Publication Date:
2015-07-18
Description:
Polar bears (Ursus maritimus) summer on the sea ice or, where it melts, on shore. Although the physiology of "ice" bears in summer is unknown, "shore" bears purportedly minimize energy losses by entering a hibernation-like state when deprived of food. Such a strategy could partially compensate for the loss of on-ice foraging opportunities caused by climate change. However, here we report gradual, moderate declines in activity and body temperature of both shore and ice bears in summer, resembling energy expenditures typical of fasting, nonhibernating mammals. Also, we found that to avoid unsustainable heat loss while swimming, bears employed unusual heterothermy of the body core. Thus, although well adapted to seasonal ice melt, polar bears appear susceptible to deleterious declines in body condition during the lengthening period of summer food deprivation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Whiteman, J P -- Harlow, H J -- Durner, G M -- Anderson-Sprecher, R -- Albeke, S E -- Regehr, E V -- Amstrup, S C -- Ben-David, M -- New York, N.Y. -- Science. 2015 Jul 17;349(6245):295-8. doi: 10.1126/science.aaa8623. Epub 2015 Jul 16.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Program in Ecology, University of Wyoming, Laramie, WY 82071, USA. Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA. ; Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA. ; U.S. Geological Survey, Alaska Science Center, Anchorage, AK 99508, USA. ; Department of Statistics, University of Wyoming, Laramie, WY 82071, USA. ; Wyoming Geographic Information Science Center, University of Wyoming, Laramie, WY 82071, USA. ; Marine Mammals Management, U.S. Fish and Wildlife Service, Anchorage, AK 99503, USA. ; Polar Bears International, Bozeman, MT 59772, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26185248" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
*Body Temperature
;
*Climate Change
;
Energy Metabolism/*physiology
;
Female
;
*Hibernation
;
Ice Cover
;
Male
;
Seasons
;
Ursidae/metabolism/*physiology
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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