The year of your birth does not just indicate your age! According to the Chinese system of Astrology, the year of birth indicates a certain phase or aspect of a sixty-year cycle of time. Three systems are used for counting and classifying the years: The ten Heavenly Stems, the twelve Earthly Branches and the twelve Animals.
The exact origins of the twelve animal system remain unknown. However, legend has it that, once upon a time, the Jade King was bored, having nothing to do in Heaven. He did not see what was happening on Earth, as he had servants satiating his every wish and desire. He decided that he wanted to see the animals that inhabited the earth so he sent word to his advisors to bring him twelve animals (which he considered to be a good sampling.) The advisor first sent an invitation to the Rat, telling him to also bring the cat. The Rat's jealousy prevented the cat from actually receiving the invitation.
Further invitations were sent on to the Ox, the Tiger, the Rabbit, the Dragon, the Snake, the Horse, the Ram, the Monkey, the Rooster and the Dog, asking for their presence at the palace the following day. When they lined up in front of the king, he found that they numbered only eleven, instead of twelve as he had requested. The king sent his servant down to Earth to retrieve a twelfth animal. The servant ran into a man carrying a Pig, and he hastily grabbed it and delivered it to the king.
The animals stood in front of the king in no particular order. The Rat, being smaller than the rest, hopped on the Ox's back and proceeded to play the flute. The king was very impressed by this display. He gave the Rat first place. Second place was given to the Ox for its good sportsmanship, and third was given to the Tiger, who appeared so courageous. The Rabbit was given fourth place, the Dragon fifth, the Snake sixth, the Horse seventh, the Ram eighth, the Monkey ninth, the Rooster tenth, the Dog...