Thermoregulatory Scope Associated with Underwater Exercise in a Polar Seal

A weakness in predicting habitat change impacts in polar regions is that little is known about thermoregulatory energetics in high-latitude seals. To better understand thermoregulatory range associated with the partitioned air-water habitat of ice seals, we collected skin surface heat flux data from 42 free-ranging Weddell seals over 1-13 day deployments. We modeled total body heat dissipation from heat flux data to address the thresholds of basal versus activity-derived heat loss over a range of swim speeds. As body size/condition affect heat loss and may manifest as altered thresholds for thermal homeostasis, we compared 4 life history categories—pups, juveniles, non-reproductive adult females and post-weaning females. Preliminary evidence indicates obligate heat dissipation, reflecting thermoregulatory costs, is elevated in water versus air, and locomotory heat generation offsets these costs. Dive activity-heat loss relationships were compared among the 4 life history stages to detect differences in ba...