Hannah Staine
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If wild sulcatas spend 90% of their time in burrows, how do they get UV and how do they walk 20 miles a day?
Wild sulcatas
- Thread starter Hannah Staine
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Speedy-1
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I would bet it's not 90% or 20 miles. I believe, if I remember correctly, the 90% is during the hottest part of the day. Not sure where the 20 miles came from. depending on where you got these from, they are either guesstimates or educated guestimates from those who have studied them and their habits
They spend 95% of their time underground and their burrows can have many tunnels and each offshoot can exceed 30 meters in length. This is all according to "The Crying Tortoise" by Bernard Deveaux, which is the best book on wild sulcatas written. Its been out of print for many years.
My friend Tomas Diagne who studies wild sulcatas in Senegal, where he lives and grew up, says that they drag vegetation into their burrows at the end of the rainy season and subsist on this for the 8 or 9 months of the year when its not monsoon season.
I don't know where you are getting the 20 miles of walking per day info. I've never seen anything anywhere near that. Wild russians have been documented walking more than a mile in a day at certain times of the year in their range. Is that what you are referring to?
Hannah Staine
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So how do they get uv being underground 95% of the time?
The father of my first two hatchlings escaped his enclosure and had reportedly walks over 30 miles, from one city to another in Florida before being found. But, I would bet that it didn't take a day to walk that far away.
They get it during the 5% of the time they are topside. They also tend to hang out near the mouths of their burrows to catch the sun and warm up, BUT remember that where they live in Africa, it is either "hot" or "hotter", so they probably avoid the sun, unlike here in temperate America where they bask for hours out in the open on cool days. When they are near the mouth of their burrow, they are technically still "underground in their burrow", but still exposed to the sun. When mine are in this position, they shoot backwards down into their burrows faster than a speeding bullet if anyone approaches. (Well, that might be exaggerating a bit, but they shoot down in there much faster than you'd think a tortoise could move.
It only takes about 15 minutes to get a full days dose of UV. Same for people. And they store the D3 in their fatty tissues for use as needed on days or weeks that they don't go topside.
All of the people that I know (and there have only been a few…) that have been near sulcatas in the wild say the same thing. You could walk right by 100 of them and never know they are there because they are leery and simply do not come above ground very often.
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Hannah Staine
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Hannah Staine
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So you're saying you buy uvb tubes for all your torts when all they need is to be put in sunlight for 15 minutes?
You'll have to ask Maggie where she got her info. I have not seen any study to indicate that, but that doesn't mean she hasn't.
I don't usually use UV tubes for my tortoises because they all get real sunshine.
I have a few UV bulbs in some of my enclosures, but not because my tortoises need the UV. I use them to light up the enclosure and more closely simulate daylight. UV bulbs are closer to the correct spectrum of light to simulate sunshine than "regular" florescent bulbs.
Also, even here in SoCal, we have cold spells in winter when my little indoor tortoises don't get outside for two or three weeks in a row. I feel better knowing they are still getting UV, even though I know they would be fine without it for that period of time.
Your tone comes across as very contentious. Are you having an issue with the info here, or someone who is sharing it? I'm happy to answer your questions, but you sound rather incredulous. Am I misinterpreting your tone from the typed word?
They don't need UV daily. They get enough from the times they are above ground to sustain them.
Hannah Staine
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I dont have a tone I am just asking a question because I have seen lots of people on here say how they need hours of uv
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The UV question is prompting of many concerns people have. They do need UV to process nutrients. The 'how much' and in 'what proportion' are not well answered at all. The concept of "provide" UV came out from zoo keepers who found with BL Black lights for reptiles in captivity did better, now some 40 years ago. Over the time since then the anecdotal evidence has preceded and corrupted the sparse 'science' on the topic. By science I mean a controlled situation with few variables can could alter the measured outcome, and then a well analysed data set.
Most tortoise while using the sun to thermo-regulate get the UV as what might be thought of as an incidental intake. I have not seen nor interpreted any evidence that tortoises or other reptiles 'bask for the UV itself' though some might.
Many tortoises will bask at the onset and decline of their active period, and during the middle of the active period (daily or seasonally) do Okay with the ambient temperature.
UV as a nutrient augment is required for bone development at a minimum. UV acts on some nutirents to help make D3 in the tortoise. I think I recall some animals can make D3 from their diet or with chemical pathways inside their bodies which do not rely on the sun (not sure on this). Some foods though, without any doubt, are a direct source of D3.
So getting back to sulcatas, based on the limited results of wild animal observation, the basking or above ground time is enough to accomplish this.
In captivity we play with the temps and humidity to best approximate what happens in the wild. So the UV light is there more than what they may actually use in the wild, but much less in terms of what is available in the wild. It's a balancing game. Best to offer water when they may not be thirsty than to limit water and cause dehydration as another example.
Most tortoise while using the sun to thermo-regulate get the UV as what might be thought of as an incidental intake. I have not seen nor interpreted any evidence that tortoises or other reptiles 'bask for the UV itself' though some might.
Many tortoises will bask at the onset and decline of their active period, and during the middle of the active period (daily or seasonally) do Okay with the ambient temperature.
UV as a nutrient augment is required for bone development at a minimum. UV acts on some nutirents to help make D3 in the tortoise. I think I recall some animals can make D3 from their diet or with chemical pathways inside their bodies which do not rely on the sun (not sure on this). Some foods though, without any doubt, are a direct source of D3.
So getting back to sulcatas, based on the limited results of wild animal observation, the basking or above ground time is enough to accomplish this.
In captivity we play with the temps and humidity to best approximate what happens in the wild. So the UV light is there more than what they may actually use in the wild, but much less in terms of what is available in the wild. It's a balancing game. Best to offer water when they may not be thirsty than to limit water and cause dehydration as another example.
Good to know. Sometimes it's hard to determine if the questions are real or just a trouble maker trying to make trouble.
I don't know where Maggie got her 20 mile info from. That does seem a little excessive to me and I wonder if a tortoise actually COULD cover that many miles in just one day. But, sticking up for Maggie, it might be something she's pulling up from the recesses of her mind - old info like what we all have stored in there, maybe even something that she got from me! that is no longer true.
I doubt the tortoises know why they bask. It just feels good. Whether they are programmed to sit in the sun because it allows them to thermo-regulate or get UV is something we can't know. I wonder why I enjoy the sun so much when I know it will give me cancer.
A related question I have is: what is the impact on their health when we raise them in less harsh environments than their native area? How much do we want to simulate their natural conditions when they might actually do better in our care?
I feel they do better in our care when it closely resembles their environment as far as heat and humidity and diet. They do better with as as far as we know because they get food and water all the time and we don't let what would try to eat them, have them. Take their dangers out of their wild and they would do as good if not better then with us.
I think Will covered this pretty well, but suffice to say that this has not been studied well enough to have even preliminary answers. No one knows how much UV is needed. No one knows what intensity is required or for what duration. I've yet to see any study that demonstrates whether or not they can use dietary D3 or not. No one knows if hatchlings need more or less than juveniles or adults. No one knows how long a 15 minute "dose" of UV will last a tortoise of any size, species or age.
So what we do in captivity is take our best guess and go with it. Will's water bowl example illustrates this fantastically. Better to offer more than they might need, than to not offer enough. We know in the wild, they have lots of sun and UV available all day every day. How much do they use it? No one knows. Very little is known about the lives of wild sulcatas. I wish we knew more. I fantasize about living out in the bush for a couple of years and studying them through all seasons and life stages, but practicality prevents this. So in captivity we do our best to simulate the warm/hot, sunny, tropical conditions that this species would enjoy in the wild, here in our decidedly temperate climate. This means creating, as best we can, an indoor "sun". Brightness, intensity, color spectrum and UV are all factors to consider in this.
Because there are no definitive studies, we look anecdotally at what has worked for many people in the past and what hasn't. People who use quality UV bulbs, and use them correctly, and have them on for hours a day, tend to experience no problems with MBD, growth, or other related issues. People who raise their tortoises indoors all the time with the wrong diet, temps, conditions and no UV end up with grotesquely disfigured animals and MBD. There are many factors in there, but providing UV, or not, seems to be a big one according to the experience of veteran keepers that have seen many cases over many years. People like Yvonne and Maggie. People like Will.
We used to have a moderator here named Kristina. She lived in Cadillac MI, and kept all of her tortoises and turtles outside for as much time as the weather would allow. When fall hit, she'd move them all indoors for the winter and she used ZERO indoor UV. As soon as warm weather returned, she moved them all back outside so they could sun as much as they wanted to. She claimed to have no UV related issues. Her tortoises looked healthy and reproduced too. This worked for her, but she also didn't do bone density study or check blood levels of D3. Maybe it was a problem, but not enough to show clinical symptoms on the outside. What would have been the harm in putting a UV tube over her tortoises in winter time? No harm at all, and that is why hours of UV is generally recommended. No one knows how much is needed, but we all know what happens if not enough is provided. By contrast, Will knows of tortoises successfully maintained indoors in zoos for years with nothing but artificial UV, and that seemed to work well for them too. Could those tortoises have done as well with less UV? Maybe. Maybe not...
