Chinese astrologers were not greatly influenced by astrologers outside China, so Chinese astrology developed along vastly different paths from Western astrology. Chinese astrology dates back to around 2800 BCE, considerably later than west. Similar to the Vedic astrologers, Chinese astrology divides the heavens into 28 mansions, based on the phases of the Moon. Chinese astrology is Moon based, unlike most other astrological practices which are based on the Sun. In addition to the 12 animals of the Chinese zodiac, the Chinese have five elements instead of four used by Western astrologers—Wood, Fire, Earth, Metal and Water. The Yin and the Yang are an integral part of Chinese astrology as is Feng Shui..
The Chinese Zodiac has twelve signs each named for an animal—Rat, Ox, Tiger, Rabbit, Dragon, Snake, Horse, Ram, Monkey, Rooster, Dog and Pig. To date no documentation has been uncovered to explain how these animals came to be chosen, but the following legend explains it all!
Long ago in a land far away, Jade Emperor decided to hold a swimming race in order to select the animals for the signs of the zodiac. Cat and Rat were the worst swimmers in the race so they decided to cross the river on the back of Ox who agreed to carry them to the other side. Just as they arrived at the distant shore, Rat pushed Cat into the water, which allowed him to gain first place in the zodiac; Ox was right behind him and won second place leaving Cat in the water.
The third animal to reach the other side of the river was Tiger who explained to Jade Emperor that heavy currents had caused his delay, but since he was so powerful he was able to reach the other side in third place. Now just as Tiger arrived, Jade Emperor heard a great thumping sound and soon after, Rabbit appeared to say he had tried jumping across the river from stone to stone but suddenly the stones disappeared; but then a log appeared as he reached the half-way point. He climbed on the log made it across the river giving him the fourth place in the zodiac.
The fifth animal to reach the shore was Dragon. Although Dragon was very, very strong and could also fly, he didn’t come in first because stopped along the way to help the creatures on earth by making it rain. Then, when he was half-way across the river, he spotted Rabbit hanging onto the log, so he took a deep dragon breath and blew him across the river. Jade Emperor was so very pleased with his good deeds and he gave him the fifth place in the zodiac.
Then Jade Emperor heard a loud galloping sound and Horse suddenly appeared on the shore. It seems that Snake hid himself on the hoof of Horse, so he reached the shore at the same time. Horse was so frightened when he suddenly saw Snake slither off his hoof, the he shied away and Snake made it to shore before him, capturing sixth place, while Horse was only seventh.
A while later Ram, Monkey and Rooster arrived at the shore together and let Jade Emperor know that they helped each other to cross the river. It seems Rooster found a raft and invited Monkey and Ram to join him to get to the other side and when they arrived, Ram and Monkey pulled the raft to shore. Jade Emperor was so delighted with their joint effort that he gave Ram eighth place, Monkey became ninth animal of the zodiac and Rooster became tenth.
Now Dog was the best swimmer of all, but he told Jade Emperor that he was so dirty and the water was so fresh and clean that he decided to take a bath and that is why he was so late. Jade Emperor made him number eleven and decided to close the competition. Just then Pig arrived squealing and yelping from the water.
Pig explained to Jade Emperor that he was so hungry that he stopped along the way to have a large meal; he ate so much he needed to take a nap and so he was late. Since he arrived before Jade Emperor closed the competition, he was lucky enough to get the twelfth and final place in the zodiac. But Cat was still in the river and arrived too late to secure a spot in the zodiac. This explains why cats hate water and Cat has hated Rat for all eternity.
So that is how these animals became the twelve signs of the Chinese Zodiac!