Temperature depending gender?

[Thomas tortoise]

I know with sulcatas high temps and humidity hatch mostly females and low temps and humidity hatch mostly males (plz correct me if I am wrong!😃) so I am wondering if anyone knows if its the same with redfoots and other tortoises?

 

[Tom]

I know with sulcatas high temps and humidity hatch mostly females and low temps and humidity hatch mostly males (plz correct me if I am wrong!😃) so I am wondering if anyone knows if its the same with redfoots and other tortoises?

They need high humidity either way, but yes. It is called TSD, or temperature sex determination. At 90 degrees (true and constant 90) you will get all females. 84 will give you all males. In between will yield a mix. All tortoise eggs of all species need high humidity in the incubation chamber.

Sulcatas are the only species where these exact temps have been studied and determined in a lab setting with accurate equipment. I know of only a few breeders working with other species that have reached some pretty good conclusions about what temps work best for their species. @biochemnerd808 just recently shared with us the temps that work for Russian tortoises in her experience, and its pretty close to the sulcata temps. For most species, like my platynota for example, the temperatures are unknown. When platynota breeders try to "temp sex for female", meaning they incubate them at the higher end of the range, they end up with almost all males.

Of interest to me is that crocodilians are the exact opposite. Higher temps result in all males and lower temps all females.

 

[biochemnerd808]

They need high humidity either way, but yes. It is called TSD, or temperature sex determination. At 90 degrees (true and constant 90) you will get all females. 84 will give you all males. In between will yield a mix. All tortoise eggs of all species need high humidity in the incubation chamber.

Sulcatas are the only species where these exact temps have been studied and determined in a lab setting with accurate equipment. I know of only a few breeders working with other species that have reached some pretty good conclusions about what temps work best for their species. @biochemnerd808 just recently shared with us the temps that work for Russian tortoises in her experience, and its pretty close to the sulcata temps. For most species, like my platynota for example, the temperatures are unknown. When platynota breeders try to "temp sex for female", meaning they incubate them at the higher end of the range, they end up with almost all males.

Of interest to me is that crocodilians are the exact opposite. Higher temps result in all males and lower temps all females.

For all the various species, I think the key is to look at probes in the ground in the specific countries and microclimates the tortoise originates from. We really need more data all around.
In an artificial incubation (in an incubator) most don't have a night time drop, e.g. and there isn't fluctuation that would occur in the wild.
'Not knowing' is exciting because it means that we have more areas to research and learn!