Thermal Significance of the Topographical Distribution of Blubber in Ringed Seals ( Phoca hispida)

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: Ryg, Morten, Smith, Thomas G., Øritsland, Nils Are
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1988
• Subjects: Phoca hispida
• Online Access: http://dx.doi.org/10.1139/f88-121; http://www.nrcresearchpress.com/doi/pdf/10.1139/f88-121

The distribution of blubber in ringed seals (Phoca hispida) and relationships between surface area, body mass, and linear dimensions are described. The blubber was distributed in such a way that the ratio of blubber thickness to body radius is nearly constant over the body, maximizing the available blubber for insulation. The hind part of the body has a higher thickness to radius ratio and is thus "overinsulated." During periods of mass loss, fat is lost fastest from this overinsulated region, thus reducing the negative thermal effects of the fat loss. We present formulae for calculating body surface area and an effective, or "equivalent blubber thickness," for calculations of heat loss and suggest that these formulae are independent of size and shape. By combining these equations, we arrive at a general formula for calculating a lower limit for heat loss from marine mammals. According to this formula, thermal stability can be maintained when blubber is lost if mass is simultaneously lost from the body core.