Original Paper

Polar Biology

, Volume 34, Issue 7, pp 975-984

Consequences of long-distance swimming and travel over deep-water pack ice for a female polar bear during a year of extreme sea ice retreat

  • George M. DurnerAffiliated withU. S. Geological Survey, Alaska Science CenterDepartment of Zoology and Physiology, University of Wyoming Email author 
  • , John P. WhitemanAffiliated withDepartment of Zoology and Physiology, University of WyomingProgram in Ecology, University of Wyoming
  • , Henry J. HarlowAffiliated withDepartment of Zoology and Physiology, University of Wyoming
  • , Steven C. AmstrupAffiliated withU. S. Geological Survey, Alaska Science Center
  • , Eric V. RegehrAffiliated withDepartment of Zoology and Physiology, University of WyomingU. S. Fish and Wildlife Service, Marine Mammals Management
  • , Merav Ben-DavidAffiliated withDepartment of Zoology and Physiology, University of WyomingProgram in Ecology, University of Wyoming

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Abstract

Polar bears (Ursus maritimus) prefer to live on Arctic sea ice but may swim between ice floes or between sea ice and land. Although anecdotal observations suggest that polar bears are capable of swimming long distances, no data have been available to describe in detail long distance swimming events or the physiological and reproductive consequences of such behavior. Between an initial capture in late August and a recapture in late October 2008, a radio-collared adult female polar bear in the Beaufort Sea made a continuous swim of 687 km over 9 days and then intermittently swam and walked on the sea ice surface an additional 1,800 km. Measures of movement rate, hourly activity, and subcutaneous and external temperature revealed distinct profiles of swimming and walking. Between captures, this polar bear lost 22% of her body mass and her yearling cub. The extraordinary long distance swimming ability of polar bears, which we confirm here, may help them cope with reduced Arctic sea ice. Our observation, however, indicates that long distance swimming in Arctic waters, and travel over deep water pack ice, may result in high energetic costs and compromise reproductive fitness.

Keywords

Climate change Energetics Long-distance swimming Polar bear Telemetry Ursus maritimus Sea ice