Ever since the night of August 13, 1967, when two women were attacked and killed by grizzly bears in two separate incidents in Glacier National Park (which was later chronicled in Night of the Grizzlies), a myth has persisted that women may be more prone to bear attacks as a result of odors associated with menstruation.
However, according to a paper recently published by the National Park Service, "there is no statistical evidence that known bear attacks have been related to menstruation".
The report pointed towards evidence from previous studies:
* Stephen Herrero (1985) analyzed the circumstances of hundreds of grizzly bear attacks on humans, including the attacks on the two women in Glacier, and concluded that there was no evidence linking menstruation to any of the attacks. The responses of grizzly bears to menstrual odors has not been studied experimentally.
* Lynn Rogers et al. (1991) recorded the responses of 26 free-ranging black bears (Ursus americanus) to used tampons from 26 women and the responses of 20 free ranging black bears to four menstruating women at different days of their flow. Menstrual odors were essentially ignored by black bears of all sex and age classes. In an extensive review of black bear attacks across North America, no instances of black bears attacking or being attracted to menstruating women was found (Cramond 1981, Herrero 1985, Rogers et al. 1991).
The paper also mentions that between 1980 and 2011, 43 people have been injured by bears in Yellowstone National Park. 79% of those attacks occurred on men. Of the 9 incidents involving women, 6 were surprise encounters with bears while the women were hiking, and were therefore probably unrelated to menstruation.
The paper also notes that your risk of bear attack is highest while hiking in the backcountry. You can reduce the risks by:
1) hiking in groups of 3 or more people
2) staying alert
3) making noise in areas of poor visibility
4) carrying bear spray
5) not running during encounters with bears
To read the full report, please click here.
Glacier National Park Hiking