# Incubating eggs to get female



## tyguy35 (Feb 27, 2014)

Hey, I just wanted to know if it's true that you can incubate eggs and actually get females with a higher temp or is it just a myth.


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## wellington (Feb 27, 2014)

It's not a myth, but it's not fool proof either.


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## tyguy35 (Feb 27, 2014)

Is it bad for the tortoise to incubate at a higher or lower temp


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## N2TORTS (Feb 27, 2014)

wellington said:


> It's not a myth, but it's not fool proof either.



Very Good answer! .......
For the Op yes it can hold true ...along with higher mortality rate at higher temps.


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## tyguy35 (Feb 27, 2014)

Mortality rates inside the eggs or once the tortoise is born two months later they can randomly pass away. Or are tey safe once outside the egg?


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## N2TORTS (Feb 27, 2014)

during the incubation process.....and development of the embryo.


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## Tom (Feb 27, 2014)

Sulcatas are the only species where the actual exact temps and how they break down are lab tested and known. Most breeders have found the sulcata numbers to be pretty close for some other species too.

At 84 you will get all male sulcatas. At 90 you will get all females. In between you'll get a mixture. Below 84 and you start getting failure to develop and lower hatch rates. Above 90 and you start seeing more birth defects, mortality and other anomalies.

From what I have seen these numbers are pretty close for other tropical species too.


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## tyguy35 (Feb 27, 2014)

Oh ok someone is offer me a female (he thinks). He has incubated at female temps he tells me but everyone here has answered my questions and I will pass on my questions to him for his answers.


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## Tom (Feb 27, 2014)

What temp did he incubate at and what kind of incubator and thermometer? The above numbers are for lab grade exact temps. In the real world, there tends to be much more fluctuation, and inaccurate equipment. That's why Wellington made the "not fool proof" statement above.


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## Yvonne G (Feb 28, 2014)

I think it is interesting to note:

I had 10 leopard eggs in a Little Giant Bird Brooder with a fairly good and accurate separate thermometer laying next to the eggs.

One day I opened the incubator and saw that the temperature had spiked up to over 100F (I don't remember the exact number). I don't check the eggs every day, so I don't know how long the higher temp was in effect. I adjusted the temp and crossed my fingers that I didn't cook the eggs.

About 3 weeks later one of the eggs hatched. Then 4 weeks after that 5 more eggs hatched. The first one to hatch looks just fine, but the four later babies all have an extra marginal scute. All four of them.


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## Maverick (Feb 28, 2014)

I'm curious how accurate incubating for sex actually is? Is it 100%? 80/20? Does this vary with species? Thanks


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## Tom (Feb 28, 2014)

For sulcatas, and only for sulcatas, this has been tested. IF (and this is a HUGE big IF) the temperatures were actually constant and actually held correctly for the entire duration of incubation, then it is 100% correct every time. A big thank you to Mr. Richard Fife for funding and providing eggs for this study, and to the scientists who carried it out.

Other species have not been lab tested to my knowledge, but anecdotally, the results are generally similar.

The problem is that in the real world, things happen. Things like Yvonne's example above, or things like a power outage during a winter storm. These are the variables that come in to play in most people's lives, and these kinds of things are the reason why "temp sexing" can never really be 100% accurate in somebody's $50 home incubator with a $10 hardware store thermometer. Eggs go through various stages of development, 12 stages, if memory serves, and what happens with what temperatures during which phases of incubation is still be studied. Lots of unknowns out there. Wild nest temps are also being charted and I don't know of a single species that has a constant incubation temp for two to four months or longer during incubation. One species of North American wood turtle had a range of 55-139 degrees during incubation, often with large temperature variations from day to night. All of the eggs hatched out of this wild nest.

There is still much to be learned.


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