Understanding Movement Patterns. With modern radiotelemetry techniques, we have gained greater understanding of movements and distribution patterns of polar bears (Amstrup et al. 1986, 2000; Garner et al. 1990; Ferguson et al. 1997, 1998, 2000a, 2000b). Seasonal movement patterns of polar bears emphasize the role of sea-ice in their life cycle (Garner et al. 1990, 1994; Gloersen et al. 1992; Messier et al. 1992; Amstrup et al. 2000; Ferguson et al. 2001). Just as clearly, distribution and availability of prey are important in movement patterns of polar bears (Stirling and Øritsland 1995). The links between sea-ice, prey, and polar bears, however, are still poorly understood. If we are to explain the movements and activities of polar bears, we need to understand the ecological and energetic components of the predator­prey interactions (Lunn et al. 1997). Also, we need to understand explicitly how that interaction is mediated by the volatile sea-ice platform on which seals and bears depend. At present, descriptions of sea-ice patterns in the Beaufort Sea are too general to provide needed explanations (Stirling et al. 1981; Gloersen et al. 1992). Many logistical obstacles will make understanding seals, sea-ice, and the activities of polar bears a formidable task. Given that polar bears may be important indicators of the health of the arctic marine ecosystem (Stirling and Derocher 1993), overcoming such obstacles is necessary.

Recent measurements, derived from many observations of numerous individuals, are unequivocal and indicate polar bears are among the most mobile of all quadrupeds (Amstrup et al. 2000). However, physiological evaluations suggest that walking polar bears are energetically inefficient (Best 1982; Hurst et al. 1982a, 1982b). The physiology of locomotion in polar bears clearly needs to be reevaluated in light of their known extensive travel. Furthermore, the cues polar bears use to navigate during long movements need to be understood. No other animal is transported as far "in the blind" as are female polar bears that den on drifting pack ice. Going to sleep in one location and waking up, months later, 1000 km from that location must challenge abilities to return, but somehow polar bears are able to do so.

An obvious shortcoming of the data on movements of polar bears is that they were collected with satellite telemetry. Building platform satellite radiotransmitters (platform transmitter terminals or PTTs) into neck collars and attaching them to polar bears has provided previously unobtainable insights into polar bear movements and behaviors (Amstrup et al. 1986, 2000; Messier et al. 1992; Amstrup and Gardner 1994; Bethke et al. 1996). However, the necks of male polar bears are larger than their heads, and radio-collaring does not work for them. Neck collar radios also cannot be fitted to subadults, for fear of injury that could result as they grow and the collar does not. Hence, inferences regarding the movements of all members of the population must be extrapolated from the movements of females only. Males and subadults constitute a large portion of the population, and are often the most likely to be harvested or otherwise interact with humans. Failing to understand what they do is a significant limitation. Males are not only necessary to maintain the population, they also may play a role in limiting population size (McCullough 1981; Young and Ruff 1982; Stringham 1983). Polar bear populations can sustain higher harvests of males than of females (Taylor et al. 1987), but males also appear to be more vulnerable to human hunters. If male polar bears move in patterns that are significantly different than those of females, adjustments to management plans that are currently based on telemetry results from females (Treseder and Carpenter 1989; Nageak et al. 1991) might be required.