The 13th zodiac sign is Ophiuchus, sometimes referred to as the Serpent Bearer. It was originally part of the Babylonian zodiac but was removed from the traditional Western astrological calendar due to its precession over time. Ophiuchus is associated with healing and medicine, and it's symbolized by a man grasping a snake. People born between November 29th and December 17th are said to be under this sign, although not all astrologers agree on its inclusion in the zodiac.