# UVB



## Jason Williams (Nov 17, 2018)

Better to expose a tortoise to colder temperatures to get some real sunshine or leave inside enclosure with UVB tube bulb.?Just for an hour or so?


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## Jason Williams (Nov 17, 2018)

Just to be clear it’s 62-64 degrees Fahrenheit today but sunshine is plentiful.Should not tortoise get some real sun or too cold?


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## JoesMum (Nov 17, 2018)

In a sheltered spot in full sun at tortoise level it will be a lot warmer than the measured air temperature (which is done in the shade). Check out the temperatures with a temperature gun. 

UVB from the sun is no better than UVB from a lamp though, so it’s up to you


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## Jason Williams (Nov 17, 2018)

Really?I read 15 minutes of natural sunshine is comparable to 6 hours of artificial.Thanks tho that’s why I’m asking.


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## JoesMum (Nov 17, 2018)

Jason Williams said:


> Really?I read 15 minutes of natural sunshine is comparable to 6 hours of artificial.Thanks tho that’s why I’m asking.



It depends on the effectiveness of your bulb. The sun’s UVB output is better known. You are not going to turn the bulb off after 15 minutes which is why I said it makes no difference. I always turfed Joe out in those temperatures but had a basking lamp in a dog kennel as insurance. 

He was a nightmare indoors. Indoors just wasn’t an option

See this about keeping a tort outside in a colder climate
https://tortoiseforum.org/threads/outdoor-accommodation-in-a-colder-uk-climate.140866/


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## Lyn W (Nov 17, 2018)

I would think it depends on the species really and ground temps which would be at his level. 
I have a Leopard so he needs higher temps and I was advised not to put him out unless ground temps were about 70'F so I check that with my temp gun.
He lives indoors all year around with a mvb for his uvb, but when it's warm enough he goes outside for some real sun, but still has some plants for shelter so he doesn't overheat.


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## Tom (Nov 17, 2018)

What species are we talking about?

In any case, if you have UV indoors, they don't need to go outside on a colder day.


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## DeanS (Nov 18, 2018)

JoesMum said:


> UVB from the sun is no better than UVB from a lamp though, so it’s up to you



Are you high?!?!? Direct sunlight...even in cooler temps...is ALWAYS better than a bulb! JEEZ!


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## JoesMum (Nov 18, 2018)

DeanS said:


> Are you high?!?!? Direct sunlight...even in cooler temps...is ALWAYS better than a bulb! JEEZ!


pragmatic not high. Maybe just using fewer words for simplicity rather than giving a long-winded answer. Yes, I agree being outside in the sun is fantastic and far better for torts in the long run. 

But when a tort is being kept inside anyway and the weather is far from perfect then, to me at least, it makes no odds whether of not you put put it outside.


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## matheny00 (Nov 21, 2018)

Being new here I will add my 2cents we all have to remember how efficient is the bulb? Most of us trust the manufacture specs and replace the bulb every 6 months. But have you ever truly checked the UV out put of your bulb? If the answer is no then the only guarantee of UV light source is the sun.


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## Yvonne G (Nov 21, 2018)

I understand that the position of the sun above the earth also makes a difference in the quality of the UVB reaching the earth. In this case, winter and autumn, in my opinion, the UVB from a fairly new, good light, is better than the sun.


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## Jason Williams (Nov 21, 2018)

Thnx everybody great information.I do have plenty UVB with the bulb and fixture recommended by @Tom(reptile basics 14 percent Arcadia-)so I won’t jeopardize redfoot or Sulcata health with less than perfect temperatures.[emoji4][emoji111]️


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## Tom (Nov 21, 2018)

matheny00 said:


> But have you ever truly checked the UV out put of your bulb? If the answer is no then the only guarantee of UV light source is the sun.



Yes. On a regular basis. Most florescent tubes last 2-3 years according to my Solarmeter 6.5. Replacing bulbs every 6 months is extremely wasteful, unnecessary, and not cost effective at all.

Further, @Will has taught me that tortoises can and do use dietary D3, thus eliminating the "need" for UVB all together for properly supplemented tortoises. Personally, I'm still going to sun my babies.


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## Joma (Nov 21, 2018)

Amount of UVB from the sun depends on latitude (seasons), altitude, cloud cover and reflexivity of the ground (ie snow etc). So I would imagine that in some places and times the UVB outdoors would surpass that provided by a bulb and the contrary may be true in other places and times. Also would depend on how active a tortoise is under the environmental circumstances (are they hiding in the dark or out and about).

I'm putting my guy out (when I am home) for between and half hour - hour a day right now despite the fact that the air temps are on the lowish side (47). My judgment has been based on the fact that I'm at 7200 ft altitude and clear skies, so ground temps are warmer - usually 72 to 95 depending on time of day. He has even been out for a short time when his carapace has registered 68ish. I'm certain that the amount of UVB far, far surpasses his bulb. Not to mention the exercise. He seems to be happy


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## JoesMum (Nov 22, 2018)

People must also remember that the hibernating species spend a few months underground every year and come to no harm. I think @Tom said that Russians can spend up to 60% of their lives burrowing. 

This is, of course, after being out in natural sunlight for the remaining months of the year, but that's only by day. So approx 20% of the year for those Russians... possibly less. Exposure to UVB year round is not essential for these species. 

Sulcatas are fond of their burrowing too. I don't think UVB is a simple topic to understand. What we do know is that torts don't seem to get the skin cancers from over-exposure to UVB, so I would err on the side of caution.


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