Bovidae in Chinese mythology include various myths and legends about a group of biologically distinct animals which form important motifs within Chinese mythology. There are many myths about the animals modernly classified as Bovidae, referring to oxen, sheep, goats, and mythological types such as "unicorns" (though perhaps not Bovidae, in the strict scientific sense). Chinese mythology refers to those myths found in the historical geographic area of China, a geographic area which has evolved or changed somewhat through history. Thus this includes myths in Chinese and other languages, as transmitted by Han Chinese as well as other ethnic groups (of which fifty-six are officially recognized by the current administration of China, according to Lihui Yang, 2005:4). There are various motifs of animals of the Bovidae biological family in Chinese mythology. These have often served as allusions in poetry and other literature. Some species are also used in the traditional Chinese calendar and time-keeping system.