Bos primigenius - Original oil painting by Czech paleo-artist Josef Moravec.

The aurochs or urus (Bos primigenius) is an extinct, very large, type of cattle originally prevalent in Europe. The animal's original scientific name, Bos primigenius, was meant as a Latin translation of the German term Auerochse or Urochs, which was (possibly incorrectly) interpreted as literally meaning "primeval ox" or "proto-ox". This scientific name is now considered invalid by ITIS, who classify aurochs under Bos taurus, the same species as domestic cattle. However, in 2003, the International Commission on Zoological Nomenclature "conserved the usage of 17 specific names based on wild species, which are pre-dated by or contemporary with those based on domestic forms"[citation needed], confirming Bos primigenius for the Aurochs. Taxonomists who consider domesticated cattle a subspecies of the wild Aurochs should use B. primigenius taurus; the name B. taurus remains available for domestic cattle where it is considered to be a separate species.

Aurochs are depicted in many Paleolithic European cave paintings such as those found at Lascaux and Liver non in France. Their life force may have been attributed with magical qualities, for early carvings of the aurochs have also been found. The impressive and dangerous aurochs survived into the Iron Age in Anatolia and the Near East, and was worshiped throughout that area as a sacred animal, the Lunar Bull, associated with the Great Goddess and later with Mithras.