The 12 Zodiac animal signs are, in order, the rat, ox, tiger, rabbit, dragon, snake, horse, sheep (ram or goat), monkey, rooster, dog, and pig.
According to Chinese legend, the twelve animals quarreled one day as to who was to head the cycle of years. The gods were asked to decide and they held a contest: whoever was to reach the opposite bank of the river would be first, and the rest of the animals would receive their years according to their finish.
The cat was a good friend of the rat, but the rat tricked him into believing that the banquet was the next day. The cat slept through the banquet, thinking that it was the next day. When he found out, the cat vowed to be the rat's natural enemy for ages to come.
All the twelve animals gathered at the river bank and jumped in. Unknown to the ox, the rat had jumped upon his back. As the ox was about to jump ashore, the rat jumped off the ox's back, and won the race. The pig, who was very lazy, ended up last. That is why the rat is the first year of the animal cycle, the ox second, and the pig last.