UV confusion

[TheLastGreen]

I found a UV scale that matches most UV readers used on the form.
Here in SA the UV reaches 9
How long should a hatchling be outside in extreme UV?
(Especially types of torts like hingebacks that like to live under cover?)

 

[Markw84]

You've kind of answered your own question - they live under cover. By providing ample, natural plant cover in an enclosure, the tortoise has the ability to get away from the direct sun. Living in their natural range, you can let them choose sun or shade or partial shade. Tortoises are good at that if given the right options in their enclosures. Different problem for folks living in areas with ground temps way colder than a tortoises' natural range or providing an enclosure with no natural hides (plants).

 

[Tom]

I found a UV scale that matches most UV readers used on the form.
Here in SA the UV reaches 9
How long should a hatchling be outside in extreme UV?
(Especially types of torts like hingebacks that like to live under cover?)

My general rule of thumb for sunning babies (putting them in safe, secure outdoor housing with ample shade and the correct temperatures) is one hour of access to sun per inch of tortoise. With proper shade covers, plants and hiding areas, the baby will regulate its own UV exposure. Leaving them out too long each day is not good for babies. Larger juveniles and adults can be outside all day, or just live outside full time with suitable shelters and warmth, but babies should be kept mostly indoors.

There is a kinxys working group here in the states, and they have found that the hingebacks do far better if simply maintained indoors in large tubs. For these successful keepers and breeders, the tortoises simply don't do well with outdoor housing regardless of weather and climate. I've not had that experience with the species I keep, but I talked to them about it, and they settled on what works and what doesn't for them. Many people have trouble just keeping hingebacks alive, but these guys are getting lots of babies annually and their torts are thriving.

 

[TheLastGreen]

My general rule of thumb for sunning babies (putting them in safe, secure outdoor housing with ample shade and the correct temperatures) is one hour of access to sun per inch of tortoise. With proper shade covers, plants and hiding areas, the baby will regulate its own UV exposure. Leaving them out too long each day is not good for babies. Larger juveniles and adults can be outside all day, or just live outside full time with suitable shelters and warmth, but babies should be kept mostly indoors.

There is a kinxys working group here in the states, and they have found that the hingebacks do far better if simply maintained indoors in large tubs. For these successful keepers and breeders, the tortoises simply don't do well with outdoor housing regardless of weather and climate. I've not had that experience with the species I keep, but I talked to them about it, and they settled on what works and what doesn't for them. Many people have trouble just keeping hingebacks alive, but these guys are getting lots of babies annually and their torts are thriving.

Thanks Tom, I don't provide UV for my tort, so I soak him for about 10 min daily in full sun, while I sit beside him. (At night I soak him for an hour)
The finicky thing comes in, as you know, that these types of torts are shade dwellers, and most hatchlings like cover, so it's almost a double thing, so that was where my confusion stemmed from.
But of course I want to make sure he has enough UVB for strong bones and a healthy shell.
But I make sure he gets between 10-60 mins of sunshine, hopefuly it's enough

 

[Markw84]

Thanks Tom, I don't provide UV for my tort, so I soak him for about 10 min daily in full sun, while I sit beside him. (At night I soak him for an hour)
The finicky thing comes in, as you know, that these types of torts are shade dwellers, and most hatchlings like cover, so it's almost a double thing, so that was where my confusion stemmed from.
But of course I want to make sure he has enough UVB for strong bones and a healthy shell.
But I make sure he gets between 10-60 mins of sunshine, hopefuly it's enough

The issue is that we really don't know how much UVB is enough. What we do know; I'm short-cutting chemical names to keep it simple.

Pre-vitamin D is formed in the skin very quickly with exposure to UVB - a matter of minutes not hours.
The conversion of pre - D to vitamin D then occurs with exposure to heat in the skin. That happens in a matter of hours, not minutes. The more heat = faster. Low heat = many hours.
The true forest tortoises that seem to prefer shade and don't bask much, all tend to be more omnivorous - redfoot & hingeback & manoria. So they get Vitamin D from diet with animal protein and some mushrooms.

So the answer to your question in regards to hingeback is complicated. There is belief that they get all the D they need from diet if their diet is complete. But dietary D can be overdosed. D from UVB exposure cannot be overdosed as the body simply will not convert pre D to D if enough is in their system.

So - some UVB exposure would seem good as a safety. But not much is needed is there is also animal protein and dietary D. Just use caution on dietary D additives.

 

[TheLastGreen]

Thanks Mark, I've read that it is recommended that hatchlings have a high protein diet.
So I feed a protein based diet, focused on store-bought mushrooms
Store-bought mushrooms 7 UI Vit D per 100g (most of the protein comes from this)
Butternut squash 0 UI
Green lettuce 0 UI
Earthworms unknown UI
A few months ago I coated a few earthworms in cuttlebone powder, but that's about it.
What are the symptoms of vitamin D overdose?