Abstract
BISON PRISCUS, THE STEPPE BISON, FROM SODA SPRINGS IDAHO Jean Allen, Ian B. Spendlove, and Renee L. Love Among other ice age megabeasts, bison were endemic on the North American mainland continent during the late Pleistocene to early Holocene. While several bison species (Bison bison, Bison priscus, Bison antiquus, and Bison occidentalis) all lived in North America, there were major differences in size and range. We examined the skeletal remains of a bison excavated from southeastern Idaho in 1966 to provide insight into its species, gender, and relative age in which it lived. The horn core length, bur to tip, and the horn core shape were key indicators of gender and species. The partial horn of the specimen measured 370 mm, which already exceeded the maximum horn length of Bison antiquus, Bison occidentalis, and Bison bison (at 364 mm, 350mm, and 270 mm, respectively). Furthermore, this measurement also exceeded the maximum Bison priscus female horn length, at 245 mm, indicating that it was a male. The skeletal remains of the Soda Springs, Idaho bison were preserved in an ancient hot spring deposit stratigraphically above the skeletal remains of a Jeffersonian Mammoth (Mammuthus jeffersonii) in a nearby pit, which was radiometrically dated at 13,700 cal BP. Bison priscus went extinct at the end of the last ice age approximately 10,000 years ago. This provides us with a relative age of the deposits, between the Bolling-Allerod Interstadial warming event and the Younger Dryas. Both these megabeasts lived during a time of major climatic fluctuations and changing biomes. This bison may have represented one of the last Bison priscus specimens recovered in mainland North America before the species' ultimate extinction. Future work will provide more assessment into the taphonomy and a more complete inventory of the skeletal remains.