During the later Pleistocene epoch, between 240,000 and 220,000 years ago, steppe wisent migrated from Siberia into Alaska across the Bering Land Bridge. Bison priscus lived throughout North America from Alaska to southern Mexico throughout the remainder of the Pleistocene. In western North America, B. priscus evolved into long-horned bison, B. latifrons, which then evolved into B. antiquus. The larger B. latifrons appears to have disappeared by about 22,000 years ago likely because of evolutionary process to adapt into the new continent including increasing in population size. After the extinction of B. latifrons, B. antiquus became increasingly abundant in parts of midcontinent North America from 18,000 until about 10,000 years ago, after which the species appears to have given rise to the living species, B. bison. B. antiquus is the most commonly recovered large mammalian herbivore from the La Brea tar pits. B. antiquus was taller, had larger bones and horns, and was 15-25% larger overall than modern bison. It reached up to 2.27 m tall, 4.6 m long, and a weight of 1,588 kg. From tip to tip, the horns of B. antiquus measured about 3 ft. One of the best educational sites to view in situ semifossilized skeletons of over 500 individuals of B. antiquus is the Hudson-Meng archeological siteoperated by the U.S. Forest Service, northwest of Crawford, Nebraska. A number of paleo-Indian spear and projectile points have been recovered in conjunction with the animal skeletons at the site, which is dated around 9,700 to 10,000 years ago. The reason for the "die-off" of so many animals in one compact location is still in conjecture; some professionals argue it was the result of a very successful paleo-Indian hunt, while others feel the herd died as a result of some dramatic natural event, to be later scavenged by humans. Individuals of B. antiquus of both sexes and a typical range of ages have been found at the site. According to internationally renowned archaeologist George Carr Frison, B. occidentalis and B. antiquus, an extinct subspecies of the smaller present-day bison, survived the Late Pleistocene period, between about 12,000 and 11,000 years ago, dominated by glaciation, when many other megafauna became extinct. Native Americans of the Plains and Rocky Mountains depended on these bison as their major food source. Frison noted, " oldest, well-documented bison kills by pedestrian human hunters in North America date to about 11,000 years ago." Excavation of B. antiquus were found in Washington State in recent years, with apparent fracture patterns on bones consistent with stone tools as opposed to carnivorous activity. https://qmackie.com/2010/04/24/orcas-bison/
