THE METABOLISM AND INSULATION OF SEALS AS BARE-SKINNED MAMMALS IN COLD WATER

• Published in: Canadian Journal of Zoology
• Main Authors: Irving, Laurence, Hart, J. S.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1957
• Subjects: harbor seal; Phoca groenlandica; Phoca vitulina
• Online Access: http://dx.doi.org/10.1139/z57-041; http://www.nrcresearchpress.com/doi/pdf/10.1139/z57-041

The metabolic rate of five harbor seals (Phoca vitulina) and two harp seals (Phoca groenlandica) was measured over a temperature range of 25° to −10 °C. in air and 20° to 0 °C. in water. Surface temperatures and tissue temperature gradients were also determined. In four normal harbor seals the critical temperature in water was 10 °C., and in air it was below −10 °C. (estimated as −30 °C). One "runt" seal had a much higher critical temperature and abnormally high metabolic rate. No critical temperature was found in harp seals in water above 0 °C. Tissue surface temperatures and tissue gradients reflected the metabolic response to cold, with cool surfaces and deep gradients (well insulated harp and harbor seals) corresponding to low metabolism in cold water and with warmer surfaces and shallow gradients (poorly insulated harbor seal) corresponding to high metabolism in cold water. Metabolic economy of the seals in ice water was preserved by exceptional cooling of all body surfaces (to about 1 °C), which cooling provided protection comparable to that of fur of large land mammals in coldest climates.