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Polar bear (Ursus maritimus) is the apex predator of the Arctic, largely dependent on sea-ice. The expected disappearance of the ice cover of the Arctic seas by the mid 21st century is predicted to cause a dramatic decrease in the global range and population size of the species. To place this scenario against the backdrop of past distribution changes and their causes, we use a fossil dataset to investigate the polar bear’s past distribution dynamics during the Late Glacial and the Holocene. Fossil results indicate that during the last deglaciation, polar bears were present at the southwestern margin of the Scandinavian Ice Sheet, surviving until the earliest Holocene. There are no Arctic polar bear findings from 8,000-6,000 years ago (8-6 ka), the Holocene’s warmest period. However, fossils that date from 8-9 ka and 5-6 ka suggest that the species likely survived this period in cold refugia located near the East Siberian Sea, northern Greenland and the Canadian Archipelago. Polar bear range expansion is documented by an increase in fossils during the last 4,000 years in tandem with cooling climate and expanding Arctic sea ice. The results document changes in polar bear’s distribution in response to Late Glacial and Holocene Arctic temperature and sea ice trends.
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A zooarchaeological analysis of bear (Ursus spp.) remains from two archaeological sites in Unalaska, Alaska (4700 BP - 2500 BP)
This dataset contains information about bear specimens (Ursus spp.) identified from two archaeological sites in Unalaska, Alaska: Margaret Bay (UNL-048, 4700 Before Present (BP)) and Amaknak Bridge (UNL-050, 2500 BP). The material is accessioned at the Museum of the Aleutians in Unalaska. Zooarchaeological data included are three dimensional scans (OBJ, MTL, and JPG files for rendering in MeshLab software) and digital photographs. 3D scans were obtained by using a DAVID SLS-3 HD Structured White Light 3D Scanner at the University of Oklahoma Laboratories of Molecular Anthropology and Microbiome Research (LMAMR). Photographs were taken with a Nikon D3400 24.2-megapixel DX format DSLR camera. Zooarchaeological analyses were performed to investigate how bears came to be in Unalaska Bay, a region where bears do not currently live. It has been suggested that this assemblage is evidence of Neoglacial expansion of sea ice in the region and subsequent range expansion of polar bears. Our goals here were to assess whether the bears can be distinguished to species and determine whether these animals were harvested locally and represent a range expansion. The results suggest that bears are very difficult to distinguish using morphological characteristics alone: we argue there is likely a mix of brown and polar bear in this small assemblage, but that morphological analyses alone are inadequate for reconstructing bear distribution in this context. However, the age profiles and butchery patterns do suggest that bears were harvested locally, and we contend that expanding Neoglacial sea ice facilitated their presence around Unalaska Island.
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- Award ID(s):
- 2139044
- PAR ID:
- 10581057
- Publisher / Repository:
- NSF Arctic Data Center
- Date Published:
- Subject(s) / Keyword(s):
- zooarchaeolgy Unalaska Unangax̂ polar bear brown bear Neoglacial sea ice
- Format(s):
- Medium: X Other: text/xml
- Location:
- Arctic Data Center
- Institution:
- University of Oklahoma
- Sponsoring Org:
- National Science Foundation
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