Yeah, the sleep/hibernating aspect of this time of the year seems to be one of the things that Civ has really removed from us. Working with patients through Chinese Medicine, so many of them breathe a deep sigh of relief when they are given permission to actually sleep more in the winter. I've heard stories of Cherokee elders who in historical times actually went into a sort of hibernation sleep for up to a month. They would just sleep for huge periods of time (like 20+ hours a day) and would barely eat or drink or even urinate or defecate. It seems like an important adaptation, especially if food stores were low.
Btw, I've also really noticed a change around Feb. 1st for Imbolg/Candelmas. I read that in parts of Europe that day was celebrated as Bear's Day. Hunters would go out and check to see if the bears were stirring in their dens. If they were, it meant winter would soon be over. If not, more winter. Obviously, this was the precursor to Groundhog's day.