Each animal has its own special characteristics. Many people believe that these characteristics affect events that happen during the year. In addition, some people believe that people born in a certain year will have qualities of that year's animal.

The animal signs serve a useful social function for finding out people’s ages. Instead of asking directly how old a person is, people often ask what is his or her animal sign. This would place that person’s age within a cycle of 12 years, and with a bit of common sense, we can deduce the exact age. More often, though, people ask for animal signs not to compute a person’s exact numerical age, but to simply know who is older among friends and acquaintances.

According to Chinese legend, the twelve animals quarrelled 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.

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.

The Chinese Lunar Calendar is a yearly one, with the start of the lunar year being based on the cycles of the moon. Therefore, because of this cyclical dating, the beginning of the year can fall anywhere between late January and the middle of February.