Figure 7.

The dive profile of Toby, a translocated juvenile northern elephant seal (Mirounga angustirostris), with the color indicating the direction of heat flux (red = heat gain, blue = heat loss) throughout the dive. The inset shows four deep dives (>200 m) and how the transition from heat gain to heat loss occurs near the thermocline (denoted with asterisks) on the descent, but the opposite transition occurs at deeper depths during the ascent. Heat flux values [W m⁻²] in (a) are preliminary values pending post-deployment calibrations. Raw voltage output has been corrected for the added thermal resistance of the sensor and attachment mechanism (determined experimentally) as well as the unique sensor’s calibration constant (provided by the manufacturer). A section of the dive profile denoted by the green box containing the seal’s deepest dive in (a) is shown in greater detail (b, left) with temperature profiles at three depths within the blubber layer (deep = red, mid = orange, shallow = yellow). The drop in blubber temperature during the deep dive (b, left) is analogous to the drop in arterial temperature (b, right) recorded in Butler, a translocated juvenile northern elephant seal by [65], although arterial temperature declined more abruptly. Both blubber and arterial temperatures rewarmed before the end of the dive, and arterial temperatures remained comparatively warmer (note the difference in temperature range of the y-axes; the range of arterial temperatures is shown on both figures with the purple dashed lines). The figure showing Butler’s data is modified from Meir and Ponganis, 2010. Blood Temperature Profiles of Diving Elephant Seals. Physiological and Biochemical Zoology, 83(3): 531–540. © The University of Chicago Press.