The snake is the sixth of the twelve-year cycle of animals which appear in the Chinese zodiac related to the Chinese calendar. The Year of the Snake is associated with the Earthly Branch symbol 巳.
Zodiac snake, showing the shé (蛇) character for snake
Old Town of Lijiang zodiac circle: a stone circle inscribed with symbols of the Chinese zodiac near the entrance to the Old Town of Lijiang, Yunnan
Detail of above, showing the Snake designated by its Earthly Branch sign (front, center right)
Terracotta zodiacal Snake from the Sui dynasty (581-618).
The twelve Earthly Branches or Terrestrial Branches are a Chinese ordering system used throughout East Asia in various contexts, including its ancient dating system, astrological traditions, zodiac and ordinals.
A carving of the Chinese zodiac on the ceiling of the gate to Kushida Shrine in Fukuoka, Japan
PDF: A study of the cardinal directions chart