Steppe bison

The steppe bison or steppe wisent (Bison priscus) is an extinct species of bison. It was widely distributed across the mammoth steppe, ranging from Western Europe to eastern Beringia in North America during the Late Pleistocene. It is ancestral to all North American bison, including ultimately modern American bison. Three chronological subspecies, Bison priscus priscus, Bison priscus mediator, and Bison priscus gigas, have been suggested.

Evolution
The steppe bison first appeared during the mid Middle Pleistocene in eastern Eurasia, subsequently dispersing westwards as far as Western Europe. During the late Middle Pleistocene, around 195,000-135,000 years ago, the steppe bison migrated across the Bering land bridge into North America, becoming ancestral to endemic North American bison species, including the largest known bison, the long-horned Bison latifrons, and the smaller Bison antiquus, the latter of which is thought to be ancestral to modern American bison.

Description
Resembling the modern bison species, especially the American wood bison (Bison bison athabascae), the steppe bison was over 2 m tall at the withers, reaching 900 kg in weight. The tips of the horns were a meter apart, the horns themselves being over half a meter long.

Bison priscus gigas is the largest known bison of Eurasia. This subspecies was possibly analogous to Bison latifrons, attaining similar body sizes and horns which were up to 210 cm apart, and presumably favored similar habitat conditions.

The steppe bison was also anatomically similar to the European bison (Bison bonasus), to the point of difficulty distinguishing between the two when complete skeletons are unavailable. The two species were close enough to interbreed; however they were also genetically distinct, indicating that interbreeding was in fact rare, possibly as a result of niche partitioning between the species.

Extinction
The steppe bison distribution contracted to the north after the end of the last glacial period, surviving into the mid Holocene before becoming extinct as part of the Quaternary extinction event. A steppe bison skeleton was radiocarbon dated to 5,400 years Before Present (c. 3450 BCE) in Alaska. B. priscus remains in the northern Angara River in Asia were dated to 2550-2450 BCE, and in the Oyat River in Leningrad Oblast, Russia to 1130-1060 BCE. The causes for the extinction of the steppe bison and many other primarily megafaunal species remain hotly debated, but the selectivity for large animals suggests that the spread of modern humans played a substantial role.

Discoveries
Steppe bison appear in cave art, notably in the Cave of Altamira and Lascaux, and the carving Bison Licking Insect Bite, and have been found in naturally ice-preserved form.

Blue Babe is the 36,000-year-old mummy of a male steppe bison which was discovered north of Fairbanks, Alaska, in July 1979. The mummy was noticed by a gold miner who named the mummy Blue Babe – "Babe" for Paul Bunyan's mythical giant ox, permanently turned blue when he was buried to the horns in a blizzard (Blue Babe's own bluish cast was caused by a coating of vivianite, a blue iron phosphate covering much of the specimen). Blue Babe is also frequently referenced when talking about scientists eating their own specimens: the research team that was preparing it for permanent display in the University of Alaska Museum removed a portion of the mummy's neck, stewed it, and dined on it to celebrate the accomplishment.

In early September 2007, near Tsiigehtchic, local resident Shane Van Loon discovered a carcass of a steppe bison which was radiocarbon dated to c. 13,650 cal BP. This carcass appears to represent the first Pleistocene mummified soft tissue remains from the glaciated regions of northern Canada.

In 2011, a 9,300-year-old mummy was found at Yukagir in Siberia.

In 2016, a frozen tail was discovered in the north of the Republic of Sakha in Russia. The exact age was not clear, but tests showed it was not younger than 8,000 years old. A team of Russian and South Korean scientists proposed extracting DNA from the specimen and cloning it in the future.

The steppe wisent is known from Denisova Cave, famous for being the site where the first Denisovan remains were discovered.