During hibernation, they don’t eat and rely on the fat stores they have built up and go into a deep and full sleep during the winter. Groundhogs are nature’s alarm clock, not weather forecasterIn the United States, the legend goes that various groundhogs can predict if spring will arrive early or if there will be six more weeks of winter weather. “We know they’re going to emerge at that photoperiod when spring is coming.”There is no correlation between the groundhog seeing a shadow and the arrival of spring.. Groundhogs emerging from their dens were seen as a symbol that spring was on its way. As for why these lowly rodents continue to remain part of our end-of-winter celebrations, McDonald says it’s pretty simple.