Hervis, my female Ibera starting to dig for the winter. It never ceases to amaze me how well they can dig and leave no trace after they are totally under!
It's quite the incredible process. Since they are not mammals they are slaves to the sun to power themselves. Their body slows, they stop eating and find an appropriate place to dig. Sounds easy! In captivity I've found it to be nerve racking!
They stop eating on their own and for three weeks after I soak 4x a week to hydrate and expel anything in their system then I provide a 2x2 foot insulated 'box' with 20 inches of soil (our freeze line is 9 inches) and they dig.
I use temp probes and maintain a temp of 40F to 45F all winter. I pull them out once a month to weigh and hydrate. They come up by themselves in April/May.