Mammalogy (Jones & Bartlett Learning Titles in Biological Science) by Vaughan Terry A. & Ryan James M. & Czaplewski Nicholas J

Author:Vaughan, Terry A. & Ryan, James M. & Czaplewski, Nicholas J. [Vaughan, Terry A.]
Language: eng
Format: epub
Publisher: Jones & Bartlett Learning
Published: 2013-12-10T22:00:00+00:00

FIGURE 21-25 Mean blubber and core body temperatures for a harp seal (Phoca groenlandica) resting in 1°C to 2°C water and in water at 23°C to 24°C. In cold water, subcutaneous temperature is only 1°C to 2°C warmer than that of the surrounding water, but deep blubber temperature (at 40 millimeter tissue depth) measures approximately 23°C. (Adapted from Kvadsheim, PH and LP Folkow. 1997. Acta Physiol Scand., 161:385–95.)

The great quantities of blubber on large whales (up to 25 centimeters thick) seem not primarily useful as insulation. Because of their size, these animals could probably maintain a constant deep-body temperature with much less insulation. These fat deposits may be useful primarily as food stores that can support an animal during periods of migration and fasting. It has been estimated that consumption of only half of a whale’s blubber could fuel the BMR for 4 to 6 months (Parry 1949). Koopman (1998) showed that blubber in the harbor porpoise can be divided into two compartments, based on blubber thickness. The thoracic-abdominal blubber varies little in thickness around the girth of the animal and probably serves as insulation and energy storage. Blubber posterior to the anus, however, forms thick dorsal and ventral ridges but is very thin laterally. This unusual distribution suggests that postanal blubber may serve primarily to maintain a favorable hydrodynamic shape of the peduncle.

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