Metabolic rate and prehibernation fattening in free-living arctic ground squirrels

Michael John Sheriff, Robert W. Fridinger, Øivind Tøien, Brian M. Barnes, C. Loren Buck

Research output: Contribution to journalArticle

48 Citations (Scopus)

Abstract

Hibernating mammals become sequestered and cease foraging during prolonged seasonal periods of reduced or unpredictable food availability and instead rely on cached food and/or endogenous reserves of fat and protein accumulated during the previous active season. The gain in weight is due to increased food consumption, but it also has been hypothesized that hibernators maximize rates of fattening by decreasing costs of maintenance before weight gain, reflected in reduced resting metabolic rate (RMR). We recorded repeated measures of total body, lean, and fat mass in individual adult male and female arctic ground squirrels across their active season and found that squirrels increased body mass by 42% (males) and 62% (females). This gain was achieved through a 17% increase in lean mass and a 7-8-fold increase in fat mass; however, mass gain was not linear and patterns differed between sexes. Contrary to our hypothesis, decreases in RMR were not associated with rapid mass gain. We found RMR of males increased (wholeanimal RMR or lean-mass-specific RMR) or remained constant (mass-specific RMR) for most of the active season and decreased only after the majority of mass had been gained. In females, although RMR (whole-animal, mass-specific, and leanmass RMR) generally decreased across the active season, the greatest decrease occurred late in the active season after the majority of mass had been gained. In conclusion, arctic ground squirrels do not trade off metabolism to facilitate rates of weight gain before hibernation, but they do use energy sparing strategies before hibernation that help maintain peak mass.

Original languageEnglish (US)
Pages (from-to)515-527
Number of pages13
JournalPhysiological and Biochemical Zoology
Volume86
Issue number5
DOIs
StatePublished - Sep 1 2013

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Basal Metabolism
Sciuridae
squirrels
Arctic region
finishing
resting metabolic rate
Fats
Mammals
Weight Gain
Metabolism
Hibernation
Animals
Availability
Food
weight gain
hibernation
Body Weights and Measures
Costs
Proteins
lipids

All Science Journal Classification (ASJC) codes

  • Physiology
  • Biochemistry
  • Animal Science and Zoology

Cite this

Sheriff, M. J., Fridinger, R. W., Tøien, Ø., Barnes, B. M., & Buck, C. L. (2013). Metabolic rate and prehibernation fattening in free-living arctic ground squirrels. Physiological and Biochemical Zoology, 86(5), 515-527. https://doi.org/10.1086/673092
Sheriff, Michael John ; Fridinger, Robert W. ; Tøien, Øivind ; Barnes, Brian M. ; Buck, C. Loren. / Metabolic rate and prehibernation fattening in free-living arctic ground squirrels. In: Physiological and Biochemical Zoology. 2013 ; Vol. 86, No. 5. pp. 515-527.
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Sheriff, MJ, Fridinger, RW, Tøien, Ø, Barnes, BM & Buck, CL 2013, 'Metabolic rate and prehibernation fattening in free-living arctic ground squirrels', Physiological and Biochemical Zoology, vol. 86, no. 5, pp. 515-527. https://doi.org/10.1086/673092

Metabolic rate and prehibernation fattening in free-living arctic ground squirrels. / Sheriff, Michael John; Fridinger, Robert W.; Tøien, Øivind; Barnes, Brian M.; Buck, C. Loren.

In: Physiological and Biochemical Zoology, Vol. 86, No. 5, 01.09.2013, p. 515-527.

Research output: Contribution to journalArticle

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