Polar Bear Locomotion: Body Temperature And Energetic Cost
The metabolic response of a 190-kg polar bear was tested at four different walking speeds within a respiration chamber mounted on a treadmill. Regressions of deep body temperature and oxygen consumption as a function of walking speed were determined. Equilibrium deep body temperature increased exponentially with speed of locomotion and indicated a relative inability to dissipate metabolic heat at high walking speeds. Metabolic rate, as measured by weight-specific oxygen consumption, was also best fit by a curvilinear equation and was twice that predicted by a general equation for quadruped locomotion. The apparent inefficiency of locomotion in polar bears suggests a compromise between thermoregulation, hunting strategies, and economy of transport.