Humans actually have vestigial muscles that activate when listening closely to something, even though people lost the ability to really move their ears about 25 million years ago.
It was a big party in Punxsutawney this weekend. "This is my favorite holiday," one local says of the fuss-free day, adding, "You don't have to even see your in-laws." This year, Phil saw his shadow.
That spontaneous restless movement plays an important role in our health. Here's what to do the next time you find yourself bouncing your knee or clicking and unclicking your pen.