Results 11 to 20 of about 22,151 (252)

Insights into bear evolution from a Pleistocene polar bear genome [PDF]

Proceedings of the National Academy of Sciences of the United States of America, 2022
The polar bear (Ursus maritimus) has become a symbol of the threat to biodiversity from climate change. Understanding polar bear evolutionary history may provide insights into apex carnivore responses and prospects during periods of extreme environmental
George K Sage, Lutz Bachmann, ØYSTEIN Wiig   +2 more
exaly   +4 more sources

Projected polar bear sea ice habitat in the Canadian Arctic Archipelago. [PDF]

PLoS ONE, 2014
Sea ice across the Arctic is declining and altering physical characteristics of marine ecosystems. Polar bears (Ursus maritimus) have been identified as vulnerable to changes in sea ice conditions.
Stephen G Hamilton, Laura Castro de la Guardia, Andrew E Derocher, Vicki Sahanatien, Bruno Tremblay, David Huard   +5 more
doaj   +2 more sources

Hundreds of Unrecognized Halogenated Contaminants Discovered in Polar Bear Serum [PDF]

Angewandte Chemie - International Edition, 2018
Yanna Liu, Evan S Richardson, Andrew E Derocher   +2 more
exaly   +2 more sources

北极熊和灰熊的杂交对北极熊灭绝的促进

Wildlife Letters, 2023
This review explores whether recent hybridization events between polar bears (Ursus maritimus) and grizzly bears (Ursus arctos horribilis) will eventually contribute to the extinction of the modern polar bear.
Craig L. Shafer
doaj   +1 more source

Genomic evidence for island population conversion resolves conflicting theories of polar bear evolution. [PDF]

PLoS Genetics, 2013
Despite extensive genetic analysis, the evolutionary relationship between polar bears (Ursus maritimus) and brown bears (U. arctos) remains unclear. The two most recent comprehensive reports indicate a recent divergence with little subsequent admixture ...
James A Cahill, Richard E Green, Tara L Fulton, Mathias Stiller, Flora Jay, Nikita Ovsyanikov, Rauf Salamzade, John St John, Ian Stirling, Montgomery Slatkin, Beth Shapiro   +10 more
doaj   +1 more source

The utility of drones for studying polar bear behaviour in the Canadian Arctic: opportunities and recommendations1

Drone Systems and Applications, 2022
Climate-induced sea-ice loss represents the greatest threat to polar bears (Ursus maritimus Phipps, 1774), and utilizing drones to characterize behavioural responses to sea-ice loss is valuable for forecasting polar bear persistence.
Patrick M. Jagielski, Andrew F. Barnas, H. Grant Gilchrist, Evan S. Richardson, Oliver P. Love, Christina A.D. Semeniuk   +5 more
doaj   +1 more source

Analyses of key genes involved in Arctic adaptation in polar bears suggest selection on both standing variation and de novo mutations played an important role

BMC Genomics, 2020
Background Polar bears are uniquely adapted to an Arctic existence. Since their relatively recent divergence from their closest living relative, brown bears, less than 500,000 years ago, the species has evolved an array of novel traits suited to its ...
Jose Alfredo Samaniego Castruita, Michael V. Westbury, Eline D. Lorenzen   +2 more
doaj   +1 more source

Determination of polar bear (Ursus maritimus) individual genotype and sex based on DNA extracted from paw-prints in snow

Frontiers in Conservation Science, 2023
Polar bears rely upon sea ice to hunt, travel, and reproduce. Declining sea ice extent and duration has led polar bears to be designated as “threatened” (ESA). Population monitoring is vital to polar bear conservation; but recently, poor sea ice has made
Andrew L. Von Duyke, Justin A. Crawford, Lori Quakenbush, Jennifer R. Adams, Lisette P. Waits   +4 more
doaj   +1 more source

Biomechanical consequences of rapid evolution in the polar bear lineage. [PDF]

PLoS ONE, 2010
The polar bear is the only living ursid with a fully carnivorous diet. Despite a number of well-documented craniodental adaptations for a diet of seal flesh and blubber, molecular and paleontological data indicate that this morphologically distinct ...
Graham J Slater, Borja Figueirido, Leeann Louis, Paul Yang, Blaire Van Valkenburgh   +4 more
doaj   +1 more source

Polar bear depredation of a thick-billed murre fledgling in open water at Prince Leopold Island, Nunavut

, 2022
Sea-ice distribution and duration are declining across the circumpolar range of the polar bear (Ursus maritimus), resulting in a reduced access to ice-obligate seals, its primary prey.
Di Corrado, Christopher, Franco, João, Obbard, Martyn E., Wise, Boris, Pimenta, Roger   +4 more
core   +1 more source