What is the physiology behind pyramiding?

[mikeh]

I'd like to go back to keratin mechanics and effect of moisture. Are keratin mechanics same in all species? Aren't some tropical species such as some red/yellow foots, manouria, wood turtles etc, exposed to constant moisture and high humid levels?
I also would like to ask specifically about manouria scutes, but have seen this in red foots as well. I have asked this some time back but it hasnt been fully explained.
I have been raising two emys emys in high moisture/humid environment. (90+% humidity and moist) I have observed when removed from this environment, even slightly, or if the humidity drops to 70-80% humidity range which is still moderate, ends of their scutes noticeably swell upward within an hour or so. They remain swelled until the carapace is moistened and reintroduced back to high levels of humidity. This again takes about an hour or longer.
What is happening there? And is this "working" of the scutes normal in long run. Should I keep them in this high humidity state, alternate humidity or slowly reduce the humidity?

Below an image of scute while moist and exposed to high humidity. They remain very smooth and flat.
View attachment 65257

And an image of the same tortoise after an hour of experiencing lower but still moderate humidity. The ends of scute noticeably raise and white/silverish lines appear between the scutes.

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Insert didn't work, here it is again, with scutes flat, under moist conditions.

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I am also including a picture from Google, of adult WC emys emys. I believe they belong to one of the members here. It can be seen that all their scute are "sunken". Is it possible same mechanics created this "raised" ends of the scutes rather then being sunken as many times its believed.

 

[Testudoresearch]

I'd like to go back to keratin mechanics and effect of moisture. Are keratin mechanics same in all species? Aren't some tropical species such as some red/yellow foots, manouria, wood turtles etc, exposed to constant moisture and high humid levels?
I also would like to ask specifically about manouria scutes, but have seen this in red foots as well. I have asked this some time back but it hasnt been fully explained.
I have been raising two emys emys in high moisture/humid environment. (90+% humidity and moist) I have observed when removed from this environment, even slightly, or if the humidity drops to 70-80% humidity range which is still moderate, ends of their scutes noticeably swell upward within an hour or so. They remain swelled until the carapace is moistened and reintroduced back to high levels of humidity. This again takes about an hour or longer.
What is happening there? And is this "working" of the scutes normal in long run. Should I keep them in this high humidity state, alternate humidity or slowly reduce the humidity?

Excellent question.

First, yes - in general terms the mechanical properties of terrestrial chelonian keratins are identical across species - however, different species do have some differences in typical scute thickness, apparently in 'hardness' and in color (of course). All are hygroscopic, for example, and all are stiffer/harder when dryer than when wet. The manner of cell proliferation is also (as far as is known) identical across species.

Scute thickness is of itself an interesting topic. Some species do have quite thick scutes, others are thinner and more 'fragile'. Even within say, Testudo, there are quite substantial differences between Turkish-origin Testudo ibera and North African origin Testudo graeca graeca, with the former typically possessing thicker, more 'hard wearing' scutes, than the latter. Also, in the wild, natural abrasion occurs and this is rarely the case in captivity - so you can very often find CB examples of the very same species with thicker accumulated keratin scutes than a wild example of the same age. Thickness matters because a thick 'sheet' of keratin will respond differently to hydration conditions than a thin sheet, and will exert quite substantially different stresses upon any connected tissue (underlying bone, for example).

Manouria is a fascinating case, and I have personally observed the same thing you are reporting. For example, in this tortoise, where you can see a kind of "dishing" of concavity in the vertebrals, and the same rise at the edges elsewhere:

The skeletal structure of Manouria impressa is, I suspect, particularly vulnerable to these influences of keratin, as the bones are very thin, and are extensively fenestrated (they have gaps and holes between the boney plates, rather than being completely fused). It is logical that this provides less of a 'firm anchor' to the scutes than does a heavily built, fully fused carapace skeleton (as seen in most other genera). The fast reaction to differing levels of hydration therefore makes sense. There is "less to hold them down" in simple terms. Less resistance than you would find, in say, a T. graeca or Geochelone pardalis.

Is this "working of the scutes normal"?

I don't know. They must experience changes in humidity and "wetness" in the wild, and clearly, the keratin and skeleton would respond in the same way.. but how much? This is another case where more extensive field-data might provide some definitive answers.

Unfortunately, a lot of field-workers just don't bother (for various reasons) to collect the kind of data that would be of most use to those of us involved in captive maintenance.

Thanks for highlighting this species. Fascinating! It is a wonderful example of humidity-induced dimensional changes in keratin in the chelonia.

 

[paludarium]

Over-feeding with highly digestible foods that lack long fibers on the kind of scale seen above are major problem areas when using artificial diets. Dietary fiber content achieved in these pens is 35-40%. Many captive diets are 12% or less, and even the best of them rarely exceeds 20%. Even then, fiber length is much shorter (due to production methods). More energy is extracted from these chopped, short fibers, prompting more rapid growth... with the consequent problems that brings. Energy release from very long fibers is much slower and more restricted. Another example of "more is not always better".

I don't think the following researches supported the concept that tortoises must be restricted to high-fiber diets.

In the study Body Size Development of Captive and Free-Ranging Leopard Tortoises (Geochelone pardalis), the leopard tortoises were kept in enclosures with a natural vegetation of grasses and small shrubs with a regular supplement of a variety of vegetables (tomato, carrot, bell pepper, zucchini, cucumber and pumpkin), fruits (melon, papaya, grapes, apple, pear, berries, banana and cactus fruits), fresh lucerne (Medicago sativa), fresh grasses, browse (Ziziphus spina-christis), flowers and grass hay ad libitum. Although the authors noted in the introduction that a growth rate exceeding that of natural populations was suspected to occur in many captive and pet tortoises, with potential pathological consequences such as obesity, high mortality, gastrointestinal illnesses, renal diseases, pyramiding, fibrous osteodystrophy or metabolic bone disease. However, the authors wrote down in the discussion that whether faster growth rates were actually linked to health problems could, so far, only be speculated upon. Although there appeared to be a consensus in this respect in the reptile literature, experimental evidence was lacking. Therefore the authors could only conclude that although experimental evidence for a negative effect of fast growth on health of tortoises or reptiles was lacking, these observations suggested that in order to mimic conditions in the wild, feeding regimes in captivity should be restricted.

In the study Nutritional Quality of Natural Foods of juvenile Desert Tortoises (Gopherus agassizii): Energy, Nitrogen, and Fiber Digestibility the authors found that tortoises lost mass and shell volume when eating grasses but gained mass and volume when eating forbs. This was partly a result of the lower availability of nutrients in dry grasses. However, voluntary intake rates for grasses were far lower than rates for forbs. That means the young tortoises did not like diets higher in fiber like grasses and they consequently lost their body weight after eating grasses. Why would a healthy tortoise lose its weight?

In the american study Food Habits and Selective Foraging by the Texas Tortoise (Gopherus berlandieri), the Male and female tortoise fecal samples had 2.12% and 6.83% animal fragments, respectively. However, the juvenile tortoises had 9.4% animal fragments. The dietary differences between adult and juvenile tortoises were significant. In another research conducted in Algeria Food choice of an Algerian population of the spurthighed tortoise, Testudo graeca, the authors found the undermined invertebrates in 0.36%, 3.10% and 7.21% in the stool fragments of male, female and juvenile tortoises, respectively. The authors wrote that invertebrates were consumed occasionally, especially by juveniles. Juveniles probably ate invertebrates of their high protein contents, which may help juvenile grow. The presence of invertebrates in diets of herbivorous tortoises was a widespread occurrence. And in agreement with their study, juveniles of other terrestrial and freshwater chelonians were more carnivorous than their adults.

Based upon the above facts and evidence, I would not come to a conclusion that the tortoises should refrain form eating animal matters. Instead I would focus on when can a juvenile tortoise eat animal matters and how many of them.

Erich

 

[FLINTUS]

I am curious by saying it is the same with Kinixys. I have only seen pictures of 3 properly pyramided kinixys species. A lobatsiana, a homeana which went very white and a nogueyi-the latter was thought of as a Russian. They seem to stay smooth even with poor care, but I would be interested to see a cross section of a smooth, captive one. I have seen a few slightly raised scutes on others, but most people would still interpret it as 'smooth'. They also seem to grow differently to other species. With my reds, and other species I have observed, you have clear white growth lines in periods of fast growth. With my erosa, the scutes kind of move apart to form a small depression which is later filled in with new growth which looks the same as the old. I will try and get some pics when I get back on Monday.

Camera was broken but Andy, any opinion on this? Since you were talking about how the scutes vary so much for every species.

 

[Yellow Turtle]

I would concentrate on keeping species that better suit your environment. I would not try to keep tropical turtles where I live (in a semi-arid habitat bordering a true desert). You will always be fighting the environment... not working with it. That is just my personal view...

It can be easier to create a humid area in a dry environment than the other way around, too....that can be very difficult. The only species I now keep are those that occur within the same bioclimatic zone that I actually live in. I used to keep many different species, but now, concentrate on just those that are best suited to the climate where I am located.

I will check on this. So far I've know 1 hobbyist who successfully breeds hermanni tortoise with our climate. Also I was told by 1 of senior member here that hermanni would match our environment pretty good compares to others.

 

[Testudoresearch]

I don't think the following researches supported the concept that tortoises must be restricted to high-fiber diets.

.....
Based upon the above facts and evidence, I would not come to a conclusion that the tortoises should refrain form eating animal matters. Instead I would focus on when can a juvenile tortoise eat animal matters and how many of them.

Erich

I would suggest that rather than try to find extremely obscure pieces of research that support opinions you already hold, and that you consistently misinterpret anyway (evidently not even having read anything except the abstract), start with some of the work on chelonian nutrition by acknowledged specialists like Susan Donoghue. Her contribution to Douglas Mader's "Reptile Medicine & Surgery" is classic, and excellent. If you want to understand this subject, there is no better place to start.

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I am curious by saying it is the same with Kinixys. I have only seen pictures of 3 properly pyramided kinixys species. A lobatsiana, a homeana which went very white and a nogueyi-the latter was thought of as a Russian. They seem to stay smooth even with poor care, but I would be interested to see a cross section of a smooth, captive one. I have seen a few slightly raised scutes on others, but most people would still interpret it as 'smooth'. They also seem to grow differently to other species. With my reds, and other species I have observed, you have clear white growth lines in periods of fast growth. With my erosa, the scutes kind of move apart to form a small depression which is later filled in with new growth which looks the same as the old. I will try and get some pics when I get back on Monday.

Camera was broken but Andy, any opinion on this? Since you were talking about how the scutes vary so much for every species.

A few examples for people who may not be familiar with these:

There are certain visual similarities with M. impressa on the face of it.. similar scutes, and - you also see that 'dip' or concavity in some. I have a couple of Kinixys skeletons on loan to someone, and will try to get some photos of them in the next couple of weeks. They are not fenestrated, however, but rather fused (apart from the rear section, obviously!). Flintus, I do have some photos of 'pyramided' Kinixys, but I'll have to dig them out and scan them. They are still on 35mm transparencies. You will see many 'convergent' features between species that occupy similar habitats, of course... moist forest vs. desert, for example, simply because those features are advantageous in those habitats. Also many species are trying to "balance" function with camouflage and other factors such as thermoregulation or the prevention of dehydration. The latter is critical to arid habitat species, but rarely a pressing matter for a tortoise from a moist rainforest.

 

[Sulcata_Sandy]

I have a juvenile G. carbonaria I acquired in very poor condition: Severely dehydrated, disturbingly light, soft plastron, and dished vertebral scutes. I've had her several months now, and other than being very shy, she's gaining weight and thriving.

Would dehydration in this sp. cause inverted scutes? And with proper environment/diet, do you suspect her scutes will become normal in shape, or will they remain dished from that growth ring and normal after?


Photo taken a week after receiving her. Unfortunately, it really does not depict how dished her scutes are. They are not too severe, but definitely abnormal. She is also very stunted for her alleged age of 2 years. I argue she is much younger, but the previous owner was quite sure of the timing he obtained her.

 

[Testudoresearch]

I think it is important we separate two distinct things.

Dehydration, which refers to the state of the entire animal, where an excessive loss of body fluids occurs, exceeding the amount taken in...

and

External over-drying, which refers to localised conditions in the epidermis and which can be entirely unrelated to the general state of hydration.

It is this latter that affects the scutes. If the underlying bone is suffering from any form of MBD, or lack of calcium or D3 ("soft shell syndrome"), then it will deform far more readily than a healthier, well formed skeleton. That tortoise looks to me to have had periods of quite rapid growth, and if the husbandry was very poor, I would think it highly likely some MBD exists.

I am sure in your capable hands, with a good environment and nutrition, it should improve substantially.

 

[FLINTUS]

I don't think the following researches supported the concept that tortoises must be restricted to high-fiber diets.

.....
Based upon the above facts and evidence, I would not come to a conclusion that the tortoises should refrain form eating animal matters. Instead I would focus on when can a juvenile tortoise eat animal matters and how many of them.

Erich

I would suggest that rather than try to find extremely obscure pieces of research that support opinions you already hold, and that you consistently misinterpret anyway (evidently not even having read anything except the abstract), start with some of the work on chelonian nutrition by acknowledged specialists like Susan Donoghue. Her contribution to Douglas Mader's "Reptile Medicine & Surgery" is classic, and excellent. If you want to understand this subject, there is no better place to start.

---

I am curious by saying it is the same with Kinixys. I have only seen pictures of 3 properly pyramided kinixys species. A lobatsiana, a homeana which went very white and a nogueyi-the latter was thought of as a Russian. They seem to stay smooth even with poor care, but I would be interested to see a cross section of a smooth, captive one. I have seen a few slightly raised scutes on others, but most people would still interpret it as 'smooth'. They also seem to grow differently to other species. With my reds, and other species I have observed, you have clear white growth lines in periods of fast growth. With my erosa, the scutes kind of move apart to form a small depression which is later filled in with new growth which looks the same as the old. I will try and get some pics when I get back on Monday.

Camera was broken but Andy, any opinion on this? Since you were talking about how the scutes vary so much for every species.

A few examples for people who may not be familiar with these:

There are certain visual similarities with M. impressa on the face of it.. similar scutes, and - you also see that 'dip' or concavity in some. I have a couple of Kinixys skeletons on loan to someone, and will try to get some photos of them in the next couple of weeks. They are not fenestrated, however, but rather fused (apart from the rear section, obviously!). Flintus, I do have some photos of 'pyramided' Kinixys, but I'll have to dig them out and scan them. They are still on 35mm transparencies. You will see many 'convergent' features between species that occupy similar habitats, of course... moist forest vs. desert, for example, simply because those features are advantageous in those habitats. Also many species are trying to "balance" function with camouflage and other factors such as thermoregulation or the prevention of dehydration. The latter is critical to arid habitat species, but rarely a pressing matter for a tortoise from a moist rainforest.

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Ah, yes it definitely gives a 'fusing' look. Oak(21 cm SCL male, LTC for approaching 4 years or so, has lived OUTSIDE a lot at both his previous owner in Scotland and here, they are very cold tolerant) is probably the best example I have seen recently for this. He has both the 'broken' look of #1 and the 'gap filling' of #3. It is always more obvious after animal matter has been fed but no surprise there as it creates faster growth. As I said, camera is broken but I will try and get some pics with my iphone-but it might not give a clear image.

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Also, what species is that baby at the bottom? It looks homeana but I can't remember you ever doing an article on homeana alone, so if not is that another picture of Ashley Woods' erosa hatchlings? Any chance of some newer pics of them as they grew up as there are very few captive successful breeding and incubation of them outside their home range.

 

[paludarium]

If you adopt a diet (for a herbivorous tortoise) that offers:

a) High fiber (aim for >30%)
b) High calcium, low phosphorus (>5:1 minimum, preferably >8:1)
b) Wet basis protein levels in the 4-5% range (DM circa 9%)
c) Avoids highly fermentable carbohydrates/starches

and

d) Provide adequate UVB
e) A suitable thermal environment
f) Adequate space and exercise and avoid overfeeding

.... you will, generally, be absolutely fine.

In his book Tortoises (Complete Herp Care) E.J. Pirog also points out that "many experienced keepers suggest limiting protein by feeding a high-fiber/low-protein diet. Inexperienced keepers who follow this advice commenly end up with a malformed tortoises or a tortoise that is not growing properly, because protein is extremely important for proper growth, development and...". Obviously I am not a loner on the issue of protein.

Do tortoises need high-calcium diets to prevent pyramiding? I don't think the following researches back up that theory.

In the study Calcium and phosphorus supplementation decreases growth, but does not induce pyramiding, in young red-eared sliders (Trachemys scripta elegans), the author found that in red-eared sliders shell pyramiding could not be induced in young turtles by supplementation with dietary Ca and/or P at levels between 1.16–2.95% Ca and 0.92–2.56% P, but that supplementation with Ca alone at 2.24% was detrimental to normal growth and development in young red-eared sliders. Pyramiding was not induced in any group during this study, with all turtles having shells of normal shape and appearance. Ok, I know that a red-eared slider is by no means a tortoise...

In the study Influence of the calcium content of the diet offered to leopard tortoises (Geochelone pardalis), the authors found no shell distortion, including pyramidal doming even in the group 1 (without calcium supplement) and group 2 (with the calcium supplement at the recommended dose). Pyramiding was one issue, health problem was quite another. In addition, the authors also noted that the calcium supplementation of group 3 (three times the recommended calcium supplementation) and group 4 (nine times the recommended calcium supplementation) was shown to have been excessive, as metastatic calcifications were observed. However, the tortoises in the study were offered a basic diet, relatively poor in calcium, consisting of a mixture of chopped vegetables such as carrots, iceberg lettuce, cucumber, sweet peppers, tomatoes and hay. Besides, each group received the same quantity of a supplement containing vitamins and minerals(with phosphorus). Unfortunately the authors did not show us the exact rations of Ca to P in the diets of all groups. However, most of the food items were not rich in calcium but phosphorus, and I speculated that the Ca to P might have been even less 1 in the group 2.

In the study Influence of different dietary calcium levels on the digestibility of Ca, Mg and P in Hermann's tortoises (Testudo hermanni) the authors found that the relative difference between the digestibility of oraganic matters between diet I and diet II was not significant. However the authors suggested that it might be prudent to feed a lower yet adequate level of dietary Ca, because higher levels might risk the pathologic accumulation of calcium somewhere in the animal.

Indeed I did not find any evidence that a healthy tortoise really needed Ca to P >5:1 minimum and preferably >8:1.

Erich

 

[Testudoresearch]

If you adopt a diet (for a herbivorous tortoise) that offers:

a) High fiber (aim for >30%)
b) High calcium, low phosphorus (>5:1 minimum, preferably >8:1)
b) Wet basis protein levels in the 4-5% range (DM circa 9%)
c) Avoids highly fermentable carbohydrates/starches

and

d) Provide adequate UVB
e) A suitable thermal environment
f) Adequate space and exercise and avoid overfeeding

.... you will, generally, be absolutely fine.

In his book Tortoises (Complete Herp Care) E.J. Pirog also points out that "many experienced keepers suggest limiting protein by feeding a high-fiber/low-protein diet. Inexperienced keepers who follow this advice commenly end up with a malformed tortoises or a tortoise that is not growing properly, because protein is extremely important for proper growth, development and...". Obviously I am not a loner on the issue of protein.

Oh, please...

Enough. I have already suggested a very well regarded introduction to chelonian diets and nutrition you should read (and preferably try to understand) first before inventing more any more "way out" scenarios and before citing yet more references you have not even read and understood adequately.

You are adding nothing of any value to this debate whatsoever. No-one is suggesting (or ever has) that protein is not of importance. There are three thresholds: too low, within range, and excessive. The consequences of excessive amounts are well documented: gout, renal damage, excess growth typically with consequential MBD. Most arid habitat tortoises have highly efficient digestive systems (microbial fermentation based) that are capable of extracting very adequate nutrition from what are (in mammalian terms) "poor quality" diets. Goats are a valid comparison. No-one has ever suggested "depriving" tortoises of levels that they perfectly obviously do extremely well on.... we have a lot of data on these levels. You have repeatedly made assertions that have no factual basis whatever.

If you wish to make any relevant or intelligent comments I will be pleased to respond to them. I am far too busy to waste time debating pure nonsense with you, however.

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Also, what species is that baby at the bottom? It looks homeana but I can't remember you ever doing an article on homeana alone, so if not is that another picture of Ashley Woods' erosa hatchlings? Any chance of some newer pics of them as they grew up as there are very few captive successful breeding and incubation of them outside their home range.

Captive-bred (UK) Kinixys erosa, though not one of Ashley's....

As I recall, I took that photo at about 8-10 weeks.

 

[Testudoresearch]

For anyone who is becoming confused by the mass of spurious and misinterpreted arguments on protein (above), it is helpful to go right back to basics. There are some incontrovertible physiological and ecological facts that determine tortoise diets.

1. A tortoises’ kidney structure is much more primitive than that of a mammal. The kidneys themselves are elongated and lobed, and are flattened against the carapace wall. In reptiles there are very few nephrons present compared to approximately a million nephrons in a typical mammal. Tortoises cannot concentrate urine in the same way that mammals can (they lack an organ known as the ‘loop of Henle’), so they cannot eliminate dissolved metabolic wastes such as ammonia and urea without losing a considerable volume of water. This is not so important to aquatic or rain forest species, but is a critical limiting factor to desert and arid habitat tortoises. Wastes from arid habitat species are normally excreted in the form of uric acid and urate salts. Aquatic and semi-aquatic turtles have free access to water, so are able to produce ammonia instead. The relationship between the proportions of ammonia to uric acid generated by individual species closely mirrors the environments they come from. As habitats become moister, the shift from water-conserving uric acid elimination to water-intensive ammonia elimination is quite marked.

2. The dietary shift from higher protein to lower protein intakes also reflects environmental constraints, particularly free water availability. So, you find omnivorous and carnivorous species in habitats where water is relatively abundant, and herbivorous species in habitats where water is scarce. This is not mere chance or coincidence. It is a absolute constraint imposed by the fact that processing high protein intakes requires access to significant quantities of free water. Alligators and crocodiles have no problem with this, because they have plenty of water available. A desert tortoise does not, and consequently is not equipped to deal with it. Their entire physiology and biology has developed to deal with a lower protein intake that requires minimal amounts of water availability. Try to think of a carnivorous desert tortoise....

3. Urine pH is also a very useful indicator of whether protein intakes are about right, or too high. We do not have to guess at this. The pH of the urine of healthy tortoises fed on herbivorous diets is typically alkaline, while the urine pH in tortoises with a high protein intakes becomes acidic - a state also associated with renal disease in these species. Uric acid crystals are also present at high concentrations in species fed on elevated protein intakes. This is also an extremely unhealthy condition. Again, this is objective data. Measurable and repeatable.

This is a simplified explanation, but nonetheless it needs to be taken into account whenever claims are being made that are inconsistent with this key area of chelonian physiology. These 'rules' do not just become irrelevant, or find themselves suspended in some way.... the renal system of tortoises is what it is, and they cannot easily be over-ridden. This is why extreme skepticism needs to be exercised when people make claims to the contrary or which apparently conflict with these basic 'rules'.

If you feed a high protein diet to a species that is ill-equipped to deal with it, and you maintain a very good state of general hydration, you might just be able to avoid some of the consequences (gout, for example). You will not avoid them all, however. Massively accelerated growth, for example.

My position on this is very clear. I believe we should aim for diets that are safe in both theory and in practice, and which it can be demonstrated are capable of sustaining healthy growth over multiple generations.

 

[FLINTUS]

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Also, what species is that baby at the bottom? It looks homeana but I can't remember you ever doing an article on homeana alone, so if not is that another picture of Ashley Woods' erosa hatchlings? Any chance of some newer pics of them as they grew up as there are very few captive successful breeding and incubation of them outside their home range.

Captive-bred (UK) Kinixys erosa, though not one of Ashley's....

As I recall, I took that photo at about 8-10 weeks.

---

Did you breed them then? Or do you have contact details of who did? Sorry but CB kinixys erosa are so rare, I thought Ashley was the only person to have bred them here.

 

[Testudoresearch]

Did you breed them then? Or do you have contact details of who did? Sorry but CB kinixys erosa are so rare, I thought Ashley was the only person to have bred them here.

That particular one was hatched by my old friend John Dickson when he was curator of reptiles at Bristol Zoo many years ago. There have been a few others too.

Certainly not a common event, but it has been done a few times. I do have incubation data for that one, incidentally. It was incubated in a moist 'jar' at around 80% RH at roughly 31C on vermiculite (notes on slide). As with many reputedly 'difficult' species, much depends on having a healthy, truly compatible pair in the first place. If you manage that, you are 90% of the way there, in my experience.

 

[Testudoresearch]

I am curious by saying it is the same with Kinixys. I have only seen pictures of 3 properly pyramided kinixys species

A couple for your collection.

Prime examples, at that...

 

[FLINTUS]

Thanks for that. Always good to have more information on incubation for these.
Those are really heavily pyramided, although it still does seem they are harder to get pyramiding signs for MBD compared to other species. In fact, those guys are so pyramided it is hard to tell the species? Not homeana or erosa and looks too patterned and orange for nogueyi, too high for spekii, so I might guess at zombensis or Madagascan?

 

[Testudoresearch]

In fact, those guys are so pyramided it is hard to tell the species? Not homeana or erosa and looks too patterned and orange for nogueyi, too high for spekii, so I might guess at zombensis or Madagascan?

Kinixys belliana belliana in Kwa-Zulu Natal, South Africa. Wild caught as small juvenile, then raised in captivity. Unfortunately on a diet of dog food and fruit, with some use of basking lamp (non-UVB).

Just shows... if you try hard enough, you can even mess up tortoises despite living in their natural habitat.....

 

[FLINTUS]

They're really colorful for belliana, but then again as you said they were raised really badly by the looks of it. Surely it would've been better to keep them outside due to the climate there?
Actually, speaking of climate, I was reading something from some South African reptile owners the other day advising someone to hibernate her hingeback-didn't say which species- as this is what they do. Now I know it has been suspected that the S.African(and from Botswana and Namibia I believe) brumate during winter, but as far as I know there have been no actual studies of hibernation of them-at least ones published in books or on the web.

 

[paludarium]

The problem is that you can have what appear to be very smooth tortoises externally, but which internally, have very poor bone mineral density - with fibrous lesions and poor mass. So, establishing the condition of bones generated under various husbandry regimes is absolutely critical. Yet, it is rarely done.

It is intriguing that so many keepers hold totally contradictory views on these matters. On the one hand, we have people who say that Leopard and Sulcata tortoises need this super high humidity regime, but Testudo do not... and then other keepers who enthusiastically argue the exact opposite. What I think many miss is that in the paper by Weisner and Iben (cited extensively by Richard Fife), they did not limit their argument to G. sulcata, but claimed it affected multiple species: "Many species of tortoises live most of their lives hidden either in caves (e.g. Testudo horsfieldii, Gopherus sp.) or on the ground surrounded by high humidity even during arid conditions”.

Unfortunately, this is plain wrong. It is useful they included Gopherus, because we have superb microclimate data for this species, including burrow humidity throughout the year. In the most detailed and comprehensive study yet carried out on Desert tortoise burrows in Nevada, Bulova (2002) established accurate environmental data for more than 70 individual burrows over an extended period and recorded burrow relative humidity levels ranging from 6.1 to 44.5%, compared to surface relative humidity levels of 4.1 to 32.2%. Other data, from other researchers in various localities for these species totally confirms this. This data conclusively destroys the argument that these tortoises experience sustained levels of RH above 80% in nature (the authors of that paper actually recommend provision of RH up to 100%!!)

There is no doubt, however, that humidity affects tortoises, and can influence the way in which a carapace develops. This is where physiology and ecology collide, and where the answers are to be found.

The paper by Weisner and Iben was neither a field research nor a retrospective review, it was indeed a prospective study or a controlled trial. I agreed with Dr. Sue Donahue that further work is needed to replicate these results, determine mineral balance (acid-base balance) under dry and humid conditions, and examine the carapacial tissue histologically. Richard Fife was one of the first but not the only keeper who replicated the results. It has been 10 years since Weisner and Iben published their study, thousands of tortoises have been raising with high humidity regime, how could we have missed any study regarding its adverse outcome. Trying to explain why and how is quite another issue.


Field researches unveiled some facts and provided us some information, but the data collected from the field have to be interpreted cautiously.

Apparently you missed or ignored some important information in the study How temperature, humidity, and burrow selection affect evaporative water loss in desert tortoises. According to Bulova, the subjects in the study were 28 adult individuals (body mass > 1600 g) and the 74 burrows selected were for the adult tortoises. The adult tortoises were not as vulnerable as the juveniles to dehydration, and they used different burrows in the wild. In the study Characteristics of Burrows Used by Juvenile and Neonate Desert Tortoises (Gopherus agassizii) during Hibernation the author observed that burrows used by juveniles were significant larger thant neonate burrows, and burrow height and width were both significant correlated with tortoises size.

The author did not measure microclimate of occupied burrows but the unoccupied burrows, because the presence of a tortoises might change burrow humidity. So there were no tortoises inside when she measured the 74 individual burrows, which showed relative humidity(RH) levels ranging from 6.1-44.5%. By the way, the RH levels were measured between 1000-1200 h from July to September in 1993, by no means throughout the year! I would never expect the RH to be high near to noon with the ambient temperature 33.5-46.0 degree celcius, and those data were not representative of humidity variations over 24 hr in the burrows. The author literally measured 4 burrows for 24 hr from 20 July 1100 hr to 1100 hr 21 July in 1993, and the range of RH fluctuated by 7.2-15.5%. With the sample size of 4 burrows and the measurement of RH for only 1 day, were those information representative of the that habitat? I don't think so. The author also observed that the tortoises passed burrows before entering others and entered and subsequently left burrows. Both observations suggested that not all burrows were suitable for use by a given tortoise at a given time. Unfortunately we did not know whether the tortoises actually utilized them or not, not to mention that the author did not show us the real humidity variations in the burrows where the tortoises indeed stayed overnight.

With all the limitations in her study, I would only come to a conclusion that between 1000-1200 h humidity was significant higher and temperature lower inside burrows than on the surface.

Erich

 

[Testudoresearch]

The paper by Weisner and Iben was neither a field research nor a retrospective review, it was indeed a prospective study or a controlled trial.

Simple question.

Do you find the methodology used in that study valid and acceptable?

Second question.

Define:

Low humidity (typical range)
High humidity (typical range)

Apparently you missed or ignored some important information in the study How temperature, humidity, and burrow selection affect evaporative water loss in desert tortoises. According to Bulova, the subjects in the study were 28 adult individuals (body mass > 1600 g) and the 74 burrows selected were for the adult tortoises. The adult tortoises were not as vulnerable as the juveniles to dehydration, and they used different burrows in the wild. In the study Characteristics of Burrows Used by Juvenile and Neonate Desert Tortoises (Gopherus agassizii) during Hibernation the author observed that burrows used by juveniles were significant larger thant neonate burrows, and burrow height and width were both significant correlated with tortoises size.

I did not miss anything... I am extremely familiar with the paper. I have also measured burrows and scrapes in multiple locations, including Arizona with Gopherus, and throughout the Mediterranean. The suggestion - if that is what you really are trying to suggest - that the RH in these burrows approaches 100% on a regular or routine basis is absolutely ridiculous. It simply does not happen like that. I have taken (using data loggers) over 25,000 measurements in such burrows to date over a continuous 4 year period at all times of year, and the typical range is 40-60%. You only have to visit these habitats to know why this is the case, and why suggestions of 80, 90 or 100% are just so plain silly and totally impossible it should not even be up for discussion.

FYI, we measured active, occupied burrows in Morocco as far back as 1996 and published the results(1). The results:

"burrow humidity rarely exceeded 60% and was typically 50% or less compared to external ambient air humidity levels of approximately 20%.... Burrow humidity was often sustained below 45% for extended periods during peak periods of tortoise activity and growth in the Spring period, and reduced to 40% or less in June, July and August....Shallow tortoise scrapes possessed marginally higher relative humidities than the prevailing ambient conditions, but not by much, typically by less than 5% over ambient (scrapes are far less efficient at sustaining a stable temperature and higher localised humidity than are true burrows). It is also necessary to point out that tortoises using such scrapes tend to only partly bury themselves, primarily covering the front limbs and head, leaving the vast majority of the carapace fully exposed and therefore entirely subject to the prevailing ambient conditions of temperature and humidity"

Fact. Based on real measurements. Not guesswork and speculation.

One of the burrows in Morocco:

Tortoise burrow in Florida also studied and measured:

How much time have you personally spent in arid and semi-arid habitats? Where is your data? Photos? Evidence that supports the claims you make? Not second-hand or anecdotal. YOUR data - please?


(1) Highfield, A. C. and Bayley, J. R (1996) Observations on ecological changes threatening a population of Testudo graeca graeca in the Souss Valley, southern Morocco. Chel. Cons. Biol. 2(1):36-42