[Stefan-A]

I really don't know, but if I remember correctly, parietalis can spend as much as 8 months in hibernation, but on the other hand, you can stimulate them into mating by lowering the temperature for as little as a day. I don't know if it works with other species and subspecies.

My guess would be that you can't apply one set of rules to all species and subspecies. Somewhere, their ability to withstand longer and colder hibernation periods has to become the factor that limits a species' distribution. I could also imagine that the newborns of the northernmost populations would enter it earlier and at a smaller size.

But like I said, I don't know. This is just an exercise in imagination.