Adaptation to cold: energy metabolism in an atypical lagomorph, the arctic hare ( Lepus arcticus )

• Published in: Canadian Journal of Zoology
• Main Authors: Wang, Lawrence C. H., Jones, Douglas L., MacArthur, Robert A., Fuller, William A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1973
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Arctic; Arctic hare; Lepus arcticus
• Online Access: http://dx.doi.org/10.1139/z73-125; http://www.nrcresearchpress.com/doi/pdf/10.1139/z73-125

Unlike other lagomorphs or any other mammals living in a cold environment, the basal metabolic rate of the arctic hare, Lepus arcticus monstrabilis (0.36 cm 3 O 2 /g per hour) was only 62–83% of the values predicted from its body weight. The minimum thermal conductance (0.010 cm 3 O 2 /g per hour per degree centigrade) was also reduced to only 51–59% of its weight-specific value (0.019–0.017 cm 3 O 2 /g per hour per degree centigrade). The normal body temperature (38.9C), however, was comparable to that of other lagomorphs. The daily energy consumption between ambient temperatures of −24 and 12.5C was between 262 and 133 kcal, which is 6–43% above the minimum resting values at corresponding ambient temperatures.It is concluded that the reduction of surface area to volume ratio and the effectiveness of its insulation are sufficient compensations so that the arctic hare can maintain a normal body temperature with a depressed basal metabolic rate. Such a reduction of metabolism is energetically adaptive for a species living exclusively in a cold and relatively barren habitat.