In the Chinese zodiac, the Rat comes first in the 12-animal cycle.
The sequence traditionally begins Rat, Ox, Tiger, Rabbit, Dragon, Snake, Horse, Goat, Monkey, Rooster, Dog, and Pig. The cycle repeats every 12 years, so people born in years separated by 12 usually share the same zodiac animal.
A popular legend says the animals competed in a race arranged by the Jade Emperor. The Rat reached the finish first after riding across a river on the Ox's back, then jumping ahead at the last moment. This story explains the order, although the zodiac's historical development predates the familiar race tale.
The Chinese zodiac is also linked with the five elements—Wood, Fire, Earth, Metal, and Water. Combining the 12 animals with the elements creates a larger 60-year cycle, so an animal sign alone does not identify a person's complete traditional designation.