# Can someone answer my teenagers question!



## Peach (Oct 1, 2015)

Good afternoon guys, my teenager has got interested in our 4 spur theigh tort eggs and is now doing a project at school about tortoises, and has asked a interesting question but I don't know the answer lol....

Do tortoise eggs get heavier if fertile if so will a infertile tortoise egg be light and have a huge weight difference? 

I did reply saying I expect so but you don't weigh the eggs u leave them alone, but I did say I will ask you guys. Thanks in advance.


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## ZEROPILOT (Oct 1, 2015)

In my limited and failed attempts to hatch out eggs, I can say that at least initially the eggs all weigh the same. It does, however make sense that an egg with a viable embryo would get heavier.
It is also VERY important that you not move the eggs after a day or two of being deposited because blood vessels and the embryo can be damaged quite easily by any further movement so weighing them later on or disturbing them in any way is not advisable.
Place an "X" on top of the egg and gently place it were it will remain until hatching. I also write the date. The x is the top orientation.
You can "candle" the eggs with a pin point flashlight to look for blood vessels and embryo development afterwards. But I would also limit the use of the bright light as well.
Good luck!


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## Peach (Oct 1, 2015)

I have been able to tell her that once dug up you don't touch and mark the top of egg, also told her about the temps and humidity, I even had to explain the mating process which she found highly " disgusting and how could a female allow the male to do it" some of her questions are crazy, so if any of you guys can give any more info I can pass on to her I would be great full. This is what u get when a vet goes into school and explains there job to class and Chelsea replys " I have a 5 year old tortoise and 4 rescued spur theighs"


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## ZEROPILOT (Oct 1, 2015)

You have them oriented correctly. They haven't been moved and they are warm and humid.
You have already gone as far as I have. Next I had rotten eggs exploding at 160 days and a stench that lasted a few days later.
I wish you luck.
I'm going to be outdone by a child.............


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## Peach (Oct 1, 2015)

Oh I don't let her touch our 4, that would be dangerous, ours at day 90 and no sign of hatching yet I hold hope on 3 but not the 4th one. As he don't look to good so have separated him or her from the others in case, I thought after few weeks there explode if infertile as they go dark, dented and smelly, so I have just learnt something new myself


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## ZEROPILOT (Oct 1, 2015)

My rotten eggs developed tiny cracks in them and they got dark. Signs I'll look for next time. Have you candled them with a small flashlight? One of those with the beam you can turn into a pin point? Actually touch it to the egg and the whole inside becomes visible.


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## Yvonne G (Oct 1, 2015)

They not only get heavier, they swell the closer it gets to hatch.


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## WithLisa (Oct 1, 2015)

Yvonne G said:


> They not only get heavier, they swell the closer it gets to hatch.


I've only had Hermanns eggs, but they didn't get heavier, they rather lost weight. Where does the additional weight come from, do you have to keep eggs of Greek tortoises moist (so they can absorb water)?


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## Peach (Oct 1, 2015)

That's interesting to know Lisa thank you she can say that about the hermanns, she's doing all kinds of tortoises as the school have said its her interest so they want to know it all lol


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## Tom (Oct 1, 2015)

My first question is about your avatar. You are asking about spur thighs, Testudo graeca, but it looks like a horsfield in your avatar. You have both species?

The weight of an egg will only change based on the water content. Damper incubation media and higher humidity will generally cause the egg to take on more water and weigh more. Horsfield eggs kept too damp will actually swell and crack open from absorbing too much water. Like wise drier incubation media and lower humidity can cause and egg to lose some moisture during the corse of incubation and then weigh less.

If water content stays the same, the weight of the egg should remain unchanged during incubation. The nutrients in the egg are simply converted into the various baby tortoise tissues. The weight should not change because of any of those processes.


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## Peach (Oct 1, 2015)

I do I have a 5 year old horsefield she's my baby, but I rescued 4 spur theigh eggs from a old lady and at present have them in incubator, question isn't about my eggs lol it's about tortoise eggs in general of any kind.


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## Tom (Oct 1, 2015)

Peach said:


> I do I have a 5 year old horsefield she's my baby, but I rescued 4 spur theigh eggs from a old lady and at present have them in incubator, question isn't about my eggs lol it's about tortoise eggs in general of any kind.



Got it.

Here is my analogy: Suppose you left me locked in a large shipping container with a bunch of tools and constructions supplies. While locked inside the container, I build a nice tortoise box from the contraction materials. The weight of the shipping container wouldn't change, but the contents certainly transformed into something different.


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## Peach (Oct 1, 2015)

Tom your a fantastic guy! I just told my daughter that and she fully understood what u was saying, thank you so much and to the rest of you thank you also u guys are the best ;-))


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## thehowards (Oct 1, 2015)

Tom said:


> Got it.
> 
> Here is my analogy: Suppose you left me locked in a large shipping container with a bunch of tools and constructions supplies. While locked inside the container, I build a nice tortoise box from the contraction materials. The weight of the shipping container wouldn't change, but the contents certainly transformed into something different.



This is what I figured it doesn't make sense for it to change weight without adding stuff from an outside source.


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## ZEROPILOT (Oct 1, 2015)

Would that be true?
I mean the cells duplicate and duplicate and the animal grows inside of the shell. The animal becomes physically larger. The cells multiply inside the egg without actually any thing else entering.
This is very interesting.


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## WithLisa (Oct 1, 2015)

thehowards said:


> This is what I figured it doesn't make sense for it to change weight without adding stuff from an outside source.


There are outside sources, air and moisture. But the space inside the egg is limited and I guess the size of the air cell has to increase when the embryo is growing.


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## Yvonne G (Oct 1, 2015)

But we DO add something. I spritz mine with water every couple days. And in my opinion, the size of the yolk does NOT decrease according to the size of the animal growing. The baby gets bigger than the yolk, and some babies still have quite a large yolk when the baby is almost grown. I have never weighed my eggs, but an egg almost ready to hatch "feels" heavier to me than a freshly laid egg.


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## Yvonne G (Oct 1, 2015)

Darned kids and their questions! Now we have another debate.


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## ZEROPILOT (Oct 1, 2015)

I'll respect the collectives thoughts on the matter, but it does have my brain working.


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## WithLisa (Oct 1, 2015)

Yvonne G said:


> in my opinion, the size of the yolk does NOT decrease according to the size of the animal growing.


But what about the egg white?



Yvonne G said:


> I have never weighed my eggs, but an egg almost ready to hatch "feels" heavier to me than a freshly laid egg.


I once compared chick, a dead chick and a plush chick with (almost) the same weight. The chick felt as light as a feather, the dead one felt normal and the plushie was way too heavy. Now I trust my scale more than my feelings.


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## Tom (Oct 1, 2015)

ZEROPILOT said:


> Would that be true?
> I mean the cells duplicate and duplicate and the animal grows inside of the shell. The animal becomes physically larger. The cells multiply inside the egg without actually any thing else entering.
> This is very interesting.



Those cells multiply, yes, but where is the raw material they are using to build new cells coming from? Inside the egg. The cells are not getting the building blocks of life that they need from any external source. The nutrients inside that egg are converted from one form of matter into another form of matter. The weight doesn't change. The only thing that can enter or leave that egg and its membranes is water. Any weight change up or down is from water weight gain or loss.


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## WithLisa (Oct 1, 2015)

Tom said:


> The only thing that can enter or leave that egg and its membranes is water.


What about air? The egg needs oxygen and has to get rid of carbon dioxide and other waste products.


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## Kapidolo Farms (Oct 1, 2015)

Tom said:


> My first question is about your avatar. You are asking about spur thighs, Testudo graeca, but it looks like a horsfield in your avatar. You have both species?
> 
> The weight of an egg will only change based on the water content. Damper incubation media and higher humidity will generally cause the egg to take on more water and weigh more. Horsfield eggs kept too damp will actually swell and crack open from absorbing too much water. Like wise drier incubation media and lower humidity can cause and egg to lose some moisture during the corse of incubation and then weigh less.
> 
> If water content stays the same, the weight of the egg should remain unchanged during incubation. The nutrients in the egg are simply converted into the various baby tortoise tissues. The weight should not change because of any of those processes.




That's awfully scientific. hahahahahahhahaahhhahhahah. Just kidding around, good answer.


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## Kapidolo Farms (Oct 1, 2015)

WithLisa said:


> What about air? The egg needs oxygen and has to get rid of carbon dioxide and other waste products.




You are correct @WithLisa air does actually change the weight of the egg, but in such a small amount it would be difficult to notice that difference alone, alongside the weight changed caused by water movement. Tracking that respiration with radio tagged oxygen isotopes was a failed thesis interest of mine (Advisers rejected the idea). I have much literature on the topic. That is one of the drivers behind the incubators that people set up that have a night time temperature drop, to help facilitate egg respiration.

The yolk does decrease in size and mass during incubation as does the whites. Metabolic waste is respired out as C02 along with some little bit put into an area that is not inside the membrane that holds the yolk or the whites. (These membranes are better called "envelopes" less we confuse cellular biologists with the term membrane, now that's a funny thing for a biologist, Gary Larson would laugh).


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## Anyfoot (Oct 1, 2015)

Peach said:


> Good afternoon guys, my teenager has got interested in our 4 spur theigh tort eggs and is now doing a project at school about tortoises, and has asked a interesting question but I don't know the answer lol....
> 
> Do tortoise eggs get heavier if fertile if so will a infertile tortoise egg be light and have a huge weight difference?
> 
> I did reply saying I expect so but you don't weigh the eggs u leave them alone, but I did say I will ask you guys. Thanks in advance.


Nice question. One I've been wondering about for a while. My thoughts are with Tom. If nothing gets in or out it can't change weight no matter the transformation. 

Does water weigh more when it's frozen?


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## Tom (Oct 1, 2015)

WithLisa said:


> What about air? The egg needs oxygen and has to get rid of carbon dioxide and other waste products.



Yes you are correct. I was referring to things that would change the weight of the egg on a conventional gram scale that any of us might use. Thank you for the clarification.


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## Tom (Oct 1, 2015)

Will said:


> That's awfully scientific. hahahahahahhahaahhhahhahah. Just kidding around, good answer.



Would you say that it is borderline mumbo jumbo, or is that me reaching just a little too far?


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## Kapidolo Farms (Oct 1, 2015)

Anyfoot said:


> Nice question. One I've been wondering about for a while. My thoughts are with Tom. If nothing gets in or out it can't change weight no matter the transformation.
> 
> Does water weigh more when it's frozen?




Yeah, well it's not a no in no out system, so weight does change, air and water go in and out. It's like a little living thing. There is even some small amount of excretion. Over all weight may appear constant, but stuff is moving in and out. How would a 19 gram tortoise come out of a 21 gram egg (when laid) when the left over shell after hatching weighs 3 grams? How indeed?? It is not a simple additive* or* subtractive process, but one of both addition *and* subtraction of materials. That darn nature, why can't it be more simple. so we can just know it by osmosis, opps what's osmosis? Another word not on the back of a cereal box. Osmosis: a process by which molecules tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, thus equalizing the concentrations on each side of the membrane. Sorta like what happens in those darn eggs.


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## Peach (Oct 1, 2015)

Thank you all for your input, I have enjoyed reading all comments, if I have any more questions I will get my mum to ask you all again, plus I will tell you my grade when I get it as you all helped so much. From Chelsea )


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## Anyfoot (Oct 1, 2015)

Will said:


> Yeah, well it's not a no in no out system, so weight does change, air and water go in and out. It's like a little living thing. There is even some small amount of excretion. Over all weight may appear constant, but stuff is moving in and out. How would a 19 gram tortoise come out of a 21 gram egg (when laid) when the left over shell after hatching weighs 3 grams? How indeed?? It is not a simple additive* or* subtractive process, but one of both addition *and* subtraction of materials. That darn nature, why can't it be more simple. so we can just know it by osmosis, opps what's osmosis? Another word not on the back of a cereal box. Osmosis: a process by which molecules tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, thus equalizing the concentrations on each side of the membrane. Sorta like what happens in those darn eggs.


 Is there any species of tort that the eggs are incubated in absolute dry air?


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## Anyfoot (Oct 1, 2015)

Will said:


> Yeah, well it's not a no in no out system, so weight does change, air and water go in and out. It's like a little living thing. There is even some small amount of excretion. Over all weight may appear constant, but stuff is moving in and out. How would a 19 gram tortoise come out of a 21 gram egg (when laid) when the left over shell after hatching weighs 3 grams? How indeed?? It is not a simple additive* or* subtractive process, but one of both addition *and* subtraction of materials. That darn nature, why can't it be more simple. so we can just know it by osmosis, opps what's osmosis? Another word not on the back of a cereal box. Osmosis: a process by which molecules tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, thus equalizing the concentrations on each side of the membrane. Sorta like what happens in those darn eggs.


Can an infertile egg change in weight due to absorption of air and water? Is this what can cause the infertile egg to blow?


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## thehowards (Oct 1, 2015)

What about " matter can't be created or destroyed" without some magic.


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## ZEROPILOT (Oct 2, 2015)

Peach said:


> Thank you all for your input, I have enjoyed reading all comments, if I have any more questions I will get my mum to ask you all again, plus I will tell you my grade when I get it as you all helped so much. From Chelsea )


Thanks, Kid!
That was actually a very good question.


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## Kapidolo Farms (Oct 2, 2015)

Anyfoot said:


> Is there any species of tort that the eggs are incubated in absolute dry air?


Irrelevant question, no such thing as "absolute dry air" unless you are asking about an egg subjected to an experimental condition in a controlled environment. In which case the egg would explode unless that environment was very gradually applied to the egg, and for what?


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## Kapidolo Farms (Oct 2, 2015)

Anyfoot said:


> Can an infertile egg change in weight due to absorption of air and water? Is this what can cause the infertile egg to blow?


Yes, see "osmosis".


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