Grizzly bears normally avoid contact with people. In spite of their obvious physical advantage they rarely actively hunt humans. Most grizzly bear attacks result from a bear that has been surprised at very close range, especially if it has a supply of food to protect, or female grizzlies protecting their offspring
Grizzly Bear Attack Victim
Within Yellowstone National Park, injuries caused by grizzly attacks in developed areas averaged approximately 1 per year during the 1930s through the 1950s, though it increased to 4 per year during the 1960s. They then decreased to 1 injury every 2 years (0.5/year) during the 1970s. Between 1980-2002, there were only 2 grizzly bear-caused human injuries in a developed area. However, although grizzly attacks were rare in the back-country before 1970, the number of attacks increased to an average of approximately 1 per year during the 1970s, 1980s, and 1990s.