Metabolic strategies for winter survival by Svalbard reindeer

• Published in: Canadian Journal of Zoology
• Main Authors: Cuyler, L. C., Øritsland, N. A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1993
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Svalbard; caribou; svalbard reindeer
• Online Access: http://dx.doi.org/10.1139/z93-254; http://www.nrcresearchpress.com/doi/pdf/10.1139/z93-254

Lying and standing metabolic rates were determined for two tame Svalbard reindeer while the animals were in their winter lethargic state during January and February. Mean nonfasting metabolic rates for the 59-kg animals were 1.25 W∙kg −1 for lying and 1.64 W∙kg −1 for standing at rest. So the metabolic rate for standing at rest was about 1.3 times the lying resting metabolic rate (RMR). For Svalbard reindeer the lying RMR was 66–78% of the values for other reindeer/caribou, and was 78–89% of the predicted value. The standing RMR was 44–88% of the values from other reindeer/caribou. Total body thermal conductance was 1.95 ± 0.17 W∙°C −1 for lying and 3.08 ± 0.77 W∙°C −1 for standing at rest. The daily energy expenditure during winter was estimated to be about 9654 kJ∙day −1 or 112 W, and was 1.5 times Kleiber's predicted basal metabolic rate. By remaining lying 45% of the time rather than 35% Svalbard reindeer may conserve the equivalent of about 15 days' energy requirement over the winter. With locomotion at 2% of the winter daily activity budget, the Svalbard reindeer conserve about 21 days' energy expenditure, more than that if locomotion were 8.2% of the budget as in caribou (Boertje 1985). Thus, their low energy expenditures for lying and standing and their sedentary activity budget may be considered energy-saving and survival strategies. It is possible that disturbances, which cause the animals to increase activity, may have a detrimental effect on their overall winter energy balance.