Bison occidentalis is an extinct species of bison that lived in North America from about 11,000 to 5,000 years ago, spanning the end of the Pleistocene to the mid-Holocene. Likely evolving from Bison antiquus, B. occidentalis was smaller overall from its ancestor and other species such as the steppe bison. B. occidentalis had a highly variable morphology, and their horns, which pointed rearward, were much thinner and pointed than Pleistocene species of bison. Around 5,000 years ago, B. occidentalis was replaced by today's smaller Bison bison.