The twelve zodiac signs are also known as the twelve-year beasts. According to Chinese calendar, the twelve year beasts take turns in duty, so the Chinese years are named after Rat, Ox, Tiger, Rabbit, Dragon, Snake, Horse, Sheep, Monkey, Rooster, Dog and Pig respectively. Namely, the Zi Rat, Chou Ox, Yin Tiger, Mao Rabbit, Chen Dragon, Si Snake, Wu Horse, Wei Sheep, Shen Monkey, You Rooster, Xu Dog and Hai Pig.