Prolonged chases of flightless snow geese can be energetically profitable over a range of pursuit speeds for polar bears in the 125–235 kg size range. The same is likely to be true for larger bears, those outside the range of available oxygen consumption data, because only postural cost (y-intercept) is mass dependent and it scales at the 0.25 power (Fig. 4; Taylor et al., 1970). Extrapolations past the upper limit of speeds for which there are data assume that the functional basis for the modelled trend remains the same, an assumption that may be violated if polar bears change gait and energy efficiency at higher speeds. Nevertheless, based on our top model, we project that a 320 kg bear running at 20 km/h would expend the calories contained in an adult goose in 33 s, a value that is reasonably comparable to the estimate of 12 s previously suggested by Lunn and Stirling (1985) using a different model. However, we note that our model also predicts that 320 kg bears can more profitably engage in much longer pursuits at slower speeds (e.g. our model predicts that pursuits of geese lasting up to 13.3 min are energetically profitable for a 320 kg polar bear running at 7.9 km/h).