Bos bonasus; Print; Bos is the genus of wild and domestic cattle. Bos can be divided into four subgenera: Bos; Bibos; Novibos; and Poephagus; but these divisions are controversial. The genus has five extant species. However; this may rise to seven if the domesticated varieties are counted as separate species; and nine if the closely related genus Bison is also included. Most modern breeds of domesticated cattle are believed to have originated from the extinct aurochs.; 1863