Holocene bison diminution on the Snake River Plain, Idaho, USA

摘要

Researchers have established a Holocene pattern of Bison spp. diminution on the Great Plains of North America. This pattern, however, is less clear west of the Rocky Mountains. This lack of clarity stems from a relative paucity of paleontological and archaeological bison assemblages sufficiently large enough to understand local bison diminution. To begin filling this important gap in knowledge, we analyze a large bison assemblage from Baker Cave, a Late-Holocene archaeological site located on Idaho's Snake River Plain. Measurements of humeri, radii, tibiae, metatarsals, and calcanei demonstrate that these animals were significantly smaller than Early-Holocene bison from both the Great Plains and Snake River Plain. Middle-Holocene bison from the Great Plains are generally larger than those from Baker Cave, but this size difference varies by skeletal element. The Baker Cave bison do fall within the range of Late-Holocene morphological variation present in both Snake River Plain and Great Plains bison populations. These results provide a necessary first step for understanding bison morphology in the region, but establishing a pattern of diminution west of the Rocky Mountains will require follow-up studies with other faunas.