Seasonal metabolic acclimatization in a northern population of free-ranging snowshoe hares, Lepus americanus

Sheriff, Michael, J., Kuchel, Louise, Boutin, Stan and Humphries, Murray M. (2009) Seasonal metabolic acclimatization in a northern population of free-ranging snowshoe hares, Lepus americanus. Journal of Mammalogy, 90 3: 761-767. doi:10.1644/08-MAMM-A-247R.1


Author Sheriff, Michael, J.
Kuchel, Louise
Boutin, Stan
Humphries, Murray M.
Title Seasonal metabolic acclimatization in a northern population of free-ranging snowshoe hares, Lepus americanus
Formatted title
Seasonal metabolic acclimatization in a northern population of free-ranging snowshoe hares, Lepus americanus
Journal name Journal of Mammalogy   Check publisher's open access policy
ISSN 0022-2372
Publication date 2009-06
Year available 2009
Sub-type Article (original research)
DOI 10.1644/08-MAMM-A-247R.1
Volume 90
Issue 3
Start page 761
End page 767
Total pages 7
Place of publication United States
Publisher Journal of Mammalogy
Language eng
Subject 970106 Expanding Knowledge in the Biological Sciences
0608 Zoology
Formatted abstract
Seasonal acclimatization in high-latitude endotherms may involve increases or reductions in body size and metabolic rate to, respectively, augment thermoregulatory capacity or reduce energy requirements. We investigated seasonal acclimatization in a northern population of wild snowshoe hares (Lepus americanus) that is exposed to low food availability and extremely cold temperatures in winter. Snowshoe hares were livetrapped and transported to a nearby mobile laboratory. Hares were placed in a metabolic chamber and oxygen consumption was measured for 55 min at each of the following temperatures: 10°C, 0°C, −10°C, −15°C, and −20°C. Hair length and density were measured on a sample of collected hares. Snowshoe hares maintained similar body mass and body temperature between the seasons, but average resting metabolic rate and thermal conductance were, respectively, 20% and 32% lower in winter than in autumn. The lower critical temperature was −10°C to −15°C in winter and 0°C to −10°C in autumn. Guard hairs were 36% longer and 148% denser in winter than autumn, whereas downy hairs were the same length but 128% denser in winter than autumn. Collectively, these results suggest that resource constraints associated with a herbivorous diet in regions and seasons of poor forage quality favors an energetically conservative approach to winter acclimatization.
Keyword free-ranging northern mammals
fur insulation
indirect calorimetry
lagomorph
Lepus americanus
resting metabolic rate
thermal conductance
winter acclimatization
Q-Index Code C1
Q-Index Status Provisional Code

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Biological Sciences Publications
 
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Created: Wed, 21 Apr 2010, 09:21:39 EST by Gail Walter on behalf of School of Biological Sciences