12 Spirit Animals Shengxiao (Chinese Zodiac)

In the Chinese zodiac, twelve animals are used to denote the year of a person's birth: rat, ox, tiger, rabbit, dragon, snake, horse, sheep, monkey, rooster, dog and pig. This is called a person's shengxiao (sheng means the year of birth, xiao means resemblance) or shuxiang.
Since ancient times, Chinese have denominated years using combinations of 10 Heavenly Stems and 12 Earthly Branches to form sixty-year cycles. The 10 Heavenly Stems are: Jia, Yi, Bing, Ding, Wu, Ji, Geng, Xin, Ren and Gui. The 12 Earthly Branches are: Zi, Chou, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu and Hai. This year, February 9 is the first day of Yiyou, which is the twenty-second year of the sixty-year cycle.

As well as being associated with each year, the same twelve animals and Earthly Branches are assigned to each month and to a two-hour period of the day. Their origin is variously explained by a number of stories and theories.