Bos mutus

*Bos mutus*, commonly known as the wild yak, is a species of mammal within the family Bovidae. It belongs to the genus *Bos* and is classified under the order Artiodactyla and class Mammalia. The species is endemic to China and inhabits grassland environments. It is a viviparous animal with a gestation period of 258 days and exhibits cathemeral activity patterns. The wild yak is the source of yak fiber.

The taxon was described by Przewalski in 1883. Its lineage dates back to about 5 million years ago. The species is listed as Vulnerable on the IUCN Red List, a status recorded in 2016, and is included in Appendix I of CITES. It is not considered extinct. Various encyclopedia sources, including the Armenian Soviet Encyclopedia and the Brockhaus and Efron Encyclopedic Dictionary, have described the animal.