The CAUSE of Pyramiding

Tom

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Mark,

There is a lot of good reading in this thread. Can you break down the high points in layman's terms? Something like my: "Pyramiding is caused by growth in conditions that are too dry."

In other words, how would you explain this in a few short sentences to a noob that is not going to read all of this?
 

Anyfoot

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Tom, reason I asked is because, you have obviously thought every aspect through, I.e diet(you don't use store bought). Heat(highs and lows,methods) hydration etc etc.
You said you can't understand why some of your hatchlings show minor pyramiding and some don't. The only thing I can think of that I imagine is incorrect(or could be) is the actual hydration method. I don't think any of us really know how a juvenile lives for certain in the wild(talking sullies here). If they hatch out in the wet season then scurry for cover in foliage growth where they probably spend most of the Time hidden until large enough to explore the big world, probably pop out occasionally but most of the time hidden.
So the soaking method is basically hydrating from below. If they are hidden in monsoon season, would it be possible they get hydration from above. I.e the rain.
Are you or could you be in a position to rear one hatchling and instead of 20min soaks give it maybe 2hr showers. Fake rain, no hides to act as an umbrella other than natural foliage(so it has to endure the rainfsll).
2 differences I can think of are, maybe rainfall doesn't empty the gut load like a soak. Would this naturally maintain a steadier growth rate? Also I would imagine that natural elements like wind and rain fall would smooth off the carapace anyway. To imitate rainfall on the carapace may smooth it off, yes it's only the cosmetic side of things and not connected to bone and keratin ratio growth.
Could this be the missing piece of the jigsaw?
 

DPtortiose

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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.

That's because I read the very next sentence as well: "Beta-keratin cells produced in more central parts of scutes maintain a homogeneous thickness of the corneous layer along the whole scute surface."

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.

Not quite, the structure form cross-bonds with the matrix. That's what's allows it to remain stiff when hydrated. These bonds are formed when the keratin is dried by the air, so when the growth is complete it's as structure sound as it can be (when it’s dry). According to your hypothesis a dry spell should fix the problem quite easily should the swelling be not irreversible. Since the pressure wouldn’t be continously as the keratin dries.

But again, if your hypothesis is correct, the most logical solution would be to remove hydration all together so everything grows nice and flat. However we seen that animals kept to dry are very prone to pyramiding.

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.

Interesting, you probably have a good point concerningcontinuous pressure and bone growth. But again, as the keratin dries the pressure is relieved. So the stress on the bone would not be continuous.

The x-ray from Yvonne also doesn’t show continuous growth of keratin down worth however. They show a pretty evenly thick layer across the shells. Abnormal growth is only observed in the bone. If your theory was correct, we would see two point of abnormal growth; one near the edges of the scutes (made from keratin that grows down into the bone ) and one in the middle of scute made from bone. Only the thickening of the bone is visible though.

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.

As far as I'm aware higher keratin synthesis isn't directly linked to an abundancy of protein to be honest. It's a very common protein and we'd all be in great trouble if eating to many proteins would lead to an increased production. Other way around as well, there are species that have a very low intake of protein, but are perfectly able to maintain a thick fur (hair is made for keratin as well)

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.

I agree. +1
 

Markw84

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Mark,

There is a lot of good reading in this thread. Can you break down the high points in layman's terms? Something like my: "Pyramiding is caused by growth in conditions that are too dry."

In other words, how would you explain this in a few short sentences to a noob that is not going to read all of this?
I think that your statement you have always maintained is a great one. I started this thread with a different definition of "CAUSE". I wanted to explore the physiological mechanism that is making a shell pyramid. Your statement is great and fits what most everyone is after =" what are the environmental factors I can control that cause pyramiding?"

so in that context: Your statement is spot on:

Pyramiding is caused by GROWTH in conditions that are too dry. They can survive periods of minimal to no growth and not pyramid, but when you start them GROWING, if dry - they will pyramid.
 

Tom

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New experiment proposal: Take some hatchlings and do the unlimited food/monsoon thing for four months. Then go 8 months hot and dry, but just enough food to maintain weight and not gain much. 4 months "on", 8 months "off". Then repeat.

Any takers?
 

Tom

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Tom, reason I asked is because, you have obviously thought every aspect through, I.e diet(you don't use store bought). Heat(highs and lows,methods) hydration etc etc.
You said you can't understand why some of your hatchlings show minor pyramiding and some don't. The only thing I can think of that I imagine is incorrect(or could be) is the actual hydration method. I don't think any of us really know how a juvenile lives for certain in the wild(talking sullies here). If they hatch out in the wet season then scurry for cover in foliage growth where they probably spend most of the Time hidden until large enough to explore the big world, probably pop out occasionally but most of the time hidden.
So the soaking method is basically hydrating from below. If they are hidden in monsoon season, would it be possible they get hydration from above. I.e the rain.
Are you or could you be in a position to rear one hatchling and instead of 20min soaks give it maybe 2hr showers. Fake rain, no hides to act as an umbrella other than natural foliage(so it has to endure the rainfsll).
2 differences I can think of are, maybe rainfall doesn't empty the gut load like a soak. Would this naturally maintain a steadier growth rate? Also I would imagine that natural elements like wind and rain fall would smooth off the carapace anyway. To imitate rainfall on the carapace may smooth it off, yes it's only the cosmetic side of things and not connected to bone and keratin ratio growth.
Could this be the missing piece of the jigsaw?

What weather and abrasion theories fail to account for is that pyramiding is bone malformation. It would take an awful lot of rain and wind to abraid pyramided bone enough to smooth out a tortoise's carapace.

Keeping them in a rain chamber would be an interesting experiment.

If you run a sprinkler over a bushy area, do you not get puddles after a while?
 

Anyfoot

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What weather and abrasion theories fail to account for is that pyramiding is bone malformation. It would take an awful lot of rain and wind to abraid pyramided bone enough to smooth out a tortoise's carapace.

Keeping them in a rain chamber would be an interesting experiment.

If you run a sprinkler over a bushy area, do you not get puddles after a while?
So your saying, even very minimal pyramiding is bone structure and not the keratin not reaching scute boarders due to an inbalance of growth rate and hydration.

Puddles would depend on how well the drainage of the soil would be, or if they are sat on foliage or bark maybe.
When It rains in my garden and boy does it rain here, I don't get puddles under the bushes, even on the flat areas, because of grass and weeds. Where it's just mud maybe.
I'll bet not every area that sullies live in is flat, if that's correct what happens to the hatchlings that live on an slight incline with no puddles?
I'm tempted to set a viv up with mesh bottom and drainage system into a tank below recycling a mini rain system. But you would see results far quicker with sullies and make a better build and you have babies and have a comparison to one that is soaked.
 

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New experiment proposal: Take some hatchlings and do the unlimited food/monsoon thing for four months. Then go 8 months hot and dry, but just enough food to maintain weight and not gain much. 4 months "on", 8 months "off". Then repeat.

Any takers?

If there was only a member who breeds sullies and has a giant ranch wheras to conduct this experiment..... hmmmmm.

I nominate you Tom.
 

wellington

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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.
I didn't really get that from this thread. I took it that fast growth is fine, as long as you have the high humidity. Cutting their food down doesn't prevent pyramiding. Lack of high humidity causes pyramiding. @Markw84 am I misunderstanding or is Steven or a little of both?
 

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I didn't really get that from this thread. I took it that fast growth is fine, as long as you have the high humidity. Cutting their food down doesn't prevent pyramiding. Lack of high humidity causes pyramiding. @Markw84 am I misunderstanding or is Steven or a little of both?
Yes. Exactly. I'm feeding all they want and getting very fast growth. The point is exactly that the high humidity must be there too.
 

Tom

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If there was only a member who breeds sullies and has a giant ranch wheras to conduct this experiment..... hmmmmm.

I nominate you Tom.

HA! Thanks…

What I'd really like to do is go to The Sahel for about 2 years with a remote probed thermometer and hygrometer and just hang out recording temps all over sulcata land. I bought lotto tickets. It could happen...
 

Anyfoot

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In the 2 x-rays that Yvonne posted, is there any MBD going on in the 2nd x-ray?
If yes
Is it possible to have a pyramided tort that has zero amount of MBD?
 

Markw84

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Which grows first, the keratin or the bone?
Based upon observation - we see the bone plates grow and expand the shell, leaving gaps in the scutes. Many have posted on the forum asking about the strange "white lines" and that they are softer, and seem more sensitive to the tortoise. They are seeing these growth seams. So it appears the bones grows the shell and the Scutes follow to fill in the seams.

In the 2 x-rays that Yvonne posted, is there any MBD going on in the 2nd x-ray?
If yes
Is it possible to have a pyramided tort that has zero amount of MBD?
I believe the tortoises Tom and I (and others) raised between 1990 and 2008 are great examples of pyramided tortoises with absolutely no metabolic bone disease.

If you look at the x-rays @Yvonne G posted earlier and superimpose the pyramided one over the smooth, you can see the bone itself is fine, just distorted to the shape of the pyramided scute. It's hard to see as the pictures she posted are of a different size tortoise and different part of the tortoise, plus the x-rays are of a different filter strength with one showing more contrast to where you cannot make out the keratin scute on top of the bone of the smooth tortoise. You can see it clearly on the pyramided tortoise and see the keratin does not thicken to produce the "hump" of the pyramid, but the bone deforms and reshapes. I adjusted them based upon scute distance and placement and did the best I could quickly:

xray-composite.jpg
 

Markw84

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New experiment proposal: Take some hatchlings and do the unlimited food/monsoon thing for four months. Then go 8 months hot and dry, but just enough food to maintain weight and not gain much. 4 months "on", 8 months "off". Then repeat.

Any takers?
That would be a good experiment, but I think perhaps in the wild they are aestivating a good portion of that time - NO food and water. Like hibernating / brumating a tortoise through the winter. To keep a sulcata / leopard / star healthy, warm, yet feed only enough to stop growth for 8 months, is an exercise I wouldn't feel comfortable with.
 

Markw84

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That's because I read the very next sentence as well: "Beta-keratin cells produced in more central parts of scutes maintain a homogeneous thickness of the corneous layer along the whole scute surface."
It is exactly that next sentence I am talking about. And that is their point of these two sentences: They say cells are only ADDED (new growth) "form a new thick corneous layer around the hinges" Yet "cells produced in more central parts" (old growth) "maintain a homogeneous thickness... along the whole scute surface." If that weren't their point, how can you have NEW cells added along the more central parts and still maintain a homogeneous thickness. And especially with them juxtapositioning this statement to contrast and make their point of differentiation in their next statement - that Aquatic turtles add cells along the entire scute.

I can't follow your reasoning with the rest of your comments about stiffening / swelling. I certainly do not in my proposal suggest a scute, once formed, will straighten out, or curl, or reform in any way with humidity or dryness. I am proposing that IN THE FORMATIVE STAGES as the new keratin is expanding and filling in the seams between the scutes, the bottom of the NEW kerating is against moist tissue / bone, while the top is exposed to environmental conditions. Just like our fingernail (you brought up earlier), most hard keratin structures in nature seem to have developed a way of developing and laying down the NEW portion protected by contact with moist tissue on all sides. Fingernails and horns come immediately to mind. A snake's or lizzard's new scales develop under the protection of the old layer, which is only shed after it is developed. Aquatic turtles lay down new keratin under the old scute and the newly developing portion is a bit LOWER. If they do not shed - they begin to pyramid. But a healthy turtle sheds and in that way retain smooth growth.

I know that shed scutes of aquatics I find constantly in my pond, whether freshly shed, or ones laying there for over a year under water, retain their shape and gentle curve, and the elements don't affect that. They don't become soft, or stiffer. They resist applied pressure to bend or reshape them. Once laid down, the scute is quite set in its form. If it is dried in the sun and I find one laying out along the pond for months - it is the same.

So, I am saying that with tortoises, they lay down new keratin as the shell expands, but the FORMING keratin is exposed on the top to environmental conditions. That situation - combined with growth exposing a wider area of NEW keratin, could very well cause the top of the layer to FORM and "set" differently or quicker, than the bottom. As the new keratin is filling in, the top dries and resists the addition of new cells, while the bottom, protected side remains more in the formative stages longer - resulting in more cells being added longer to the bottom surface than the top. This would result in a slight downward growth direction Since the top of the scute is harder / stiffer / more set earlier, that would then create slight downward pressure as the scute edges continues to form mostly on the bottom side.

With tortoises I watch grow, and now watch grow rapidly - so the process is more pronounced, I see when kept humid, the new keratin is adding in a way that appears to actually create upward bulges (probably the same as on the bottom) but now it is even - so level growth. With dry tortoises growing quickly (so the affect is more pronounced) I see the new keratin adding slight lower, flat to the middle of the previous "set" growth ring. This results in each successive ring to be lower than the previous one. And it pyramids.

SO... @DPtortiose You obviously know more about the actual cellular development of keratin. (I am no way sarcastic here. I mean that. I appreciate and love your comments) Why don't you turn your hat around for a while and look at what I am proposing and try to find reasons why this could be happening, instead of coming from why it shouldn't happen. Kind of like all the aeronautical engineers who KNOW a bumblebee cannot fly. But it does.

I am not as technically versed as the great scientists. But I do know the process of discovery. It begins with observation and conclusions drawn from consistent, real-world results of things we can see and measure. Someone starts to draw conclusions and makes a hypothesis of why this is happening. That theory is what science then runs on. Finding results that will consistently fit the model, or getting results that disproves the model. So far, all the results I have seen, and read about, and can look at in actual tortoises are consistent with this model.
 

Anyfoot

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It is exactly that next sentence I am talking about. And that is their point of these two sentences: They say cells are only ADDED (new growth) "form a new thick corneous layer around the hinges" Yet "cells produced in more central parts" (old growth) "maintain a homogeneous thickness... along the whole scute surface." If that weren't their point, how can you have NEW cells added along the more central parts and still maintain a homogeneous thickness. And especially with them juxtapositioning this statement to contrast and make their point of differentiation in their next statement - that Aquatic turtles add cells along the entire scute.

I can't follow your reasoning with the rest of your comments about stiffening / swelling. I certainly do not in my proposal suggest a scute, once formed, will straighten out, or curl, or reform in any way with humidity or dryness. I am proposing that IN THE FORMATIVE STAGES as the new keratin is expanding and filling in the seams between the scutes, the bottom of the NEW kerating is against moist tissue / bone, while the top is exposed to environmental conditions. Just like our fingernail (you brought up earlier), most hard keratin structures in nature seem to have developed a way of developing and laying down the NEW portion protected by contact with moist tissue on all sides. Fingernails and horns come immediately to mind. A snake's or lizzard's new scales develop under the protection of the old layer, which is only shed after it is developed. Aquatic turtles lay down new keratin under the old scute and the newly developing portion is a bit LOWER. If they do not shed - they begin to pyramid. But a healthy turtle sheds and in that way retain smooth growth.

I know that shed scutes of aquatics I find constantly in my pond, whether freshly shed, or ones laying there for over a year under water, retain their shape and gentle curve, and the elements don't affect that. They don't become soft, or stiffer. They resist applied pressure to bend or reshape them. Once laid down, the scute is quite set in its form. If it is dried in the sun and I find one laying out along the pond for months - it is the same.

So, I am saying that with tortoises, they lay down new keratin as the shell expands, but the FORMING keratin is exposed on the top to environmental conditions. That situation - combined with growth exposing a wider area of NEW keratin, could very well cause the top of the layer to FORM and "set" differently or quicker, than the bottom. As the new keratin is filling in, the top dries and resists the addition of new cells, while the bottom, protected side remains more in the formative stages longer - resulting in more cells being added longer to the bottom surface than the top. This would result in a slight downward growth direction Since the top of the scute is harder / stiffer / more set earlier, that would then create slight downward pressure as the scute edges continues to form mostly on the bottom side.

With tortoises I watch grow, and now watch grow rapidly - so the process is more pronounced, I see when kept humid, the new keratin is adding in a way that appears to actually create upward bulges (probably the same as on the bottom) but now it is even - so level growth. With dry tortoises growing quickly (so the affect is more pronounced) I see the new keratin adding slight lower, flat to the middle of the previous "set" growth ring. This results in each successive ring to be lower than the previous one. And it pyramids.

SO... @DPtortiose You obviously know more about the actual cellular development of keratin. (I am no way sarcastic here. I mean that. I appreciate and love your comments) Why don't you turn your hat around for a while and look at what I am proposing and try to find reasons why this could be happening, instead of coming from why it shouldn't happen. Kind of like all the aeronautical engineers who KNOW a bumblebee cannot fly. But it does.

I am not as technically versed as the great scientists. But I do know the process of discovery. It begins with observation and conclusions drawn from consistent, real-world results of things we can see and measure. Someone starts to draw conclusions and makes a hypothesis of why this is happening. That theory is what science then runs on. Finding results that will consistently fit the model, or getting results that disproves the model. So far, all the results I have seen, and read about, and can look at in actual tortoises are consistent with this model.
Mark I need to go back and read this thread through. Ive only scan read most of it except this last post. I'll read back tomorrow.
What your are saying in lame man terms is.
The layer of keratin is moist underneath and dry on top thus turning up on the edges. This is because the underside surface area is bigger because it's expanded with moisture and the outer surface area is smaller because it's dry and shriveled up(so to speak). Am I understanding you correctly?
 

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Mark I need to go back and read this thread through. Ive only scan read most of it except this last post. I'll read back tomorrow.
What your are saying in lame man terms is.
The layer of keratin is moist underneath and dry on top thus turning up on the edges. This is because the underside surface area is bigger because it's expanded with moisture and the outer surface area is smaller because it's dry and shriveled up(so to speak). Am I understanding you correctly?
No. The scute grows at the edges. This new keratin as it fills in is moist on the bottom (in contact with rich blood supply and living bone) while exposed on top. If subject to drying conditions, it will dry out more on the top of the new growth - becoming stiffer, and more resistant to new cell growth. So since the scute retains it same thickness as it expands, this forces more of the growth on to the bottom of the new portion - this makes the new growth ring lower than the previous. Let me redraw what I showed in a previous post.IMG_3421.JPG

Let's call this a three growth spurt tortoise. In the wild could well coincide with a three year old. The top one would be growing with a more balanced hydration differential top vs bottom of new growth of scute. The new growth would add cells and expands pretty balanced top and bottom. We would see a growth ring, but it's ridge is level with the original scute and subsequent 'rings".

The second would be where the new keratin is forming in too dry conditions. This does cause the keratin to stiffen and become very resistant, causing the rest of the growth adding more to the bottom of the new growth. So now the growth ring is lower in each successive growth period. The growing, pliable bone conforms to the scute - which retains the same thickness, but is forced to grow downward. = Pyramided scute.
 

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No. The scute grows at the edges. This new keratin as it fills in is moist on the bottom (in contact with rich blood supply and living bone) while exposed on top. If subject to drying conditions, it will dry out more on the top of the new growth - becoming stiffer, and more resistant to new cell growth. So since the scute retains it same thickness as it expands, this forces more of the growth on to the bottom of the new portion - this makes the new growth ring lower than the previous. Let me redraw what I showed in a previous post.View attachment 179635

Let's call this a three growth spurt tortoise. In the wild could well coincide with a three year old. The top one would be growing with a more balanced hydration differential top vs bottom of new growth of scute. The new growth would add cells and expands pretty balanced top and bottom. We would see a growth ring, but it's ridge is level with the original scute and subsequent 'rings".

The second would be where the new keratin is forming in too dry conditions. This does cause the keratin to stiffen and become very resistant, causing the rest of the growth adding more to the bottom of the new growth. So now the growth ring is lower in each successive growth period. The growing, pliable bone conforms to the scute - which retains the same thickness, but is forced to grow downward. = Pyramided scute.
No. The scute grows at the edges. This new keratin as it fills in is moist on the bottom (in contact with rich blood supply and living bone) while exposed on top. If subject to drying conditions, it will dry out more on the top of the new growth - becoming stiffer, and more resistant to new cell growth. So since the scute retains it same thickness as it expands, this forces more of the growth on to the bottom of the new portion - this makes the new growth ring lower than the previous. Let me redraw what I showed in a previous post.View attachment 179635

Let's call this a three growth spurt tortoise. In the wild could well coincide with a three year old. The top one would be growing with a more balanced hydration differential top vs bottom of new growth of scute. The new growth would add cells and expands pretty balanced top and bottom. We would see a growth ring, but it's ridge is level with the original scute and subsequent 'rings".

The second would be where the new keratin is forming in too dry conditions. This does cause the keratin to stiffen and become very resistant, causing the rest of the growth adding more to the bottom of the new growth. So now the growth ring is lower in each successive growth period. The growing, pliable bone conforms to the scute - which retains the same thickness, but is forced to grow downward. = Pyramided scute.
Got ya. I was assuming everytime the keratin comes from the centre of the scute, your saying the next bout of new keratin starts from the end of the last growth.
Not disagreeing, I'm purposely trying to think of something that goes against this so it's full proof.
What happens when the tort stops growing and the keratin keeps growing. My old wc torts plastron and carapace is super thick.

One of my 3 juveniles has minor pyramiding, he's also a greedy sod, if he eats more protein that then creates more keratin but all 3 get same soaks and humidity levels, what happens? I'm thinking that humidity and rain from above overcompensates for any variation in protein intake within a species in the wild. Hydrating from below doesn't quite compensate for protein variation intake because the amount or speed of keratin growth is relevant to protein intake.
 

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Got ya. I was assuming everytime the keratin comes from the centre of the scute, your saying the next bout of new keratin starts from the end of the last growth.
Not disagreeing, I'm purposely trying to think of something that goes against this so it's full proof.
What happens when the tort stops growing and the keratin keeps growing. My old wc torts plastron and carapace is super thick.

One of my 3 juveniles has minor pyramiding, he's also a greedy sod, if he eats more protein that then creates more keratin but all 3 get same soaks and humidity levels, what happens? I'm thinking that humidity and rain from above overcompensates for any variation in protein intake within a species in the wild. Hydrating from below doesn't quite compensate for protein variation intake because the amount or speed of keratin growth is relevant to protein intake.
I would still advocate a relatively low protein diet. I referenced protein earlier in regard to keratin production, but agree with @DPtortiose in that it doesn't take much. I was referring to a few times, years ago, out of frustration, I kept trying artificially lower and lower protein as that was promoted as a cause of pyramiding. It didn't work - they still pyramided.

The more I learn the more I stay to the belief that the keratin and scute formation is pretty even and uniform, and once laid down, stays that way. So would resist the idea of more protein = more keratin / thicker scutes. Wear changes that, of course and we see old, wild tortoises with extremely worn scutes.
 
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