?

Now that we have a good understanding of the types of overhead heat, let’s go over what you should purchase.

The two primary parts of every lighting and heat source are the bulb and the fixture. The fixture provides electricity to the bulb and illuminates it. It is essential that your bulb and fixture are compatible. In the specs list below, we will highlight the important specifications that need to match.

There can be an overwhelming number of specs listed on most heat sources, so let’s break it down and make it more digestible!

• Wattage (W) - think of this as how strong the heat source is. The higher the wattage, the more heat it will produce.

  • Note: it is absolutely imperative that your fixture (hood, etc.) is rated for an equal or higher wattage than your bulb is, you are safe. A 75W bulb in a 60W fixture is a recipe for a fire.

  • When using a dimming thermostat, you want the lowest wattage halogen bulb possible that still achieves the desired temperatures. This is because when the halogen is dimmed, its spectrum can change. A halogen's spectrum at 100% power is closest to the sun.

• PAR - specific to the recommended halogen bulbs, PAR is essentially how far the light spreads; think a spotlight versus a flood light. PAR38 is a great option for most reptiles. It provides a good amount of spread, but enough concentration that they can comfortably bask.

  • The PAR number must match the fixture

• Voltage (V) - this is the operating voltage of your bulb. 

  • The voltage of your bulb must be compatible with your fixture

Please note - we cannot provide the exact specs for your specific application. There is a lot of variation that must be taken into account such as species and desired temperature, ambient temperature of your home, size and material of the enclosure, and more. 

Ultraviolet Light Requirements and the Ferguson Scale

The third and final piece to providing reptiles the closest thing to natural sunlight is providing UVB. With infrared, visible light, and ultraviolet light all being provided in appropriate doses, you are giving your reptile the closest thing you can to the natural light that allows them to thrive. 

The amount of UVB needed varies from species to species. A good starting place for determining how much UVB to provide each species is using the Ferguson scale. Dr. Gary Ferguson created four levels based on desired UV Indexes (UVI) of different species. Zone 1 has the lowest UVB requirement, and Zone 4 has the highest. Some quick examples of species from each zone are:

Zone 1 (Crepescular or Shade Dweller) - Zone range UVI 0 – 0.7

• Leopard gecko

• Green anaconda

• Reticulated python

• Crested gecko

Zone 2 (Partial Sun or Ocassional Basker) - Zone range UVI 0.7 – 1.0

• Ball (Royal) python

• Eastern box turtle

• Everglades rat snake (and most other rat snakes)

• Jackson’s chameleon

Zone 3 (Partial or Open Sun Baskers) - Zone range UVI 1.0 – 2.6 

• Bearded dragon (some studies have them in Zone 4)

• Black and white tegu

• Red-eared slider

• Ackie monitor

Zone 4 (Mid-day Sun Basker) - Zone range UVI 2.6 – 3.5

• Bearded dragon (some studies have them in Zone 3)

• Uromastyx

• Chuckwalla

• Savannah (Bosc) monitor

Some species may fall somewhere in the middle of two zones. These are only guidelines.