Seasonal trends in body mass, food intake and resting metabolic rate, and induction of metabolic depression in arctic foxes (Alopex lagopus) at Svalbard |
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Authors: | E Fuglei N A Øritsland |
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Institution: | Norwegian Polar Institute, N-9296 Troms?, Norway e-mail: eva.fuglei@npolar.no Tel.: +47-77-75-05-28; Fax: +47-77-75-05-01, NO Norwegian Polar Institute c/o NGU, Oslo, Norway, NO
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Abstract: | Post-absorptive resting metabolic rates (RMRs), body mass and ad libitum food intake were recorded on an annual cycle in
captive arctic foxes (Alopex lagopus) at Svalbard. During the light season in May and in the dark period in November, RMR during starvation and subsequent re-feeding
were also measured. In contrast to earlier findings, the present study indicated a seasonal trend in post-absorptive RMR (in
W · kg−1 and W · kg−0.75). The values in the light summer were 15% and 11% higher than the values in the dark winter, suggesting a physiological adaptation
aiding energy conservation during winter in arctic foxes. Body mass and ad libitum food intake varied inversely through the
year. A significant reduction in RMR (in W and W · kg−0.75) with starvation (metabolic depression) was recorded both in May and November, indicating an adaptation to starvation in
arctic foxes. The lack of metabolic depression during a period of starvation that was concomitant with extremely cold ambient
temperatures in November 1994 indicates that metabolic responses to starvation may be masked by thermoregulatory needs. At
very low ambient temperatures, arctic foxes may require increased heat production which cannot be achieved via below-average
rates of metabolism.
Accepted: 7 June 1999 |
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Keywords: | Metabolic rate Seasonal variation Energy intake Starvation Arctic mammals |
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