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From: dkelly@bio4.acpub.duke.edu (Diane Kelly)
Newsgroups: alt.folklore.urban
Subject: Menstruation and Bears
Date: 11 Apr 1994 15:25:59 GMT

As some of you may remember, around a month ago I took it upon myself to determine whether or not bears were really attracted by the scent of human menses. Well, after spending weeks poring over grisly accounts of bear attacks in my spare time, here's what I found out:

First, I found the statistics documenting bear attacks in the wild and in National Parks. These fell into two groups: dry numbers, and detailed accounts. Some of the detailed accounts were really gross.

In any case, I tabulated these data into groups. My hypothesis was this: out of any random sample of 10 women, one in four (or approximately 20-30%) will be menstruating at that time. If bears are attracted to menstruating women, then (1) more than 50% of the women attacked by bears will be menstruating, and (2) more women than men will be attacked by bears, proportionately.

In the 41 detailed accounts of bear attacks, 13 involved women being either mauled or killed. Out of these 13, 1 woman was menstruating, 6 were not, the status of 6 are unknown. Since it's standard procedure to determine whether the woman was menstruating after the attack, it's likely that these 6 women were not menstruating -- since it wasn't mentioned in the report, and is usually something they use to explain the attack. However, I decided to be more conservative, and scored the unknowns as if one in 4 were menstruating, Scoring the mensruating woman first gave me 2 menstruating and 4 not. Combined, this gives us a ratio of 3 menstruating/10 not, or 23% menstruating. This is no different from the percentage of menstruating women in the general population.

In tabulating the general statistics of bear attacks in the US and Canada, I decided to use only National Parks statistics to avoid complications with skew in sex ratios -- men are more likely to be out in the "wilds" hunting than women, so those statistics will be skewed toward attacks on males. I assumed that men and women visit parks at around the same rate -- so I could expect a 50/50% sex ratio within park visitors. Here are the stats:

        VICTIM          Maulings        Fatalities      TOTALS
        Male            91              7               98
        Female          34              9               43
        Unknown         6               0               6
        
        TOTALS          131             16              147 cases total

Notice that men are attacked by bears approximately twice as often as women.

I've also found research that implies that black bears couldn't care a whit about human menstrual odors (Rogers et al., 1991). In this study, black bears were given a choice between (1) garbage and menses-soaked tampons, or (2) tampons soaked in a. nothing, b. menstrual blood, c. regular human blood, d. rendered beef fat. In the first experiment, bears selected garbage over the tampons in every case. In the second experiment, bears always selected the tampons soaked in beef fat.

Stephen Herrero (1970, 1988) suggests that many bear attacks are the result of habituating bears to human activities -- particularly by feeding them garbage. Garbage fed bears begin to associate humans with food, and can't tell when marshmallows stop and your arm begins. They also have a hard time telling the difference between plastic garbage bags and sleeping bags.

Diane "I don't think I want to go camping now" Kelly Duke Zoology

Refs:
Cramond, M. 1981. Killer Bears. Outdoor Life Books, Charles Scribner &

Sons, New York.
Cramond, M. 1989. On Bears and Man. (same publisher, I think) Herrero, S. 1970. Human injury inflicted by grizzly bears. Science

170:593-598.
Herrero, S. 1985. Bear Attacks. Nick Lyons Press, NY. Rogers, L. L., Wilker, G. A., and Scott, S. S. 1991. Reactions of black

bears to human menstrual odors. J. Wild. Manage. 55(4): 632-634.