Laura Elizabeth Bagge

Major: Maine Biology

University Honors with Honors in Marine Biology

Supervisor: Dr. Ann Pabst

THE THERMAL PROPERTIES OF THE BLUBBER OF FEMALE

SHORT-FINNED PILOT WHALES (Globicephala macrorhynchus)

This study investigated the thermal properties of the integument of female short-finned pilot whales (Globicephala macrorhynchus) of different reproductive status (sub-adults, n=3; adults, n=7; and pregnant, n=5). The entire integument’s thermal conductivity (Wm-1°C-1), conductance (Wm-2°C-1), and insulation (m2°CW-1) were calculated by the simultaneous use of the heat flux disc and standard material methods. The thermal conductivity values of the deep, middle, and superficial layers of blubber were also investigated using the standard material method. Pregnant females and adults possessed thicker blubber than sub-adults. The blubber of pregnant females displayed a significantly lower mean conductivity value (0.17±0.01Wm-1°C-1) than that of adults (0.20±0.01Wm-1°C-1), but had a similar value to that of sub-adults (0.20±0.03Wm-1°C-1). Only conductivity values from the middle blubber layer differed significantly across reproductive classes, in a pattern similar to that of the integument’s thermal conductivity. Pregnant females had the lowest conductance values of all reproductive classes (7.10±0.97Wm-2°C-2). The insulation values for pregnant females (0.15±0.02m2°CW-1) were significantly higher than those of sub-adults (0.07±0.01m2°CW-1), but similar to those of adults (0.10±0.01m2°CW-1). Data from the heat flux disc method suggested that reproductive class in short-finned pilot whales influences blubber’s capacity to store heat. These results suggest that blubber’s thermal properties vary dependent upon reproductive status in short-finned pilot whales.