The Analysis of a Late Holocene Bison Skull from Fawn Creek, Lemhi County, Idaho, and Its Implications for Understanding the HIstory and Ecology of Bison in the Intermountain West

In 1995 the skull of a subadult male bison was recovered from the cutbank of Fawn Creek, Lemhi County, Idaho, by a ranger for the Salmon-Challis National Forest. After slowly drying the skull for about a year it was turned over to the Midwest Archeological Center in order to be stabilized and analyzed for clues to the ecology of Late Holocene bison
in the Intermountain West. A number of analytical techniques were applied to the skull in order to understand its age of deposition and ecology. Radiocarbon dating revealed a recent age of 170 ± 70 yr B.P., which calibrates to about the late eighteenth to early nineteenth century. Identification of macrobotanical remains recovered from the infundibulum of the molars, in association with the analysis of pollen and phytoliths extracted from tooth tartar, indicates this bison subsisted on festucoid grasses and other cool-season grasses in an open forest setting. The stable-carbon-isotope analysis is consistent with the plant data—this particular bison lived its life in the mountainous region of the Salmon River. There is no indication of long distance migrations into the lower valleys of the Lemhi or Snake rivers.
In addition to the physical analyses, an overview of the historic and archeological literature citing bison is presented. The information from these sources indicates that bison were most abundant in the wide grass-covered valleys of the
Lemhi River and Snake River. Archeological data indicate that bison may have become more abundant during the Late Holocene, although the statistical correlation is weak.

1995年，爱达荷州莱希县（Lemhi County）鹿溪（Fawn Creek）的侵蚀岸坡处，萨蒙-查利斯国家森林（Salmon-Challis National Forest）的一名护林员发现了一具亚成年雄性野牛的头骨。该头骨经约一年的缓慢干燥处理后，被移交至中西部考古中心（Midwest Archeological Center），以开展稳定化处理，并针对山间西部（Intermountain West）全新世晚期（Late Holocene）野牛的生态特征展开分析。研究团队采用多种分析技术以明确该头骨的沉积年代与生存生态。放射性碳定年（Radiocarbon dating）结果显示其距今年代为170±70年BP，经校准后大致对应18世纪末至19世纪初。通过对臼齿漏斗腔（infundibulum of the molars）中提取的大植物遗存进行鉴定，并结合对牙菌斑（tooth tartar）中分离出的花粉与植硅体（phytoliths）的分析，确认该野牛以禾草类（festucoid grasses）及其他冷季型草本植物为食，生存环境为开阔林地带。稳定碳同位素分析结果与植物遗存分析结论相互印证：这头野牛生前活动于萨蒙河山区，未出现向莱希河或斯内克河下游谷地的长距离迁徙迹象。
除实物分析外，本研究还梳理了收录野牛相关记录的历史与考古文献。上述来源的信息表明，野牛曾大量栖息于莱希河与斯内克河沿岸开阔的草甸谷地。考古数据显示，全新世晚期野牛种群数量或有所增长，但二者的统计相关性较弱。