# UVB not a necessity???



## nrfitchett4

O.K. after the pyramiding thread almost got hyjacked by uvb, let's have it out. 
Seems there are some out there that don't UVB. Is this bad or not?
And for those that don't UVB, do your torts get natural rays or vitamin d supplement?
I am curious because I read that ig's don't process dietary d3 very well and they need sunlight or UVB every day to prevent MBD. 
I wonder if this is true for torts?
Right now I don't have a UVB because I ordered it online and it hasn't come yet. But Shelly has been getting about an hour a day of sun outside here in SA.


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## Millerlite

Reptiles need UVB to produce D3, Some people dont use the bulbs, but it doesnt mean the tortoises never go out during the warm months. There are a few people that dont use it i personally have a MVB bulb but others can let you know how it goes with out it.


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## TKCARDANDCOIN

Your tortoise needs uvb!!!!


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## Jacqui

At my house, some have the UVB lights, some don't. All the youngsters have the lights. The redfoots and hingeback kids have a lower power one, then the other youngsters. Any new tort I get in, I assume may not have been getting outside time, so they also get the light.

The rest of my collection of adults don't get UV lights, but do get lighting. My adults live outside when the weather permits. So far, I am not seeing problems with health issues, activity levels, eating, ect.., This is the first year I have gone this way with all the adults. I tried it for many years with my hingebacks and had no trouble, but once more they are not high UV users.


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## -EJ

Reptiles don't need artificial UVB... give it a little thought. There are other sources of vitamin D.

So... UVB is not necessary.


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## Meg90

So, if I lived without sunlight for 20 years, but still took a multivitamin, I wouldn't have any bad health effects?

That makes no sense.


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## Millerlite

I know for my Greek tortoises i use to have, i didn't use UVB bulbs. They were healthy and growing quite well. My greek tortoises had Vitamin supplements and on warm days, they would go outside. I still used a heating bulb which was just a bulb that gave off heat and light so they can have a day night cycle.


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## KQ6AR

I use the t-rex active heat uvb bulb when I have some indoors. Its also acts as the heatlight. Supposedly their UV output is good for 12 months. There's no substitution for sunlight though.

Is it necessary to keep them alive- NO
Is it beneficial & good for them- Yes

If you're using the electricity anyway, why not use the good bulbs?


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## nrfitchett4

-EJ said:


> Reptiles don't need artificial UVB... give it a little thought. There are other sources of vitamin D.
> 
> So... UVB is not necessary.



my question is whether they can handle dietary d3. Apparently igs don't very well which is why they can get mbd even with supplementation. 
Of course you could take them outside, but that isn't going very well for most of the country right now.


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## Madkins007

A few key points...

1. There are almost certainly different requirements for UVB or D3 in different species. Rainforest tortoises live in places with only about 2% of the light hitting the ground, while equatorial grassland species are getting big doses.

2. Humans only need about 2 exposures a week of about 15 minutes a time for their D3 needs. Tortoises are smaller and have slower metabolisms so it is unlikely they would need more than that.

3. While I can find no study that suggests an average dose of vitamin D, the 'industry accepted' ratio of fat-soluble vitamins is A:E of 100:10:1

4. I cannot find a good study that suggests that one form of D3 is better than another for tortoises. I cannot find an article that says that tortoises need D3 (sun/meat) over D2 (plant)- a lot of species do not differentiate between the two- rats, for example, cannot use D3.

5. All fat-soluble vitamins can store up in the tissues- overdoses are possible. Overdoses of D create sun-burn-like symptoms. D is available in the natural light, UVB lights, fatty fish, organ meats, eggs, mushrooms (D2), vitamins, some calcium supplements, etc. Giving extra D 'just in case' is not a good idea.

6. Skin predicts UBV abilities- comparing iguana skin to tortoise skin is comparing apples to pineapples. There is a good article at http://www.uvguide.co.uk.

7. A lot of people and zoos raise Red-foots and other turtles and tortoises with no UVB, and yet chart growth rates and reproduction rates comparable to people who DO use UVB. Here is an article about a study on Sliders comparing the growth with and without UVB when D3 is in the diet: "Anders, Ben and Moll, Dan Ã¢â‚¬Å“Do ultraviolet lights affect growth in captive turtles?Ã¢â‚¬Â Turtle Survival Alliance, 2007 (http://www.turtlesurvival.org/resou...7annualmeeting/abstract07/ultraviolet-affect/)"

(OK- one of the things that gets attacked about this and similar studies is the idea that growth rates are not a good predictor of health. That 'may' be so, but there are few other hard and fast guidelines we can measure to compare. This is the standard for most studies like this.)

8. Meg said "So, if I lived without sunlight for 20 years, but still took a multivitamin, I wouldn't have any bad health effects?" This is a common sort of comment, but it really does not apply. You cannot compare humans and tortoises, it completely ignores the effects of D2 (which humans can use for calcium metabolism according to our company dietitian) and dietary D3 (the sources of D3 are good for us for a lot of things), and it ignores the fact that there ARE people who are raised in such environments with fewer problems than might be predicted.

9. Sadly, UVB has become almost a 'magic lamp' for keepers- I have to admit that I am really tired of hearing people shout 'UVB UVB UVB' for every issue. I also worry about 'sunblasting'- too much of a good thing is often a bad thing. Long periods of high UVB are probably not a real good thing overall.


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## nrfitchett4

Madkins007 said:


> A few key points...
> 
> 1. There are almost certainly different requirements for UVB or D3 in different species. Rainforest tortoises live in places with only about 2% of the light hitting the ground, while equatorial grassland species are getting big doses.
> 
> 2. Humans only need about 2 exposures a week of about 15 minutes a time for their D3 needs. Tortoises are smaller and have slower metabolisms so it is unlikely they would need more than that.
> 
> 3. While I can find no study that suggests an average dose of vitamin D, the 'industry accepted' ratio of fat-soluble vitamins is A:E of 100:10:1
> 
> 4. I cannot find a good study that suggests that one form of D3 is better than another for tortoises. I cannot find an article that says that tortoises need D3 (sun/meat) over D2 (plant)- a lot of species do not differentiate between the two- rats, for example, cannot use D3.
> 
> 5. All fat-soluble vitamins can store up in the tissues- overdoses are possible. Overdoses of D create sun-burn-like symptoms. D is available in the natural light, UVB lights, fatty fish, organ meats, eggs, mushrooms (D2), vitamins, some calcium supplements, etc. Giving extra D 'just in case' is not a good idea.
> 
> 6. Skin predicts UBV abilities- comparing iguana skin to tortoise skin is comparing apples to pineapples. There is a good article at http://www.uvguide.co.uk.
> 
> 7. A lot of people and zoos raise Red-foots and other turtles and tortoises with no UVB, and yet chart growth rates and reproduction rates comparable to people who DO use UVB. Here is an article about a study on Sliders comparing the growth with and without UVB when D3 is in the diet: "Anders, Ben and Moll, Dan Ã¢â‚¬Å“Do ultraviolet lights affect growth in captive turtles?Ã¢â‚¬Â Turtle Survival Alliance, 2007 (http://www.turtlesurvival.org/resou...7annualmeeting/abstract07/ultraviolet-affect/)"
> 
> (OK- one of the things that gets attacked about this and similar studies is the idea that growth rates are not a good predictor of health. That 'may' be so, but there are few other hard and fast guidelines we can measure to compare. This is the standard for most studies like this.)
> 
> 8. Meg said "So, if I lived without sunlight for 20 years, but still took a multivitamin, I wouldn't have any bad health effects?" This is a common sort of comment, but it really does not apply. You cannot compare humans and tortoises, it completely ignores the effects of D2 (which humans can use for calcium metabolism according to our company dietitian) and dietary D3 (the sources of D3 are good for us for a lot of things), and it ignores the fact that there ARE people who are raised in such environments with fewer problems than might be predicted.
> 
> 9. Sadly, UVB has become almost a 'magic lamp' for keepers- I have to admit that I am really tired of hearing people shout 'UVB UVB UVB' for every issue. I also worry about 'sunblasting'- too much of a good thing is often a bad thing. Long periods of high UVB are probably not a real good thing overall.



I didn't see a single ig on their study, so not sure what you are trying to say. Not sure an animal can OD on uvb as long as it has proper hides and ways to get out of the "sun".
I'm also not sure if being in the sun automatically causes the reptile to make vit d or if it is only made as needed.
Pretty much all of those animals were exposed to one certain bulb. That does not make all uvb bad. It also doesn't describe other habitat conditions.


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## gummybearpoop

I don't think every animal needs uvb...

I take my star tortoises out a few times a week for a least half an hour. I do use a uvb light for them...but I believe there is no substitute for the sun. 

My redfoots don't get a uvb light and I take them out about once a month. 

My redfoots tend to run from the sun, while the stars soak in it.

I am starting to really thinking about eliminating uvb lamps from my collection though....


How does a company "put uvb into a flourescent bulb" or how does a company get a flourescent bulb to "emit uvb rays"?


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## -EJ

The gas that is used in the bulb causes the light to be emmitted in a specific frequency range based on the type of gas.




gummybearpoop said:


> I don't think every animal needs uvb...
> 
> I take my star tortoises out a few times a week for a least half an hour. I do use a uvb light for them...but I believe there is no substitute for the sun.
> 
> My redfoots don't get a uvb light and I take them out about once a month.
> 
> My redfoots tend to run from the sun, while the stars soak in it.
> 
> I am starting to really thinking about eliminating uvb lamps from my collection though....
> 
> 
> How does a company "put uvb into a flourescent bulb" or how does a company get a flourescent bulb to "emit uvb rays"?


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## KQ6AR

Several years ago people where saying that "if 
you use a good uv bulb, you shouldn't feed 3D supplement". The claim was that they could OD. I don't know whether it was ever proven or not.


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## Millerlite

reptiles can have to much D3, it becomes poisonous if to much.


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## loogielv

i just briefly scanned through this, but I had to chime in. Reptiles might not need artifical UVB, but I will NEVER go without again. When I plugged an MVB in above my beardies tank, his colors changed and brightened up almost instantly. I still get slack jawed when I see him sometimes as hes not even the same lizard. His oranges started coming out, his whites got whiter. 

That alone is proof in the pudding


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## -EJ

last time I looked... I thought we were discussing the necessity of UVB for tortoises. If you could cite a similar example considering a tortoise... that might be impressive.

Your example really doesn't provide evidence for the necessity of UVB outside of the point that it makes the lizard prettier.




loogielv said:


> i just briefly scanned through this, but I had to chime in. Reptiles might not need artifical UVB, but I will NEVER go without again. When I plugged an MVB in above my beardies tank, his colors changed and brightened up almost instantly. I still get slack jawed when I see him sometimes as hes not even the same lizard. His oranges started coming out, his whites got whiter.
> 
> That alone is proof in the pudding


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## loogielv

-EJ said:


> last time I looked... I thought we were discussing the necessity of UVB for tortoises. If you could cite a similar example considering a tortoise... that might be impressive.
> 
> Your example really doesn't provide evidence for the necessity of UVB outside of the point that it makes the lizard prettier.


hrmm.. you have a valid point. I would venture to argue that it's common sense that when a lizard has brighter, prettier colors, it's certainly feeling good. However that doesn't prove my point, and certainly doesn't have bearing on torts... i'll have to ponder this awhile.

I'd suggest an experiment: 2 light bulbs, one UVA/UVB with a basking spot of say...85F (27c) and then across the enclosure, a basking spot under a regular incandescent household bulb with a basking temp of closer to 32-33c. If the tort chooses the slightly cooler basking spot, then I'd say he's feeling better from the UV rays then he would from an additional 4 or 5 degrees celsius.

Perhaps i'll give this a go one day. Anyone wanna try it first?


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## -EJ

The only point we are discussing is if UVB is a necessity or not. There's no doubt that it probably has benefits but it is not a need as far as tortoises are concerned.



loogielv said:


> -EJ said:
> 
> 
> 
> last time I looked... I thought we were discussing the necessity of UVB for tortoises. If you could cite a similar example considering a tortoise... that might be impressive.
> 
> Your example really doesn't provide evidence for the necessity of UVB outside of the point that it makes the lizard prettier.
> 
> 
> 
> hrmm.. you have a valid point. I would venture to argue that it's common sense that when a lizard has brighter, prettier colors, it's certainly feeling good. However that doesn't prove my point, and certainly doesn't have bearing on torts... i'll have to ponder this awhile.
> 
> I'd suggest an experiment: 2 light bulbs, one UVA/UVB with a basking spot of say...85F (27c) and then across the enclosure, a basking spot under a regular incandescent household bulb with a basking temp of closer to 32-33c. If the tort chooses the slightly cooler basking spot, then I'd say he's feeling better from the UV rays then he would from an additional 4 or 5 degrees celsius.
> 
> Perhaps i'll give this a go one day. Anyone wanna try it first?
Click to expand...


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## TKCARDANDCOIN

UVB is a necessity as far as i am concerned.I would never starve my tortoises of beneficial light!!!!!!!!!!!!!!


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## Millerlite

UVB is necessary to all reptiles, and its healthy for them, the only thing i argue is, do they need artificial UVB. Like i said before many people dont use the bulbs and have nice looking tortoises. Dont confuse this with never having UVB because most let theres have natural sun.


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## Madkins007

loogielv said:


> -EJ said:
> 
> 
> 
> last time I looked... I thought we were discussing the necessity of UVB for tortoises. If you could cite a similar example considering a tortoise... that might be impressive.
> 
> Your example really doesn't provide evidence for the necessity of UVB outside of the point that it makes the lizard prettier.
> 
> 
> 
> hrmm.. you have a valid point. I would venture to argue that it's common sense that when a lizard has brighter, prettier colors, it's certainly feeling good. However that doesn't prove my point, and certainly doesn't have bearing on torts... i'll have to ponder this awhile.
> 
> I'd suggest an experiment: 2 light bulbs, one UVA/UVB with a basking spot of say...85F (27c) and then across the enclosure, a basking spot under a regular incandescent household bulb with a basking temp of closer to 32-33c. If the tort chooses the slightly cooler basking spot, then I'd say he's feeling better from the UV rays then he would from an additional 4 or 5 degrees celsius.
> 
> Perhaps i'll give this a go one day. Anyone wanna try it first?
Click to expand...


Something similar has been done-
Anders, Ben and Moll, Dan Ã¢â‚¬Å“Do ultraviolet lights affect growth in captive turtles?Ã¢â‚¬Â Turtle Survival Alliance, 2007 (http://www.turtlesurvival.org/2007annualmeeting/ultraviolet-affect)

While not perfect, it reveals interesting elements. When Red-ears were raised from hatching to 8 months under several light options, there was no observed difference in growth patterns. This is especially interesting considering how much sliders are thought to need UVB.



Millerlite said:


> UVB is necessary to all reptiles, and its healthy for them, the only thing i argue is, do they need artificial UVB. Like i said before many people dont use the bulbs and have nice looking tortoises. Dont confuse this with never having UVB because most let theres have natural sun.



Davis, Sam, Ã¢â‚¬Å“Husbandry and breeding of the Red-footed tortoise, Geochelone carbonaria, at the National Zoological Park, Washington.Ã¢â‚¬Â International Zoo Yearbook, 19: 50-53. 1979

This is just one of many documented reports of people, zoos, etc. raising tortoises completely indoors without UV or UVB lighting (or even UV transparent glass) that grow and reproduce in about the same way as outdoor tortoises do. This particular report is biased towards Red-foots because that is what most of my research is based on.

UVB is also going to be tough for nocturnal and subterranean reptiles. 

Please understand- I AM NOT sayng UVB is bad or evil- just that it is not a miracle drug or an essential to life for every species. UVB will not fix bad Ca ratios, humidity levels, etc.


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## loogielv

-EJ said:


> The only point we are discussing is if UVB is a necessity or not. There's no doubt that it probably has benefits but it is not a need as far as tortoises are concerned.
> 
> 
> 
> loogielv said:
> 
> 
> 
> 
> 
> -EJ said:
> 
> 
> 
> last time I looked... I thought we were discussing the necessity of UVB for tortoises. If you could cite a similar example considering a tortoise... that might be impressive.
> 
> Your example really doesn't provide evidence for the necessity of UVB outside of the point that it makes the lizard prettier.
> 
> 
> 
> hrmm.. you have a valid point. I would venture to argue that it's common sense that when a lizard has brighter, prettier colors, it's certainly feeling good. However that doesn't prove my point, and certainly doesn't have bearing on torts... i'll have to ponder this awhile.
> 
> I'd suggest an experiment: 2 light bulbs, one UVA/UVB with a basking spot of say...85F (27c) and then across the enclosure, a basking spot under a regular incandescent household bulb with a basking temp of closer to 32-33c. If the tort chooses the slightly cooler basking spot, then I'd say he's feeling better from the UV rays then he would from an additional 4 or 5 degrees celsius.
> 
> Perhaps i'll give this a go one day. Anyone wanna try it first?
> 
> Click to expand...
Click to expand...


well I would still argue a point that anything that has obvious benefits would be a necessity. you could feed a tort dog food for several months before pyramiding would occur. would that mean that it's acceptable? Or that a low protein diet is not a necessity? I wouldn't think so.


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## -EJ

For the sake of the average keeper or the keeper who is totally lost by this thread...

A necessity is a component that the animal cannot do or survive without... it is a need... a must have.

UVB is not a need. Tortoises can be provided with other sources to aid in the synthesis of calcium... So... uvb can be done without... pretty simple point.


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## Kristina

-EJ said:


> For the sake of the average keeper or the keeper who is totally lost by this thread...
> 
> Tortoises can be provided with other sources to aid in the synthesis of calcium...



It might also be helpful for some to list those sources 

Kristina


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## -EJ

There is actually only one source but it can be found in a few forms... vitamin D. A little internet searching should reveal those sources.



kyryah said:


> -EJ said:
> 
> 
> 
> For the sake of the average keeper or the keeper who is totally lost by this thread...
> 
> Tortoises can be provided with other sources to aid in the synthesis of calcium...
> 
> 
> 
> 
> It might also be helpful for some to list those sources
> 
> Kristina
Click to expand...


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## nrfitchett4

how about:
1. Natural sunlight (best)
2. UVB light (probably second best)
3. Supplements

did I miss any?


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## Millerlite

i dont know if there is proof to say if UVB light is better then supplements. To many people use 2 and 3 and have good results.


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## nrfitchett4

I prefer UVB because the tort can make what it needs.


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## Madkins007

nrfitchett4 said:


> how about:
> 1. Natural sunlight (best)
> 2. UVB light (probably second best)
> 3. Supplements
> 
> did I miss any?



4. Diet. D3 is available from things like organ meats, oily fish, eggs, etc. in moderate levels, and in almost all meat in lower levels. D2 is available from mushrooms and fungi in high levels (very high in some fungi), and in lower levels in many other plants.

For most biological processes in most animals, any vitamin D seems to work, although D3 works 'better' than D2, so it takes a little more D2 to accomplish the same results.


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## Millerlite

and i believe to much D3 is bad, for any animal.


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## loogielv

-EJ said:


> For the sake of the average keeper or the keeper who is totally lost by this thread...
> 
> A necessity is a component that the animal cannot do or survive without... it is a need... a must have.
> 
> UVB is not a need. Tortoises can be provided with other sources to aid in the synthesis of calcium... So... uvb can be done without... pretty simple point.



*whoa whoa whoa, a "necessity" as YOU SEE IT, is something an animal cannot do without. a "necessity" as I see it, is something MY ANIMALS cannot do without.

I could literally feed a tortoise dog food for years AND YEARS and he wont die, but then again he'd look like the following:







or






or even










so by your definition, a low protein diet is not a "necessity" but by my definition, it most certainly is.

however your point that what UVB provides (vit d3 and thus better calcium binding) can be achieved through other means does prove that UVb is not a necessity, as long as the d3 is provided elsewhere. or the end result (more calcium) is achieved. You could easily say calcium dusting isn't a necessity either, or even a high calcium diet, as long as the calcium is being provided elsewhere. 

for the sake of the average keeper, as you put it, UVB is easiest way route to provide additional d3 (and thus calcium) so by that token I'd still say it was a necessity

I look forward to your reply. I am enjoying this wholeheartedly. thanks

pics from tortoise trust web: http://www.tortoisetrust.org/articles/webdiet.htm*



Madkins007 said:


> nrfitchett4 said:
> 
> 
> 
> how about:
> 1. Natural sunlight (best)
> 2. UVB light (probably second best)
> 3. Supplements
> 
> did I miss any?
> 
> 
> 
> 
> 4. Diet. D3 is available from things like organ meats, oily fish, eggs, etc. in moderate levels, and in almost all meat in lower levels. D2 is available from mushrooms and fungi in high levels (very high in some fungi), and in lower levels in many other plants.
> 
> For most biological processes in most animals, any vitamin D seems to work, although D3 works 'better' than D2, so it takes a little more D2 to accomplish the same results.
Click to expand...

*I will admit up front that I am a little ignorant in the d2 area, however it is my understanding that d2 is basically worthless to a reptile. lemme see if i can find the quote i know of...

found it, but it's for beardies. the point remains i believe:

Many calcium supplements and multi vitamins contain vitamin D3. Vitamin D3 (cholecalciferol) is essential to calcium metabolism, and is made in the Beardie's skin by contact with sufficient UVB wavelengths. Plants contain another type of vitamin D, called D2 (ergocalciferol). Vitamin D2 is not nearly as efficient (in fact it is really worthless) at metabolizing calcium, hence the need for D3. Research suggests that Beardies may not utilize much or any of the D3 they ingest (as given in a vitamin supplement), only that made by the UVB-skin interaction. Therefore, buying a calcium supplement that contains D3 is not necessary for the calcium metabolism. Products such as Solar Drops and Moon Drops are a waste for Beardies as it misleads people who think that they are making up for the lack of sun or other proper UVB access, and harms the Beardie who ultimately suffers from metabolic bone disease from inadequate calcium being metabolized.​
It doesn't quite say WHY d2 is worthless, but does go into d3 and all that.


edit: i want to express again, the above quote is for bearded dragons. I believe that d3 dusting is essential in tortoise care, and whether it is for lizards is up in the air in my opinion*


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## nrfitchett4

I've read the same thing about igs and d3 which is why I think it is better just to let them have a uvb or natural sunlight. Why mess with nature if you don't have to?


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## -EJ

I've read the same thing about D2 and D3 in reptiles.

As far as the TT propaganda goes... I'll not go there... maybe just a little... those photos are use for the viv argument... for the protein argument... and not the UVB argument... that's gotta make a person wonder.

Needless to say... many people have raised wonderful looking animals without the use of UVB bulbs... so... they are not a necessity.

I do hope the new keeper is not snowed by the scare tactics of the propaganda of some organizations/individuals.



nrfitchett4 said:


> I've read the same thing about igs and d3 which is why I think it is better just to let them have a uvb or natural sunlight. Why mess with nature if you don't have to?


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## loogielv

-EJ said:


> I've read the same thing about D2 and D3 in reptiles.
> 
> As far as the TT propaganda goes... I'll not go there... maybe just a little... those photos are use for the viv argument... for the protein argument... and not the UVB argument... that's gotta make a person wonder.
> 
> <snip>
> 
> I do hope the new keeper is not snowed by the scare tactics of the propaganda of some organizations/individuals.






*You sorta skimmed over my response and didn't really address anything but "scare tactics". I find it hard to believe you'd say showing people what an improper diet can do to a tort would be "scare tactics". 

I personally would hope the new keeper is not snowed by the sales tactics of a local pet store trying to off load as many torts as possible before his next shipment.

And yes, my pics are for the protein argument, which I stated, and I was not arguing the use of protein. I argued that a high protein diet would not kill a tort, and thus by your definition is not a "necessity".
*


-EJ said:


> Needless to say... many people have raised wonderful looking animals without the use of UVB bulbs... so... they are not a necessity.


*
I think that is the point of this thread. It isn't needless to say, but actually needful to say. Please provide proof of these individuals raising torts long term with no ill effects. "Pics or it didn't happen" so to speak.*


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## Yvonne G

I have no scientific proof, but it is my opinion that the UV rays from the sun bounce around the environment and you don't have to be actually "in the sun" to reap their benefits. I have NEVER used a UVB bulb. All of my tortoises are outside, even the ones that are in "indoor" habitats. I have the hospital habitats set up on my car port and on sunny days I prop open the lids. And even though the sun doesn't actually shine inside the open lids, I feel the animals inside are getting the beneficial uvb from the sun. I don't have any soft-shelled tortoises. The tortoises in my own collection that I have raised from hatchlings are all fine and normal, with the exception of a little leopard that is now 3 years old and a bit pyramided. But I believe his pyramids are from being kept on oat hay pellets and dry, rather than lack of uvb. 

I don't believe you need to provide your tortoise a uvb _*bulb*_ as long as he is able to be outside for a bit every week.

Yvonne


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## loogielv

emysemys said:


> I don't believe you need to provide your tortoise a uvb _*bulb*_ as long as he is able to be outside for a bit every week.
> 
> Yvonne



I would agree with this. I would think just the occasional, indirect UVB from the sun would be far greater than constant "UVB" from a bulb. 
Of course, that would also stand to reason that UVB is still needed


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## Millerlite

thats what i been saying the whole time. There are people that use no UVB bulbs and still have healthy tortoises.


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## loogielv

Millerlite said:


> thats what i been saying the whole time. There are people that use no UVB bulbs and still have healthy tortoises.



the title of this thread is "UVB NOT A NECESSITY?" 

Not "UVB BULBS NOT..." so we were arguing whether UVB is a necessity and the last person was stating that UVB bulbs weren't needed because their torts get plenty-o-real UVB.


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## Madkins007

D2 and D3- humans can use either, although D3 is processed more efficiently. (Sources: company dietitian, and articles like http://ods.od.nih.gov/factsheets/vitamind.asp or http://www.nutraingredients-usa.com/Research/Vitamin-D3-more-potent-than-D2-further-evidence

The second article points out clearly that D2 and D3 have similar initial effects in humans, but that D3 lasts longer in the system- not an issue if there is daily or so supplementation. Wikipedia states that D2 is about 1/6th as potent as D3.

As for being less potent, that sort of depends on what levels the animals require. High-UVB need animals, like bearded dragons or tree-top dwelling iguanas, with thin skin that easily absorbs UVB and who have diets low in any form of vitamin D, obviously have a higher need than a species like Yellow-foot or Hinge-back Tortoises that live in deep shadow, have thick skin with heavy scales, and eat a lot of proteins and mushrooms.

Rats, among other species, cannot use D3 as easily as D2. Stating that "All mammals need UVB" would be wrong, so why do we automatically seem to think that we can say this for all reptiles? 

Again, I am not saying do not use UVB, just that there are people out there raising Red-foot Tortoises indoors with no UV light, and the tortoises are doing well on good diets with lots of variety, some protein, and some supplementation.


----------



## Millerlite

I already said i think its necessary and most people are making it as if they cant survive without the UVB bulb. which they can.


----------



## nrfitchett4

but red foot tortoise get a lot more protein than most other torts right? and with that protein is usually vitamin d. (redfoots are the ones that eat cat food, right?). 
So I guess for the starter tort keepers, a uvb bulb would probably be a good investment to keep their torts as healthy as possible. Just make sure they have hides to get out of the "sun".


----------



## -EJ

No... they don't. They get as much animal matter as any tortoise. 





nrfitchett4 said:


> but red foot tortoise get a lot more protein than most other torts right? and with that protein is usually vitamin d. (redfoots are the ones that eat cat food, right?).
> So I guess for the starter tort keepers, a uvb bulb would probably be a good investment to keep their torts as healthy as possible. Just make sure they have hides to get out of the "sun".


----------



## nrfitchett4

-EJ said:


> No... they don't. They get as much animal matter as any tortoise.
> 
> 
> 
> 
> 
> nrfitchett4 said:
> 
> 
> 
> but red foot tortoise get a lot more protein than most other torts right? and with that protein is usually vitamin d. (redfoots are the ones that eat cat food, right?).
> So I guess for the starter tort keepers, a uvb bulb would probably be a good investment to keep their torts as healthy as possible. Just make sure they have hides to get out of the "sun".
Click to expand...


So they get as much as by baby sulcata?


----------



## -EJ

Ironic that you should pic a perfect well documented example.



nrfitchett4 said:


> -EJ said:
> 
> 
> 
> No... they don't. They get as much animal matter as any tortoise.
> 
> 
> 
> 
> 
> nrfitchett4 said:
> 
> 
> 
> but red foot tortoise get a lot more protein than most other torts right? and with that protein is usually vitamin d. (redfoots are the ones that eat cat food, right?).
> So I guess for the starter tort keepers, a uvb bulb would probably be a good investment to keep their torts as healthy as possible. Just make sure they have hides to get out of the "sun".
> 
> 
> 
> 
> 
> Click to expand...
> 
> 
> So they get as much as by baby sulcata?
Click to expand...


----------



## nrfitchett4

my point being that an exclusively veggie diet doesn't lend itself to much dietary d3 in the wild.


----------



## -EJ

Another important point... these animals are not in the wild... they are pets. In order to maintain those pets compromises have to be made.

The bulb itself is an artificial source that is supposed to help in the metabolism of calcium... so... why not use supplements as an alternative?



nrfitchett4 said:


> my point being that an exclusively veggie diet doesn't lend itself to much dietary d3 in the wild.


----------



## Madkins007

-EJ said:


> No... they don't. They get as much animal matter as any tortoise.



I know that most wild tortoises eat some insects, carrion, etc., and I know that Red-foots are documented to eat about 10-15% proteins in the wild.

What I am wondering is are there documented levels of 'wild meat-eating' for the various 'grassland' species, and if so, what are they?

(And please, this is not meant to be argumentative or anything. I am just curious. I've done a ton of research on Red-foots, and not nearly as much on grasslanders.)


----------



## Yvonne G

I watched my desert tortoise eat a dead lizard once. 

Yvonne


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## Macheteslaststep

My leopards try to shove their heads in my mouth after I eat steak or chicken, does that count?  If not I have seen them both attack insects out in the yard. And I know that they have been known to eat carrion in the wild.

Sara


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## chadk

Millerlite said:


> UVB is necessary to all reptiles, and its healthy for them, the only thing i argue is, do they need artificial UVB. Like i said before many people dont use the bulbs and have nice looking tortoises. Dont confuse this with never having UVB because most let theres have natural sun.



All reptiles? What about many snakes and lizards that only come out at night?


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## nrfitchett4

Reptiles that are primarily veggie eaters need sunlight/uvb. Iguanas, desert type tort's. There's not much dietary d3 in veggies and from what I've read about iguanas they don't thing that igs can process dietary d3.


----------



## -EJ

Huge... I mean... really huge assumption... misconception.

You really need to to a little more research.

Both of the animals mentioned... do eat carrion and whole critters.



nrfitchett4 said:


> Reptiles that are primarily veggie eaters need sunlight/uvb. Iguanas, desert type tort's. There's not much dietary d3 in veggies and from what I've read about iguanas they don't thing that igs can process dietary d3.


----------



## Maggie Cummings

Several years ago I had a yearling Gopherus agassizii and I watched her one summer spot a bluebelly who was sunning on the fence and that little tortoise ran over and snatched that lizard up and ate it all. How did a small tort like that know the lizard was eatable???


----------



## nrfitchett4

-EJ said:


> Huge... I mean... really huge assumption... misconception.
> 
> You really need to to a little more research.
> 
> Both of the animals mentioned... do eat carrion and whole critters.
> 
> 
> 
> nrfitchett4 said:
> 
> 
> 
> Reptiles that are primarily veggie eaters need sunlight/uvb. Iguanas, desert type tort's. There's not much dietary d3 in veggies and from what I've read about iguanas they don't thing that igs can process dietary d3.
Click to expand...


I eat mcdonalds. doesn't mean it won't kill me in the long run.

makes me also wonder why the life spans of igs in capitivity used to be shorter than in the wild. Probably nothing to do with all the dog and cat food they were fed (and iceburg lettuce for that matter).


----------



## Yvonne G

nrfitchett4 said:


> I eat mcdonalds. doesn't mean it won't kill me in the long run.
> 
> makes me also wonder why the life spans of igs in capitivity used to be shorter than in the wild. Probably nothing to do with all the dog and cat food they were fed (and iceburg lettuce for that matter).





I believe the subject matter was D3, not bad stuff we eat. EJ's point was that the animals you previously mentioned DID get some D3 from some of the food they were eating.

Yvonne


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## Lynn DeVries

I took 1.3 Russian Tortoises and set them up indoors with only Incandescent Lighting for light and warmth. I fed them ONLY Commercially prepared Dry Iguana food (Zeiglers) . They always had access too drinking water. The adults lived, bred and Laid eggs. The eggs hatched and I raised those babies the same way and on the same diet. At 4 years of age the babies were adults and they also bred, laid eggs and the eggs hatched. I raised those babies the same way and 4 years later the process repeated itself. The process continues to this day 21 years later. When Zeiglers came out with a Tortoise diet I switched to it and discontinued the Iguana diet, That was years ago.
At the same time that this experiment was underway I took 2 baby Green Iguanas and set them up the same way as the Russians and fed them only dry Zeiglers Iguana food, They also ALWAYS had access to drinking water. As Luck would have it they turned out to be a pair. The female lived for 15 years and produced 3 clutches of eggs that hatched and resulted in aprox 60 baby Green Iguanas. The male lived for 19 years. Upoun their deaths the Vets did necropsys to try and determin cause of death as they both said the Iguanas would die at an un naturally early age of Renal failur. In both instances they concluded that the internal organs looked normal and cause of death was old age. I did not keep any of the babies as there were just too many.
I am not saying this proves anything and that is why I never published the information as other people may have varying results. These were just my results.
I do not own a UV, UVA or a UVB light and I have never purchased one.

The End

Lynn

Also it should be noted that all the Russian Tortoises raised on the commercial diet and no UV (no windows either as the experiment took place in my basement) developed smooth and normal. The Green Iguanas also were completely Normal. And No I dont work for Zeiglers Hahahaha 

Lynn


----------



## chadk

I knew a guy who spent nearly his whole life living in his basement living off of fast food his wife bought him - and plenty of fresh drinking water. They had chrildren, and he live to be about 60 and died of 'natural causes'.


----------



## Madkins007

So, what is the bottom line? 

From what I can see, it is that there are several documented cases of tortoises and turtles being raised without access to natural or artificial UVB who nonetheless seem to have grown and reproduced in a normal way. These animals were offered some form of vitamin D in their diets or through supplements.



So- the flip side question would be: Is artificial UVB BENEFICIAL for tortoises? After all, there is risk to the eyes and of overdosing on vitamin D, there is the short useful life-span of the bulbs, etc.

I would suggest that when used properly- proper rating for the enclosure, mounted at the right height, replaced as needed, and making sure that the animals in the habitat have plenty of ways to get out of the light, AND limiting other vitamin D sources, that UVB lights are fine if you have tortoises with a higher D3 need and/or want to go that route.

But I DO think that too many keepers do the 'more is better' bit, sunblast their animals, oversupplement them, or just plain overdo the UVB instead of treating it like the rather delicate issue it is.


----------



## Lynn DeVries

My favorite method of raising Tortoises is outdoors on natural feed with access too calcium carbonate so they can eat it as they feel the need. but in my climate some species are just too delicate to be outdoors more than a month in summer. For these I feed zeiglers Tortoise diet or Mazuri and I am experimenting with Zoo Med. The Calcium/phospherus ratios and D3 are supposedly at correct levels in the diets already, so no supplements are needed.
I stressed the point of having fresh drinking water earlier, because on a dry commercial diet their water intake is higher than when they are eating vegetation that already has water in it.
The experiment I mentioned earlier with the Russian Tortoises is in my basement Tortoise room, not in some dark cold cellar. And the reason I let it continue is not too prove anything, but rather because they seem very content and healthy. And as I have heard Ed say..."If it isnt broke, why fix it?"
One last point I would like too bring up is Commercially prepared aquatic Turtle food such as Reptomin and even Purina Trout chow. Both of these pelleted diets are commonly used (as are others) in the raising and maintenance of aquatic Turtles and widely accepted by keepers and Zoos. I have raised hundreds of aquatic turtles on these two aformentioned diets without any problems. And yet the commercial Tortoise foods come under heavy fire by the Tortoise community. I think its just a matter of time before they become the norm.

Lynn


----------



## sift

Just a quick couple points...

Not all reptiles require UVB. As previously mentioned, some rainforest species go their entire lives under the canopy without seeing anything more than a stray sunbeam that happens to penetrate the leaves overhead. Nocturnal animals (or, to make it even better) nocturnal rainforest animals never see the light of day. They are concealed when the sun is out and are active only when there is no chance of them being exposed to UVB. These reptiles do, however, require calcium supplements when kept as pets as their diets are somewhat more restricted than when in the wild. For example, my crested geckos (nocturnal arboreal species) are fed an MRP (meal replacement powder) that provides a complete balance of their dietary needs. I do feed them crickets on occasion (2-3 time per week, typically, sometimes less often) and those are dusted with a calcium supplement. 

The UVB lighting debate is one that occurs in almost all arenas of herpetological care. Monitor lizards being a prime example. Some people believe that it is an absolute necessity in order to raise a monitor properly. Others rely on dusting the monitor's food. Still others regulate this arena with a wide variety of consumables. You will find a variety of extremely knowledgable people in each camp who have been successful in raising, keeping, and breeding monitor lizards while each using one of the aforementioned methods. 

Further, if you answer the question of "Is UVB beneficial to tortoises?" and the answer is "Yes." then you next must answer the questions of, "How MUCH UVB is beneficial to tortoises?" and "How much UVB is beneficial to _________ (Russian, Redfoot, Sulcata, etc.) tortoises?" 

Not trying to be inflammatory or anything, I just love a good debate.

P.S. For the record my monitor lizards are not exposed to UVB bulbs (they have floodlights for basking) and my snakes only have belly heat (i.e. under tank heaters). They are kept in a room with a window that is never bright, bright but receives some level of sunlight throughout the day. They all seem to thrive (eat, eliminate, shed, etc.) with this as their UVB staple. 

P.P.S. I don't know if the gentleman who bred my hatchling Russian (18 more days!!) uses UVB but I intend to find out being as he is one of the few people in Canada who have successfully bred Russians for a number of consecutive years.


----------



## -EJ

this is kind of funny...

Why do you think they add vitamin D to human food products? 

Well... let me tell you... those that live in the northern/southern extreme lattitudes were developing rickets... aka MBD. It was found that they did not get enough exposure to the sun to produce their own vitamin D.

With the wonders of the internet... check out vitamin D and rickets... interesting story.




Meg90 said:


> So, if I lived without sunlight for 20 years, but still took a multivitamin, I wouldn't have any bad health effects?
> 
> That makes no sense.




What get's me is how were reptiles kept 20 years ago with the vita-lite having a minimal impact. It was argued then that they didn't need it.



sift said:


> Just a quick couple points...
> 
> Not all reptiles require UVB. As previously mentioned, some rainforest species go their entire lives under the canopy without seeing anything more than a stray sunbeam that happens to penetrate the leaves overhead. Nocturnal animals (or, to make it even better) nocturnal rainforest animals never see the light of day. They are concealed when the sun is out and are active only when there is no chance of them being exposed to UVB. These reptiles do, however, require calcium supplements when kept as pets as their diets are somewhat more restricted than when in the wild. For example, my crested geckos (nocturnal arboreal species) are fed an MRP (meal replacement powder) that provides a complete balance of their dietary needs. I do feed them crickets on occasion (2-3 time per week, typically, sometimes less often) and those are dusted with a calcium supplement.
> 
> The UVB lighting debate is one that occurs in almost all arenas of herpetological care. Monitor lizards being a prime example. Some people believe that it is an absolute necessity in order to raise a monitor properly. Others rely on dusting the monitor's food. Still others regulate this arena with a wide variety of consumables. You will find a variety of extremely knowledgable people in each camp who have been successful in raising, keeping, and breeding monitor lizards while each using one of the aforementioned methods.
> 
> Further, if you answer the question of "Is UVB beneficial to tortoises?" and the answer is "Yes." then you next must answer the questions of, "How MUCH UVB is beneficial to tortoises?" and "How much UVB is beneficial to _________ (Russian, Redfoot, Sulcata, etc.) tortoises?"
> 
> Not trying to be inflammatory or anything, I just love a good debate.


----------



## sift

-EJ said:


> What get's me is how were reptiles kept 20 years ago with the vita-lite having a minimal impact. It was argued then that they didn't need it.



I'm not familiar with Vita-lite but I do know that if the crested geckos aren't supplemented (either in a balanced MRP or with additional dust for insects) that they develop debilitating and oftentimes fatal cases of MBD. Same goes for leopard geckos. On the flip side of the coin, montior lizards (eating large numbers of insects or fed solely on whole food items (i.e. mice, fish, etc.)) have been raised successfully without any supplementation of any kind (including UVB bulbs).


----------



## -EJ

Vita-lite was the first uvb bulb that made it into the herp keeping industry.

They do need a source of vitamin D... no doubt. I've used Centrum for years. My oldest Leopard gecko... 29 years... never had uvb... crickets, centrum and (****, I can't remember the calcium supplement).



sift said:


> -EJ said:
> 
> 
> 
> What get's me is how were reptiles kept 20 years ago with the vita-lite having a minimal impact. It was argued then that they didn't need it.
> 
> 
> 
> 
> I'm not familiar with Vita-lite but I do know that if the crested geckos aren't supplemented (either in a balanced MRP or with additional dust for insects) that they develop debilitating and oftentimes fatal cases of MBD. Same goes for leopard geckos.
Click to expand...


----------



## tortoisenerd

Side note: I've always been told not much UVB if any gets through typical windows.


----------



## sift

tortoisenerd said:


> Side note: I've always been told not much UVB if any gets through typical windows.




I think that you're probably right. We seem to tend to want to block out ANYTHING potentially harmful as humans. My windows, however, date back to the construction of the house (at least 60-70 years) and are the old style single pane glass. I have a feeling that if any windows let through UVB it's gonna be these bad boys. 

I have since spoken to the breeder I'm getting my little guy from and he doesn't use UVB on his torts, either. He indicated that he does on some of his animals (not which ones, unfortunately) but that he feels diet is the most important factor in keeping/raising Russians. I'm not saying I necessarily agree with him as I'm still on the fence about this one but as far as I know he's one of three or four known tort breeders in Canada (Russians, again) that has been doing it successfully for over a decade. He didn't happen to mention whether or not he takes his outside either but I know I intend to let my little squirt go out for a walkabout and a graze every day that it's nice enough once I've gotten her established.


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## Madkins007

A quick google check shows that plain glass (old or new) blocks about 98.7% of UVB light. Most plastic is almost as bad at about 96-98%, coated 1/4" hardware mesh blocks a good 30%+ of the UVB, and even chicken wire blocks about 7%.


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## tortoisenerd

Thanks for the backup, Madkins. That sounds right.


----------



## Silvers24

So question, (this is after reading about how to much D3 could be poisonous)
I have a Ornate Wood Turtle, I know they are forest/tropical.
So, is running the UVB flourescent light bulb 8-10 hours a day bad?
As it's the only source she has for light aswell. (Albiet probably to much light, but she does have something to go under when she wants)
(This is how she was treated in stores though. And they really didn't have anything to hide under)

Should I cut it down, or what?? It's been about 7 months since I had her, and she is still just fine.


----------



## -EJ

yea... supplemental... D2 can be a problem. D3... not a problem. With Calcium present.




Millerlite said:


> reptiles can have to much D3, it becomes poisonous if to much.


----------



## DoctorCosmonaut

I just saw a young Reptile and Avian vet doctor (my Redfoot has been sick, but is on the mend) and she told me she had just been to a conference and new study shows that most UVB bulb brands' bulbs (e.g. ZooMed) have random inconsistent levels of UVB that they put off (aka you can't trust that it is working) and many of them put off too much UVA and can actually do harm to Tortoise eyes. She told me to NOT use any UVB bulbs and just ensure that my girl gets outside during the warm months for now. Even before that I was under the opinion, after talking to a breeder and doing some reading, that UVB bulbs are not that great.


----------



## Meg90

I would not recommend that you stop using a UVB bulb. 

Brands that are good are Trex, and MegaRay. These brands are mercury vapor bulbs. Compact bulbs (the coil ones) are the bulbs that are causing problems.


----------



## DoctorCosmonaut

Meg90 said:


> I would not recommend that you stop using a UVB bulb.
> 
> Brands that are good are Trex, and MegaRay. These brands are mercury vapor bulbs. Compact bulbs (the coil ones) are the bulbs that are causing problems.



I have a D3 vitamin powder I apply to her food once a week. But I am going to follow my vets advice and not use one until we meet again.


----------



## Meg90

Now for redfoots, I know they don't require as mush UVB as other torts, because they have a diet that is much higher is protein. But I still would recommend that you use some form of UVB as well. I have a Trex bulb on both of my torts, and I have never experienced a problem. They came highly recommended to me here as well, by other experienced keepers.


----------



## DoctorCosmonaut

Meg90 said:


> Now for redfoots, I know they don't require as mush UVB as other torts, because they have a diet that is much higher is protein. But I still would recommend that you use some form of UVB as well. I have a Trex bulb on both of my torts, and I have never experienced a problem. They came highly recommended to me here as well, by other experienced keepers.



Do you know where they carry them? I am always open to looking into new things. Always gotta do my research first


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## Millerlite

Trex bulb like the MVB? for a redfooted tortoises it would be way to bright, for sulcatas and leopards and other desert speicies it would be good. I dont use uvb anymore though.


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## Meg90

I was going to get back to this thread today, and then I blanked on it...

no, you want a tube light UVB. Something like a 2.0 I think, would do nicely.


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## DoctorCosmonaut

Do the tube lights break when splashed or in high humidity? Can you buy aquarium tube bulbs that would do the job?


----------



## terryo

Jordan, I have a long tube 10.0 UVB on one side of Pio's enclosure for the past two years. (changing it every 6 months or so) It doesn't give off too much light and NO heat at all. So it is good for Redfoots. I used to use a 5.0 when he was in a 30 gal vivarium. I got the 10.0 since I enlarged his enclosure. The high humidity never bothered it. I wouldn't spray it though. Just spray the plants for humidity. Nothing has to be wet.


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## DoctorCosmonaut

Wasn't planning on watering the bulb  just in case. Thanks


----------



## terryo

I know, Jordan....I was kidding...lol


----------



## Millerlite

I been just letting my tortoises out everyday, Only reason i dont have a uvb light.


----------



## Gulf Coast

Waldo gets natural sunshine, his tort table is on a screen porch, so right now I am not worried about a light for him.. But what about winter time? Our winters here are really crazy. lol.. I mean you just never know what you gonna get.. I can't count the days we were running the AC on Christmas Day and wearing shorts... But then have a couple of cold days and its back to sunshine.. 

God I think this whole debate thread has me more confused than I was before I read it.. lol.. I have never been so SURE and UNSURE at the same time. Who would have THUNK finding that little boy in the back yard would bring on so much damned if you do damned if you don't worries...

I feel like John Travolta in Welcome back Kotter... IM SOOOO CONFUSED!!!!


----------



## Madkins007

This is MY OPINION currently, based on a lot of different kinds of input.

UVB is not a biological necessity in the sense that air is, but when you have the right UVB levels for the species and age, with the right bulb type (or sunlight), set up the right way, for the right duration, it seems to be beneficial enough to justify its use.

While many people do not use it (at least in the winter time, etc.), the question is whether their animals would be better off with it? This is an old debate, and one that will not be absolutely solved without controlled, long-term tests. 

Even though it is not a necessity, I think it offers several benefits, such as:
- Possibly better skeletal, shell, and organ development
- More natural behaviors (this benefit is well-documented, and is by itself a good argument for some UVA and UVB)
- Mild germ- and mold-fighting characteristics
- Possibly better resistance to respiratory and viral diseases
- Seems helpful (but not necesarily required) for better reproduction

Therefore, to me the 'Best Practice' would be to offer at least some low-level UVB to all ages of all species of tortoises all year as part of an overall proper care program.

But- if you have them outside for part of the year, they have a good diet and cares, and are doing well- I certainly won't knock you for not doing it.


----------



## terryo

Even though it is not a necessity, I think it offers several benefits, such as:
- Possibly better skeletal, shell, and organ development
- More natural behaviors (this benefit is well-documented, and is by itself a good argument for some UVA and UVB)
- Mild germ- and mold-fighting characteristics
- Possibly better resistance to respiratory and viral diseases
- Seems helpful (but not necesarily required) for better reproduction


Just out of curiosity, Mark, can you show me what you based your above opinions on?....Care sheets? or something??


----------



## Redfoot NERD

Madkins007 said:


> This is MY OPINION currently, based on a lot of different kinds of input.
> 
> UVB is not a biological necessity in the sense that air is, but when you have the right UVB levels for the species and age, with the right bulb type (or sunlight), set up the right way, for the right duration, it seems to be beneficial enough to justify its use.
> 
> While many people do not use it (at least in the winter time, etc.), the question is whether their animals would be better off with it? This is an old debate, and one that will not be absolutely solved without controlled, long-term tests.
> 
> Even though it is not a necessity, I think it offers several benefits, such as:
> - Possibly better skeletal, shell, and organ development
> - More natural behaviors (this benefit is well-documented, and is by itself a good argument for some UVA and UVB)
> - Mild germ- and mold-fighting characteristics
> - Possibly better resistance to respiratory and viral diseases
> - Seems helpful (but not necesarily required) for better reproduction
> 
> Therefore, to me the 'Best Practice' would be to offer at least some low-level UVB to all ages of all species of tortoises all year as part of an overall proper care program.
> 
> But- if you have them outside for part of the year, they have a good diet and cares, and are doing well- I certainly won't knock you for not doing it.



Mark you don't have the authority [ or personal experience ] to knock anyone. 

What good does it do to spend 5X what it costs for a good 'full-spectrum' bulb.. when redfoot tortoises won't make use of them anyway?
Source: Turtletary.. 1998 to present.

Herbivorous tortoises 'need' UVB because they don't get it from their diet.. so they have to bask. So what's the debate all about anyway?

If you or anyone else doesn't give credit where credit is due.. you will be [ questioned ] held accountable.

Terry K


----------



## -EJ

Talk to some of those cultures in the norther and extreme southern latitudes. Up until not too long ago in historic terms Rickets was a common problem. This problem was partially resolved through the use of supplements.

What doesn't make sense is how all these reptiles survived long before the UVB lighting. A good number did die but a good number survived.

Also there is no debate whether UVB is beneficial... the debate is whether it is a necessity. As mentioned before... I ran into arguments 10 years ago that the UVB lamps were any good or not. It would surprise you to see the names of some who were dead set against them.




Meg90 said:


> So, if I lived without sunlight for 20 years, but still took a multivitamin, I wouldn't have any bad health effects?
> 
> That makes no sense.


----------



## Redfoot NERD

-EJ said:


> Talk to some of those cultures in the norther and extreme southern latitudes. Up until not too long ago in historic terms Rickets was a common problem. This problem was partially resolved through the use of supplements.
> 
> What doesn't make sense is how all these reptiles survived long before the UVB lighting. A good number did die but a good number survived.
> 
> Also there is no debate whether UVB is beneficial... the debate is whether it is a necessity. As mentioned before... I ran into arguments 10 years ago that the UVB lamps were any good or not. It would surprise you to see the names of some who were dead set against them.
> 
> 
> 
> 
> Meg90 said:
> 
> 
> 
> So, if I lived without sunlight for 20 years, but still took a multivitamin, I wouldn't have any bad health effects?
> 
> That makes no sense.
Click to expand...


Bobby Paul.. EJ?


----------



## Madkins007

terryo said:


> Even though it is not a necessity, I think it offers several benefits, such as:
> - Possibly better skeletal, shell, and organ development
> - More natural behaviors (this benefit is well-documented, and is by itself a good argument for some UVA and UVB)
> - Mild germ- and mold-fighting characteristics
> - Possibly better resistance to respiratory and viral diseases
> - Seems helpful (but not necesarily required) for better reproduction
> 
> 
> Just out of curiosity, Mark, can you show me what you based your above opinions on?....Care sheets? or something??



- Skeletal/organ development- this is what UVB-based D3 does for most vertebrates. (Wikipedia, uvguide.uk.com)
- Natural behaviors- wikipedia, Dr. Mader, and most books on reptile care mention this
- Germ-fighting- a natural effect of UV light (wikipedia)
- Resistance- side effect of germ-fighting, natural behavior, and an article on the effects of UV on immunity
- Reproduction- a benefit noted in many other reptiles- seems to spur mating, egg production, etc. in several species.

Unfortunately, we don't KNOW if UVB does any of this for Red-foots, but since many, possibly even MOST Red-foots live in non-rain forest habitats, it would make sense for them to apply here as well.



Redfoot NERD said:


> Mark you don't have the authority [ or personal experience ] to knock anyone.
> 
> What good does it do to spend 5X what it costs for a good 'full-spectrum' bulb.. when redfoot tortoises won't make use of them anyway?
> Source: Turtletary.. 1998 to present.
> 
> Herbivorous tortoises 'need' UVB because they don't get it from their diet.. so they have to bask. So what's the debate all about anyway?
> 
> If you or anyone else doesn't give credit where credit is due.. you will be [ questioned ] held accountable.
> 
> Terry K



1. Of COURSE I don't have the 'authority' or experience to knock anybody- thats why I don't write answers that say 'if you don't use UVB your tortoise will die' like some people do. 

I was only trying to answer Gulf Coast's comment about being confused. I did not realize until you and EJ posted that it was an old post.

2. "What good does it do to spend 5X what it costs for a good 'full-spectrum' bulb.. when redfoot tortoises won't make use of them anyway?
Source: Turtletary.. 1998 to present."

Prove it. You are making an absolute scientific statement here- prove to me that they cannot use the light-based UVB. You challenge me to prove my comments- now it is your turn. 

You can show that your indoor animals look good- but that does not prove anything scientifically. Have you had the diet and droppings analyzed to see what the calcium absorption rates are? Have you done side-by-side studies to see the differences with and without?

3. Red-foots bask in their native habitat in Venezuela, Brazil, Panama, some of the islands, Paraguay, and other areas. This has been observed by Moscovitz, Pritchard, Vinke, and others. 

4. The debate is whether UVB is a benefit even if not a necessity.

5. What credit is due? I post my sources whenever asked, and you indeed are a source I have used and credited. I obviously did not use you as a source in that opinion statement because you clearly state they don't need UVB... even though your animals are outside in the nice weather.


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## cdmay

4. The debate is whether UVB is a benefit even if not a necessity.

This above quote by Madkins007 seems to be the center of this very old (and tired) debate. 
The fact is, despite some folks denying that redfoots and even yellowfoots bask, these animals do indeed bask both in nature and in captivity. They certainly have in my collection and in all of the keepers care that I know down here in Florida. My big females line up along the western edge of my fence to catch the early morning rays. My hatchlings climb up on top of each other to catch rays. Mind you, this is even during the summer.
In addition I know of many folks who have found both redfoots AND yellowfoots and who have come upon these tortoises while they were basking in exposed patches of sunlight from Colombia to Paraguay. YES, even yellowfoots that according to some avoid sunlight like they were vampires. True, they do prefer more shaded and humid habitats than redfoots but they still expose themselves to sunlight for at least part of the time.
Does this mean that you absolutely must provide some sort of UVA/UVB bulb or direct sunlight for them? I dunno. But if they seek out these things when given the opportunity why not provide it?
Regarding smooth growth without sunlight or UVA/UVB bulbs I would say this: smooth growth on young animals does not in itself mean anything except that their food intake and humidity were well regulated. It does not mean that they will have good internal bone structure or that they will go on to produce large numbers of well calcified and fertile eggs. I would bet that the fertility, egg production and overall health of long term adults is better when they have access to sunlight.
I would also add that the color of their carapace will be more natural as I have seen some captive redfoots (leopard tortoises too) that were raised completely indoors with no natural light that had unusually pale shells. When placed outdoors, the new growth laid down by these tortoises was a healthy black like it is supposed to be.


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## Madkins007

CD May- thanks for pitching in. The skin color thing makes sense- in most other animals, the melanin (black pigment) in the skin reacts to UV exposure, so why not on tortoises as well.


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## -EJ

Once again we've kind of burried the point...

UVB is not a necessity for good development. You really can't argue that point.

Artificial UVB produces the same results indoors as not using UVB. It probably is beneficial... but, again, not a necessity.

UVB is NOT sunlight. I think there is no replacement for natural sunlight.

I think that simplifies things.


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## t_mclellan

cdmay said:


> 4. The debate is whether UVB is a benefit even if not a necessity.
> 
> This above quote by Madkins007 seems to be the center of this very old (and tired) debate.
> The fact is, despite some folks denying that redfoots and even yellowfoots bask, these animals do indeed bask both in nature and in captivity. They certainly have in my collection and in all of the keepers care that I know down here in Florida. My big females line up along the western edge of my fence to catch the early morning rays. My hatchlings climb up on top of each other to catch rays. Mind you, this is even during the summer.
> In addition I know of many folks who have found both redfoots AND yellowfoots and who have come upon these tortoises while they were basking in exposed patches of sunlight from Colombia to Paraguay. YES, even yellowfoots that according to some avoid sunlight like they were vampires. True, they do prefer more shaded and humid habitats than redfoots but they still expose themselves to sunlight for at least part of the time.
> Does this mean that you absolutely must provide some sort of UVA/UVB bulb or direct sunlight for them? I dunno. But if they seek out these things when given the opportunity why not provide it?
> Regarding smooth growth without sunlight or UVA/UVB bulbs I would say this: smooth growth on young animals does not in itself mean anything except that their food intake and humidity were well regulated. It does not mean that they will have good internal bone structure or that they will go on to produce large numbers of well calcified and fertile eggs. I would bet that the fertility, egg production and overall health of long term adults is better when they have access to sunlight.
> I would also add that the color of their carapace will be more natural as I have seen some captive redfoots (leopard tortoises too) that were raised completely indoors with no natural light that had unusually pale shells. When placed outdoors, the new growth laid down by these tortoises was a healthy black like it is supposed to be.



I have attached photo's of 2 Brazilian CH Rf's taken this morning.
Ages are 2 & 4 They have been outside all but there 1st 6 months of life.
They both show marbling just like I expect in this type of RF.
Mine bask for some portion of the day. Although not extensively.
After about a year the marbling tends to darken considerably. 
Whether due to sun light or dirt over time I don't know, But its harder & harder so see the older marbling each year.
Do RF's need UV? Not as much as others I think.
Will I turn off the sun because I think they don't need it? No.
Do I give UV to tortoises when they are inside? Yes.
Do they need it? I duno!


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## Madkins007

I found something interesting that I wanted to share, and it has little to do with the 'needed or beneficial' part of the debate.

Dr. Mader's book "Reptile Medicine and Surgery" chapter 84, page 1082, has a section on lighting that I just finally got around to and found something FASCINATING! 

A little background. All fluorescent tubes produce SOME UVA and UVB lighting, and different UV meters will measure things a bit differently. Mader offers a chart showing two major meters and what they 'see' in several different fluorescent lamps at 30cm/12" from the center of the bulb.

Now- what is REALLY cool is that they took a glass vial of 'provitamin D3' and exposed it to each tested bulb in a controlled way and measured what percent of it converted to 'previtamin D3'- the stuff the reptiles use- in other words, they simulated what happens in the skin with each bulb. In general, the higher the percent converted, the better the bulb is for doing this.

Here is the chart, as best I can replicate it. I will only show the readings from the Spectronics Corp meter for simplicity, the original graph includes the UVP Inc meter as well. I am also going to rearrange the bulbs from least to most effective, and I added a price comparison:

Bulb - UVA Level - UVB level - % of conversion - price of an 18"/15w bulb on-line
- ZooMed Reptisun 2.0 - 6 - 2 - none detected - $10
- ESU Desert 7% - 30 - 9 - none detected - $20
- Verilux Instant Sun - 4 - 2 - 0.03% - $10
- GE Cool White - 2 - 2 - 0.09% - $6
- ESU Super UV Daylight - 4 - 3 - 0.10% - $13
- ZooMed Reptisun 5.0 - 12 - 13 - 0.13% - $16
- Sylvania 350 Blacklight - 53 - 16 - 0.24% - $8

If I am reading this section of the book correctly (and I am pretty sure I am), plain white fluorescent tubes OUTDID some UVB bulbs in vitamin D3 production, and cost less. 

It also suggests a possible answer to the mystery of the 'I never used UV bulbs and got great results' issue in some situations- they may have got enough UVB from the overhead fluorescent bulbs.

What is driving me nuts right now is that there does not seem to be a solid connection between the UV levels and the % of conversion- so there might be something else in play here and I'd love to know what it is!

I've been suggesting a small Reptisun 2.0 or similar as a 'just to be safe' bulb for Red-foots... and maybe I should have been recommending a plain old GE Cool White instead!

A few caveats:
- When talking about the % of converted vitamin D3, I saw no mention as to what was the 'right' percentage. In other words- higher may not automatically be better.
- I saw no mention as to the age of the bulbs. I would assume all were new or had been subjected to the same 'burn in', but it would have been interesting to see the results at the 6 month and 1 and 2 year marks as well. Would the UVB emission of the 'Cool White' hold more steady since it is a lower level and might not burn out the phosphors as quickly? How about the Blacklight since it was MADE to throw off UV for a long time?


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## Madkins007

Update on the bulb effectiveness. I figured out why some bulbs did better than others with worse specifications. It seems that a very specific wavelength does the optimal D3 change- 295 nanometers, and the bulbs that do best in the percentage column are those that emit the most of that wavelength. 

UVB itself is defined as between 280 and 320 nanometers.

Oh, and fluorescent plant lights would emit UVB as well. Isn't that what you use, TurtleTary?


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## -EJ

One very important bulb has been left out of the study... Active UV Heat/aka Dragon Lamps/aka...

Does Maders new book address the newer lamps. Again... when this who thing started about 30 years ago... there was one lamp... Vitalites... from Europe.



Madkins007 said:


> Update on the bulb effectiveness. I figured out why some bulbs did better than others with worse specifications. It seems that a very specific wavelength does the optimal D3 change- 295 nanometers, and the bulbs that do best in the percentage column are those that emit the most of that wavelength.
> 
> UVB itself is defined as between 280 and 320 nanometers.
> 
> Oh, and fluorescent plant lights would emit UVB as well. Isn't that what you use, TurtleTary?


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## Madkins007

Actually, EJ, the studies we want seem to have been done by a W. H. Gehrmann. I'm trying to locate some of his articles and papers on the subject. Do you have access to any of the journal sites or anything?

Also- ALL of the bulbs in the study are fluorescent, so the mercury vapors were not included. Maybe in some of Gehrmann's stuff?


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## -EJ

As with every vertibrate there are levels. The statement I love to make is that biology is one huge grey area. That is why we have statistics... to provide the numbers to demonstrate we are probably right. There is a black and white in very few cases in every field of biology. That's a very easy statement to make.

Dr. Gehrmanns studies are/were(when I was reading his studies) based on chameleons for the most part. His studies have to be the earliest and most long running. These are/were one of the most delicate reptiles in captivity. They seem to require UVB... why?... can anyone really say... but it is a fact they do. Now... tortoises... the study of UVB on tortoises is in it's infancy. I like to think I had something to do with the movement of the idea. When I expressed how they reacted to UVB I was met with the usual stuff. Notice all I observed is a behaviorial change. 

Oh... that was before Calaphratus(sp?)

Again... there is no doubt UVB is benificial to tortoises... it is definately not a necessity. 



Madkins007 said:


> Actually, EJ, the studies we want seem to have been done by a W. H. Gehrmann. I'm trying to locate some of his articles and papers on the subject. Do you have access to any of the journal sites or anything?
> 
> Also- ALL of the bulbs in the study are fluorescent, so the mercury vapors were not included. Maybe in some of Gehrmann's stuff?


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## nearpass

Madkins007 said:


> Actually, EJ, the studies we want seem to have been done by a W. H. Gehrmann. I'm trying to locate some of his articles and papers on the subject. Do you have access to any of the journal sites or anything?
> 
> Also- ALL of the bulbs in the study are fluorescent, so the mercury vapors were not included. Maybe in some of Gehrmann's stuff?



There's an article here by W. H. Gehrmann which discusses a few more bulbs, but refers mainly to lizards. Interesting none the less: http://www.naturallighting.com/articles_reptile_lighting_current_perspective.php


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## Madkins007

Thanks, Nearpass, but that is one of the few I had already found of his stuff, actually on Melissa Kaplan's site.

For both you and EJ- I know a lot of his work deals with lizards, but the mechanics/physics of UV and the bulbs would be species-independent. That is, this bulb will work this way, no matter what is under it- and that is what I was looking for- how the bulbs actually worked.

EJ- I am not jumping on the 'You NEED TO OFFER UVB' bandwagon, but I did think that the study that shows that a lot of the lights used by those ON that bandwagon don' do much was really, really interesting!

By the way, I found a partial PDF from a Gehrmann article (don't ask me how that happened), but it shows the '% of product converted' by natural sunlight in Boston. Obviously, the numbers would be different closer to the equator, and they vary throughout the day and year, but... 

At high noon, it is at about 0.2% in January (already more than the Reptisun 5.0 does) to about 1% in March, and almost 7% in July, then to almost 3% in September.

I'm going to try to make a coherent article out of this and post it soon. Rest assured, its focus will be for those that choose to use UV, not saying you MUST use UV.


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## nearpass

I'm a newbie, I know, mostly a lurker and reader on many forums, but I have kept reptiles of quite a variety for almost 30 years. What I have summized, and this is strictly my opinion based on what I've experienced, is that UVB does effect behavior and health in some animals, most especially in the lizards that I've had, and I am quite sure that many of them (lizards) can do much better when it's provided in some form, as they are more difficult for us to 'get' into the sun. But, as has been stated here a few times, it is NOT sunshine and can not replace the sun for tortoises. 

My main interest in this whole discussion is what I frequently read in my 'travels,' namely that turtles and tortoises with a variety of problems, from pyramiding to MBD (which in MY opinion) are not one and the same in many cases, to lack of appetite, and on and on in some discussions, can have their problems solved by the addition of UV/UVB. I feel this is very overly simplistic, and neglects many other aspects of their care which may be just as important. There is so much we just don't really know, I'm always concerned when there's "one solution" presented. On that, I guess I do have to agree with EJ.

Sorry if this is a bit disjointed, hope you understand what I'm getting at...I have a cold and my head is in a fog


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## -EJ

My point was that the studies are species dependent.

Chameleons seem to be very sensitive to the need of UVB. Tortoises in general are obviously not.

Dr. Gehrmanns studies were first geared at the need and second, how effective each product was. 

Those studies were also done long before the use of mercury vapor lamps.

I know someone has posted the link for the UK group that has been following the use of UVB in reptiles. I can't think of it off hand but it is probably the best resourse on the topic.



Madkins007 said:


> Thanks, Nearpass, but that is one of the few I had already found of his stuff, actually on Melissa Kaplan's site.
> 
> For both you and EJ- I know a lot of his work deals with lizards, but the mechanics/physics of UV and the bulbs would be species-independent. That is, this bulb will work this way, no matter what is under it- and that is what I was looking for- how the bulbs actually worked.
> 
> EJ- I am not jumping on the 'You NEED TO OFFER UVB' bandwagon, but I did think that the study that shows that a lot of the lights used by those ON that bandwagon don' do much was really, really interesting!
> 
> By the way, I found a partial PDF from a Gehrmann article (don't ask me how that happened), but it shows the '% of product converted' by natural sunlight in Boston. Obviously, the numbers would be different closer to the equator, and they vary throughout the day and year, but...
> 
> At high noon, it is at about 0.2% in January (already more than the Reptisun 5.0 does) to about 1% in March, and almost 7% in July, then to almost 3% in September.
> 
> I'm going to try to make a coherent article out of this and post it soon. Rest assured, its focus will be for those that choose to use UV, not saying you MUST use UV.


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## Madkins007

www.uvguide.uk.co is a great site, but I so far find no mention of the 295 nanometer/D3 conversion aspect of the issue there. They seem to treat all UVB about the same.

I would ASSUME (which I know is dangerous) that bulbs that produce D3 because of the temperature of the filaments, etc. would produce a more even gradient of wavelength outputs than fluorescent tubes, which are 'engineered' to emit specific wavelengths. I'm trying to figure out if this is true, and if there is a way to find out how much of their output is in the 295 nm zone, which might help us predict how much D3 conversion is going on.

I think it is kind of scary that none of the fluorescents tested converted even a full 1%. Sorta makes you wonder if they are worth it at all if you choose to use them.

For anyone interested, I just found an interesting article (through a link at the aforementioned ukguide.uk.co site) that is more recent (2004)- http://www.testudo.cc/

I have not read it in depth yet, but it looks interesting.


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## -EJ

The wavelength is a given... the intensity/power of the wavelength...variable.

Bulbs don't produce D3. They provide the body to produce D3 from D2.

It is the gas in the bulb that allows the production of the light wavelength that allows the production of D3.

From what you wrote... how much UVB does a reptile actually need?





Madkins007 said:


> www.uvguide.uk.co is a great site, but I so far find no mention of the 295 nanometer/D3 conversion aspect of the issue there. They seem to treat all UVB about the same.
> 
> I would ASSUME (which I know is dangerous) that bulbs that produce D3 because of the temperature of the filaments, etc. would produce a more even gradient of wavelength outputs than fluorescent tubes, which are 'engineered' to emit specific wavelengths. I'm trying to figure out if this is true, and if there is a way to find out how much of their output is in the 295 nm zone, which might help us predict how much D3 conversion is going on.
> 
> I think it is kind of scary that none of the fluorescents tested converted even a full 1%. Sorta makes you wonder if they are worth it at all if you choose to use them.
> 
> For anyone interested, I just found an interesting article (through a link at the aforementioned ukguide.uk.co site) that is more recent (2004)- http://www.testudo.cc/
> 
> I have not read it in depth yet, but it looks interesting.


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## Madkins007

I know the bulb does not produce the D3, I meant that as a shorthand of saying 'the bulbs that produce the needed 295nm range of UVB to produce D3 in the skin'. And from what I can tell, the wavelength is not a given in fluorescents, which are tuned to produce their UVB on the 320nm zone more than the 295nm. After all, the visible range ends about 400nm, UVA is 400-320nm. I can call my bulb a UVB bulb if I design it to emit 319nm- but it will not really help convert proD3 to preD3. To get that conversion, you have to emit at closer to the UVC level (280-100nm).

Sorry- on the more important part of the comment... UVB needs.

As you know, there is not an accepted standard for vitamin D dosage, period, for reptiles, and almost by definition, no clinical standard for UVB needs. We can extrapolate guesses from climatic data, behaviors, diet, and skin structure- but that is just another name for 'guess'.

What I find most ironic about this discovery is that all these people yelling about NEEDING UVB may not be offering anything the reptile can use for D3 production in their bulbs. 

My main interest here is to help those who choose to offer UVB select something that works for their animals.


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## fifthdawn

Just curious, there are obviously cases where tortoises get MBD and those that don't. Lets assume the UVB bulbs really isn't providing more than 1% conversion.

What do you think is the difference between those with MBD and those without? Diet? Being kept outdoors? Or maybe 1% is enough?


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## -ryan-

The bottom line is that you have to ask yourself a couple basic questions. Would a tortoise deprived of calcium grow quickly and smoothly, without deformity or softness of the shell? Would a tortoise deprived of calcium continue to live a strong and active life after the main growth period? Would a tortoise deprived of calcium reproduce and lay dozens of eggs year after year?

Those are the questions that I ask myself. My russians have done all of those things (and my red foot, to a lesser extent though because I don't breed him and he has only grown 2" since I've had him since he was already 9" when I got him). I don't use UVB producing bulbs with any of those animals. Not even the hatchlings just out of the egg. They grow and grow, and my adults make more babies (now that I figured out how to incubate the eggs effectively). I unfortunately cannot keep them outdoors where I live (but for a few short times in the summer), and I wish I could, but not for the UVB. For the space, free heating, and free food.

I think we all need to make our own decisions about how we would like to care for our animals. I respect that some people wish to buy expensive light bulbs for their animals in hope that it will help them. I personally have spent my time trying to better understand the big three (heat, hydration, and diet) with a lot of success.

Here's a three year old russian, hatched from an egg just over three years ago. She has never had a UVB producing bulb, and she has not yet been outside in the natural sunlight. She does, however, have access to a toasty hot spot, dirt to burrow in, and a pretty basic diet that I feel hits the important points. I did make a lot of mistakes with this one, but I think she turned out just fine


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## Sudhira

Now I am really confused.


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## Madkins007

Sudhira said:


> Now I am really confused.



The problem is that this issue is not black and white and there is a lot we don't know for sure.

There is little proof they need UVB, and lots of evidence that tortoises raised with no intentional UVB seem to do just fine.

That said, there are a lot of benefits to reasonable levels of UVB- ideally from natural, unfiltered sunlight. Besides helping with vitamin D3 production in the skin, it also helps control germ growth, enhance natural colors, and may play a helpful role in many aspects of breeding.

My personal opinion would be to offer access to natural sunlight whenever possible. When it is not, I would suggest that using a decent amount of UVB light would probably help your tortoise, but if you cannot, it does not seem to really hurt it... as long as other elements are in good shape- temps, hydration, diet, etc.


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## DeanS

I'm only going to say...as long as torts receive 5-7 hours of quality sunlight...that's all they need. Me? I leave them outside from 8-5 (living in the high desert, I can do that). However, at night, EVERYONE (big and small) comes in. I have a Zoo Med Tortoise House for the little ones (with chopped up timothy in the den) and the larger boys go into EXTRA LARGE VariKennels full of timothy with a hole cut in the top to allow for night lamps. BTW, Mortimer and Aladar's crates are in the laundry room where the humidity is a constant 15% and minimum 65 degrees (during winter and early spring) and as high as 80 during the late spring, summer and fall. It's only during the winter and early spring that I use UVB at all.


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## Kristina

Does anyone have a test meter? I would love to see what the typical "grocery store" brands of MV bulbs produce, compared to a "reptile" MVB.


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## moswen

sorry guys i didn't read the whole thread, but a vet that i took tula to 2 years ago told me that uv light really isn't necessary in the winter time as long as tula gets sun in the summer. i thought about this and the tortoises that hibernate don't get uv obviously under ground, but those species are obviously designed to not need it... however, tula is a big girl so i'm not sure what she would have said about growing babies. 

also, something i just thought of that may sound stupid in a little while if someone disproves my thoughts is that tortoises that don't hibernate live in hot climates, and only come out in the morning and evening so they only get those weakest hours of actual sunlight per day anyways, so they may actually be fine without it...?

but just for the record, i use uv in the winter when they're not outside daily!


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## fifthdawn

moswen said:


> sorry guys i didn't read the whole thread, but a vet that i took tula to 2 years ago told me that uv light really isn't necessary in the winter time as long as tula gets sun in the summer. i thought about this and the tortoises that hibernate don't get uv obviously under ground, but those species are obviously designed to not need it... however, tula is a big girl so i'm not sure what she would have said about growing babies.
> 
> also, something i just thought of that may sound stupid in a little while if someone disproves my thoughts is that tortoises that don't hibernate live in hot climates, and only come out in the morning and evening so they only get those weakest hours of actual sunlight per day anyways, so they may actually be fine without it...?
> 
> but just for the record, i use uv in the winter when they're not outside daily!



No species are "designed to" not need UVB during certain seasons. When you get down to the molecular level in all biological species, they're almost exactly the same. 

First, you need to understand the scientific reasoning for UVB. UVB help create vitamin D3 which is necessary for calcium metabolism. If theres no calcium, theres no need for vitamin d3 (there are other uses but the problem in reptiles concerning vit D has always been calcium related). A tortoise who hibernates over the winter would not be eatting, thus no need for UVB. 

As to your second question, tortoises will synthesize enough vitamin D3 in about 1-2 hour of uvb exposure. Majority of basking is not to make vitamin D3, but simply regulate body temperature for digestion. The vitamin D3 pathway stops working once their body gets enough D3. In order words, reptiles will always make EXACTLY enough D3 and the D3 pathway will stop.


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