Factors affecting oxygen consumption in wild-caught yellow-bellied marmots (Marmota flaviventris).
1. All age groups gained mass during the active season, but mass-gain of adult females was delayed during lactation. 2. The relationship of body mass to metabolic rate varied widely; when the relationship was significant, R2 varied from 10.3 to 72.6%. Body mass affects VO2 more during lactation than at any other period. 3. Mean VO2 of adult males was higher in June than that of adult, non-lactating females. 4. VO2 of reproductive females was significantly higher during lactation than during gestation or postlactation because specific VO2 varied. Specific VO2 of non-reproductive females declined over the active season. 5. Specific VO2 of all age groups declined between the premolt and postmolt periods. The reduced maintenance costs can contribute 20-46% to daily growth. 6. Observed VO2 was lower than the value predicted from intraspecific or interspecific Bm:M regressions. 7. VO2 of wild-caught marmots was lower than that of marmots maintained in the laboratory, probably because of dietary differences. 8. Because basal metabolism is a stage on a food-deprivation curve, we suggest that basal metabolic rate is not an appropriate measure of the metabolic activity of free-ranging animals.
Department of Systematics and Ecology, University of Kansas, Lawrence 66045-2106.
K B
KB
Armitage
C M
CM
Salsbury
D000818:Animals; D000830:Animals, Laboratory; D000835:Animals, Wild; D001835:Body Weight; D004734:Energy Metabolism; D005260:Female; D008297:Male; D008392:Marmota / Q000033:anatomy & histology / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology*; D011247:Pregnancy; D012098:Reproduction; D012621:Seasons