IMMEDIATE REACTIONS OF GRIZZLY BEARS TO HUMAN ACTIVITIES

Abstract

Humans pursue a variety of activities in habitats occupied by grizzly bears (Ursus arctos), but we know little about how they react to us. Responses of bears to human activities are of concern because predictable human use may displace bears, forcing them to increase their use of less productive habitats; overt behavioral responses of bears may be energetically expensive and disruptive to them; and previous interactions with humans may affect subsequent aggressive responses of bears to people. Jope (1985) studied immediate reactions of grizzly bears to hikers in Glacier National Park, Montana, where hunting and resource extraction do not occur. Bears were more likely to react aggressively (full charge) to hikers when the interaction occurred on low-use than on high-use trails, and she suggested that bears in high-use areas had habituated to people. Jope (1985) also reported that in Glacier National Park, 5% of grizzlies encountered initially moved away from hikers she interviewed, whereas 33% moved away eventually. Researchers in more open, northern areas observed that 67% of bears ran from fixed-wing aircraft, and 80% ran from helicopters (Klein 1974, Quimby 1974, Harding and Nagy 1980). Some grizzly bears avoid roads (McLellan and Shackleton 1988) and industrial sites (McLellan and Shackleton 1989). We tested the null hypothesis that grizzly bears show the same immediate reaction to a number of different human activities. An area, typical of southern grizzly bear range, containing extensive forest cover, industrial activities (logging, petrocarbon exploration and extraction), and hunting (bears and other large mammals), provided suitable conditions for this test.