The is foremost a Daoist emblem of longevity and is the companion of Shoulao, the God of Longevity, while the inclusion of peaches and lingzhi fungus in the decoration is often a further symbolic of longevity. It also represents filial piety which comes from the folk tale of Zhou Yanzi. This is a story of a young boy who tries to get milk from a deer to cure his ailing father. To achieve his goal he wears deer skin and joins a deer herd to gather milk.
Said to be the only animal that can find the holy linghzi funguses of immortality. Also a symbol of wealth since the Chinese word for deer, lu, is a homonym for the salary of an official.