# Sunlight-how much?



## samstar

Not sure wether to pist this under the general section or here but here it goes,
I have always been curious as in how much sunlight is enough for our torts: 
-to what extend of sunlight do our torts need?, just normal bright daylight or the shine from the sun is a must? 
-do they need UVB from the bulbs if they get 10-20 minutes of sunlight everyday?
-do different species of torts need different amounts of UVB?


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## tortoisenerd

I would personally want my tort to have access to (just because you place them in the sun doesn't mean they are getting UVB, because they should have a hide in their enclosure, and they might go hide) more than 10-20 minutes a day, but some people would say thats enough for a breed such as Stars. Yes, the amount of UVB varies. Desert torts need a lot more than forest type torts (many of which only need D3 from their diet, not UVB). The sun puts out more UVB at the hottest part of the day, but in some areas this might be too hot, so if you put your tort out earlier or later in the day when there are less rays, you would want to have more time than high sun. Similar to if your tort has a UVB bulb with less output they will just spend more time under it to get the same amount of UVB than a high output bulb. Natural sun is always better than UVB bulbs, but the good MVBs on the market like the T-Rex Active UV Heat and Mega Ray are about the closest you can get.


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## samstar

tortoisenerd said:


> I would personally want my tort to have access to (just because you place them in the sun doesn't mean they are getting UVB, because they should have a hide in their enclosure, and they might go hide) more than 10-20 minutes a day, but some people would say thats enough for a breed such as Stars. Yes, the amount of UVB varies. Desert torts need a lot more than forest type torts (many of which only need D3 from their diet, not UVB). The sun puts out more UVB at the hottest part of the day, but in some areas this might be too hot, so if you put your tort out earlier or later in the day when there are less rays, you would want to have more time than high sun. Similar to if your tort has a UVB bulb with less output they will just spend more time under it to get the same amount of UVB than a high output bulb. Natural sun is always better than UVB bulbs, but the good MVBs on the market like the T-Rex Active UV Heat and Mega Ray are about the closest you can get.



Thank you, I understand better now.


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## Yvonne G

Also, just to add one more confusing fact...where you are on the earth also changes the amount of UV that the sun is sending your area. Lots of UV at the equator, but not so much in jolly olde England.


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## tortoisenerd

Good point! I could put my tort out whenever its warm, but here in the Seattle WA area there isn't much sun coming through the clouds a lot of days. Its rare when its warm enough, not raining, and I'm actually home, so our little buddy doesn't get outside much.


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## Madkins007

Let the tortoise figure it out. It cannot get too much D3 from the sun- skin has a built-in protection against that. 

If they get some unfiltered light every day, most species probably do not need additional UVB/vit. D, but a small occasional dose (as in a pinch of multivitamin) might be good insurance.

Do different species need different amounts? We simply do not know. In fact, we have no idea what the recommended D3 level is for torts. Heck, I just saw an article that argued that the current recommended D3 level for humans may be 10 times too low!

We can easily assume that different species have different responses to UVB- light colors tend to reflect it, thicker scales tend to absorb it more slowly, different basking and denning practices mean some get more while others get less, etc., so a Sulcata in full sun may (note the use of the word 'may' here- this is not a proven fact) get the same dose per minute as a Red-foot in dappled light.


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## Tom

1. Access to full sun as much as possible for most species.
2. No.
3. Yes. Forest types and omnivores need less than desert types.


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## samstar

Just got mine out in the sun today for a good half hour, it's about 33 c today which is why they were probably running for cover. Very rare do I actually see them basking under the sun, I guess the MVB in their enclosure is doing the trick.


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## Tom

Some of them are just more secretive than others, and babies or small ones tend to run for cover anyway. They are still getting lots of UV just from being outside. UV bounces around and refracts you get get a lot, even in the shade.


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## samstar

Tom said:


> Some of them are just more secretive than others, and babies or small ones tend to run for cover anyway. They are still getting lots of UV just from being outside. UV bounces around and refracts you get get a lot, even in the shade.



Never knew that about the UV bouncing and refracts


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## ISTortoiseLover

I thought that only visible light bounces of the objects we see. I didn't know UV rays would react the same way.. No idea really.


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## geekinpink

Does sliding glass doors filter the UV on sunlights? Because sometimes i go out and since I don't want the help to handle my tort, i ask her to open the sliding doors to let the sunlight in and let the tort decide if she wants to bask or not(instead of carrying her to her outside enclosure), There are days that's very windy (the wind is super hot though) and i was wondering if i close the doors, will she get the UV as well?

my tort would bask like 1 minute only then goes into her hide but with her head peeking out where she catches the sunlight, does this everytime.


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## ekm5015

Glass will filter out nearly all UV. Screens even filter out some UV depending on the size of the holes in the screen. Direct sunlight is best to get maximum uv exposure.


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## tortoisenerd

Its also dangerous to have a tort enclosure next to a window inside because it can get very hot. Your tort will also get much less UVB from being inside the house with the sliding door open than being outside because of the angle of the rays. I would put the tort in the enclosure outside and provide a hide for if it wants the shade. Just ensure the temperatures are appropriate for the species to be outdoors and provide water if its going to be out awhile.


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## tortoises101

Some species should almost never get access to direct, bright, sunlight, while for others it's almost mandatory. Species like sulcatas live in deserts and grasslands and get copious exposure to natural UV and high levels of illumination. However, some species like hingebacks spend their life on the forest floor or in the undergrowth and hardly get any exposure to UV. Too much sun for tropical species may actually cause eye problems and stress them out (just my 2 cents). Research your species' needs as much as possible. Also, depending on the species, some don't need UVB at all (tropicals), while others depend on it (Mediterranean, sulcatas, desert, etc). But I think that all torts should get exposure to natural sunlight some point or another.


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## Terry Allan Hall

During the winter, my Europeans get out on my fenced in porch every sunny day, for as long as possible (this week, we had two reasonably warm/sunny days one day in the low 70s and one day on the higher mid-70s, so they got about 12 good huours some time basking, some time sitting in the shade)...next "outside days" might be the latter part of next week.


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## Madkins007

tortoises101 said:


> Some species should almost never get access to direct, bright, sunlight, while for others it's almost mandatory. Species like sulcatas live in deserts and grasslands and get copious exposure to natural UV and high levels of illumination. However, some species like hingebacks spend their life on the forest floor or in the undergrowth and hardly get any exposure to UV. Too much sun for tropical species may actually cause eye problems and stress them out (just my 2 cents). Research your species' needs as much as possible. Also, depending on the species, some don't need UVB at all (tropicals), while others depend on it (Mediterranean, sulcatas, desert, etc). But I think that all torts should get exposure to natural sunlight some point or another.



Just to clarify a couple things...

There are few tortoise species that live entirely in the deep forest, and as far as I can find, even they bask when the option is available, especially after cooler periods or longer dark periods. There is no evidence that their eyes react to light much differently than other tortoises do, although baby tort eyes are more sensitive than the adults.

All tortoises need vitamin D, and as far as we can tell, no tortoise gets it entirely from diet, not even the deepest forest species. If I recall the report correctly, there is enough UV in a tropical forest to tan a person over time, so there is some present for the tortoise's to use as well.


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## Jermosh

If you are in a hot climate, best sun is morning and let them regulate with shade or hidebox. If you are in a cold climate and its at least 40-50f out, I would make up a heat box with basking light that is open to eastern(morning) or western(afternoon) sun and let them bask.


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## tortoises101

Madkins007 said:


> tortoises101 said:
> 
> 
> 
> Some species should almost never get access to direct, bright, sunlight, while for others it's almost mandatory. Species like sulcatas live in deserts and grasslands and get copious exposure to natural UV and high levels of illumination. However, some species like hingebacks spend their life on the forest floor or in the undergrowth and hardly get any exposure to UV. Too much sun for tropical species may actually cause eye problems and stress them out (just my 2 cents). Research your species' needs as much as possible. Also, depending on the species, some don't need UVB at all (tropicals), while others depend on it (Mediterranean, sulcatas, desert, etc). But I think that all torts should get exposure to natural sunlight some point or another.
> 
> 
> 
> 
> Just to clarify a couple things...
> 
> There are few tortoise species that live entirely in the deep forest, and as far as I can find, even they bask when the option is available, especially after cooler periods or longer dark periods. There is no evidence that their eyes react to light much differently than other tortoises do, although baby tort eyes are more sensitive than the adults.
> 
> All tortoises need vitamin D, and as far as we can tell, no tortoise gets it entirely from diet, not even the deepest forest species. If I recall the report correctly, there is enough UV in a tropical forest to tan a person over time, so there is some present for the tortoise's to use as well.
Click to expand...


Oh. Thanks Madkins for the reply and the correction.


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## Madkins007

Tort101- LOL, there is so much written about tortoises, and so much of it is confusing, contradictory, based on theory rather than research, etc. that I find myself having to adjust my old opinions all the time as I learn new stuff. 

My stance on UV is one that has changed a lot in the last couple years, doing almost a 180 from 'eh' to 'really important' for lots of reasons. My stance on vitamin D just took a big hit so I wrote the article in the Articles section about it. Always something new to learn, isn't there?


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## djschantz

Tom said:


> Some of them are just more secretive than others, and babies or small ones tend to run for cover anyway. They are still getting lots of UV just from being outside. UV bounces around and refracts you get get a lot, even in the shade.



Thank you for the valuable info!


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