Parker Lillian Draper, West Catherine F, Tatum Kaylee Hope, Etnier Michael, Bethke Brandi, Reedy Katherine, Shellikoff Nikkita, Hofman Courtney A
Laboratories of Molecular Anthropology and Microbiome Research, Department of Anthropology, University of Oklahoma, Norman, OK, USA.
Department of Anthropology and Archaeology Program, Boston University, Boston, MA, USA.
Sci Rep. 2025 Feb 17;15(1):5767. doi: 10.1038/s41598-025-88996-0.
The archaeological record offers the opportunity to infer the effects of regional climatic shifts on species distributions and human-animal interactions. In Alaska's temperate Aleutian Islands, the archaeological record suggests that the Neoglacial climate phase (ca. 4700 - 2500 rcyr BP) was significantly colder and the region likely supported sea ice and ice-dependent animals. Previous analyses have identified polar bear (Ursus maritimus) remains in archaeological sites in Unalaska Bay, which have been used to infer bear range expansion and significant climate changes during this period. However, morphological similarities between polar and brown (Ursus arctos) bears make it difficult to distinguish between the two species, and the presence of bear material in Unalaska Bay could be the result of long-distance travel or trade rather than local harvest. Here, we applied zooarchaeological methods to address potential morphological and size differences, to age the bears, and to interpret human use of the bears. Our results suggest that the small assemblage is likely composed of both brown and polar bear remains, but that morphological analyses alone are insufficient to definitively reconstruct bear distributions in this context. Bear age profiles and butchery patterns suggest that the animals were harvested locally and the extension of sea ice in the Neoglacial phase likely facilitated their presence around Unalaska Island. Future analyses that use ancient DNA, collagen fingerprinting, and stable isotopes to determine the species, sex, number of individuals, and relationships to modern populations will be necessary to illuminate regional bear population dynamics in the Neoglacial.
考古记录为推断区域气候变化对物种分布及人类与动物互动的影响提供了契机。在阿拉斯加气候温和的阿留申群岛，考古记录表明新冰期气候阶段（约公元前4700 - 2500年放射性碳年）明显更寒冷，该地区可能存在海冰及依赖海冰生存的动物。此前的分析已在乌纳拉斯卡湾的考古遗址中发现了北极熊（ Ursus maritimus ）的遗骸，这些遗骸被用于推断该时期熊的活动范围扩张及显著的气候变化。然而，北极熊和棕熊（ Ursus arctos ）在形态上的相似性使得很难区分这两个物种，且乌纳拉斯卡湾存在熊的遗骸可能是长途迁徙或贸易的结果，而非当地捕杀所致。在此，我们运用动物考古学方法来解决潜在的形态和大小差异问题、确定熊的年龄，并解读人类对熊的利用情况。我们的研究结果表明，这一小型组合可能同时包含棕熊和北极熊的遗骸，但仅靠形态分析不足以在此背景下确切重建熊的分布情况。熊的年龄分布和屠宰模式表明这些动物是在当地被捕杀的，新冰期海冰的扩张可能促使它们出现在乌纳拉斯卡岛周边。未来有必要运用古DNA、胶原蛋白指纹识别和稳定同位素分析来确定物种、性别、个体数量以及与现代种群的关系，以阐明新冰期该地区熊的种群动态。
