Dear A Moment of Science, I know that the whole thing about groundhogs coming out of their burrows to look for their shadow doesn't really have anything to do with how long winter will last. But groundhogs do emerge around the beginning of February. So if they're not acting as weather forecasters, what are they doing? --Phil
Groundhogs don't care about the weather. But they do care about sex.
Around the first week of February, male groundhogs emerge from hibernation to start looking for female groundhogs before mating season. The males hang around for about a week, until the females show their faces. Then, once the guy groundhogs have spotted the gals, they all go back to their burrows for a little more shuteye.
So when hibernation season end around March, they don't have to waste a lot of time looking for each other.
Once mating season begins, the groundhogs are ready to rumble and get busy making baby groundhogs.
So where did the "groundhogs predicting the weather" thing come from? It's an old German tradition. When German immigrants came to Pennsylvania they brought it with them. Which is why the famous groundhog, Phil, lives in Punxsutawney, Pennsylvania.
"Groundhogs Aren't Looking for Their Shadow--They're Scoping Out the Opposite Sex" (National Geographic)