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The CAUSE of Pyramiding

Discussion in 'Advanced Tortoise Topics' started by Markw84, Jul 6, 2016.

  1. Markw84

    Markw84 Well-Known Member 5 Year Member

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    1. I just posted this on anther thread, but as it developed, I thought the title of that thread took away from the message and was best in a thread of its own titled appropriately.


    1. I have come to believe through all my trial and error, all the things I read and study, all the experiments done - heat, no heat, night heat, no night heat, fast growth, slow growth, higher protein, more calcium, better UVB, on, and on, and on - all to me only fit one basic take on this. I can't imagine a variable that hasn't been tried, yet all do fit one conclusion. Pyramiding is seen when you have high metabolism triggered WITHOUT humidity. If you give the tortoise higher heat and more food, without humidity, you will get Pyramiding.

      If I think about the tortoise in its natural environment, they ENDURE periods of food scarcity, and hot, dry weather. They basically stop growing and estivate during these periods to survive - waiting for the time to thrive. When the monsoons come, they have ample food with the rains and humidity. They grow in those conditions. They don't grow in food-scarce, dry conditions. It's really logical - food is available when it is wetter allowing the food to grow. So warm + humid = grow time. In dry times, the food dries up, and tortoises stop growing. It's when we create an artificial condition they would never see naturally in their home environments that we see pyramiding. We provide ample food and heat & UVB in DRY conditions. We get their metabolism going, yet without one key ingredient - proper hydration. So they grow, but don't grow naturally.

      Sulcatas seem to follow this pattern the most strictly. It seems where they come from, when it dries up, there is no water available, nor food, so they go in a real slow or no growth mode in those dry times. If you look at leopards and stars, some seem get pyramided in the wild. But they also come from areas where it may end up a dry year, but water sources may linger longer into dry periods, and I believe you would see tortoises (especially growing their first few years) through abnormally dry years - actually finding food and growing in dry conditions - and pyramiding.

      3 1/2 months ago now I got a group of Burmese Stars from the Behler Center. Their philosophy is to purposely slow grow their Star tortoises a bit along the belief that fast growth would lead to more pyramiding. I got them and they were pretty significantly pyramided and quite small for their age. So despite purposeful slow growth in conditions meant to more mimic a natural environment temperature wise - They pyramided. The humidity in their enclosures was always quite low. They do keep other species in greenhouses with controlled humidity, but the Burmese are kept drier. The average weight of the goup when they arrived was 454.2 grams despite being just over 5 years old. I have since convinced them the monsoon season has finally arrived, with a closed chamber I posted my build in that was a basic copy of @Tom 's chambers. So in 3 1/2 months the group had now averaged adding 301.8 grams! So the average for the group was going from 454 g (in five years) to 756 g in 3 1/2 more months. So, I grew them too fast and they will surely pyramid after 5 years of a set growth pattern - right? NO! All the new growth is coming in flat. Here's a picture I just went out to take of the growth pattern you can see in one of them...

      [​IMG]


      For me this continues to confirm that fast growth has nothing to do with pyramiding. This study this thread is about says high heat may cause pyramiding. While actually, my closed chamber is in my second garage that the past several weeks has been close to 93 dropping to 80 at night. The chamber constantly struggled to stay in the low 90's as I had to put the basking lights on a separate thermostat to turn off at 90 to avoid overheating. Their nighttime temps averaged 85. Despite this higher heat, faster growth, AND 5 years of a pyramiding growth pattern in a drier environment - I saw immediate change in growth pattern and what looks to be a total stop to the pyramiding. I did not expect to see it so immediate!

    1. For me - I'm still convinced more than ever, if they grow - it must be humid!

    After posting that, @mark1 posted a reply mentioning what he had learned in a study about the growth of keratin in horns in cattle. He referenced that article - I read it and a the light bulb went on in my head...

    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3574435/

    NOW THAT'S INTERESTING AND SHOWS CAUSE FOR PYRAMIDING!!!

    According to that study, keratin, while forming, if exposed to dry conditions will become more stiff and resistant to additional swelling if later exposed to water, while hydrated keratin will swell more resulting in a thicker layer.

    I just seems to me all this mystery about pyramiding causes could be something simple. What would fit all scenarios is that the keratin as it fills in over new growth areas, will stiffen, and become resistant to filling in in a thicker layer above, yet add additional keratin below. That would cause downward growth with successive layer. As the bone growth beneath (especially in younger tortoises) is much more pliable, it would follow this growth pattern. However when kept in a moist environment, the keratin retains it ability to swell and add volume to the new scute in a more even, top to bottom, profile. Thus an even, straight growth pattern.

    Everything would fit this... extremely slow growth would not pyramid and the keratin layer is barely filling in over new bone and this effect does not have a chance to happen. However, whenever there is faster growth, the larger new bone area we all see as those white lines in many species, will require faster keratin growth as well to follow. If in a dry environment, this effect will then cause the keratin to push the bone downward as the top layer of keratin becomes stiffer much faster than the bottom of the keratin. Through measurements over the years I had always believed pyramiding was not an UPWARD growth of the scute, but a downward growth of the seams. A pyramided tortoise most always measured just as tall to the top of the pyramid as a smooth tortoise is to the top of the smooth shell. So valleys are forming, not peaks.

    Every scenario we have seen of pyramiding vs no pyramiding, including this study, exactly fits this proposed cause.

    A few more responses were posted, and I explained my hypothesis further. Asked if that meant I was proposing "the shell needs moisture to grow properly in the up and out direction? That without the moisture it may stiffen too quick, causing the growth to pyramid?" I responded...

    Basically, yes. But I'm proposing an actual CAUSE.

    @Tom showed so well in his experiments that growth in a very humid environment resulted in virtually no pyramiding, However, we still don't know what CAUSES that. @deadheadvet mentions above his belief that temperature is a factor that drier air is a more stable temperature. Yet I personally have grown dozens of tortoises in very controlled stable temperature environments, and only when humidity was increased, and still using the exact temperatures as before, did I see a dramatic decrease in Pyramiding. For decades fast growth was also stated as a factor. Yet again I personally tired that, and did different diet experiments, yet only now see consistent and repeatable results of no pyramiding if humid - despite very fast growth, and different diets.

    deadheadvet's assertion that pyramiding obsession is way too extreme has merit. The overall health is of chief concern. However, Everyone, including deadheadvet take pride in showing off the beauty of the animals we raise. All of us loving to post prideful pictures. That is a great satisfaction of raising tortoises, or any animal successfully. A smooth, non-pyramided shell, I believe, is a very desirable and sought after result. Although in a vast majority of the cases it is cosmetic, I personally see it as a sign of great husbandry. Not to eliminate it, but to minimize it.

    In extreme cases, I believe some may actually be bone problems. But I don't feel we are talking about that here. It's the "cosmetic" deformity of the shell growth I feel is reflected in husbandry techniques.

    So many of us have spent decades experimenting with FACTORS that will contribute to or minimize pyramiding. But what is the CAUSE metabolically? I'm 1proposing that the growth of the scute above the bone is the primary cause of pyramiding. The study Mark! referenced showed that Keratin acts and forms differently in a dry vs moist environment. When dried the fibers actually form differently and become more stiff and resistant to a swelling that occurs with keratin that has not been excessively dried. SO...

    I'm proposing that in dry environments, and very slow growth, the keratin as it forms at the edges of the scutes does so in a fairly uniform manner. But when moderate to fast growth occurs - the faster spread of keratin, exposed to dry conditions, will cause the top to stiffen, and not continue to swell as it continues to form, while the bottom of the new scute keratin continues to grow in a thicker way. This pressure is exerted on the bone below and causes the new scute seam to be lower than the previous seam. In a humid environment, the keratin as it spreads, does so much more evenly, with stiffness and swelling equal top and bottom - and grows straight.

    The more I think this over, the more it makes sense to me. I went back and reread Tom's "the End of Pyramiding" thread. It answers all the issues and questions always posed on this contentious subject. Many always seen to refute the humidity, or say there is no scientific basis - based on the way metabolically bone grows. They're right -its not the bone affected - its the scute affecting the bone! Just a braces can straighten teeth in a jaw or a corrective helmet's gentle pressure can straighten the growth of an infants head. Or they partially accept it and say it is complex and many factors come into play. Yet we see time and again examples of smooth growth with humidity no matter which of the other "contributing factors" are left out in the care of the tortoise. Smooth with inadequate D3, Smooth with no sunlight, smooth with fast growth, food with inadequate calcium and even metabolic bone disease - yet smooth! Yet we never see smooth without humidity somewhere in the equation. It also speaks directly to the issue I have noticed, and Tom and others have mentioned but there was never a WHY... How come tortoises seem to be very resistant to pyramiding once they reach a certain size? Well, it would make sense that as the tortoise ages, it reaches a point where the underlying bone hardens enough to resist the pressure the scute applies.
  2. SteveW

    SteveW Active Member

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    Hi Mark. I'm not around here much these days and I don't think I have posted anything in months, but I appreciate the time and thought behind this post and wanted to give you a virtual thumbs up enough to actually sign and and type something. Nicely done.
    Markw84 likes this.
  3. bouaboua

    bouaboua Well-Known Member TFO Supporter Platinum Supporter

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    My wife need to read this. She spoiled all our torts with too much food because she cannot bear the look on there face every time when they know she is coming near.

    After so many arguments, now we feeding them three times a week.
  4. DPtortiose

    DPtortiose Member

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    Well actually it does not.

    First; the research clearly states that it's researching mammalian keratin structures. While it's likely that reptilian structures could work similar, it's still a bit to soon to state that it does. For example; the research you linked to is about α-keratin while the shells of tortoise is made from β-keratin. This difference is important because it's about the structure of the proteins. Which is what the above research is making statements about. While it would be logical that several features of α-keratin would also be found in β-keratin, you can't use this research to draw a definitiveconclusion relevant to β-keratin from.

    Second; The research is focused on how keratin stays hard in wet conditions and explains how one structure (like horns vs finger nails) is more prone to swelling in wetter conditions. The difference between structures (Rhino horn vs whale baleen for example) are quite significant. Again, since no testing was done on a tortoise shell, we don’t know how prone shells are to swell when hydrated.

    Further, you assume the lower layer will stay more hydrated then the upper layer without any explanation why this situation would be maintained for long periods of time. If your conclusion is correct we would see that fast growing tortoises kept in periods of dry and wet seasons (like they have in the wild) would be more prone to pyramiding. Since hard flat keratin would cover the swollen hydrated keratin quickly. As far as I’m aware animals kept continuously dry are far more likely to pyramid then animals kept in wet and dry spells.

    Are you working from the assumption that the lower keratin layer is hydrated after it's covered? How would this work exactly? To my knowledge the keratin is waterproof, it would be a very poor protective layer if it wasn't (exposing bone to water isn't healthy). So the upper layer would be the one hydrated and swelling, not the lower one. Is the lower keratin layer hydrated through the bone (again a very poor unlikely evolutionary adaption)? This would mean a tortoise would continuously loose water through it shell, which would disastrous for large tortoises in deserts.

    Besides, if dry keratin stays flat, wouldn't an tortoise raised in a completely dry environment show less signs of pyramiding? A hydrate keratin layer swells and would therefore cause greater 'bumbs' in the shell.

    I think it's far more likely that hydrated keratin is a bit softer and wears down easier as Highfield suggested in a lecture (http://www.tortoisetrust.org/articles/pyramiding.html).
  5. Gillian Moore

    Gillian Moore Well-Known Member

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    A very interesting and important thread.

    Thanks a lot for posting it, Mark!:D
  6. mark1

    mark1 Well-Known Member

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    I think you make some great observations DPtortoise ….. initially I thought the humidity thing was a stretch , and that’s putting it nicely ….. most of these tortoises come from arid regions where the average humidity , for most of the year , is practically negative , they get rain 3 months of the year if their lucky , where I live looks like a swamp compared to much of their natural ranges ……. what causes me to give it more weight at this point is the realization that environmental conditions do effect the properties and actually the composition of keratin . yes there are different types of keratin , I think skin is keratin ? I am assuming all types of keratin are effected by the environment they are exposed too ……. You can correct me if I’m wrong , I picture keratin as finished fiberglass , the matrix being the epoxy and the fiberglass being the fiber ? The conditions alpha keratin are formed in effects the amount of matrix to fiber , I think wet conditions dictate a higher percentage of matrix and dry conditions a higher percentage of fiber , or vice versa ? I’m also going to assume tortoises in these arid regions don’t grow evenly throughout the year ….. they are adept at finding micro-environments within their environment ……. They don’t really grow much when conditions are not favorable , because it’s a energy expenditure …. The protein needed for the matrix part of alpha keratin is in demand , so I understand at times of survival hardship the keratin put down has a higher percentage of fiber to matrix …….. another way in which keratin is effected by environment ……. Another argument I had against the humidity deal was that since the introduction of a high energy foreign food source into Madagascar they are seeing pyramided wild radiated tortoises , it could be it's available when native food sources were not …… I think Mark’s conclusion that growing when they’re not supposed to be growing has a leg to stand on …….as far as pyramiding not being a health issue , i also think in more extreme cases it's an indication something is wrong , and as hobbyist i think the idea is to keep getting better until it's perfect ....jmo
  7. DPtortiose

    DPtortiose Member

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    To give some context; as most people probably know we all exist out of cells. Every living creature is a very large collection of (specialized) cells working in unison. So cells need to know what itsneighbor is doing and make sure it stays next to its neighbor. Cells do this by building an extra cellular matrix (or ECM). This matrix allows cells to stick together, communicate which each other and build structures like bone, cartilageor a tortoise shell.

    These complex structures are made from strands of protein, the building blocks of our body. Biologist call these strands filaments. Keratin is one of those building proteins (or filaments) our cells can produce. If your a mammal (like us), you can only produce a single type of keratin (alpha). Reptiles (which includes birds as well but that's another discussion) however can produce two types of keratin (Alpha and Beta). Alpha and beta keratin are made from the same materials, but are different in structure. I think (not 100% sure) that α-keratin is shaped like a helix, while β-keratin is twisted. This structures makes β-keratin a bit more though, since strands can attach to each other more easily.

    The interesting part is that while keratin remains hard in water, the protein strands it’s made from become flexible.The research suggests that the strands bind with the matrix and that’s why the keratin keeps it's shape and hardness.

    Since α-keratin and β-keratin are differently shaped and form bonds differently, you can't assume that these result are as relevant to β-keratin (which make up the shell). Though I have read that T. hermanni does produce a bit of α-keratin around hinge areas in hibernation periods. But these are replaced by β-keratin cells in spring. 'Normal tortoise skin' is made from α-keratin.

    In any case the only thing I'm sure about is that humidity helps prevent pyramiding, why it does this and if it is the correct method to combat pyramiding is disputable. Though I do think keeping certain species outside is also an important aspect for smooth growth.
  8. Tom

    Tom The Dog Trainer 5 Year Member

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    Which species? And in which climate? Arizona? Southern CA? Seattle? NYC? Southern Florida?

    What factors that occur outside, but not inside, do you think are controlling aspects of smooth growth?
  9. Yvonne G

    Yvonne G Old Timer TFO Admin 5 Year Member Platinum Supporter

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    I've always wondered how people in Arizona, who don't know about moisture and pyramiding, manage to grow smooth sulcatas in that hot, dry climate.
  10. Tom

    Tom The Dog Trainer 5 Year Member

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    Me too. I know that most of them burrow to escape the 100+ temps they have there for 9 or 10 months of every year and I think that is a big contributing factor. Many people also use no heat anytime of the year and the tortoise do a sort of "artificial climate induced hibernation" where they are not active and don't eat for a few weeks or months every year. I'm sure some die from this, but it sure seems like most of them survive it.
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  11. Markw84

    Markw84 Well-Known Member 5 Year Member

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    Thanks for the food for thought, but to say the study I quoted was used to draw a definitive conclusion is not the case at all. This study got me thinking about the POSSIBILITIES of what and how keratin is being formed and since moisture is something shown there to effect stiffness and swelling, that could very well translate into keratin in general. This piece of the puzzle makes perfect sense to show how pyramiding works, and is reasonable to expect here. It was the smallest of pieces but the missing link I was looking for. I came to the conclusion of the scute forming the pyramid long ago, I just couldn't find any logical way it could only be happening, and then NOT HAPPENING in the instances so many keepers found working.

    Here is how I came to this conclusion:

    I have for many years now, believed that pyramiding is a scute issued, not a bone issue. People always point to UVB, calcium, exercise, diet, etc. yet to me if it were a bone problem why wouldn't it follow the pattern of the bones of the shell? We all know the bones are a completely different pattern, and as they grow and expand the shell, the bone seams are completely different places than the scute seams. If the bone is what is pyramiding, wouldn't that follow the bone pattern? While if the scute were the causative agent, we should see the pyramiding following the scute pattern - and that is exactly what you see. The scute is affecting the bone. The bone isn't growing in a fashion totally contrary to its seam and plate pattern and the scutes simply are covering it.

    So my question was always how could the scute cause the bone to pyramid? We know we certainly can cause bone to reshape all the time in humans. Gentle pressure consistent over an extended period causes bone to reshape. They did it with my grandson's head to round it out with a contouring helmet prescribed. We do it with teeth. An African tribe used to do it with the skulls of their women. So for some years now I was sure the pyramiding was being driven by the scute, but HOW? And how come in the past 7 years or so we pretty much have shown it only does not happen when some type of hydration is present? Of all the variables argued - fast growth, protein, sunlight, exercise, calcium, D3, night cooling, and hydration - we see smooth tortoises with plenty of examples with one or many of all those variables missing - except one. We never see smooth tortoises without hydration. In captivity is the examples I look at since we can only theorize about those elements in their natural environment being present and to what degree. And then we have some cases, like the heat study posted here a few months ago, and I started this response on that thread. That study does show significantly reduced pyramiding with nighttime cooling and slower growth. Not just slower pyramiding because they were growing slower, but proportionately significantly less pyramiding when adjusting for the size. And without the humidity we have found works. How can we account for that along with what I just stated two sentences ago??

    Then I come to looking at the formation of the scute itself. If we take one off a tortoise shell, we do see a uniform thickness of the scute across its width. It does not seem to add any additional volume or height as the tortoise grows once it is laid down. In fact it can often be worn off and will not grow back in the center of scutes on older tortoises. So all the active laying down of keratin happens at the edges. New keratin is ONLY formed along the seams when the tortoise is actively growing. It does not continue to add along the entire bottom of the scute and develop thicker centers like an aquatic turtle would if it didn't shed. No, if you look at scutes you peel off a tortoise shell, the scute is an even thickness, and if pyramided - the bone is shaped into the pyramid shape exactly under and following the shape the scute "cap" created. When tortoises are growing fast we even see the obvious growth lines between the scutes, and can see where it appears the keratin has not yet caught up to the new bone growth. As I constantly soaked tortoises over the year, I watched growth separate the scutes, and the scutes then fill in the gaps with their new growth. With leopards its fun to watch what new patterns come with this new growth.

    Now we fast forward to my new Burmese group. I got them just after I read the study posted about nighttime high temps causing pyramiding. I however, was firmly committed to growing these very rare tortoises the best I knew how. And thanks to a lot I learned and copied from @Tom that meant I was going to "monsoon" them. Now these tortoises are coming from one of the most respected and awarded chelonian centers in the world. With veterinarians on staff, they have the best of care. The Managing director of the facility was voted by his peers the Reptile Vet of the year in 2009, he served as president of the Association of Reptile and Amphibians. So they know what they are doing. But I found they still adhered to and believe in "slow growing" their Burmese Stars. Kept in lower humidity with nighttime temp drops, and fed a carefully controlled diet to ensure more "natural" growth. I on the other hand, had already decided and was committed to the monsoon approach. When I got them I was a bit disappointed to see how pyramided and small they were! 4 were 5 years old, and one was 7 years old. They averaged 5.3" SCL and 454.2 grams. I felt this was a perfect chance to see the difference the monsoon method could make.

    As I watched them grow, and inspected them (I know - watching grass grow) every day with their soak, it became apparent very quickly I was kicking their metabolism into full gear. The group averaged adding 71 grams the first two weeks. OK, mostly hydration probably. The first of the next month on measurement day, they were now at an additional 97 g added average in just that month. As of the 1st of July, they now have added an average of .966 inches SCL, and 301.8 grams. Since they came with complete records and history, I could compare results in the two methods. For example, Betelgeuse is the smallest male. I got him at 346 g. The 12 months prior to my getting him, he had gained a total of 20 grams in weight - TOTAL. In the 3 1/2 months since, he has gained 271 grams. Sirius, the largest male, came to me at 7 yrs old and 548 grams. His previous 12 months saw a 119 g weight gain. In the 3 1/2 months since - he has gained 407 grams. So I had convinced them the monsoons had finally come! But was the fast growth and constant high heat and humidity, only contributing to pyramiding that was already so well established?

    What really started my mind working - again - on pyramiding and the scutes, was watching them grow. I began to see a different look to the seams as the scutes grew, than I was used to seeing for so many years. If you look back at the picture of one of my females, Vega, above in post #1, you can see the new growth is coming in completely smooth, but - I was seeing more of a hump, or swelling upward to the new growth than I had seen before. I thought maybe the keratin layer was just being laid down a bit thicker than I was used to.

    NOW we go to the study, that may or may not relate to tortoises on keratin and moisture. What IF scute keratin also becomes stiffer and resistant to initial swelling in dry conditions just as the horn keratin does? Is what I am seeing on Vega's seams the natural growth and initial swelling of new keratin vs what would happen if the new keratin dried to quickly on top? That could force the top to become stiffer, and the continued growth of new keratin and/or swelling forced to be more downward, while to top is comparatively more rigid? I could see something like this happening:

    IMG_3418.JPG

    The first case would be what I was seeing with Vega. Normal fast scute growth with the perceptible "swelling" look to new growth.
    The second would be fast growth where the condition are drying. The top of the new keratin does not swell or fill in as much as it dries quicker and becomes stiffer and more resistant. This forces the swelling / or addition of keratin to occur mostly in a downward direction. Every successive growth ring would continue to press down on the bone creating a bigger, and bigger valley between the scutes - pyramiding.
    The third would be a slower growing tortoise like in the temperature experiment. There would not be enough of the exposed new growth as compared to relative scute height to affect it as much.

    Now, I am not saying I now know the keratin in the scute works this way. That would have to be the scientists with their million dollar labs looking at the cellular growth and triple helix structures in the keratin to see if indeed tortoise scute keratin works this way. What I am saying, is this is more than simply possible. There is cause to believe it could work this way too. But most importantly THIS MODEL, hypothesis, fits every scenario I, and so many others have debated, and wondered about. It fits perfectly. And I have never seen any other explanation of the workings of pyramiding, showing how it happens.

    So, @DPtortiose I do believe this study shows a cause for pyramiding. Or should I say, shows something that very well could be the cause. You yourself say its likely reptilian keratin works similarly. In all my studies, that's how science works. Most everything in our world is based on theory. - Based upon experience and study, and evidence at hand, you postulate a theory. That working theory is then poked at and tested, and perhaps the scientists can find the interest, and money and time to devote to our chelonians and see what the cellular mechanism at work really is.

    For me - at least I have a working theory now.
  12. Yvonne G

    Yvonne G Old Timer TFO Admin 5 Year Member Platinum Supporter

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    I thought these pictures might be beneficial to the thread. First the non-pyramided carapace:

    [​IMG]

    Then the carapace with pyramids:

    [​IMG]

    You can see that the underlying bone does indeed grow upwards, however, not nearly as bad as the keratin.

    http://startortoises.net/pyramiding.html
    PJay, bouaboua and DPtortiose like this.
  13. DPtortiose

    DPtortiose Member

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    I'm not sure the rate of growth is affected. It's the erosion on the shell I'm revering too. The elements as the wind, rain and the sun, but also burrowing, walking underneath vegetation, probably the copious amount of bacteria and fungi living on the shell. Don't get me wrong, I know perfectly well that indoor animals experience some of these conditions as well, but life outside is bit more variable (perhaps harsher). Since keratin productions is continuouslythroughout their life, it’s logical that it suppose to wear down. Since outside conditions tend to be less stable with more extreme weather conditions (in certain climates), it stands to reason that an shell would wear down more.

    I wasn't referring to a specific species in a specific location, more a suitable species in suitable location. Though I suppose some climates have higher humidity and it's easier to maintain an higher humidity in an outdoor enclosure.
  14. Markw84

    Markw84 Well-Known Member 5 Year Member

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    I'm not an xray technician, but the section defined in red marks looks like porus bone, not scute. If you look at some of the other photos and info referenced on that website, the marked area is bone. The scute the darker thin layer on top.

    I also believe it is not growing up. The edges are growing down. Put the profile of a pyramided tortoise against a profile of one not pyramided. The "normal profile" matches the Pyramided one from the TOP of the pyramids not the valleys.
  15. Tom

    Tom The Dog Trainer 5 Year Member

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    I've noticed this too. I agree.
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  16. Yvonne G

    Yvonne G Old Timer TFO Admin 5 Year Member Platinum Supporter

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    Yes, I misspoke. The section between the ends of the red lines is the bone, so yes, the bone is also pyramided.

    You are, of course, correct in saying the new growth is growing down and not up. The existing part at the top of the pyramid is not growing. The new growth is at the bottom of the pyramid, growing down and pushing the old growth up.
  17. DPtortiose

    DPtortiose Member

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    This not true, I was wondering how and where scutes grow as well. Keratin growth is added near the 'hinges' of a scute, but there is keratin growth in the center of a scute as well. An abstract of the article that stated this: http://www.ncbi.nlm.nih.gov/pubmed/15880409

    I think it's a interesting theory, but there are several things that don't quite 'fit'.

    There is the assumption that the swelling is irreversible and continuously (it has to be for it to push the bone down), while the report suggest otherwise. The process of swelling seems reversible and becomes less severe when it dries out. The water messes with the structure of the filaments, but the filaments seem perfectly able to return to their normal state when dry again. We would have serious problems with our nails if this wasn't the case. Besides, the filaments form bonds with the matrix as it 'dries' further reducing the swelling when it does get wet again.

    I like the theory that the keratin pushes the bone down. But bone has a higher density then keratin (can also be seen on the x-ray, bone is way brighter then the keratin), so it's unlikely that the bone is pushed down instead of the upper layer. Besides keratin is more flexibility then bone, it's far more likely that the top layer bends a bit rather then the bone. The amount of swelling also seems hardly enough to actually push the bone down.

    The research state that the largest increase in transverse swelling (rhinohorn) was only 1.5%. Meaning if the keratin layer of a hatching is a millimeter thick, it would expand with 0.015 millimeter (or 0,00059 inch). I sincerely doubt this amount of swelling could inflict the pyramiding already seen in some youngsters.

    I think it might be good starting point, but do not underestimate the difference of the structure. For example, take the polysaccharide cellulose. It's indigestible because it's structured as β-sheet. While a polysaccharide with an α-structure can be broken down as glucose. It's the difference between dietary fiber and 'normal' food.

    On a side note, Tom had some spot on criticism on the study on the effects of an night time drop.
  18. Anyfoot

    Anyfoot Well-Known Member

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    @Tom. Couple of questions.

    When you have a night time low, what heating method do you use?

    I've read before you saying that hatchlings during monsoon season bathe in puddles. Do you know this for a fact or is it an educated assumption because of the torrential downpour?
  19. Tom

    Tom The Dog Trainer 5 Year Member

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    Night time heating varies with the season and enclosure. I use CHEs, RHPs, and oil filled radiant heaters, all controlled by thermostats.

    The puddle assertion is an educated guess based on several things. I have never read anything about sulcata babies in the wild. The man who would know better than any other is Tomas Diagne. One of his research students saw one baby, and the next day Tomas returned to that spot and saw three babies in one day. He had never seen one before this, and has not seen one since, unless something has changed since I last spoke with him. He suspects these babies were from his reintroduced tortoises, but could not verify. Theses 4 babies are the only ones I have ever heard about in the wild and Tomas found the near a marsh. Sulcatas are extinct in several countries, near extinct in several others, and we know almost nothing about their wild lives. Most of what I know is from Tomas and the book he helped Bernard DeVoux write. It went out of print more than 10 years ago. He is supposed to have another book coming out, but nothing yet...
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  20. Markw84

    Markw84 Well-Known Member 5 Year Member

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    Not sure what you read here, but I read it differently

    "Beta-cells form a new thick corneous layer around the hinge regions, which constitute the growing rings of scutes. Beta-keratin cells produced in more central parts of scutes maintain a homogeneous thickness of the corneous layer along the whole scute surface."

    Specifically stating the cells that were produced in the central parts of the scute retain a homogeneous thickness along the whole scute surface. So no new cells are adding - only growth along the "hinges" as they call it. Then goes on to say how with aquatic turtles there is growth along the whole scute with cells added.

    I am not assuming the 'swelling' is irreversible. I noted two things had been found. Hydration swells keratin. Drying changed the helix strand structure making it stiffer than keratin that had not been dried out. One or both of these factors could be at work to lesser or greater degrees here. Or similar factors this opens up the possibilities for. And we do have extreme tendency for our nails to curl downward if left to grow. Despite the adaptation we have developed to have the bulk of the keratin growth of our nails done under the protective cuticle where both sides of the nail are in contact with moist tissue.

    By personal experience I can tell you it takes very little pressure, just consistent pressure, to change bone growth. The helmet my grandson wore had only foam pressing against his head in the proper areas. Foam much softer and more pliable than bone, and soft enough not to interfere with blood flow to that part of the scalp. Yet the scull was reshaped in a few months. Even shed scutes I get from my aquatic turtles, which are much thinner than the full scutes of tortoises I have removed, have enough stiffness and "spring" to their shape to apply the pressure I would envision it would take. And that goes with younger tortoises being most susceptible, while once to a certain size, many tortoises seem to have a much more resistant bone structure developed and simply resist further pyramiding.

    And I don't believe it would be identical scenarios and swelling is not what I would look for if I were the researcher with the equipment. I would look for a modification of the stiffness of the keratin layer - drying on top - that reduces the additional adding of keratin in that direction and forces the additional keratin growth downward.

    and on your side note - I agree with Tom's comments about the experiment and that it was extremely flawed. However, if you read the data, and even look at the pictures, they really did get a significant reduction in pyramiding beyond any size differential. That is why I believe we must account in any theory for the ability to reduce pyramiding with slowing growth. My hypothesis is slow growth with minimal new keratin exposed at the same time reduces this effect, especially if the diet still has an adequate amount of protein - the most necessary building block for keratin.

    Now I am not promoting slow growth at all. I am just trying to account for the question of why the smooth growth when presumably wild tortoises go through periods of dry, yet little or no growth, and the experiment that partially mimicked that. But why would we want to purposely starve a tortoise if we now see they can thrive and grow "normally" in conditions we understand better.
    Last edited: Jul 7, 2016
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