# Is UVA NEEDED for indoor tortoise keeping?



## ZEROPILOT (Feb 21, 2020)

I've been asked by another member if UVA is needed for their Redfoot tortoise.
Truth is, even though I'm thinking no. I simply don't have the answer. Mine all live outside.
So, we're talking Redfoot here. Redfoot need some UVB. Not a lot. But do they also need UVA? 
For food recognition or to help with being housed indoors in any way?

Thank you for your thoughts.


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## Tom (Feb 21, 2020)

No. No species "needs" UVA. In some cases it improves appetite and activity, but in most cases I've seen, it doesn't matter at all. Many of mine in years past only had an incandescent bulb.


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## Kapidolo Farms (Feb 22, 2020)

It could be argued that at least some species don't "need" UVB if D3 and calcium are appropriately supplemented in their diet.

Another member here on TFO has begun some experiment and anecdotal observation UVA might be associated with a slight level of pyramiding.

As much as is know, there is more not know. To tease this out a lab with well controlled environmental parameters would be helpful. All I need is a grant a few million (LOL) and I'll get right on it.


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## Tom (Feb 22, 2020)

Kapidolo Farms said:


> As much as is know, there is more not know. To tease this out a lab with well controlled environmental parameters would be helpful. All I need is a grant a few million (LOL) and I'll get right on it.


While you are at it, would you please test a few thousand cfl type bulbs and share the findings?


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## Markw84 (Feb 22, 2020)

UVA is quite important to tortoises. However, just like all types of light, we must not overdo it! So be careful to not go overboard.

Tortoises have excellent color vision. Much better than we do! Their eyes have a 4th type of cone that is good at seeing UVA spectrum lighting. Bees use this for example as it makes colors more vibrant and much more contrasting so very useful in distinguishing types of flowers they frequent for making honey. Many plants and flowers have special colors that really show up under UVA light and look quite different under UVA. These are signals some animals use to distinguish different plants and flowers as food potential. Tortoise are one of the animals who probably use their greater UVA assisted vision for seeing the world and making their choices.

I also find UVA light can help trigger basking reflexes and tortoise use this to find basking spots. The UVA spectrum is also most affected by the height of the sun in the sky and I believe very much controls the circannual rhythms of tortoises. UVA has been linked to a very definite overall "well-being" of reptiles and having.

The other side of the issue, is that UVA is also used extensively for curing paints, acrylics, etc. It is commonly used to acrylic nail polish in nail salons. It has a know aging affect on skin (which is a form of keratin). It is the UVA in sunlight that deteriorates the cloth is outdoor furniture and umbrellas, and ages our windshield wipers so quickly. So, I think we can overkill on UVA and it may well have a "curing" effect on new keratin growth. This could add to potential pyramiding problems if we put too much UVA in an enclosure without proper shade and hide areas best created by lots of plant cover.


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## ZEROPILOT (Feb 22, 2020)

Markw84 said:


> UVA is quite important to tortoises. However, just like all types of light, we must not overdo it! So be careful to not go overboard.
> 
> Tortoises have excellent color vision. Much better than we do! Their eyes have a 4th type of cone that is good at seeing UVA spectrum lighting. Bees use this for example as it makes colors more vibrant and much more contrasting so very useful in distinguishing types of flowers they frequent for making honey. Many plants and flowers have special colors that really show up under UVA light and look quite different under UVA. These are signals some animals use to distinguish different plants and flowers as food potential. Tortoise are one of the animals who probably use their greater UVA assisted vision for seeing the world and making their choices.
> 
> ...


OK
@willee638
There you go.
We're kind of split on this issue.
Many of us have never used any UVA.
However, at least one of us that also happens to be a trusted lighting guru says we might be wrong.
You have a very good question there.
One that requires further converstaion.


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## willee638 (Feb 22, 2020)

ZEROPILOT said:


> OK
> @willee638
> There you go.
> We're kind of split on this issue.
> ...


Thanks very much this is invaluable information & very in depth, from my personal limited experience I noticed my red foot tortoise responded much quicker in recognising her food in natural sunlight & her appetite was stimulated & actually ate more than in my home enclosure with an artificial UVA+UVB bulb. I guess it's true man made artificial anything can't ever replicate nature...kudos for sharing your knowledge.


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## Markw84 (Feb 22, 2020)

ZEROPILOT said:


> Many of us have never used any UVA.



It should be noted that all our UVB bulbs also emit even more UVA than UVB. The reptile fluorescent tubes we use today put out approximately 40% of their energy as UV and 60% as visible light. (discounting for inefficiency)

A 10% UVB tube puts out in the range of 30% UVA and 10% UVB.
A 5% tube is about 35% UVA, 5% UVB
Etc., etc.

Other UVB bulbs used like MVB are similar in that. However, they have a fairly large % of energy emitted as IR-A that changes the %s but ther ratios are about the same.

So if you have used any UVB bulbs, you have definitely been providing UVA to your tortoise as well.


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## willee638 (Feb 22, 2020)

Markw84 said:


> It should be noted that all our UVB bulbs also emit even more UVA than UVB. The reptile fluorescent tubes we use today put out approximately 40% of their energy as UV and 60% as visible light. (discounting for inefficiency)
> 
> A 10% UVB tube puts out in the range of 30% UVA and 10% UVB.
> A 5% tube is about 35% UVA, 5% UVB
> ...


That is definitely interesting to know, this information retailers wouldn't want reptile pet owners to know because they insist there's a huge difference in the 2 UV lights & one has completely different effects "applications" on the reptiles. I was told I can either get a UVA or a UVB only for different purposes & getting a UVA+UVB full spectrum is most beneficial for my tortoise, this means I can arrange an ordinary incandescent bulb for heat only that has no UVA emitted & a UVB bulb that can still emit a % of UVA & UVB in a separate lamp? This solution is possibly most cost effective for me...


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## ZEROPILOT (Feb 22, 2020)

Markw84 said:


> It should be noted that all our UVB bulbs also emit even more UVA than UVB. The reptile fluorescent tubes we use today put out approximately 40% of their energy as UV and 60% as visible light. (discounting for inefficiency)
> 
> A 10% UVB tube puts out in the range of 30% UVA and 10% UVB.
> A 5% tube is about 35% UVA, 5% UVB
> ...


I've learned something new then.
Thanks


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## William Lee Kohler (Feb 23, 2020)

Markw84 said:


> It should be noted that all our UVB bulbs also emit even more UVA than UVB. The reptile fluorescent tubes we use today put out approximately 40% of their energy as UV and 60% as visible light. (discounting for inefficiency)
> 
> A 10% UVB tube puts out in the range of 30% UVA and 10% UVB.
> A 5% tube is about 35% UVA, 5% UVB
> ...



It had been my impression that this was the case and I was about to ask the question.


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