Is a redfoot ever “fully grown”? How do sex-specific characteristics develop, exactly?

[jockma]

Bean is recovering from a flagellate problem right now so I’m spending a lot of time wiping off diarrhea from his plastron. Today I noticed 2 things: One, he has a ton of new growth on his plastron. Two, he barely has any concavity on his plastron. He also doesn’t have much of a wasp waist yet.

~10” SCL and weighs about 8 lbs (he’s sick now so that may go up quickly in the coming months).

I assumed concavity and wasp waist played some part in reproduction, concavity obviously for the tortoise to actually mount females, not sure about the wasp waist. Yet he’s 10” long and barely has either...just a long tail.

I see some mature males with fist-sized dents in their plastron without being much bigger than Bean. I’m curious HOW the concavity would develop if he’s already 10”! Does it just cave in independently of the growth of the rest of the shell? Is it possible Bean will never have a concave plastron?

Curious.

 

[Ellen & Toby]

That is a really good question, will watch this thread with interest

 

[MysticCaribou]

Is it possible Bean is a female?

 

[Yvonne G]

I've always wondered how a seemingly hard shell can all of a sudden develop concavity too. Let's see if @Markw84 has any words of wisdom for us.

 

[Markw84]

Bone is not as hard and stable as most people would think. In all animals, bone is constantly remodeling. Most of the bone you have in you now will have been replaced within a decade. Over your lifetime, your bones will have been rebuilt several times! Older bone is constantly being dissolved and new bone formed to keep the bone stronger and doing its job. That's one reason why forensics use teeth to try to determine the age of a person's remains and not bone.

Not to get boring, but the process involves the "gensis" or creation of a cell called osteoclasts from a form of stem cell in your body. The osteoclasts are special cells that start dissolving older bone, and then osteoblast genesis also occurs to replace that with new fresh bone. But sometimes come into play when the body reshapes bone not just replacing older bone. Such as in orthodonture in moving teeth and in pyramiding in tortoises. This is acccompanied by osteoblasts genisis, which creates new cells that build new bone but in a slightly different position. With the development of secondary sexual characteristics in male tortoises, that process starts reshaping the plastral bone which makes the concavity. The bone is basically dissolved at the bottom side of the bone, while more new bone is formed on the top side of the plastral bone. With some tortoises, osteoblast genesis is triggered at the front of the gulars while no excessive osteoclast genesis is happening and the gulars start enlarging.

 

[Anyfoot]

Bean is recovering from a flagellate problem right now so I’m spending a lot of time wiping off diarrhea from his plastron. Today I noticed 2 things: One, he has a ton of new growth on his plastron. Two, he barely has any concavity on his plastron. He also doesn’t have much of a wasp waist yet.

~10” SCL and weighs about 8 lbs (he’s sick now so that may go up quickly in the coming months).

I assumed concavity and wasp waist played some part in reproduction, concavity obviously for the tortoise to actually mount females, not sure about the wasp waist. Yet he’s 10” long and barely has either...just a long tail.

I see some mature males with fist-sized dents in their plastron without being much bigger than Bean. I’m curious HOW the concavity would develop if he’s already 10”! Does it just cave in independently of the growth of the rest of the shell? Is it possible Bean will never have a concave plastron?

Curious.

My male Brazilian started to concave at around 7.5” SCL (I believe he’s a smaller species)
Over a period of about 2 yrs he went from flat to very concave. In that 2 yr period he barely gained any size at all, Maybe 1/2” on length maximum.
What makes the bone structure alter I don’t know. Why northerns wasp and Brazilians don’t is another question I’ve often asked myself.

 

[Anyfoot]

Bone is not as hard and stable as most people would think. In all animals, bone is constantly remodeling. Most of the bone you have in you now will have been replaced within a decade. Over your lifetime, your bones will have been rebuilt several times! Older bone is constantly being dissolved and new bone formed to keep the bone stronger and doing its job. That's one reason why forensics use teeth to try to determine the age of a person's remains and not bone.

Not to get boring, but the process involves the "gensis" or creation of a cell called osteoclasts from a form of stem cell in your body. The osteoclasts are special cells that start dissolving older bone, and then osteoblast genesis also occurs to replace that with new fresh bone. But sometimes come into play when the body reshapes bone not just replacing older bone. Such as in orthodonture in moving teeth and in pyramiding in tortoises. This is acccompanied by osteoblasts genisis, which creates new cells that build new bone but in a slightly different position. With the development of secondary sexual characteristics in male tortoises, that process starts reshaping the plastral bone which makes the concavity. The bone is basically dissolved at the bottom side of the bone, while more new bone is formed on the top side of the plastral bone. With some tortoises, osteoblast genesis is triggered at the front of the gulars while no excessive osteoclast genesis is happening and the gulars start enlarging.

Is the same process happening when anal scutes on a redfoot start to take shape to sexual maturity?

You know what’s coming next don’t you Mark?

 

[Markw84]

Is the same process happening when anal scutes on a redfoot start to take shape to sexual maturity?

You know what’s coming next don’t you Mark?

Bone growth occurs by osteoblast genesis and the formation of new bone cell. I would imagine the shape the anal scutes develop is a process where a localized abundance of new osteoblasts are triggered in a specific location in greater amoung than the "normal" growth of the bone. That is most likely genetically programmed. Same as the extending gulars on a sulcata or desert tortoise. The plastral concavity is bone reshaping. Existing bone is reshaped as well as simple growth. That is a process of osteoclast genesis to remove bone mass from one side while osteoblast genesis is adding more bone to the other side. I would also imagine this is genetic, however "perhaps" mounting behavior of the male putting repeated compressive force on the plastron "could" help or further trigger this.

 

[jockma]

I’m surprised the bone completely reshapes itself instead of growing outward (downward? inward?) along with the overall growth of the tortoise. My idea was that the bone will “stretch out” and take a concave shape as the tortoise gets larger and concavity would not develop if the tortoise does not grow significantly in size, therefore Bean would either be a flat boy or he’d have a massive growth spurt to accommodate the concavity. If that makes sense? I guess I couldn’t understand what would happen to their organs with that big dent in the plastron otherwise. It also surprises me that these sexual characteristics develop independently of each other, Bean’s anal scutes and tail look nearly fully developed yet he doesn’t look concave enough to mount a female without slipping off.

@MysticCaribou he is definitely male, just a few minutes ago he knocked his water bowl over and made love to it. Not bad for a sick tortoise. There is some SLIGHT concavity, just definitely not to the extent of the mature males I’ve seen on here.

@Anyfoot your boy has mine beat at 7.5” SCL! Bean looked female at 7.5” save for some slight male development of the anal scutes. Sexual maturity for torts is so confusing to me. Bean should be around 8-9 years old by now and is still growing steadily, but not sexually mature. It feels like age is irrelevant when it comes to tort sexual maturity.

 

[Anyfoot]

@Anyfoot your boy has mine beat at 7.5” SCL! Bean looked female at 7.5” save for some slight male development of the anal scutes. Sexual maturity for torts is so confusing to me. Bean should be around 8-9 years old by now and is still growing steadily, but not sexually mature. It feels like age is irrelevant when it comes to tort sexual maturity.[/QUOTE]
This guy of mine is a Brazilian, and I think his growth was stunted. His shell looks too small for his body. So this may be a bad example. But in the space of approx 2 years he went from a flat plastron to a concave plastron. He is growing very very slowly.
They all grow at different rates depending on care. Maybe your guy is just hitting maturity and you’ll see some vast changes over the coming yrs.

 

[jockma]

I had 2 vets tell me Bean’s growth was stunted as well due to bad husbandry in his early life, but that was before his growth spurts. He did not grow for almost 2 years when I first got him. I wonder if that contributes to his weird delayed puberty.

 

[Anyfoot]

I had 2 vets tell me Bean’s growth was stunted as well due to bad husbandry in his early life, but that was before his growth spurts. He did not grow for almost 2 years when I first got him. I wonder if that contributes to his weird delayed puberty.

I found mine living with a sully and 2 Herman’s in an uninsulated shed with 1 spot light between them. Living on straw. In the 5 years I’ve had him he’s gained about 1” on SCL.

 

[jockma]

I found mine living with a sully and 2 Herman’s in an uninsulated shed with 1 spot light between them. Living on straw. In the 5 years I’ve had him he’s gained about 1” on SCL.

Woah, that’s REALLY stunted. Was he extremely malnourished when you found him or did he have early stage MBD that stopped his shell and bones from growing properly? I don’t know exactly what conditions mine was living in during his early life but since he grew like a weed after the first two years I figured the “stunting” observed by the vets was a coincidence.

I’ve seen a sulcata on here whose body grew but not the shell similar to yours, I wonder if that has a specific cause or if it’s a combination of factors?

 

[Anyfoot]

Woah, that’s REALLY stunted. Was he extremely malnourished when you found him or did he have early stage MBD that stopped his shell and bones from growing properly? I don’t know exactly what conditions mine was living in during his early life but since he grew like a weed after the first two years I figured the “stunting” observed by the vets was a coincidence.

I’ve seen a sulcata on here whose body grew but not the shell similar to yours, I wonder if that has a specific cause or if it’s a combination of factors?

I suspect a touch of MBD. Rear knees were touching floor as he walked.