Figure 3.

A cross-section from an adult Weddell seal (Leptonychotes weddellii) with blood vessels visible within the blubber layer. The orange box denotes the area represented in (b). Adapted with permission from Springer Nature: Marine Mammals by Randall W. Davis © 2019 (a). A conceptual figure depicting blubber’s various thermal states dependent on peripheral perfusion, and blubber’s functional roles due to its stratification. The temperature gradient across the blubber layer will vary based on the degree of peripheral perfusion during a dive. A larger gradient will generally occur at depth where lower water temperatures and peripheral vasoconstriction associated with the dive response lead to cooling of the periphery. The inner and outer blubber layers primarily serve different functions (energy store and insulation, respectively). This stratification is due to the relative proportional composition of fatty acids which confers different physical and biochemical properties (b).