night time lows.

[Anyfoot]

Well, there were all of the times I visited areas where I have found a number of species in situ and where I found them during the day was of a temperature higher than where I found them at night. I have found tortoises in Europe, Central/South America, and Asia. The US, too, if we count Gopherus in this. I have yet to visit a place where the nighttime temperature of the tortoise at an activity nadir was equal to its daytime temperature at its activity apex unless it was completely buried for brumation.



Would you mind linking me to a study by an actual researcher that has measured sulcata burrow temperatures and showed zero delta between diurnal apex and nocturnal nadir with statistically significant data sampling? I assume, for your position, that you would use that kind of data. Were the studies you are referencing based on probes inserted into the ground and allowed to equilibrate while buried with substrate making contact on all sides or in an otherwise enclosed space (to know the ground temperatures since you mentioned ground temperatures)? Or were the studies done in open-air sulcata burrows? My sulcatas do not bury themselves in the ground material when they retire to their burrows excavated from the ground material, so a buried probe lacks equivalence to an unburied sulcata and that is only in the context of the burrow.

When my sulcatas reside in burrows, they do not reside within them for 24 hours per day. If mine only lived in their burrows and never emerged for active periods, I would assume there was something wrong with them. When they are out and active, their burrow temperature is not the daily high temperature that the animals experience. My burrows are around two feet wide and air flows into and out of them. There is even a low howl like a seashell when the wind really picks up before or during storms. That the air is warmer in the day and cooler in the night is sped up some when wind is higher. Like a cave, the temperatures are muted, but have fluctuations. It is a tube. Not a capsule. My sulcata burrows experience daily highs and lows on a more narrow range of temperatures than the surface highs and lows, but my sulcata tortoises themselves are exposed outside of the burrow to highs much higher than the lows they are exposed to within the burrow at the nighttime low. But again, my sulcatas do not sit in their burrows for 24 hours per day, so I would not be one to use the burrow temperature range to extrapolate to the animal's temperature range. Nor would I use data from a buried probe to speak for a burrow experiencing air exchange because I would not want to come across as intellectually dishonest on the matter. The burrow temps have a delta that is greater than zero. The animals are exposed to a delta that is much greater still compared to their burrows. I am not breeding and raising burrows. I am breeding and raising sulcatas.



Does this study's methodology have the probe placement performed in a sulcata burrow? Or is it a buried probe? If it is a buried probe and the species to be discussed are not buried beneath substrate to that depth, how does it support your point? Speaking of Cyprus (and Greece; I have been to both), when I have been there and observed the multiple species of tortoises in situ, their shells were rather warm to the touch in the daytime while active and somewhat cool to the touch at night while tucked into underbrush. Some with condensate on their shells during the early mornings at daybreak. Even going by my hand, that does not represent a delta of zero. These were primarily summertime visits. Spring and autumn seasonal variations combined with basking behaviors could make for an even larger delta for the animal's temperature within a day. In Greece, this involved a variety of terrains. Mountains. Valleys. Agriculturally developed areas. Undeveloped chaparral-like scrublands. Pine forests. Deciduous forests with springs or rivers (both seasonal and persistent). Three species in the Testudo genus in aggregate when dealing with exeriences combined from both countries.



With what probe placement methodology? Buried or with access to direct air exchange? If with access to direct air exchange, over what dimensions?



Even if you are talking about buried (substrate-encased) probes (apples) and not sulcata burrows (oranges) with air exchange or the actual sulcata tortoises (pears?) themselves, that is not the full range of exposures the animal experiences within its full day. You are taking data twice removed and making a conclusion based on measurements that were not taken of the very thing you are concluding on. A buried probe is not a burrow space. A burrow space is not a tortoise. A tortoise at night in a burrow is not the same temperature as it is during the day outside of that burrow. If I buried a tortoise completely at a particular depth to replicate a probe reading, that in no way represents what the tortoise would experience without me doing so.

And that is only speaking to sulcata tortoises since you decided to focus on that species. Other species experience a night drop as well. Their lowest resting temperatures at night are not the same as their highest active temperatures during the day unless you want to somehow reasonably conclude otherwise with measurements taken of the tortoises themselves. That delta or difference is the night drop. A leopard tortoise under the cover of brush and grass during the lowest temperature of a night is experiencing a night drop relative to if it stayed in that position while in the shade of the same brush and grass during the highest temperature of that day (which is still not the highest temperature it experiences while active during the day with direct exposure to sunlight). When a South African pardalis is observed having frost on its shell before dawn breaks, that is probably at a lower temperature than what the animal experiences at noon on the same day. That, too, is a night drop. When I have found redfoot and yellow foot tortoises during the day and then again at night, the temperatures were not the same at the level of the tortoises at those different times of day. Also a night drop.

As before.



At least for tortoises not brumating. Not talking about buried probes that do not represent active tortoises in a day/night cycle.

Would all the information of this post apply to a 4 month old tortoise that is hidden away most part(day and night)or are we saying a 4 month old is also active during the hotter day sun then retreats to cooler safety at night to give a night time low?

If a tortoise was hidden in the under growth where the temperatures are more stable throughout a 24hr period but above this micro climate the air exchange temperature varied through the 24 hr period, how would this effect dew in the microclimate where the tortoise hides?

 

[Baoh]

Would all the information of this post apply to a 4 month old tortoise that is hidden away most part(day and night)or are we saying a 4 month old is also active during the hotter day sun then retreats to cooler safety at night to give a night time low?

If a tortoise was hidden in the under growth where the temperatures are more stable throughout a 24hr period but above this micro climate the air exchange temperature varied through the 24 hr period, how would this effect dew in the microclimate where the tortoise hides?

It may be a mix of both. A smaller tortoise will retreat earlier in general and tends to stay under cover more, although I have found bolder hatchlings out during hotter and brighter periods, too. I think there are multiple survival strategies at play with that. Staying hidden leads to reduced frequency of predation and desiccation (strategy one). Venturing out leads to greater food consumption and a higher metabolic rate to spur faster growth (strategy two). Strategy one's main benefit is improved survival rate. Strategy two probably has two benefits. A) Reduced time to a larger size reduces the number of predators that can make a meal out of you. B) Reduced time to a larger size increases your ability to outcompete "hiding" babies if there is a goal of spreading genetic material. Strategy 1 is to reach the finish line more reliably. Strategy 2B is to cross the finish line before others and direct the flow of the subsequent generations. Cosmetic benefits are probably a side effect. You could also argue a 1B exists in a time of relative famine where staying tucked in, eating less, and growing slower leads to survival where a bolder baby is burning energy. Hard to say. I sometimes wonder if there is a health or longevity benefit that has evolved from being subjected to a night drop. It might trigger an endocrine cascade that is beneficial, for example, that we do not know of. Kind of like how female fertility is variable with size and age. Size being primary. Age has some secondary benefit from what I observe. If I get a female carbonaria to large adult size in three years, she may not start to produce mature follicles until the fifth year while others in her situation do start at three. Meanwhile, I might have a female take seven years to eke out growth to a bare minimum reproductive size and she may then immediately produce upon reaching that minimum size. In the first case, there is size outpacing seasoning. In the second case, there is seasoning occurring in pace with size. I do not know why some females in the first case go right away while others have to season more. Just like I do not know if some benefit to symbiotic microorganisms might occur during the night drop. Or if there are bodily/cellular enzymes whose optima are set better for the lower temperature of the night for some function they serve during that portion of the day. I cannot say if any of these have any relation to a night drop, but these hypothetical examples are possibilities that fall under what I mean when I say we do not know what we do not know. For some of my projects with keystone animals, I move them forward swiftly. In the context of a concept like the Hayflick Limit, I may be spending the "bank" of cellular division earlier to get to a size milestone faster. Maybe and maybe not, but few things come without trade-offs. I suspect I am sacrificing the years of life that would have been spent growing out that animal to a given size. Say I get a female to ten inches in three years and her identical twin to ten inches in ten years and they have a lifespan of something like seventy years (for the sake of argument; these numbers are pulled out of the cloaca and are only meant to be for the concept discussion). It would not blow my mind to discover that supergrown female 1 lives for 63ish years and her more casually grown sister lives for 70ish years. With the way reptiles grow and live, this may not be the case, but I am also not too arrogant to state it will not be the case. A night drop, in this scenario, might stretch out the years. Unknown unknowns. Will this alter my plan for my more swiftly grown keystone animals? No, but I accept it is a possibility without hesitation rather than try to make myself feel better about it. I do not want to cherrypick this and that to start inductively feeding a narrative I want to support (this is too common).

A dew point should be easier to achieve in a cooler area of undergrowth. That means condensate more easily forms on the surface of the shell at the lower temperature and the condensate can then directly hydrate (and therefore lower tension of) the keratin. That flexible keratin will then not place as much tension on the underlying bone at acute angles and the force that is present is more diffuse. The bone should then grow in a more planar fashion and pyramiding should be reduced or minimized. The growth during periods of relaxation and "tightening" (as well as starts and stops) will result in annuli. More growth per relaxed phase should have wider annuli of fewer number. More relaxation/tightening cycles in a span of time should result in greater numbers of annuli of smaller widths. Fewer cycles with less extensive growth per cycle would mean narrower annuli, but at lower accumulation rate. Harder starts and stops, from what I see, lead to deeper grooves between annuli and this seems exacerbated if the beginning of the new growth phase lines up with the tightened portion (where keratin tension is high and that groove occurs from a more acute angle of pull).

 

[Anyfoot]

@Baoh.
Can you shed any light on when tortoises actually grow. I was reading something a while back about bone growth. One of the things I read was that mammals grow when at rest (sleeping) and not during active times. So basically the energy at rest is used to grow and energy at active times is used for the actual activity. Whether this is true or not I'm not sure, I struggle to trust anything I read on the open Internet
If it is true would that also apply to ectotherm animals providing they were above a certain temperature.
So for example, a baby tortoise is hidden in the dense moist foliage with its carapace moist and relaxed whilst asleep and is growing (growing in moist conditions).
During some parts of the day it's active out in the sun with the carapace dry and tight but it's not growing because the energy is expended into activities not growth.
If there is any possibility of that being correct then basically a tort sleeping whilst dry would grow and pyramid. So sleeping in the sun or under a basking light or in bone dry foliage would all contribute to pyramiding. This would also answer why babies may venture into the suns heat and not pyramid.
It's all relivent to night time lows to, because we need the low to create dew in the wild is what I'm thinking.

 

[Baoh]

@Baoh.
Can you shed any light on when tortoises actually grow. I was reading something a while back about bone growth. One of the things I read was that mammals grow when at rest (sleeping) and not during active times. So basically the energy at rest is used to grow and energy at active times is used for the actual activity. Whether this is true or not I'm not sure, I struggle to trust anything I read on the open Internet
If it is true would that also apply to ectotherm animals providing they were above a certain temperature.
So for example, a baby tortoise is hidden in the dense moist foliage with its carapace moist and relaxed whilst asleep and is growing (growing in moist conditions).
During some parts of the day it's active out in the sun with the carapace dry and tight but it's not growing because the energy is expended into activities not growth.
If there is any possibility of that being correct then basically a tort sleeping whilst dry would grow and pyramid. So sleeping in the sun or under a basking light or in bone dry foliage would all contribute to pyramiding. This would also answer why babies may venture into the suns heat and not pyramid.
It's all relivent to night time lows to, because we need the low to create dew in the wild is what I'm thinking.

They grow both while awake and asleep. So do humans, but that is a little different since human anabolism is not dependent on our immediate external environment's temperature (within reason). There is a nighttime growth hormone secretory pulse in mammals, but that is not a temperature-driven phenomenon in humans. Growth will be faster at rest than while active simply due to the allocation of Calories being less divided. With ectotherms, anabolism will be higher while warmer. Sleeping and warmer will grow faster than sleeping and cooler. Having a cooler nighttime period should lead to smoother growth to a degree compared to a warmer nighttime period *if* no compensatory keratin flexibility is induced while warmer. Many keepers keep tortoises warmer than they would experience naturally at night, but the provision of a humidity boost and the more supple state of the keratin compensates for that (mostly). That really only lets us observe the pyramiding part. If there are some unknown compromises (or benefits...or nothing at all), I am not sure anyone has studied them.

I think the warm-versus-cool nighttime sleeping condition and its effect on pyramiding (without compensation) has been studied.

Something in relation to growth and temperature was examined in developing chelonian embryos before. A low incubation temperature causes a greater difficulty in both maintaining the tissues and expanding them, whereas the warmer temperatures allow easier maintenance and growth. This assume adequate Calories (yolk for embryos). One thing to consider that feeds back into something I mentioned is endocrine pulses and cascades. I have not looked into chelonian growth hormone pulses if that information is even available. I remember the peptide sequence for sea turtles being worked out, but little else last time I looked.

As for babies, they do get up a bit after morning warmth sets in. In Testudo in the summer, that goes until maybe 10-11am (usually no longer and it seems to cut off by 10am more often than not with the little ones). There is then the second period of activity as the Sun is lower in the sky again until they retire by dusk for the cooler night and the dew it brings (plus they tend to dig in slightly in rootstock and other little sheltered areas). I have found exceptional babies and small juveniles walking along in the blazing sunlight out in the open at 1-3pm (asking for death, little fellows), but this is not the norm.

 

[Markw84]

@Baoh

The discussion is: if I provide a stable ambient temperature of 80° in captivity for my tortoise, and certainly provide a daytime basking area of about 95°-100°, would the nighttime ambient be better if we allowed it to drop below 80°?

It is exactly the statements that "when I see tortoises in the wild, they are certainly warmer in the daytime than they are at night" and the reliance on weather data of air temperatures in their natural range that I believe is misleading. From that we ASSUME things as wrong as "sulcatas are an arid species, coming from an arid habitat and should be kept dry and not humid in captivity". Anyone observing a sulcata in the wild would certainly agree with that. But where we are observing them in the wild, is not where they live the vast majority of their lives.

Knowing the temperature of the extensive thermal mass surrounding an uninsulated, narrow tunnel in the ground is far more telling than air temperatures or what we observe when we find them above ground -when they spend about 95% of their time in their borrows. That is what they seek out to maintain their lives in an environment they have found ways to endure. I know of no one who has spent more time studying sulcatas in their natural range than Bernard Devaux and Thomas Diagne. Thomas's comments to @Tom in visiting a sulcata enclosure in Arizona, was that he was amazed at how differently sulcatas act here as opposed to in the wild. He couldn't believe how much time the tortoises were out! In Africa he says they rarely are seen. To find them you look for burrows. They spend at least 95 of their time in those burrows, rarely coming out. It seems that indeed they use those burrows to not only find more humidity, but to keep their bodies at a stable temperature as much as possible. In their native range, for the reasons I laid out above, I believe they have found that stable temp of around 80° in that burrow. Not night drop, no daytime rise. The use the sun and daytime "outside" temperatures to heat their body to a more active level for foraging and seeking a mate. But always retreat to that stable climate of their burrow as temps climb to 115° + or dip to the low 70°'s in a cold night. They do not endure or experience a night drop. In our areas, with a much more temperate climate, the tortoise does not have to spend as much time hiding from conditions that will overheat it. So staying at a comfortable temperature does not require a burrow. Here, it is the night that is more of a problem and all our tortoises are very good about finding their night boxes as temperatures drop. Totally different than in the wild where it is the heat that is the main threat. Here, where we are keeping them, they have to learn how to deal with cool temperatures. Our tortoises become so active throughout the day as it is no longer a problem for them to keep their bodies at their preferred temperatures when the sun is out and it is anywhere from 70°-100°. Just move in the sun, or move to the shade. 80°-85° body temp - no problem. But when it cloudy and 60°, or at night and 60° suddenly our tortoise act like a wild sulcata, and retreat to the burrow seeking a way to maintain that body temp. How many people endlessly ask about how their sulcata slows down in winter and barely comes out, eats far less. But heat their night box, their "burrow" to 80° and see how they act. Much more active, and needing to seek out the burrow much less until their thermal mass is overcome by the ambient air. So are they seeking out, or "do better" with a night drop? I see no evidence of that anywhere.

You discount the value of knowing ground temperatures in trying to figure out what our tortoises really need or 'prefer'. Yet I find value in this information. Looking at the chart I posted above, you can see according to that data it is about 10" deep where temperature stabilizes and becomes almost totally resistant to daily swings. I don't believe it is coincidental that the sulcata is the only tortoise that digs a body pit prior to digging the egg chamber. They are in this way getting the top of the nest chamber, and the topmost eggs, below 10". According to my conclusions above, at that level, the nest chamber is now able to maintain a steady 82°-90° throughout the times of year eggs would be in the ground. Using the same data, we can see that if they dug nests any shallower, the eggs would cook and die. We see going deeper, those temperatures are maintained. Would I rather see lots of great data from someone sticking a data logger in actual nests and recording and then publishing the results. YES! But we don't have that. But understanding basic thermodynamics, heat transferring processes for soil and actual ground temperatures - and then combining that with what we have found is actually working in incubators - we can draw some pretty convincing conclusions.

I would love to see some actual data from a data logger in a burrow. But would it have the accuracy of the data that has been developed by companies investing 100's of million of dollars in developing the most efficient heating and cooling system for adverse climate areas around the world? What tortoise field researcher has those types of resources to invest in state of the art equipment and monitoring? You would also have to account for the movement of the tortoise and the fact that the tortoise is actually blocking the burrow with it's body where only 20% or so is even exposed to the "open" side of the tunnel. But I would even discount that as the amount of thermal exchange from any air that could make its way into a single-opening tunnel is negligible. Also, the way a tortoise constantly scratches at the soil as it enters its burrow (or night box) and settles in - exposing fresh, and more moist, soil. Those actions would produce different readings than a data logger laying in a burrow. Perhaps someone can attach a data logger just under the rear margin of the carapace?? That would be interesting!!!

But we do not have that data. We have been keeping sulcatas in numbers for about 3 decades now and still only recite weather station statistics, and anecdotal stories of how we felt and how it seemed when we found a tortoise that we happened to catch in the rare times it was out and about. We have done a lot now to see the results of husbandry practices. They grow faster, smoother, and are much more active when kept humid. That has caused us to rethink the "dry" conditions that exist in the wild and indeed find evidence they find ways to avoid dry and stay much more humid in the wild than any weather data suggests. (or stories of how hot and dry it was when someone found one in the wild!) We find the same is true when we keep them at 80° with basking area provided. We see them slow down and not eat as well, and reproduction is less as temperatures drop below that level. So now I look and see that all the data supports that indeed ground temperatures fall exactly within those ranges we find works in captivity best. Not weather station data, but ground temperatures. And that same data, combined with the way the tortoises actually lives is telling us there is no night drop below 80°.

I focused on sulcatas because it becomes a futile case of varying scenarios to shift from species to species while trying to make the point. But if we do see that the conclusions about this do apply, then it is a better set of values than weather station data alone - to then apply to the different species. We can look at average ground temperature in their native ranges. We can use that to mitigate the weather station data. We would need to apply if they burrow, or make pallets, or hide under leaf litter, or logs, or in crevices - those would have varying effects on how much the thermal mass of the earth overcomes the heating power of the air that is able to get to the hide. We can also look at burmating species and average air temperature data - apply that to known ground temperature constants and see when and at what temperature brumation is actually maintained.

My main contention - tortoises have developed ways to stay much warmer than any weather station data suggest, or the evidence we see when we catch them out and about may suggest. And when that information alone is used to justify why it's advisable to give your tortoise a night drop - I respectfully disagree!

 

[Baoh]

The discussion is: if I provide a stable ambient temperature of 80° in captivity for my tortoise, and certainly provide a daytime basking area of about 95°-100°, would the nighttime ambient be better if we allowed it to drop below 80°?

No, the original post is as follows.

One aspect of tortoising I've neglected to look at is lower temperatures at night.
I just don't bother with a drop in temps with my redfoots or homeana. Maybe this is an area I need to look at.
For my radiated I've got temps dropping at night.
For the last few weeks I've been watching the weather in Madagascar(Toliara). Basically at this time of year it's around 86f/91f and 60/70% in the day and 75/80f and 80/90% at night.
I'm curios of what impact having night time lows has on our tortoises.
Also would the micro climates that the babies live in be more stable through day and night?

I have addressed the elements of the original post. It leads the discussion and then it can sprout tangents during the course of responses. You are now trying to reframe that within goal posts of your own choosing.

It is exactly the statements that "when I see tortoises in the wild, they are certainly warmer in the daytime than they are at night" and the reliance on weather data of air temperatures in their natural range that I believe is misleading. From that we ASSUME things as wrong as "sulcatas are an arid species, coming from an arid habitat and should be kept dry and not humid in captivity". Anyone observing a sulcata in the wild would certainly agree with that. But where we are observing them in the wild, is not where they live the vast majority of their lives.

I did not assume any of that. Nor did I rely on weather data of air temperature readings from weather stations in their natural range.

As for being misleading, you seem to be focused on using data from ground temperatures that do not represent burrow temperatures (caves "breathe" and so do burrows) to then represent burrow temperatures and by proxy represent the animals' temperatures. It is like trying to speak to precipitation exposure in the burrow based on rainfall on the surface. If I did that, I would be intellectually dishonest. If I used values from a probe buried in the ground to speak for a burrow as fact and then tried to say that the buried probe's environmental condition is what animals not buried are experiencing, I would be intellectually dishonest.

So are they seeking out, or "do better" with a night drop?

Not sure if anyone has said the tortoises are expressly seeking out a night drop for the sake of a night drop itself. Rather, they are exposed to one incidentally through a combination of hiding behavior and nighttime temperature cycles (which someone does not want to believe exist) and it is possible that this could serve one or more benefits to the biology of the tortoises. No overly hard conclusions on specious data (which is exactly what using ground data here is doing; this tends to be looked upon poorly by any ethically-minded scientist). No rushing to close a case that is incomplete.

You discount the value of knowing ground temperatures in trying to figure out what our tortoises really need or 'prefer'. Yet I find value in this information. Looking at the chart I posted above, you can see according to that data it is about 10" deep where temperature stabilizes and becomes almost totally resistant to daily swings. I don't believe it is coincidental that the sulcata is the only tortoise that digs a body pit prior to digging the egg chamber. They are in this way getting the top of the nest chamber, and the topmost eggs, below 10". According to my conclusions above, at that level, the nest chamber is now able to maintain a steady 82°-90° throughout the times of year eggs would be in the ground. Using the same data, we can see that if they dug nests any shallower, the eggs would cook and die. We see going deeper, those temperatures are maintained. Would I rather see lots of great data from someone sticking a data logger in actual nests and recording and then publishing the results. YES! But we don't have that. But understanding basic thermodynamics, heat transferring processes for soil and actual ground temperatures - and then combining that with what we have found is actually working in incubators - we can draw some pretty convincing conclusions.

Moving goal posts again, I see. Buried (encapsulated by earth) data are useful for a buried application. There is better representation of a nest by a probe buried at nest depth. That ground temperature data would indeed be useful for examining that topic (that is not in dispute here). We were not talking about that and I am sure you realize it, however.

I would love to see some actual data from a data logger in a burrow.

So would I since that is central to some elements of your positioning.

But we do not have that data.

Then it is intellectually dishonest to hand-waivingly choose and accept an inaccurate substitute that does not serve as the proxy for what is lacking. If I tried to use core body temperature to speak to phalange temperature in a weather exposure condition, I would be quite remiss.

I focused on sulcatas because it becomes a futile case of varying scenarios to shift from species to species while trying to make the point.

The totality of tortoise species have been included in the discussion, breaking out particular examples, but not hinging on any single one. You focused on using twice-removed data measuring something else to speak directly for something that was not measured. At least if it had been burrow temperature versus animal temperature, there could be some kind of trending relationship established, but that is not what was done.

My main contention - tortoises have developed ways to stay much warmer than any weather station data suggest, or the evidence we see when we catch them out and about may suggest. And when that information alone is used to justify why it's advisable to give your tortoise a night drop - I respectfully disagree!

Yeah, but I do not care if you disagree with me or if you agree with me and want to give me endless hugs and back rubs. I do care that you misrepresent things on purpose with data of one type because the data that matter are not actually available to you. Makes me distrust other things you might say. Like claiming chelonians use the bloodstream as a medium for glycogen storage (when glycogen is not stored in the bloodstream; it is kept in tissues) or claiming it is a fact that tortoises do not store fat as an energy reserve (as an absolute assertion) when they do have distributed peripheral adipose depots that function quasi-similarly to human subcutaneous WAT (although not nearly so extreme; this has been studied in chelonians by Pond and Mattacks).

 

[Markw84]

Misrepresent things on purpose??

 

[Markw84]

As for being misleading, you seem to be focused on using data from ground temperatures that do not represent burrow temperatures (caves "breathe" and so do burrows) to then represent burrow temperatures and by proxy represent the animals' temperatures. It is like trying to speak to precipitation exposure in the burrow based on rainfall on the surface. If I did that, I would be intellectually dishonest. If I used values from a probe buried in the ground to speak for a burrow as fact and then tried to say that the buried probe's environmental condition is what animals not buried are experiencing, I would be intellectually dishonest.

Caves "breathe" if there are more than one opening to the surface. A burrow is more like a mine. In a mine, you need forced ventilation in order for anyone to even work there. But even in caves, they are well know for their extremely stable air temperatures. Once you get a few cave-opening-diameters into a cave, the temperature will stay year-round with a degree or so of the average yearly temperature of the area in which the cave is located. Not only no daily fluctuation at all, but no annual fluctuation at all! Texas caves are know for being a constant 70°. Minnesota caves, a constant 50° or a bit colder further north in the state. In studying passive heating and cooling systems and the concepts a lot of design is based upon, it is the thermal inertia of the ground that totally overcomes the minute thermal inertia of air that is used to help these systems be so efficient. The value of a probe buried in the earth is DIRECTLY relative to the temperature in a burrow. Are you implying the thermal inertia, and thermal mass of the small amount of air that is in a burrow, and has very little exchange, can overcome the thermal inertia of the uninsulated bare earth walls, floor and ceiling of a burrow? I cannot in a wine cellar. It cannot in a buried pipe used to pump cool air for a very basic cooling/heating system (active air flow). It cannot in a mine or in a cave. But it can in a small burrow with no active air flow?

Intellectually dishonest???

 

[Markw84]

Yeah, but I do not care if you disagree with me or if you agree with me and want to give me endless hugs and back rubs. I do care that you misrepresent things on purpose with data of one type because the data that matter are not actually available to you. Makes me distrust other things you might say. Like claiming chelonians use the bloodstream as a medium for glycogen storage (when glycogen is not stored in the bloodstream; it is kept in tissues) or claiming it is a fact that tortoises do not store fat as an energy reserve (as an absolute assertion) when they do have distributed peripheral adipose depots that function quasi-similarly to human subcutaneous WAT (although not nearly so extreme; this has been studied in chelonians by Pond and Mattacks).

Let's see who misrepresents on purpose. Here's what I actually posted. I found it in the thread "Hibernation Help" post #10 Nov 19, 2017

"A brumating reptile has very little fat stores and instead uses increases glycogen levels as their energy source during brumation. They do not "store fat" for the winter as a mammal does. They add increased levels of glycogen that is stored in the bloodstream and cells throughout the body. (This also actually serves as a sort of antifreeze as well. The freezing point of the tissue is actually lowered which protects many aquatic species that hibernate where they can sometimes be exposed to temperatures slightly below freezing!!) So they do not lose any appreciable weight from body mass. Any weight loss is an indication of water / hydration loss. A brumating turtle or tortoise should normally have practically NO weight loss. If there is - it is an indication of them becoming dehydrated."

I did say "bloodstream and cells throughout the body." Are you saying they do not carry glycogen/glucose in the blood? The glycogen is allowing the blood and cells to have a lower freezing point as shown in studies on C. picta and C. serpentia plus providing the little energy reserves needed by functioning organs. It also allow for existence in an anoxic environment many aquatic chelonians can survive during brumation.

I did say "do not 'store fat' for the winter like a mammal does." Are you saying chelonians do store fat for the winter like a mammal does?? That they use fat stores to provide the energy needed for brumation as opposed to glycogen stores?? You cite reference to Pond and Mattacks. I am aware of quite a few article by them exploring the various places adipose tissue is stored in the body and looking at how that can be an indicator of health problems. I have never seen any study by them of chelonians. Mostly human related illness explorations. I've seen them reference many animals as examples of the very common way adipose tissue is located beneath the skin and how universal that is, even when fat is not stored as a primary energy reserve. Is that what you are referring to??

Who is misrepresenting on purpose??

 

[Ernie Johnson]

I'll chime in with regard to tropical forest torts - Redfoot's. I'm in the nighttime temp drop has no effect on them camp and here's why.

If you look at Guyana (where my breeding pairs parents are from originally) it's a fairly accurate representation of any around the equator tropical country with a high percentage of tropical forest from a temperature range perspective.

In Georgetown (right on the coast) you can see how little variation there is from night to day all year long. Obviously this is not a "hot spot" for Redfoot's or Yellowfoot's, I provide it to show that when you go to another part of the country (southwest area) with open Savannah's -Lethem - there is still no variation in temp.

If you went smack dab into the think forest areas you'd see even less of a temperature range.





This is obviously over simplifying things, however I add this to provide evidence for tropical species like Redfoot's and Yellowfoot's (both indigenous to Guyana) the night time temp drop theory doesn't apply because it simply doesn't happen.

So, what "may" apply to tortoises from arid environments can't be seen as a universal across the entire range of species.

 

[Anyfoot]

@Baoh. Off topic. Where did you see tortoises wild in Cyprus? I didn't think there was any native torts in Cyprus. We've only been to the south side of the island.

 

[Markw84]

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@Baoh. Off topic. Where did you see tortoises wild in Cyprus? I didn't think there was any native torts in Cyprus. We've only been to the south side of the island.

I don't think he referenced finding tortoises on Cyprus. I referenced Cyprus only as I had very exact data on hand for ground temps at very precise and shallow depths done for a passive cooling/heating system there.

 

[Anyfoot]

@Markw84

It's the post after you referenced Cyprus.
If it's a mistake I'm not bothered, but Cyprus is a preferred holiday destination for Dawn, it will also be mine if torts are on the island

Baoh said. "Speaking of Cyprus (and Greece; I have been to both), when I have been there and observed the multiple species of tortoises in situ, their shells were rather warm to the touch in the daytime while active and somewhat cool to the touch at night while tucked into underbrush".

 

[mark1]

to use body fat I believe they need to have a body temp high enough to metabolize it , personally I believe that happens in the beginning and end of hibernation(brumation) or in the winter in unusually warm spells when they are active but not feeding .......... I have to think glycogen in the bloodstream is just a misnomer , in that you mean glucose , which as much as most tend to see them as the same , yet they are not , but one is responsible for the other........... when glucose levels rises in the blood in a hibernating reptile , it's been shown glycogen levels in the liver lowers .....

As for lows in terms of tolerance, this will depend on a bunch of things. Species. Subspecies or locality. History of exposures allowed (huge, huge factor). There are few good reasons to explore an animal's limits of tolerance. That is more for knowledge-gathering than anything of benefit to the animal, although it is valuable to other animals in future applications or considerations. However, the rise of over-coddled animals is something interesting. Animals which experience an accidental 50-60-degree night and suddenly are weakened and experience rapid illness are a shame to see. Animals which are allowed to experience gradual exposures tend not to react like that. There is a tempering process that can be achieved if done with some intelligence (or luck for some that do not plan it, but that does not necessarily end well often). Hardened animals are more safe when an unforeseen event occurs. You have no express need to explore this, but there is a benefit. It is also cool to observe it. An excellent example that has been showcased here is Len's male sulcata (Walker). I have countless personal examples. The principles apply to any species of tortoise, although the extent varies with species and individual. It is not all-or-nothing.

this is a great observation , I've done both , out of ignorance with redfoot tortoises , and on purpose with P.Manni ....... the tortoises I just kept in my parents backyard all summer because it seemed where they should be ....... when I first got manni , I kept them in a room with a humidifier at 80degrees , 90-100 degree basking area , i'd put them outside in northeast ohio in july and august , 30yrs later , I put them out in june and bring them in in October , just provide a spot for them to get hot , same in the house ....... finding these tolerances served a purpose , they are much better off being kept outside as long as possible ..... they lay more eggs now than ever before , I think that's an indication of better husbandry ,imo reptiles need the sun ..........

I'll chime in with regard to tropical forest torts - Redfoot's. I'm in the nighttime temp drop has no effect on them camp and here's why.

If you look at Guyana (where my breeding pairs parents are from originally) it's a fairly accurate representation of any around the equator tropical country with a high percentage of tropical forest from a temperature range perspective.

In Georgetown (right on the coast) you can see how little variation there is from night to day all year long. Obviously this is not a "hot spot" for Redfoot's or Yellowfoot's, I provide it to show that when you go to another part of the country (southwest area) with open Savannah's -Lethem - there is still no variation in temp.

This is obviously over simplifying things, however I add this to provide evidence for tropical species like Redfoot's and Yellowfoot's (both indigenous to Guyana) the night time temp drop theory doesn't apply because it simply doesn't happen.

So, what "may" apply to tortoises from arid environments can't be seen as a universal across the entire range of species.

I don't believe air temperature is what reptiles use to thermoregulate ............ I think you'll find Georgetown temps are moderated by sitting next to a massive constant 80 degree heat sink ....... if you move 40 miles southwest you'll see lows in jan-feb in the 60's ......... regardless 90degrees and sun is way hotter for a reptile than 75 and dark , they will not thrive at 75 and dark , they can do just fine at 75 and sunny ........ I would think galapogas tortoises on the island even see nighttime cooling ........have no idea of the benefits , but I have to think the fact is a no brainer .......

 

[Anyfoot]

In my radiated 6x2x2ft vivarium I have 6" depth of substrate. For their hide I have an area that is 2x1ft with only 2" depth that slopes up at either side to the 6" depth substrate. On the 2" depth area I have 4" depth of foliage for bedding. This is where they sleep. I am using a proportional day/night thermostat. My max daytime air temp is 91f and my max nighttime low air temp is 81f. This is measured about 1" above the substrate right next to the bedding.
I have a probe inside the bedding where the torts sleep. Max daytime temp is 80f and max nightime low is 78f inside the bedding.
So in my enclosure my air temp variation is 10f at the measured point and my bedding temperature varies by 2f at 3" deep where the torts sleep. My night time temp kicks in at 9pm for 10hrs.

 

[Anyfoot]

One of the areas of our methods for trying to grow a smooth tortoise that I can get my head around is soaking. It definitely makes a difference and is one method to grow a smooth tortoise. Even though I do soak my babies I've often thought how and where does this artificial method fit in with natures way of combating the carapace hydration problem so the keratin is not tight. We've talked about hatching in babies hatching in wet season but wet season doesn't last a whole yr and our babies need to be soaked for longer that an wet season lasts. Or there is they soak in puddles thought, but surely every single baby out there of every single species doesn't happen to have access to puddles. Many Greeks live in pine forests on hill sides. Puddles and hillsides don't mix.

So to get the equivalent to soaking our tortoises in nature must be dew. At night where ever they live in the world the night time air cools down and humidity increases to the point of dew (100% RH).
This does not mean the the microclimates that babies live in have vast temp differences from day and night. But it does mean the air above these microclimates falls at night causing the dew point.
Even in South America in Bahia where it is a dryer climate than let's say Suriname it only 40% in the day and 85f, it increases to 90% and down to 70f at night. In the microclimate at ground level it will be 100%(dew point)
Or in Madagascar when it's 60% and 90f in the day then 85% and 75f at night the microclimates we are interested in will be 100%.
These micro climates will be relatively stable compared to the open climates that endure the full force of weather, wind, rain and sun.

I have a friend who lives in Brazil, he is adamant that babies bask in the morning and says this is why only 2 or 3 survive out of 100s It's the risk they have to take but a predators buffet. He's on the task of getting me photos of this. So maybe the microclimates that have 100% RH for most part makes basking for an hour in the morning and in the evening not harsh enough to dry the carapace to the point of pyramiding.
How's it all relevant to night time lows, if there is no highs and lows, there is no dew. This doesn't mean there has to be highs and lows in the microclimates but in the open climates above.
Giant Galapagos do endure heat of the sun and obviously when the sun goes down so does the suns heat. But what about the baby Galapagos that are hidden away, they don't endure the day/night open climate like the adults have to endure. Do you think these baby Galapagos have 100% RH at night then bask for an hour in the morning or not?

Below is an interesting link.

http://biomet.ucdavis.edu/frostprotection/Measure Dewpoint/fp003.html

 

[mark1]

it appears to me , turtle and tortoise behavior is aimed at maintaining a stable body temperature , their biology is to deal with circumstances when they can't ........ as far as cooling for part of a day , they appear to have behaviors to minimize it as much as possible , if it was beneficial you'd see them trying to get colder than their preferred body temp , which I've never seen , but you will see them move out of a spot that's too hot or cold to maintain it ....... it's been shown that given the choice they do move to maintain a preferred body temp ....... I don't believe it's ever been shown they move to get below those preferred temps .............hibernation I would think is a different circumstance , obviously a survival behavior , it does appear to me it's benefit is that it does have a biological place in the life cycle of reptiles evolved to naturally hibernate ....... cooling at night naturally happens , and I'd think it also happens in your enclosure just by turning off the lights ........ when I kept redfoot tortoises they had no basking lamp , they were kept under fluorescent lights in an 80-85 degree room with a humidifier , kept outside for 3 months a year , I had not a clue about pyramiding , and those tortoises were barely pyramided , I looked for pics , couldn't find any , I actually think they were not pyramided at all , hard to remember as it was a long time ago, the elongateds I do remember seeing those pics , and they were not even a bit pyramided , I don't even remember seeing growth lines on them ....... I have to think the pyramiding I see in some of these tortoises is a result of constant optimum body temp, they're constantly growing , and the drying effect of the lights and heat we use in the enclosures ....... I am a believer in the humidity theory and shell keratin..........

I would correct myself in that I believe I've seen the urge to hibernate override the urge to maintain a preferred body temp .

 

[Anyfoot]

As usual I was in a rush and constantly being interrupted when I wrote the above post and didn't proof read. Re-done it.


One of the areas of methods for trying to grow a smooth tortoise that I can not get my head around is soaking. It definitely makes a difference and is one method to grow a smooth tortoise. Even though I do soak my babies I've often thought how and where does this artificial method fit in with natures way of combating the carapace hydration problem so the keratin is not tight. We've talked about babies hatching in wet season but wet season doesn't last a whole yr and our babies need to be soaked for longer than just a wet season lasts for.
There is they soak in puddles thought, but surely every single baby out there of every single species doesn't happen to have access to puddles. Many Greeks live in pine forests on hill sides. Puddles and hillsides don't mix.

So to get the equivalent to soaking our tortoises in nature must be dew. At night where ever they live in the world the night time air cools down and humidity increases to the point of dew (100% RH).
This does not mean the the microclimates that babies live in have vast temp differences from day and night. But it does mean the air temp above these microclimates falls at night causing the dew point.
Even in South America in Bahia where it is a dryer climate than let's say Suriname its only 40% in the day and 85f, it increases to 90% and down to 70f at night. In the microclimate at ground level it will be 100%(dew point).
Or in Madagascar when it's 60% and 90f in the day then 85% and 75f at night the microclimates we are interested in will be 100%.
These micro climates will be relatively stable compared to the open climates that endure the full force of weather, wind, rain and sun.

I have a friend who lives in Brazil, he is adamant that baby redfoots bask in the morning and says this is why only 2 or 3 survive out of 100s. It's the risk they have to take but a predators buffet. He's on the task of getting me photos of this.
Maybe the microclimates that have 100% RH for most part makes basking for an hour in the morning and in the evening not harsh enough to dry the carapace to the point of pyramiding.

How's it all relevant to night time lows, if there is no highs and lows, there is no dew. This doesn't mean there has to be highs and lows in the microclimates but in the open climates above to create dew that maintains the microclimates for smooth growth.
Giant Galapagos do endure heat of the sun and obviously when the sun goes down so does the suns heat. But what about the baby Galapagos that are hidden away, they don't endure the day/night open climate like the adults have to endure. Do you think these baby Galapagos have 100% RH at night then bask for an hour in the morning or not?

Below is an interesting link.

http://biomet.ucdavis.edu/frostprotection/Measure Dewpoint/fp003.html