First Mechanical Gear Found in a Living Creature
Some proteins like ATP synthase kind of act like gears as well: <a href="http://www.mrc-mbu.cam.ac.uk/sites/default/files/images/image/atpsynanim.gif" rel="nofollow">http://www.mrc-mbu.cam.ac.uk/sites/default/files/images/imag...</a>