The twelve animals of the Chinese zodiac, or Sheng Xiao, are as follows: Rat, Ox, Tiger, Rabbit, Dragon, Snake, Horse, Goat, Monkey, Rooster, Dog, and Pig. Associated with each sign are years of birth, personality traits, fortunes, compatibility, and more.
The Chinese Zodiac was originally created as a calendar, with it first being used during the Han Dynasty, as is still used in Chinese traditions today. However it has been phased out as the main calendar in favour of the Gregorian calander. The animals of the Chinese Zodiac were not picked by random, they are actually part of a traditional story told in China.
The story starts with the Jade Emperor, and his need for guards. In particular he wanted twelve animals to serve as the guards, and determined the best way to find these twelve was by having a race. The first twelve to enter the Heavenly Gate would be the guards, and the faster they are, the higher rank they would have.
Rat was the first to arrive. He had got up quite early but found himself stuck at a river on the way to the gate. The Ox, who was second, was able to cross the river because of its large size, and the Rat seized the opputunity and rode the Ox across. He stayed there in fact, right until the finish line, where, at the last second, he jumped out and claimed first place, with the Ox finishing second
The Tiger and Rabbit, both fast and competitive animals were the next to arrive, finishing third and fourth respectively. The also quick Dragon arrived next, and the Emperor, taken aback by his good-looks, said the Dragon's son could take sixth place, if he so desired. As the son was not present that day, the Snake came forward, claiming to be son to the Dragon, and so he became the sixth guard.
The Horse and Goat arrived next in seventh and eigth respectively, each wanting the other to proceed first, an attitude which impressed the Emperor, and the late Monkey was next to arrive, coming in ninth. Finally the Rooster, the Dog, and the Pig arrived, in that order, and the Emperor had his Twelve Guards.