Diapause in Tortoise Eggs

[egyptiandan64]

Diapause is a period of time that a tortoise embryo isn't doing any developing inside the egg. Some eggs diapause at the beginning of development, as in Pancake, Spider and Flat-tailed tortoises. Pancake tortoises don't need a trigger to start developing, but can take up to 3 months to start to do so. Spider and Flat-tailed tortoises on the other hand do need a trigger to start to develop. They need cooling down for a month or so and then incubating normally. This can take up to 4 cooling down period, a friend had to do this, to start development on some eggs.
Other eggs diapause during development and at the end of development. Some southern hemisphere tortoises, Leopards, Radiateds and Chacos, stop development during cold weather. All other tortoises that have eggs that diapause, Leopards, sulcatas, Radiateds, Chacos, hingebacks and all South African tortoises, Redfoots and Yellowfoots diapause at the end of development waiting for favorable conditions to hatch, usually the start of the rainy season. Leopard tortoise eggs in captivity seem to all hatch with the coming of a low pressure system at the end of incubation. Leopard tortoises eggs are also the one's with the longest incubation period of any tortoise, 540 days :shock: . It's just amazing a tortoise can live that long inside the egg!
Here is a picture of my pancake egg that has only just started to develop, so ignore the little red bit for now :wink: :D . The first thing a fertile pancake egg will do is get an air pocket as shown in the picture and be just yellow inside. Then the little one will start to develop after 1 to 3 months of diapause.
http://i22.photobucket.com/albums/b303/egyptiandan/fertilepancakeegg1a.jpg

Danny

[stells]

great informative thread Danny :D

[piglet]

Thanks for putting that together Dan.

Just like to add as Dan has said red and yellows need a humidity boost to about 80 % for reds and a touch higher for yellows to trigger the hatching process if this is denied they will often stay dormant for several weeks longer than the due date ,if humidity is denied for a great length of time especially in yellow eggs they will die.

Darren

[sandy]

A great thread, I knew that eggs can start to develope at different stages. Also that some
later than others. But didnt know the name, or that there was a lot of info about it. So this
is my learn for the day<g>.
I suppose I knew temps started eggs going, but not the other conditions. We live and learn.

[Henry-flash]

Great information Dan, thanks for doing it.
Can this be a sticky please?

[piglet]

Done Pete. :D

D

[Henry-flash]

Thanks Darren, these are the sort of threads I like to see as stickys, we need more like this :D

[aprillinda]

thank you dan :D

a very interesting thread

learning is for life :D :D

[egyptiandan64]

I was very glad to do it :D and everyone is very welcome :D

Danny

[Glitter]

This is facinating - thank you Danny

[Eire_Ade]

Brilliant information Dan.

Its great to see even people with years and years of experience housing tortoises and breeding still being able to learn. Goes to show we never know everything eh! :D

Ade :wink:

[nina]

Thanks, Dan - that is such useful information!

[Cpx]

Fantastic infomation :D

[Bride2b]

Wow, its so interesting it must utterly fascinating to watch them grow inside their shells.

Tanya

[KearasNana]

That is so amazing, you are so knowledgable! :shock:

[EJ]

The readers should be aware that this is a theory. A theory that is very difficult to prove.

The first I heard of diapause is with the Egyptian tortoises... they were thought to require a diapause... where the idea came from with them... I can't imagine.

My idea is that diapause is an adaptation to unfavorable conditions... just like hibernation. Think of those eggs laid late in the season (cold or dry)... they have to have a mechanism to survive.

I don't believe it is a necessity. I think it is a fallback for keepers not getting it right in the first place.

It is now suggested that Leopard tortoise eggs 'require' a diapause.

This is an after thought... what triggers diapause... not the top end but the bottom end. There are eggs that require diapause in a single species... and some do not. I'm wondering if there is a trigger that would cause the requirement of diapause...

(Hey, Danny... I'm just jealous you're a god. Someday these people will do a little of their own research and see the point)