To UV or not to UV?
There is an ongoing controversy over providing UVB light for
nocturnal animals. The main point of the argument seems to be that the sun does
not shine at night, so why provide artificial sunlight?
The trouble is that the question is not as simple as it
first appears.
Very few animals never see the sun. At all. Ever. Some
burrowing species, perhaps, or specially adapted cave geckos; species whose
requirements are so specific that they don’t really fall under the discussion
here, which is whether our common pet species should be provided with UV light.
So which species are we talking about?
The commonly kept nocturnal species include leopard geckos,
crested geckos – most of the gecko family, with the obvious exception of the
day geckos – skinks, corn snakes, royal pythons, king snakes, horned frogs,
fire bellied toads, fire salamanders, and the various tree frog species.
Amphibians (frogs, toads, newts and salamanders) do seem to
actively avoid strong UV light; a 2% UVB compact won’t do them any harm, but it
doesn’t seem to do them any particular good, either. So it’s safe to say that,
unless you are keeping them in a setup with live plants, that UV is very much
optional.
Snakes vary tremendously in their exposure to natural
sunlight. Most will occasionally be seen basking in the early morning sunlight
to warm up after a night’s activity, although they will also make use of
sun-warmed rocks (or road surfaces) after the sun has gone down. Different
species have different activity levels at different times of day, so there
isn’t really a rule of thumb that covers all snakes. However, it’s safe to say
that by providing low levels of UVB you are replicating the occasional contact
that they would have in the wild.
Snakes have the added advantage in that their diet
automatically provides them with levels of vitamin D3 from the liver of their
prey; this has always been the argument against providing them with artificial
light. However, by giving them the opportunity to ‘top up’ in the same way they
would in the wild we can only improve their overall health and general
wellbeing.
(Interestingly, my Mandarin Ratsnakes – a Chinese species
renowned for their shy natures, and for remaining burrowed in leaf litter when
given the chance – often come out to bask first thing in the morning when their
lights come on. Because they like it cooler than a lot of other species, I use
2% UV compact bulbs, which don’t put out a lot of heat. So are they basking to
gain benefit from the slightly raised temperature, or making use of the UV?)
But it’s the nocturnal lizards where the discussion can get
quite heated. It’s certainly true that leopard geckos have been kept and bred
for many years without the use of UV light, and have done very well. Many of
the largest, most successful leopard gecko breeders in the world use rack systems where
the geckos have no access to UV light, and they do just fine.
Anyone who has worked with reptiles has, however, seen the
other side of the coin all too frequently. Sometimes, it appears that these
nocturnal lizards simply cannot metabolise the supplements we give them to
mimic exposure to UV light. So even if the animal’s food is supplemented
regularly with the correct amount of the correct formulation of
multivitamin/multimineral powders it can still get sick… and metabolic bone
disease (MBD)is a terrible, sad, debilitating condition that will eventually
prove fatal for the unfortunate creature that has it.
We occasionally see MBD I geckos kept without UV light but I
can’t think of any cases we have seen where UV light was provided.
In the wild a lot of these nocturnal animals aren’t totally
hidden away from the light. Crested geckos hide amidst foliage at the end of
branches, with at least part of their skin accessible to sunlight filtered
through the canopy. Leopard geckos can be seen with either their heads or tails
at the mouth of their caves, taking advantage of early morning or late
afternoon sunlight. Many species will be
found hunting at dawn or dusk, where they are again exposed to sunlight; in no
way is this the same strength of sunlight (and hence UV) found when a bearded
dragon is sitting in the full blast of the Australian sunshine at midday!
By providing access to lower levels of UVB light, whether
it’s from a traditional style strip light or a compact lamp, your pet can
regulate its level of UV in the same way that it regulates its temperature. And
while you should still keep up with the supplements, you can be sure that your
pet is actually getting the full benefit of them. We want our pets to be
healthy and happy, and it really does seem that by providing access to UV light
we are maximising the chances of this.
For more information on UV light and why we should be
providing it for more animals than we used to think, please see http://www.uvguide.co.uk/ These guys really, really know what they’re
talking about!
There is a wide variety of lights available so if you need any help choosing the right light for your animal please call us on 01865 764269 or email info@evolutionreptiles.co.uk
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