Bear Inflicted Human Injuries and Fatalities in Yellowstone
From 1980-2011, over 90 million people visited Yellowstone National Park. During the same 32 year period, 43 people were injured by bears in the park. For all park visitors combined, the chances of being injured by a bear are approximately 1 in 2.1 million. The probability is significantly lower for those visitors that don't leave park developments or roadsides, but much higher for those hiking in backcountry areas. When backcountry hiking, you can reduce the odds of being injured by a bear by: 1) hiking in groups of 3 or more people, 2) staying alert, 3) making noise in areas with poor visibility, 4) carrying bear spray, and 5) not running during encounters with bears.
Grizzly Bear-Inflicted Human Injuries
Grizzly bear-inflicted injuries to humans in developed areas averaged approximately 1 per year during the 1930s through the 1950s, and 4 per year during the 1960s. Grizzly bear-caused human injuries in developed areas then decreased to 1 injury every 2 years (0.5/year) during the 1970s. During the last 32 years (1980-2011), there have been only 3 (0.1/year) grizzly bear-caused human injuries in developed areas, an average of approximately 1 every eleven years.
During the 32 year period from 1980-2011, there have been 32 human injuries caused by grizzly bears in the backcountry, an average 1 per year. The park does not have statistics on how many park visitors hike in the backcountry, so the probability of being injured by a bear in backcountry areas cannot be calculated.
Black Bear-Inflicted Human InjuriesHuman injuries caused by black bears have decreased from averages of 46 per year from 1931-1969, to 4 per year during the 1970s, and less than one (0.2) per year from 1980-2011 (approximately 1 every 6 yrs). Over the last 32 years, an additional 3 (0.1/year) bear-inflicted human injuries occurred where the species of bear could not be determined.
Bear-Caused Human Fatalities
During the 140-year (1872-2011) history of Yellowstone National Park, seven people have been killed by bears in the park. More people in the park have died from drowning, burns (after falling into thermal pools), and suicide than have been killed by bears. To put it in perspective, the probability of being killed by a bear in the park (7 incidents) is only slightly higher than the probability of being struck and killed by lightning (5 incidents).