UVB Lighting Part 2 Sunbeam or Shaded?

In our last post, we talked about methods of lighting your reptile enclosure. These came down to two main focuses – the Sunbeam method or Shaded method. It was seen from the work done by Frances Baines and co, in their latest publication on Journal of Zoo and Aquarium Research, that reptiles can be categorised into Ferguson Zones, as originally laid out by Dr Gary Ferguson. Within these zones, there is a UV Index range, a description of the species behaviour, and also a specific method by which they should be given their UV, as seen here;

Zone 1 – Crepuscular or Shade Dweller, thermal conformer

UVI 0 – 0.7 Shaded method

Zone 2 – Partial Sun/Occasional basker, thermoregulator

UVI 0.7 – 1.0 Shaded method (up to UVI 3 with Sunbeam method)

Zone 3 – Open or Partial Sun basker, thermoregulator

UVI 3 – 7.4 Sunbeam method

Zone 4 – Mid-Day Sun basker, thermoregulator

UVI 4.5 – 8 Sunbeam method

Dr Gary Ferguson, 2010

So what is the difference between the Sunbeam and Shaded method? And how can you be sure to provide them in the correct way in captivity? Due to the huge variety in reptiles, there is obviously differences in how they get all their required needs, from food to water, and through to lighting as well, including both UV and heat for energy.

It was found by Dr Ferguson that Zones 1 and 2 did better with a method of lighting called Shaded, whilst reptiles that needed higher UV, those in Zones 3 and 4, did best with the Sunbeam method. There are instances where the Sunbeam method is preferred for Zone 2 species, mainly if the enclosure is particularly large.

Shaded Method

The Shaded Method is designed for low level UV, and is really giving an UV Index reading of up to 1.0. This technique is designed to cover a large volume of an enclosure with low level UV, namely as “background” UVB. This is for species that either come out mainly at dawn and dusk (crepuscular), or spend most of their time in shade or partial shade. It can be extended for those that occasionally bask as well.

The main purpose of this is to provide UV across a proportion of the enclosure, so the most popular choice of bulb will be fluorescent UVB strip, mainly T8, though T5 may be suitable for some species. The same effect could be created with multiple compact bulbs in a canopy style hood on a glass terrarium as well though. The aim is to create an area with a maximum UV Index of the specific Zone, either 0.7 or 1.0. This should be in one area, the closest point the reptile could get into, such as on a rock or branch, and then the rest of the enclosure should have much lower levels, leading down to areas with no UV at all, that are completely sheltered.

For our nocturnal species, such as Crested and Leopards, and the snakes we looked at last time, this will mean that they have the option to reach the highest level of UVI for their respective Zone, but that the majority of the time they will be a much lower area of the enclosure, which will create a completely naturalistic environment. To get some ideas of specific data here, let’s look at them in more depth:

Crested Geckos, Tokay Geckos and other Zone 1 arboreal species

These are usually housed in a glass terrarium, so would have the lighting set up with either a strip UV bulb above the mesh (losing around 30-40% of the UV by going through the mesh top) or sitting inside, or by the use of a canopy hood with compact fluorescent bulbs in. Each of these set ups would require different bulbs, so how you have your habitat laid out will drastically impact what you need to buy.

To start, if you’re using a strip UV outside of the terrarium, going through mesh, with a highest branch for your Gecko to sit on around 20cm down from the mesh, meaning it is around 25cm away from the bulb itself, and losing 40% through the mesh, then the best bulb would be a ExoTerra Repti Glo 5.0 T8, or even a ZooMed ReptiSun 10.0 T8, which will surprise many keepers. A canopy with compact bulbs, with the same distances, would be best using Exo Terra UVB 100.

However, if using a T8 bulb inside of the enclosure, then an Arcadia 6% T8 would be suitable, at a distance of 20cm from the highest basking branch.

Leopard Geckos, Crocodile Skinks and other Zone 1 terrestrial species

Leopards are usually kept in wooden terrariums, so lighting will be internally, and often at a distance of around 40 – 45cm from ground level, though this needs to take into account the highest point the gecko can get, so most will have a hide or branch they can walk on to gain 5cm at least – so between 35 – 40cm from the bulb. To get the correct readings accurately from a T8 bulb, ideally an Arcadia 12% bulb is best (without reflector), or a ZooMed ReptiSun 10.0. Another option is an Arcadia T5 6% bulb, which would also be suitable (without reflector)

Sometimes Leopards are housed in glass terrariums as well though, so for a bulb to go through the mesh, in a low terrarium of 30cm tall for example, the 6% Arcadia T5 would again be perfect, or if using compact bulbs through the mesh in a canopy, an Arcadia 10% would be more suitable. Quite a step up from providing nothing at all!

Corns, Kings, and other Zone 1 Snakes

Ideally kept in wooden vivariums, these low level snakes will tend to move around the space more freely, so lighting can seem to be more tricky – I personally have 1 Corn that is constantly scaling his decoration and floating around his vivarium, and another that moves along the bottom a lot, but doesn’t venture upwards at all. Although this may seem that these two snakes require different bulbs, in reality you are only offering for the highest level to be at the highest the point the snake goes to – around 15cm from the bulb. Whether they choose to move into the light more or not is their own choice.

In this case, an Arcadia Natural Sunlight 2% T8 is perfect, or an ExoTerra 2.0 T8 could be used, but should have a reflector on to enhance it better.

Royals, Boas, Garters, Hognoses and other Zone 2 Snakes

In a similar set up to those above, snakes of Zone 2 should be using an Arcadia 6% T8, or potentially the 2% with a reflector, based on the optimum distance of around 15cm.

With this method, it is best to create a the UV range over about two-thirds of the vivarium, so if you have a 36” or 3ft vivarium, a bulb only needs to cover around 24” or 2ft, and the bulb should be placed to one side, the hot end, creating a cool end that will have no UV penetration at all, which is more naturalistic for these animals, and then they can move out of the UV completely.

Sunbeam Method

This method is much more naturalistic to the way we think UV should be provided – higher levels given to basking species, the same UV they would be getting directly from the sun whilst sitting out in it to warm up in the mornings. This still tends to be provided through the use of fluorescent strip bulbs, either T8 or T5, but can also be established from combined Mercury Vapour Bulbs or Metal Halide bulbs, which give an intense section of heat and UV, which is great for larger or open top habitats. Strip bulbs need to be set up in the same way as the Shaded method, with the bulb taking up around two-thirds of the enclosure, and off centre to be situated on the heat side, so that the UV is still absorbed whilst basking in heat. This method moves away from what we think of as the “basking spot” and creates more of a basking zone, an area of space that an animal can sit in to fully bask and absorb heat and UV light.

Compact bulbs are rarely suitable for these Zones as they don’t provide high enough levels for the higher UV required, with the exception of the Arcadia 10% compact, which measures up very well, and would be suitable for some species in a canopy set up, as long as they could get within 25cm of the bulb after it has gone through a mesh top.

Chameleons, Day Geckos and other Zone 3 arboreal species

In a standard arboreal terrarium with mesh top, a combined bulb or metal halide tends to be the best option for these species, as they would naturally use the plant life to shelter and move into the heat and light during the day. As this will be above the mesh, losing 30-40%, something like an Arcadia combined bulb 160w would need to be at a distance of around 25-30cm (from bulb to nearest basking branch) for optimum levels, and then the rest of the enclosure would be much lower, providing the required shelter from the UV. Alternatively, the Lucky Reptile Bright Sun 70w (separate ballast required) could be situated at around 20cm.

Bearded Dragons, Plated Lizards, European Tortoises and other terrestrial Zone 3 species

Usually kept in a wooden terrarium, the fluorescent strips are best used, and will tend to be around 40 – 45cm from the top of a hide (or shell!). If your lizard may climb and you provide more decoration, please take into account any extra height. The best bulbs to choose from would be Arcadia T5 12% with reflector, or the new 14% T5 without. If your basking spot is higher, up to 25 – 30cm, remove the reflector to get better ranges, or change to a T8 bulb, such as the ZooMed ReptiSun 10.0 with reflector.

The main thing to remember is that UV doesn’t need to be offered across the length of the vivarium – gone are the day of squeezing in a 46” bulb into a 48” vivarium. It’s important that there is a cool corner that offers a respite, even for a species like Chuckwallas or Uromastyx, which thrive in the heat. Hides will provide that shelter mostly, but animals shouldn’t feel that they are confined to them.

The other important aspect when thinking about UV is to remember that these figures are only relevant and correct when your species is kept at their required temperature, on both the hot end and more ambient zones as well. If they are too hot, they will move out of the heat and miss out on UV they may have otherwise required, or vice versa, spend more time in UV than optimum in order to gain enough warmth. Ideally, get hold of a UV Index meter, to read the levels in the areas around your enclosure. This most popular choice of meter with hardcore lighting enthusiasts tends to be the Solarmeter 6.2, though watch this space for a new product on the market making UV checking more available to the masses.

As much as some of this information is new for our crepuscular species, it’s also new to many day time basking owners as well, thinking that our sun-loving Bearded Dragon may want a shady UV free area, but in reality your dragon would spend some time in shade to get some respite. This is still new, and if you think about the mountains of information we have learnt in the last 5 years, just think of what we can continue to discover in the next 5 years. We can only work with the information that we have now – but it’s important to really use that information fully and not overlook it at all, especially for an “easier” method.

“It’s easy to get comfortable with “the way it’s always been done” where animal husbandry is concerned, perhaps because a particular method has been considered the standard for years, if not decades, and may come with just as many years of success breeding and raising a certain species. If people have had such tremendous success with species such as crested geckos or royal pythons without the use of any UV lighting, what would be the point of changing what clearly works? While certainly easier and cheaper to not provide UV lighting if it’s not strictly necessary, there are very few examples in exotic animal husbandry where the easy method also happens to be the best. Take for example the dietary needs of leopard geckos; while these can live many years on a diet of 100% mealworms, which are cheap and convenient for the keeper, new thinking is encouraging the use of a varied diet of well gut-loaded insects instead, which simply makes sense as the naturally superior way to approach nutrition.

Said another way, just because an animal has done well under certain conditions does not mean that there is no room for improvement, improvement which might enable the animal to really thrive. These new techniques may drag us kicking and screaming into more advanced ways of caring for our reptiles and amphibians, but they are necessary if the goal is to recreate their natural environment as closely as possible and ensure that these species truly thrive in captivity. We have to be open to pushing ourselves to try out new and potentially superior techniques the more we learn instead of settling for how things have always been done just because they’re easier.”

Olimpia Martinotti, www.muchadoaboutchameleons.com

Next in the series is UV in depth – what do our reptiles gain from UV? Everyone knows its important for bone strength and structure, in reality it used in a multitude of aspects across the body, so we can look at it in depth and really see why it is so important.