Answer:
The number 12...just as the months in year. Mercury, aka Aquarius, and Chinese Zodiac for the Rat both mirror the same story. Mercury was the messenger and told the message too quickly. The planet Mercury follows the sun very closely as a messenger would if he were the messenger of his king. The Chinese zodiac of the Rat cheated his way into the zodiac and was the first to see the king on a challenge that cost him his best friend, the cat, and the using of the ox to achieve his status. Most of the signs can be compared in this manner. Another characteristic is the 12 months in a year. Until now, the zodiac has always had 12 zodiac--we have know moved to 13. I wonder what the new animal is for the Chinese zodiac---if I had to guess, I would say the rabbit.