Bison antiquus, sometimes called the "ancient bison", was the most common large herbivore of the North American continent for over 10,000 years, and is a direct ancestor of the living American bison. During the later Pleistocene epoch, between 240,000 and 220,000 years ago, steppe wisent (B. priscus) migrated from Siberia into Alaska. This species inhabited parts of northern North America throughout the remainder of the Pleistocene. In midcontinent North America, however, B. priscus was replaced by the long-horned bison, B. latifrons, and somewhat later by B. antiquus. The larger B. latifrons appears to have died out by about 20,000 years ago. In contrast, B. antiquus became increasingly abundant in parts of midcontinent North America from 18,000 ya until about 10,000 ya, after which the s