Dissection.

[Anyfoot]

If your squeamish don’t read this thread.

This tortoise was 5 months old.
SCL is 66mm
Weight is 57g
Carapace weight is 14g.

I had one of my 5 month old babies die a couple days ago. Why it died I don’t know. The other 23 babies are thriving.
I’ve noticed that they are all getting that crevice that I dread, and as usual it’s around the 5 month old period. I reckon I’ve got about a 30% rate of growing smooth tortoises. So from super smooth to pyramided. I’ve tried every single diet, hydration method you can think of and still I get a variation in growth.
There’s on going debates regarding pyramiding, grow them slow and keep them wet being the main two methods.
All my babies and I mean every single one are super smooth up until around the 5 month old stage. Then for some reason some of them start to pyramid at different degrees. This always coincides with that first crevice.
These (now) 23 babies are in a closed system with no intense heat spots, I have a uvb tube over the feeding area, I soak them daily, I spray them regularly and the humidity is 99%. I have fed zero protein until today.
Because we’ve had such a hot summer the weeds have struggled to grow in 2018, the majority of food has been grocery bought greens, with occasional mushroom and fruit. I’ve sprinkles nutrobal on food every other day.

In an attempt to learn more about how they grow I’ve dissected the baby that died. Disgusting I know, but sick of 2nd guessing how these animals grow at such a young age.

Here are some photos that I have taken.



You’ll have to excuse me because I’m an engineer, not a scientist or biologist and I’m out of my comfort zone. Please, anyone who can speak on a more professional term about this, then do so. My version is the lame mans version

From what I’m seeing it’s basically a frame made up of bones, the spine and 16 ribs with a canopy(carapace) of bone and keratin laid over the frame. All the areola are anchored down to the ribs, The ribs, 8 on each side come from the spine down to marginal scutes 3 to 10 and to the opposite numbers.
I’m not seeing any fontanels at this age, the whole carapace is very very flexible.

I cut it length ways down the middle of the coastal areola. You can see where that crevice is digging into the bone at the 5 month mark. You can also see that the keratin is a constant thickness(about 0.2mm). I’m not see any thickening of keratin where it expands to fill the crevice.
So that means that unless the bone grows thicker and pushes the supple keratin up it will always remain a groove.
I then made a 2nd cut vertically through the coastal scute to see if it was the ribs that are causing crevice, as I thought it is not. Because the crevice between marginal and coastal scute is the same, the keratin is dig into the bone.

Thinking outside the box knowing that there are many well respected breeders on here, and I do listen too every one. Some say slow growth and some say hydration. Imo both have valid points and both methods produce smooth and bumpy tortoises. For this reason we are not on the right track. I we can not produce 100% smooth tortoises then we haven’t nailed it.

Soooo.... this is where I could get shot down and I’m pretty certain I’ve not thought of everything and I may well be off the right track.

If we imagine a tortoises carapace and bone framework like an umbrella. When we open an umbrella it pulls the fabric taut and creates a smooth tight canopy. (Or a tent).
If we don’t get the spine and ribs to grow strong and healthy it will not pull the carapace taut. This combined with growing too dry or too wet may cause pyramiding.
If we grow the bone frame in a dry climate then all that’s happening is it’s pushing the areola away from the seems of the scutes creating pyramiding because the seems are not flexible.

If we grow them slow in a dry climate then the carapace and keratin are forced to push on each other, it will force the keratin to push down into the bone.

If we grow them slow and wet then the carapace and keratin are not kept taut because it’s too flexible and not being stretched.

If we grow the bone framework fast and keep the tortoise hydrated it will keep the supple carapace taut and in theory grow smooth. (I’m hoping).

The only way to get bones to grow strong and fast is protein. This doesn’t necessarily mean animal protein. It could be plant protein. I’m pretty sure my diet is not good regarding protein because I’ve had to rely on grocery greens for most part.
Then I ask myself, so why would they grow smooth for 5 months then all of a sudden pyramid slightly. I can only think the initial eggsack supply of protein has come to an end.
I know there are thoughts about kidney damage with higher protein. Higher protein levels also increase calcium absorption I believe.
Maybe they require higher protein levels for a short while when young and as they grow to adult hood that changes. Maybe insects and bugs are a big part of the diet whilst young to get the boost for the bone framework to grow fast and strong. They would also get the vitamins required from let’s say, ants.

When we say vitamin D is a soluble vitamin that can be stored in fat, where are the fat stores. In the blood?

I keep thinking back to my baby homeana. 90% protein and they’ve all grown on to be super smooth and seem healthy.
I also keep thinking back to the first 3 redfoots I raised, being a novice I fed them everything and anything. Loads of protein. They all grew up smooth.
Then I seen Carl’s Feral redfoot. That doesn’t look like it’s grown slow to me.
Is there main priority as a hatching to find rich foods and methods of hydration.

Has anyone ever raised them on a high protein diet with high hydration until their carapace and plastron become hard?

Even if I’m 100% wrong and way off with this ludicrous thought, it doesn’t matter if someone else can think of something more realistic from these photos.

What I’ve learnt from dissecting this tort is, there’s no fontanels and the keratin doesn’t seem to swell up. The keratin and carapace bone can not be split apart which suggests they grow in tandem.

If the bone framework grows too slow it can not keep the carapace taut. If the carapace is kept too dry it will deform the bone framework is what I’m thinking.

Need a beer.

 

[Markw84]

Love your experiment and investigation here. I have not had a chance to respond to some of your later emails about this project yet as I was out yesterday afternoon. When I got back on the computer now and saw this, though I would respond here.

So much to respond to. I do see things quite a bit differently than you here. First, perhaps a bit of explanation on bone growth. The framework for bone first starts as cartilage. As vertebrates develop and grow that cartilage is the encased or replace by ossification and becomes bone. For example, when you look at pictures of embryos, what you see as developing skeleton is all cartilage, not bone. Most of the rib growth in a tortoise shell is going on through endochondral ossification. The cartilage will be repaced by bone, but the process takes quite a while. This will replace the cartilage with bone and the bone will eventually fill in and thicken as it grows. In this tortoise I see mostly cartilage, in the mid to lower costal regions. Towards the spine you can see thickened areas of paired ribs. That is where bone is building. Fontanelles are not open areas - as "nothing" there. Fontanelles are open areas of bone development where the bone has not yet replaced the cartilage. A good portion of this carapace is still cartilage. In your earlier dissection pictures you can even see the translucent nature of the cartilage as you can see the areolae of the costals through the inside of the carapace. A good portion of the plastron is also cartilage and initially thicker than carapace cartilage protecting the vital organs, yet still somewhat pliable.

The areolae is not truly connected to bone (or cartilage). It does remain over the same original area as the tortoise grows, however. Bone growth does not only happen at bone sutures as bones can lengthen and scute seams do not coincide with bone sutures. A very important strength adaptation. So the scute is "floating" over the bones with sometimes a few bones beneath a single scute, and a vertebral scute as well as a costal over the same rib, for example. There is a vital, thin epithelial layer separating the two. The area of bone under the original areolae location does remains constant.

Much of what you see as groove, is what I see as the epithelial layer fold, that is the site of Keratin production. This is the seams of the scutes as - in tortoises, the only place of any substantial new keratin growth is at the scute seams. This is (extremely simplistically) sort of like a hair follicle would be to hair production. Since this is at scute seams, as pyramiding, or a growth seam develops, this is the center of where bone would be deflected by downward pressure of the forming keratin.

As you can see from your dissection, the first places to ossify and become harder bone, is from the spine outward. With this tortoise, the areas under the vertebrals is already well into ossification and bone thickness is already building. That is why we see pyramiding in young tortoises happening around the vertebral scutes while the lower costal scute seams will remain flat. There is no bone to reform there yet. It is only older tortoises that can develop some pyramiding of the lower costals when the bone more fully develops there.

These types of observations are a lot of what helped me develop my theory on how pyramiding works. And seeing the development in this tortoise fits everything perfectly.

As to your umbrella analogy - I do not see this holding value in relation to pyramiding. In fact, in cases of severe dehydration in young tortoises, you actually see the opposite happening where the cartilage looses so much water that the scutes actually sink in a bit and there is an upward ridge at the scute seams. The exact opposite of pyramiding. You see this most obviously in the plastron in severely dehydrated tortoises and turtles. But dehydration to that extreme is causing far more damage than just pyramiding.

I still firmly believe that pyramiding is caused by pressure on the epithelial layer causes osteoclast genesis. Actual bone loss to relieve the pressure. Osteoblast genesis will happen on the reverse side of the bone as more cells are called into play to build new bone there and retain thickness to the overall bone. This reshapes the bone creating the valleys. This has not happened yet in this tortoise. At this stage it is still simply a groove that could be just a growth ring, but has not yet developed into the beginning of pyramiding.

I love all the experiments and questions you come up with. Thank you, Craig!

 

[TechnoCheese]

This is extremely interesting. I am definitely not knowledgeable to give theories, but I can’t wait to see other people’s thoughts.

 

[Anyfoot]

Love your experiment and investigation here. I have not had a chance to respond to some of your later emails about this project yet as I was out yesterday afternoon. When I got back on the computer now and saw this, though I would respond here.

So much to respond to. I do see things quite a bit differently than you here. First, perhaps a bit of explanation on bone growth. The framework for bone first starts as cartilage. As vertebrates develop and grow that cartilage is the encased or replace by ossification and becomes bone. For example, when you look at pictures of embryos, what you see as developing skeleton is all cartilage, not bone. Most of the rib growth in a tortoise shell is going on through endochondral ossification. The cartilage will be repaced by bone, but the process takes quite a while. This will replace the cartilage with bone and the bone will eventually fill in and thicken as it grows. In this tortoise I see mostly cartilage, in the mid to lower costal regions. Towards the spine you can see thickened areas of paired ribs. That is where bone is building. Fontanelles are not open areas - as "nothing" there. Fontanelles are open areas of bone development where the bone has not yet replaced the cartilage. A good portion of this carapace is still cartilage. In your earlier dissection pictures you can even see the translucent nature of the cartilage as you can see the areolae of the costals through the inside of the carapace. A good portion of the plastron is also cartilage and initially thicker than carapace cartilage protecting the vital organs, yet still somewhat pliable.

The areolae is not truly connected to bone (or cartilage). It does remain over the same original area as the tortoise grows, however. Bone growth does not only happen at bone sutures as bones can lengthen and scute seams do not coincide with bone sutures. A very important strength adaptation. So the scute is "floating" over the bones with sometimes a few bones beneath a single scute, and a vertebral scute as well as a costal over the same rib, for example. There is a vital, thin epithelial layer separating the two. The area of bone under the original areolae location does remains constant.

Much of what you see as groove, is what I see as the epithelial layer fold, that is the site of Keratin production. This is the seams of the scutes as - in tortoises, the only place of any substantial new keratin growth is at the scute seams. This is (extremely simplistically) sort of like a hair follicle would be to hair production. Since this is at scute seams, as pyramiding, or a growth seam develops, this is the center of where bone would be deflected by downward pressure of the forming keratin.

As you can see from your dissection, the first places to ossify and become harder bone, is from the spine outward. With this tortoise, the areas under the vertebrals is already well into ossification and bone thickness is already building. That is why we see pyramiding in young tortoises happening around the vertebral scutes while the lower costal scute seams will remain flat. There is no bone to reform there yet. It is only older tortoises that can develop some pyramiding of the lower costals when the bone more fully develops there.

These types of observations are a lot of what helped me develop my theory on how pyramiding works. And seeing the development in this tortoise fits everything perfectly.

As to your umbrella analogy - I do not see this holding value in relation to pyramiding. In fact, in cases of severe dehydration in young tortoises, you actually see the opposite happening where the cartilage looses so much water that the scutes actually sink in a bit and there is an upward ridge at the scute seams. The exact opposite of pyramiding. You see this most obviously in the plastron in severely dehydrated tortoises and turtles. But dehydration to that extreme is causing far more damage than just pyramiding.

I still firmly believe that pyramiding is caused by pressure on the epithelial layer causes osteoclast genesis. Actual bone loss to relieve the pressure. Osteoblast genesis will happen on the reverse side of the bone as more cells are called into play to build new bone there and retain thickness to the overall bone. This reshapes the bone creating the valleys. This has not happened yet in this tortoise. At this stage it is still simply a groove that could be just a growth ring, but has not yet developed into the beginning of pyramiding.

I love all the experiments and questions you come up with. Thank you, Craig!

Thank you Mark.
I here what your saying about sunken scutes regarding total dehydration.
Almost the entire carapace and plastron is yet to ossify. At this stage it’s like boot leather. Very floppy.

I can not see any bones what’s so ever in the plastron not even down the length of the seam. Which makes sense with soaking the eggsack up and then the healing process.
So why don’t we have a problem with the plastron pyramiding? There’s no bones to interfere like on the plastron, well that and the fact the carapace is a curvature.

That means for the plastron we are waiting for the ossification of the bone alone to gain rigidity.
Same surely applies to the carapace, except we are dealing with a bone structure too. The bone structure is growing outwards constantly in every direction from where the hatchling first started out.(the carcass is getting bigger). With that we have ribs, spine and scute plates which are all either bone or cartilage. Is that correct?
On top of the scute plates which is still cartilage we have a layer of keratin growing at the scute seams. In my case you can see how the keratin is in a downward position digging into the cartilage at the seams.
How can a soft playable cartilage push that keratin back level? And why as it taken 5 months for me to see an irregular growth pattern.

I now understand when a the scute plates are totally ossified that the keratin growth no longer dictates to the hard ossified bone plates.

Is there a way to speed up ossification, what causes the actual ossification of cartilage to bone. Vitamin D, calcium???? Is protein a major player in that process.

If you are correct then my tortoises in no way should pyramid. There is not a cat in hells chance that these tortoises are dehydrated.

After I posted this I went back to look at the plastron cause I wasn’t sure if there was any bones in it. Here are a few photos.
What I did notice is the keratin dips in at the seam just like on the carapace. This supports your theory IMO.

I have to say, I’m absolutely dumbfound with how little there is to a tortoise once you’ve taken all the organs out. I expected to see a scaffolding of bones.

Where is the fat in a tortoise?

 

[Markw84]

yCraig. Easier to answer by copying your text and answering with my thoughts in blue.

I here what your saying about sunken scutes regarding total dehydration.
Almost the entire carapace and plastron is yet to ossify. At this stage it’s like boot leather. Very floppy.

I can not see any bones what’s so ever in the plastron not even down the length of the seam. Which makes sense with soaking the eggsack up and then the healing process.
So why don’t we have a problem with the plastron pyramiding? There’s no bones to interfere like on the plastron, well that and the fact the carapace is a curvature.

Ground contact. The plastron is almost constantly in contact with the soil. The tortoise chooses moist spots to stay. No dehydration. I believe young tortoises in the wild remain buried almost all the time. Soil, or leaf litter, mud, etc. We alter that in captivity. Even with high humidity, you will still have desiccation, especially under lamps where enclosure temps are higher and therefore humidity lower. Plus the desiccation of IR. Let alone the fact that many keeper use very barren, unnatural enclosures even when humidity is high.

That means for the plastron we are waiting for the ossification of the bone alone to gain rigidity.
Same surely applies to the carapace, except we are dealing with a bone structure too. The bone structure is growing outwards constantly in every direction from where the hatchling first started out.(the carcass is getting bigger). With that we have ribs, spine and scute plates which are all either bone or cartilage. Is that correct?
On top of the scute plates which is still cartilage we have a layer of keratin growing at the scute seams. In my case you can see how the keratin is in a downward position digging into the cartilage at the seams.

Scute plates are always keratin. Scutes are never cartilage. Bone begins as cartilage. I believe a lot of what we are seeing in your dissection is the epithelial layer fold. That is the area of new keratin production. It is produced there and flows into the seams created by growth and the carapace expansion. The bone is growing, so the scutes are being pulled apart. The epithelial fold is the "keratin follicle" that is producing new keratin to fill in that gap.

How can a soft playable cartilage push that keratin back level?

Cartilage is not being deformed. It does not dissolve and get removed by metabolic processes like bone would here. So although the keratin may be drying on top and grow more downward, that downward pressure is not removing cartilage. It remains and the keratin is pushed level. With bone, the pressure on the epithelial layer, as the new keratin fills in next to the epithelial fold, actually causes osteoclast genesis. That means a type of stem cell that epithelial tissue can contain, actually turns into cells that absorb existing bone - osteoclasts. Bone is dissolved. This creates a permanent dip in the bone that cannot "spring back". Bone growth is being redirected. This cannot happen with cartilage. It can only happen when cartilage has ossified into bone.

And why as it taken 5 months for me to see an irregular growth pattern.

Good question. We can only conjecture as you have. I would say that there is a natural pattern of growth activity. In nature it coincides with weather and food availability. Perhaps tortoises are inclined to grow optimally for several months, then metabolically redistribute nutrients/growth/let keratin production "reset"?? Perhaps bone growth goes through periods of more thickening vs lengthening. Keratin production would have to vary to accommodate any changes.

I now understand when a the scute plates are totally ossified that the keratin growth no longer dictates to the hard ossified bone plates.

No sure if I follow this statement. We are talking two totally different processes. Scute, and bones. Scutes do not ossify. They are keratin. They grow and expand by new keratin added at the seams only. Bones are separated by sutures. They first form as cartilage and ossify to bone. As "hard" bone, that is when pyramiding can occur. The pressure at scute seams actually deforms hard bone below. The older the tortoise is, the more ossified the bone. The older the bone, the more resistant it appears to get to this reforming. I would conjecture because of the relative size of the bone to the size of the reforming at the seam. A young tortoise has a scute seam much larger as a percentage of the total scute width.

Is there a way to speed up ossification, what causes the actual ossification of cartilage to bone. Vitamin D, calcium???? Is protein a major player in that process.

My current belief would be - no. Fast or slow growth, ossification seems to take time. The portions of the carapace and the pace at which they ossify seems to be independent of speed of growth. Bone is a collagen framework hardened by Calcium and Phosphorus. The collage is protein based. So some protein is a necessary component and major player to growth in general.

If you are correct then my tortoises in no way should pyramid. There is not a cat in hells chance that these tortoises are dehydrated.

I think we need to think of ways keratin could have surface desiccation at a growth seam as opposed to a general metabolic dehydration. Can be two very different things. As I noted in my more detail explanation of my pyramiding thesis, tortoise keratin is the only keratin I know of in nature that is exposed while still in the forming stage. Internal hydration would only effect the inner side of the keratin of a scute. It is the outer surface that is exposed to the elements that causes the pyramiding effect. All other keratin in animals is protected by tissue while forming. I believe tortoises have evolved with the "habits" to stay buried and protected to compensated during their more fragile growth stages. Plant cover, mud, moist soil, leaf litter.

After I posted this I went back to look at the plastron cause I wasn’t sure if there was any bones in it. Here are a few photos.
What I did notice is the keratin dips in at the seam just like on the carapace. This supports your theory IMO.

Yes, the dip is the epithelial fold.

I have to say, I’m absolutely dumbfound with how little there is to a tortoise once you’ve taken all the organs out. I expected to see a scaffolding of bones.

Where is the fat in a tortoise?

Another tortoise myth! Tortoises do not get fat. Checking weight prior to brumation is checking hydration, not fat stores. Mammals and endotherms (homeotherms) use fat as insulation and energy stores when metabolic activity must be maintained even if food availability drops. Tortoises evolved a different strategy. They do not need to maintain any body heat metabolically. When food availability drops, they shut down their metabolism. As ectotherms, they do not need insulation. It would do no good. They also use glycogen levels to store the energy they do need for the little metabolic activity in periods of dormancy. This is stored in the blood stream and intercellular. They do have some small fat stores, but nothing like you would see in the intramuscular and subcutaneous fat stores you are used to seeing in mammals.

 

[Anyfoot]

yCraig. Easier to answer by copying your text and answering with my thoughts in blue.

I here what your saying about sunken scutes regarding total dehydration.
Almost the entire carapace and plastron is yet to ossify. At this stage it’s like boot leather. Very floppy.

I can not see any bones what’s so ever in the plastron not even down the length of the seam. Which makes sense with soaking the eggsack up and then the healing process.
So why don’t we have a problem with the plastron pyramiding? There’s no bones to interfere like on the plastron, well that and the fact the carapace is a curvature.

Ground contact. The plastron is almost constantly in contact with the soil. The tortoise chooses moist spots to stay. No dehydration. I believe young tortoises in the wild remain buried almost all the time. Soil, or leaf litter, mud, etc. We alter that in captivity. Even with high humidity, you will still have desiccation, especially under lamps where enclosure temps are higher and therefore humidity lower. Plus the desiccation of IR. Let alone the fact that many keeper use very barren, unnatural enclosures even when humidity is high.

That means for the plastron we are waiting for the ossification of the bone alone to gain rigidity.
Same surely applies to the carapace, except we are dealing with a bone structure too. The bone structure is growing outwards constantly in every direction from where the hatchling first started out.(the carcass is getting bigger). With that we have ribs, spine and scute plates which are all either bone or cartilage. Is that correct?
On top of the scute plates which is still cartilage we have a layer of keratin growing at the scute seams. In my case you can see how the keratin is in a downward position digging into the cartilage at the seams.

Scute plates are always keratin. Scutes are never cartilage. Bone begins as cartilage. I believe a lot of what we are seeing in your dissection is the epithelial layer fold. That is the area of new keratin production. It is produced there and flows into the seams created by growth and the carapace expansion. The bone is growing, so the scutes are being pulled apart. The epithelial fold is the "keratin follicle" that is producing new keratin to fill in that gap.

How can a soft playable cartilage push that keratin back level?

Cartilage is not being deformed. It does not dissolve and get removed by metabolic processes like bone would here. So although the keratin may be drying on top and grow more downward, that downward pressure is not removing cartilage. It remains and the keratin is pushed level. With bone, the pressure on the epithelial layer, as the new keratin fills in next to the epithelial fold, actually causes osteoclast genesis. That means a type of stem cell that epithelial tissue can contain, actually turns into cells that absorb existing bone - osteoclasts. Bone is dissolved. This creates a permanent dip in the bone that cannot "spring back". Bone growth is being redirected. This cannot happen with cartilage. It can only happen when cartilage has ossified into bone.

And why as it taken 5 months for me to see an irregular growth pattern.

Good question. We can only conjecture as you have. I would say that there is a natural pattern of growth activity. In nature it coincides with weather and food availability. Perhaps tortoises are inclined to grow optimally for several months, then metabolically redistribute nutrients/growth/let keratin production "reset"?? Perhaps bone growth goes through periods of more thickening vs lengthening. Keratin production would have to vary to accommodate any changes.

I now understand when a the scute plates are totally ossified that the keratin growth no longer dictates to the hard ossified bone plates.

No sure if I follow this statement. We are talking two totally different processes. Scute, and bones. Scutes do not ossify. They are keratin. They grow and expand by new keratin added at the seams only. Bones are separated by sutures. They first form as cartilage and ossify to bone. As "hard" bone, that is when pyramiding can occur. The pressure at scute seams actually deforms hard bone below. The older the tortoise is, the more ossified the bone. The older the bone, the more resistant it appears to get to this reforming. I would conjecture because of the relative size of the bone to the size of the reforming at the seam. A young tortoise has a scute seam much larger as a percentage of the total scute width.

Is there a way to speed up ossification, what causes the actual ossification of cartilage to bone. Vitamin D, calcium???? Is protein a major player in that process.

My current belief would be - no. Fast or slow growth, ossification seems to take time. The portions of the carapace and the pace at which they ossify seems to be independent of speed of growth. Bone is a collagen framework hardened by Calcium and Phosphorus. The collage is protein based. So some protein is a necessary component and major player to growth in general.

If you are correct then my tortoises in no way should pyramid. There is not a cat in hells chance that these tortoises are dehydrated.

I think we need to think of ways keratin could have surface desiccation at a growth seam as opposed to a general metabolic dehydration. Can be two very different things. As I noted in my more detail explanation of my pyramiding thesis, tortoise keratin is the only keratin I know of in nature that is exposed while still in the forming stage. Internal hydration would only effect the inner side of the keratin of a scute. It is the outer surface that is exposed to the elements that causes the pyramiding effect. All other keratin in animals is protected by tissue while forming. I believe tortoises have evolved with the "habits" to stay buried and protected to compensated during their more fragile growth stages. Plant cover, mud, moist soil, leaf litter.

After I posted this I went back to look at the plastron cause I wasn’t sure if there was any bones in it. Here are a few photos.
What I did notice is the keratin dips in at the seam just like on the carapace. This supports your theory IMO.

Yes, the dip is the epithelial fold.

I have to say, I’m absolutely dumbfound with how little there is to a tortoise once you’ve taken all the organs out. I expected to see a scaffolding of bones.

Where is the fat in a tortoise?

Another tortoise myth! Tortoises do not get fat. Checking weight prior to brumation is checking hydration, not fat stores. Mammals and endotherms (homeotherms) use fat as insulation and energy stores when metabolic activity must be maintained even if food availability drops. Tortoises evolved a different strategy. They do not need to maintain any body heat metabolically. When food availability drops, they shut down their metabolism. As ectotherms, they do not need insulation. It would do no good. They also use glycogen levels to store the energy they do need for the little metabolic activity in periods of dormancy. This is stored in the blood stream and intercellular. They do have some small fat stores, but nothing like you would see in the intramuscular and subcutaneous fat stores you are used to seeing in mammals.

We are on the same page regarding “scute plate”. My bad. I was referring to the bone underlying the scute keratin plate. The bone can’t be a scute plate because scute plates seams and bone sutures overlap creating a brick effect. Correct?

Can they store vitamin D in the fats of the blood stream?

If my tortoise pyramid Mark and we make the assumption that it is hydration that causes pyramiding.
Then it’s because they have stopped hiding under the moss. They’ve started sitting on top of the moss, all big and bold. They’ve tamed up.
But this also means 99% relative humidity at 82/83f and daily soaks is not fullproof.

What do you think about them getting a storage of protein from the eggsack? How long would that initial source last(5 months maybe).

 

[Anyfoot]

If the carapace ossification is a set period of time and not relative to tortoise general growth then surely growing them slow whilst waiting for ossification would be the best case for keeping the carapace in shape.

Theoretically speaking, if we didn’t grow the tortoise at all and waited for ossification and then grew it the carapace bone would have to follow its natural path.
Im thinking the more advanced we grow it in size whilst carapace is still cartilage the more unstable the whole structure of the the carapace becomes.(pyramiding).

 

[Yvonne G]

I'm still not quite sure what you are referring to as the crevice. So you mean the space between the scutes where the new growth happens?

 

[Anyfoot]

I'm still not quite sure what you are referring to as the crevice. So you mean the space between the scutes where the new growth happens?

Yes. You can see a gap between scutes. Up until this growth gap(crevice) you could only see a very thin white line of keratin following the growth. The thin white lines give a very smooth carapace. When I see the wider growth crevice, it’s then when there’s a chance of pyramiding to follow. I like to see the very thin white lines.
Give me a minute and I will find a couple of photos showing the crevice in a 5 month old compared to it at about 15 months old. It’s very obvious the pyramiding started from the crevice.

 

[Anyfoot]

Look at the wider growth ring(crevice) on the front coastal scute that appeared at 5 months old. Then look at where the pyramiding started on the 15month old photo. My care did not change.
My opinion is either lack of protein or there habits change and they stop digging into the moss which keeps the carapace moist.

 

[Markw84]

If the carapace ossification is a set period of time and not relative to tortoise general growth then surely growing them slow whilst waiting for ossification would be the best case for keeping the carapace in shape.

Theoretically speaking, if we didn’t grow the tortoise at all and waited for ossification and then grew it the carapace bone would have to follow its natural path.
Im thinking the more advanced we grow it in size whilst carapace is still cartilage the more unstable the whole structure of the the carapace becomes.(pyramiding).

I certainly do see things the way you do here! I see "slow growing" a tortoise as purposely retarding growth. To do that you limit the nutritional items it needs to grow. A tortoise has evolved the ability to slow down its metabolism to accommodate that. Not because it is healthy, but because it is a survival not thriving mechanism. The more the metabolism slows (the less nutritional value it gets) the more vital metabolic functions have to be slowed or stopped to conserve resources. Giant tortoises were known for their ability to live up to a year with no food - hence their use by sailors as a source of fresh meat for up to a year after their last chance to supply their ships. That doesn't mean the tortoises did well, or benefited from not growing. It means they have the ability to shut down most metabolic processes to survive. I believe this happened as tortoise were left in "left over" habitats as mammals out competed them and took over all the more favorable habitat locations. So their "strategy" was to be able to survive where others could not as opposed to competing for prime habitat. This strategy means most of them die. It is very risky. Larger reproductive output to generate very few successful individuals. Look at sulcatas - an adult female can produce well over 2000-3000 babies in her lifetime in an effort to replace herself and a mate. That's a goal of 2 out of 3000 if populations are stable, 3 out of 3000 if populations are growing!

So is the ability to slow metabolism an indication of prime condition? I don't believe so at all. What animal do we ever consider purposefully stunting their growth to help them be more healthy? The ability to shut down metabolic function is a risky survival tactic, not a tactic to improve health.

When you slow down metabolic function, growth slows. So the necessary nutrients for muscle, bone, organ growth is limited so the adaptation the tortoise has made to do these things means choices are made about what to sacrifice. True growth balance and optimal growing conditions are sacrificed. A tortoise may survive, but may live a much shorter life. May be stunted in eventual size potential. May have breeding functions reduced. May die next year? In the wild when this occurs, the tortoise also aestivates or semi-aestivates. They are not pulled from their hide and bathed every day and put in front of food. The conditions that cause slower growth also provides for this reduced activity behavior. Do you know how to create that in captivity and then retain the necessary marginal balance?

As far as reducing pyramiding, I see the opposite. Keeping parameters in balance and allowing optimal growth conditions means metabolic resources can be spent on all necessary functions. Bone ossification proceeds in proportion to overall growth. Ossification is taking place rapidly and on pace with growth. When you start slowing growth, Ossification and the needed balance between calcium phosphorus, magnesium and the proteins is very much at risk.

The pyramiding is actually not occurring over the less ossified bones. Look at the lower costals. So your idea of reducing pyramiding by allowing bone to more fully ossify before growth, means more of the tortoise will be prone to pyramid once growth begins or speeds up again. The "natural path" as you put it of bone is the path the cartilage framework provides. Once ossified is where and when bone remodeling occurs and new paths can be determined. Good growth in optimal conditions will allow the best growth outcome.

The active agent for pyramiding is the scute. Pyramiding ONLY occurs along scute patterns. Scutes only grow from the seams. So scute seams and new keratin are the only factor that drives pyramiding. Bone responds to pressure and remodels according to the pressure. The agent for this action is an epithelial layer that contains stem cells that can alter themselves into bone dissolving cells. The pressure on an epithelial layer is what triggers this osteoclast genesis. To reduce pyramiding we therefore need to think about ways to keep new keratin growing optimally and evenly developing top and bottom as it forms. An imbalance top vs bottom causes pyramiding. The bottom is in contact with the epithelial layer. Protected from any premature drying and hardening/stiffening by living tissue. The top is fully exposed. This little area controls pyramiding. Protecting this is how to affect pyramiding.

My belief is that baby tortoises "know" how to do this. They hide. Dig in and bury. They keep their shells protected by a moist layer of something. Leaf litter, mud, soil, thick grass. They do not venture out in the open. That's why they are so hard to find. I believe the ones you do occasionally find are the ones that wouldn't make it. A successful tortoise in the wild stays hidden and protected its first several years. We alter all that in captivity. We teach our baby tortoises to be bold and out begging for food. With daily baths, we show them there is nothing to feat. We place them in enclosures that are quite barren as opposed to the dense vegetation or leaf litter they would choose in the wild. I believe if it is easy to see your tortoise resting in its enclosure, your enclosure is not optimal.

 

[Markw84]

Look at the wider growth ring(crevice) on the front coastal scute that appeared at 5 months old. Then look at where the pyramiding started on the 15month old photo. My care did not change.
My opinion is either lack of protein or there habits change and they stop digging into the moss which keeps the carapace moist.

Maybe at 5 months, we simply have well trained, unafraid, bold baby tortoises who no longer feel the need to be protected?????

 

[Anyfoot]

I certainly do see things the way you do here! I see "slow growing" a tortoise as purposely retarding growth. To do that you limit the nutritional items it needs to grow. A tortoise has evolved the ability to slow down its metabolism to accommodate that. Not because it is healthy, but because it is a survival not thriving mechanism. The more the metabolism slows (the less nutritional value it gets) the more vital metabolic functions have to be slowed or stopped to conserve resources. Giant tortoises were known for their ability to live up to a year with no food - hence their use by sailors as a source of fresh meat for up to a year after their last chance to supply their ships. That doesn't mean the tortoises did well, or benefited from not growing. It means they have the ability to shut down most metabolic processes to survive. I believe this happened as tortoise were left in "left over" habitats as mammals out competed them and took over all the more favorable habitat locations. So their "strategy" was to be able to survive where others could not as opposed to competing for prime habitat. This strategy means most of them die. It is very risky. Larger reproductive output to generate very few successful individuals. Look at sulcatas - an adult female can produce well over 2000-3000 babies in her lifetime in an effort to replace herself and a mate. That's a goal of 2 out of 3000 if populations are stable, 3 out of 3000 if populations are growing!

So is the ability to slow metabolism an indication of prime condition? I don't believe so at all. What animal do we ever consider purposefully stunting their growth to help them be more healthy? The ability to shut down metabolic function is a risky survival tactic, not a tactic to improve health.

When you slow down metabolic function, growth slows. So the necessary nutrients for muscle, bone, organ growth is limited so the adaptation the tortoise has made to do these things means choices are made about what to sacrifice. True growth balance and optimal growing conditions are sacrificed. A tortoise may survive, but may live a much shorter life. May be stunted in eventual size potential. May have breeding functions reduced. May die next year? In the wild when this occurs, the tortoise also aestivates or semi-aestivates. They are not pulled from their hide and bathed every day and put in front of food. The conditions that cause slower growth also provides for this reduced activity behavior. Do you know how to create that in captivity and then retain the necessary marginal balance?

As far as reducing pyramiding, I see the opposite. Keeping parameters in balance and allowing optimal growth conditions means metabolic resources can be spent on all necessary functions. Bone ossification proceeds in proportion to overall growth. Ossification is taking place rapidly and on pace with growth. When you start slowing growth, Ossification and the needed balance between calcium phosphorus, magnesium and the proteins is very much at risk.

The pyramiding is actually not occurring over the less ossified bones. Look at the lower costals. So your idea of reducing pyramiding by allowing bone to more fully ossify before growth, means more of the tortoise will be prone to pyramid once growth begins or speeds up again. The "natural path" as you put it of bone is the path the cartilage framework provides. Once ossified is where and when bone remodeling occurs and new paths can be determined. Good growth in optimal conditions will allow the best growth outcome.

The active agent for pyramiding is the scute. Pyramiding ONLY occurs along scute patterns. Scutes only grow from the seams. So scute seams and new keratin are the only factor that drives pyramiding. Bone responds to pressure and remodels according to the pressure. The agent for this action is an epithelial layer that contains stem cells that can alter themselves into bone dissolving cells. The pressure on an epithelial layer is what triggers this osteoclast genesis. To reduce pyramiding we therefore need to think about ways to keep new keratin growing optimally and evenly developing top and bottom as it forms. An imbalance top vs bottom causes pyramiding. The bottom is in contact with the epithelial layer. Protected from any premature drying and hardening/stiffening by living tissue. The top is fully exposed. This little area controls pyramiding. Protecting this is how to affect pyramiding.

My belief is that baby tortoises "know" how to do this. They hide. Dig in and bury. They keep their shells protected by a moist layer of something. Leaf litter, mud, soil, thick grass. They do not venture out in the open. That's why they are so hard to find. I believe the ones you do occasionally find are the ones that wouldn't make it. A successful tortoise in the wild stays hidden and protected its first several years. We alter all that in captivity. We teach our baby tortoises to be bold and out begging for food. With daily baths, we show them there is nothing to feat. We place them in enclosures that are quite barren as opposed to the dense vegetation or leaf litter they would choose in the wild. I believe if it is easy to see your tortoise resting in its enclosure, your enclosure is not optimal.

I’ve gone around this circle numerous times and now back full circle again. The bloody things get too tame in captivity, some still hide and some do not. That’s why I’m seeing a variation of smoothness within the same group.

Think I need a fake hawk flying through the enclosure from time to time to keep them at bay.

 

[TechnoCheese]

Maybe having a very well planted and cluttered enclosure would help?

 

[Anyfoot]

Maybe having a very well planted and cluttered enclosure would help?

I’ve done it. It doesn’t work. They need to be lost in the ground. These 23 I’m raising now, up until about 4 week ago I had to dig down into the substrate to find them. I’m not exaggerating, it could take me a good 20minutes to find them all in a 4x8 vivarium. They would dig into the coir 2 or 3” below the moss. Impossible to see. Feel around by digging fingers in.

 

[Markw84]

I am intrigued by the use of coconut oil. since we are altering their behavior plus - what fun is a tortoise you can never see! - perhaps we need to help with altered ways of retaining moisture. There have been a few example on the forum of one keeper I know who admitted to being sloppy about humidity, had open top, and bathed irregularly but had a quite nice, smooth tortoise - I recall leopard? She said she was good at keeping coconut oil on after every bath that was normally about 2x week. I also always am impressed with @Pearly 's redfoots and I know she says she uses oil regularly.

It seems to be something that would have value. Have you tried a strict regimen of keeping cold pressed coconut oil on the carapace? Since the carapace is totally keratin, oil would have great value in keeping it more supple. That is on my list of experiments for this next year.

 

[Anyfoot]

I am intrigued by the use of coconut oil. since we are altering their behavior plus - what fun is a tortoise you can never see! - perhaps we need to help with altered ways of retaining moisture. There have been a few example on the forum of one keeper I know who admitted to being sloppy about humidity, had open top, and bathed irregularly but had a quite nice, smooth tortoise - I recall leopard? She said she was good at keeping coconut oil on after every bath that was normally about 2x week. I also always am impressed with @Pearly 's redfoots and I know she says she uses oil regularly.

It seems to be something that would have value. Have you tried a strict regimen of keeping cold pressed coconut oil on the carapace? Since the carapace is totally keratin, oil would have great value in keeping it more supple. That is on my list of experiments for this next year.

I’ve never tried coconut oil. It’s slways kind of rubbed me up the wrong way because I see it as not natural. That said neither is keeping a tortoise in an indoor enclosure, so I’ve warmed to the method over time. It’s not what I’ll be trying out but let me know how you go on with your experiment please. I considered putting it on a selected few within a group to see if they grew smoother. But then I thought it was pointless because I get smooth to pyramided within same group now, who’s to say the ones that were coconuted weren’t going to grow smooth anyway. The only way to really test the coconut oil is to not allow any cover for them that keeps the carapace moist.

BTW, pearly also kept her torts in a well planted aquarium with a fogger, extremely wet.

 

[Anyfoot]

@Yvonne G

This is what I like to see Yvonne. Thin white lines. This one never developed a crevice, It’s nearly 20 months old now. Not sprayed these for about 3 days so that’s why his new keratin is so obvious. He’s hardened off anyway so no way will he pyramid from here on.
And a photo after spraying them.

 

[Anyfoot]

Maybe at 5 months, we simply have well trained, unafraid, bold baby tortoises who no longer feel the need to be protected?????

Exactly

 

[Kapidolo Farms]

@Markw84 are these areas of differential bone and scute growth explanations from your own observation, or from published works that come to mind as you review @Anyfoot 's post? Maybe both? Could you please offer the sources from your readings?

I am able to make a slow motion video in my minds eye of the bone filling-in/overtaking the shell's marrow from your explanation. It bears out precisely for a weird type of pyramiding seen by many in developing Pyxis planicauda. In them, as they grow, the side of the coastal scutes nearest the middle of the carapace can pyramid while the rest of the shell does not, giving them a somewhat two keeled look. Thanks much for the visually rich narrative. Exactly the sentences that I made bold. It's an explanation that fits the observation with P. planicauda.

Love your experiment and investigation here. I have not had a chance to respond to some of your later emails about this project yet as I was out yesterday afternoon. When I got back on the computer now and saw this, though I would respond here.

So much to respond to. I do see things quite a bit differently than you here. First, perhaps a bit of explanation on bone growth. The framework for bone first starts as cartilage. As vertebrates develop and grow that cartilage is the encased or replace by ossification and becomes bone. For example, when you look at pictures of embryos, what you see as developing skeleton is all cartilage, not bone. Most of the rib growth in a tortoise shell is going on through endochondral ossification. The cartilage will be repaced by bone, but the process takes quite a while. This will replace the cartilage with bone and the bone will eventually fill in and thicken as it grows. In this tortoise I see mostly cartilage, in the mid to lower costal regions. Towards the spine you can see thickened areas of paired ribs. That is where bone is building. Fontanelles are not open areas - as "nothing" there. Fontanelles are open areas of bone development where the bone has not yet replaced the cartilage. A good portion of this carapace is still cartilage. In your earlier dissection pictures you can even see the translucent nature of the cartilage as you can see the areolae of the costals through the inside of the carapace. A good portion of the plastron is also cartilage and initially thicker than carapace cartilage protecting the vital organs, yet still somewhat pliable.

The areolae is not truly connected to bone (or cartilage). It does remain over the same original area as the tortoise grows, however. Bone growth does not only happen at bone sutures as bones can lengthen and scute seams do not coincide with bone sutures. A very important strength adaptation. So the scute is "floating" over the bones with sometimes a few bones beneath a single scute, and a vertebral scute as well as a costal over the same rib, for example. There is a vital, thin epithelial layer separating the two. The area of bone under the original areolae location does remains constant.

Much of what you see as groove, is what I see as the epithelial layer fold, that is the site of Keratin production. This is the seams of the scutes as - in tortoises, the only place of any substantial new keratin growth is at the scute seams. This is (extremely simplistically) sort of like a hair follicle would be to hair production. Since this is at scute seams, as pyramiding, or a growth seam develops, this is the center of where bone would be deflected by downward pressure of the forming keratin.

As you can see from your dissection, the first places to ossify and become harder bone, is from the spine outward. With this tortoise, the areas under the vertebrals is already well into ossification and bone thickness is already building. That is why we see pyramiding in young tortoises happening around the vertebral scutes while the lower costal scute seams will remain flat. There is no bone to reform there yet. It is only older tortoises that can develop some pyramiding of the lower costals when the bone more fully develops there.

These types of observations are a lot of what helped me develop my theory on how pyramiding works. And seeing the development in this tortoise fits everything perfectly.

As to your umbrella analogy - I do not see this holding value in relation to pyramiding. In fact, in cases of severe dehydration in young tortoises, you actually see the opposite happening where the cartilage looses so much water that the scutes actually sink in a bit and there is an upward ridge at the scute seams. The exact opposite of pyramiding. You see this most obviously in the plastron in severely dehydrated tortoises and turtles. But dehydration to that extreme is causing far more damage than just pyramiding.

I still firmly believe that pyramiding is caused by pressure on the epithelial layer causes osteoclast genesis. Actual bone loss to relieve the pressure. Osteoblast genesis will happen on the reverse side of the bone as more cells are called into play to build new bone there and retain thickness to the overall bone. This reshapes the bone creating the valleys. This has not happened yet in this tortoise. At this stage it is still simply a groove that could be just a growth ring, but has not yet developed into the beginning of pyramiding.

I love all the experiments and questions you come up with. Thank you, Craig!