Sulcata egg incubations

[M.beaver]

Hi everyone.
I’m just enquiring about the temperature with incubating sulcata eggs. I’ve incubated before and been successful. But this time round I have a different incubator and for some reason it won’t let me drop the temperature on it. The lowest it will go to is 37.5•c. Is that too high because I really think it is but just wanted to double check. Thank you!

 

[wellington]

If I remember right, the temp should be in the 80'sF
@Tom
@Markw84
@Yvonne G

 

[Tom]

Hi everyone.
I’m just enquiring about the temperature with incubating sulcata eggs. I’ve incubated before and been successful. But this time round I have a different incubator and for some reason it won’t let me drop the temperature on it. The lowest it will go to is 37.5•c. Is that too high because I really think it is but just wanted to double check. Thank you!

That is way too high. The embryos will not survive at 37.5 You want it no higher than 32C and I prefer 31C. You can go as low as 29C and that would give you all or mostly males, and would make incubation take a bit longer.

 

[Pák]

Hi Tom, what do you mean under a bit longer? a few days or 1-2 week? I am just curious.

 

[M.beaver]

That is way too high. The embryos will not survive at 37.5 You want it no higher than 32C and I prefer 31C. You can go as low as 29C and that would give you all or mostly males, and would make incubation take a bit longer.

Thank you!

 

[M.beaver]

That is way too high. The embryos will not survive at 37.5 You want it no higher than 32C and I prefer 31C. You can go as low as 29C and that would give you all or mostly males, and would make incubation take a bit longer.

Sorry Tom, if I can manage to turn the temperature down would they be okay now or is it too late considering I haven’t been able to change the temperature since the 15th of March

 

[Tom]

Hi Tom, what do you mean under a bit longer? a few days or 1-2 week? I am just curious.

This is highly variable. Depends on many variables, but yes, incubating at 29C instead of 31C would probably make it take around two weeks longer. I have never tested this theory, but that is what I can deduce from what I have seen over the years. There are many variables involved.

 

[Tom]

Sorry Tom, if I can manage to turn the temperature down would they be okay now or is it too late considering I haven’t been able to change the temperature since the 15th of March

If these eggs have been at 37C for two weeks they are most likely dead. You can try to incubate them at the correct temperature and see what happens, but it is unlikely that any of them are viable any more. Worst case, you can throw them away if they begin to rot. Best case, maybe I am wrong and some somehow survived.

For future reference, it is fine to leave the eggs cold for months at a time until you can get a proper incubator and take the time to get it set correctly and stable. My sulcatas always laid in winter when ground temps are always around 10C and can be as low as 4C at nest depth. There have been times when I left the eggs in the ground at those temps for a couple of months, and then had exceptionally healthy large babies and very high hatch rates once I moved them into an incubator. Many times those "cooled" clutches would produce the largest babies I hatched. Normally sulcatas hatch at around 35 grams. New, smaller moms might produce babies closer to 30 grams. My cooled eggs would frequently hatch out at 40 grams, and my largest hatchling ever was 44 grams out of an egg that was left in the ground in winter. 40-42 grams was pretty normal.

I got the idea to try this when @Neal reported much better hatch rates from his leopard tortoise eggs after leaving them in the ground all winter. I speculate that is because most leopards have South African genetics mixed in, but I decided to give it a try with a single sulcata clutch just to see what would happen. I left that clutch in the ground for a month after it was laid in cold weather in January, and almost all of the eggs hatched into large healthy vigorous babies. I tried it with more of them and got the same positive result each time. Just one more way to add to the list of ways that this forum has advanced tortoise knowledge and improved the lives of tortoises and tortoise keepers all over the world.

 

[M.beaver]

If these eggs have been at 37C for two weeks they are most likely dead. You can try to incubate them at the correct temperature and see what happens, but it is unlikely that any of them are viable any more. Worst case, you can throw them away if they begin to rot. Best case, maybe I am wrong and some somehow survived.

For future reference, it is fine to leave the eggs cold for months at a time until you can get a proper incubator and take the time to get it set correctly and stable. My sulcatas always laid in winter when ground temps are always around 10C and can be as low as 4C at nest depth. There have been times when I left the eggs in the ground at those temps for a couple of months, and then had exceptionally healthy large babies and very high hatch rates once I moved them into an incubator. Many times those "cooled" clutches would produce the largest babies I hatched. Normally sulcatas hatch at around 35 grams. New, smaller moms might produce babies closer to 30 grams. My cooled eggs would frequently hatch out at 40 grams, and my largest hatchling ever was 44 grams out of an egg that was left in the ground in winter. 40-42 grams was pretty normal.

I got the idea to try this when @Neal reported much better hatch rates from his leopard tortoise eggs after leaving them in the ground all winter. I speculate that is because most leopards have South African genetics mixed in, but I decided to give it a try with a single sulcata clutch just to see what would happen. I left that clutch in the ground for a month after it was laid in cold weather in January, and almost all of the eggs hatched into large healthy vigorous babies. I tried it with more of them and got the same positive result each time. Just one more way to add to the list of ways that this forum has advanced tortoise knowledge and improved the lives of tortoises and tortoise keepers all over the world.

Brilliant! Thank you so much for this!! 🤗