Ancient legend about bear attacks and Menstruating Women debunked

Kerry Gunther, Yellowstone bear management/biology leader, says no evidence for this in Park-

The story goes back a long time. Fortunately my spouse never believed it or we wouldn’t have written so many books and articles about camping, backpacking, outdoor medicine, etc. in the West. From the start there was the rumor that a menstruating woman who entered bear country, especially grizzly country like Yellowstone Park and camped out on the ground in the backcountry, was maybe living on borrowed time.

This fear has been debunked a number of times, but it seems to be growing again. As a result Kerry Gunter who manages YNP bears has debunked it again in Bears and Menstruating Women.

National Parks Traveler and other publications are covering the issue and Gunther’s report. Here is the article about the report.  Yellowstone Bear Biologist Debunks Myth That Menstruating Women Attract Bears. By Ruffin Prevost.




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  1. Mark L Avatar
    Mark L

    So bears knew what we’ve known all along…just leave her alone and you will be much better off. Easy…

  2. Larry Thorngren Avatar

    There are some flaws in the study.
    Maybe the reason bears are not attacking menstruating women in the parks recently, is because they (women)have been reading the park brochures and the story about the two menstruating women killed in Glacier and not are not camping or hiking in grizzly country while having a period. You can’t get attacked by bears during your period if you are not out where the bears are during that time.

    1. Ralph Maughan Avatar
      Ralph Maughan


      I think my spouse is going to come crack you on your head. 😉

  3. Linda Jo Hunter Avatar

    This is an interesting topic to women who guide on bear watching excursions . . All of us spent everyday all summer for years in the company off bears. It stands to reason that if bears noses are 40 times (or greater) sensitive than our noses that they can easily smell through skin so they smell your insides anyway. As I remember from the book neither one of the two women killed on the same night in Glacier were menstrating but one had some tampons in her purse in case she needed them. It appears to be s non factor unless you just want to scare women out of the woods.

  4. Mark L Avatar
    Mark L

    Agreed, I think there may be an attempt by men to do just that, and it’s not ‘fair’ in a conventional sense. I do think a bear (and a dog) can smell a difference, but that would not necessarily be a bad thing. I think they both can smell A LOT of things ‘off’ or different about 1 individual from others. Note-off not meant in a condescending way…..
    Imagine an Indian village 1000 years ago with most of the women menstrating at the same time (happens) in close proximity to each other with ‘the men’ gone hunting/fishing/etc. Kids all around being kids, moms frustrated and trying to keep a sense of humor, working, it’s hot…summertime…..
    and a bear enters the village.
    That’s a bad day for all, but the bear more than the moms I bet….repeat this scenario over a few lifetimes and which bears carry on? The ones to enter the village or the ones that avoid it?

  5. Pronghorn Avatar

    “…unless you just want to scare women out of the woods.”

    The first time around, after the Glacier deaths in the late ’60s, the Second Wave of the feminist movement was picking up steam, challenging patriarchal assumptions and more. By happenstance, two women died and their biology was made the culprit. I don’t know this for a fact, but I’m guessing it was NOT a woman who first proposed the menstrual period as a hypothesis (and a warning). Could the NPS–certainly a more formidable patriarchy then than it is now–have been behind shifting the responsibility to women’s biology?

    Gunther says, “I have no idea why there has been such an increase in interest about this subject in the last two weeks.” Maybe because the idea that biology is destiny is making an unwelcomed reappearance what with all the talk of “legitimate rape” and how women’s bodies “shut down” in that instance…and because a struggle for the control of women’s bodies is YET AGAIN playing out by predominantly male actors. Let’s remind everyone that biology is destiny: 77 cents on the dollar in earnings, motherhood uber alles, and geez, stay outta the woods when Aunt Flo is visiting!

    Review this synopsis of the events
    to see how ludicrous the period hypothesis was/is, and who was far more culpable.

    1. Immer Treue Avatar
      Immer Treue

      Perhaps we need a revisit of Lysistrata, in variation.

  6. Ida Lupine Avatar
    Ida Lupine

    I always thought this was a tall tale as well, but it might have had some merit many many years ago, before modern hygiene. It no longer applies today in modern times, I would imagine, if you are careful about it, and careful about disposing of refuse of all kinds. Why take a chance. Men just don’t have to worry about these things. Sorry to be so blunt! 🙂

    And the wearing of fragrance I have heard about too – it’s just not the place for it anyway!

  7. Mike Avatar

    Regardless of the study, you don’t want to sleep in grizzly country with any odors. I’d consider blood an odor.

    I’ve had them sniffing my tent at two in the morning, even pressing their paws on it. This is not fun. But, I keep an incredibly clean camp, and there was no reason for them to investigate further.

    1. Savebears Avatar


      No matter how clean you camp is, you still emit odors as do the items you carry with you when you camp. I am glad Kerry addressed this, the myth has perpetuated for far to long.

      1. Mike Avatar

        Save Bears,

        Yes, this is true. But in my experience, certain odors will prod an animal to investigate further. I’ve seen it with dog food, perfume, and even a person who didn’t do a good enough job washing their hands after cleaning fish.

        Some odors are indeed alluring for animals.

        Many campgrounds are set in bear travel routes. People would be shocked to learn how often they come by and investigate campgrounds at night. The difference between getting an unwelcome visitor IN your tent, and a curious one that wanders off is a judicious practice of eliminating the most alluring odors.

  8. Linda Jo Hunter Avatar

    Honestly! The imaginations you all have. Especially Mark L. It must be mentioned that men should be aware that their bodies have several by-products which could be just as curious and worth investigating. I believe there are some statistics hidden somewhere that show that couples have caused bears to visit due to the odors of sex… and heaven help the man who has sex for one in grizzly country. You should be very scared.

  9. Ida Lupine Avatar
    Ida Lupine

    Probably TMI, but here we go:

    Personally, I am well aware that any and all bodily functions out in the wilderness alert wildlife to your presence, for either sex. Besides the obvious ones, cooking odors, smoke, trash, perspiration, even exhaling CO2, as we know from battling mosquitos! Some mosquitos are attracted more to certain people than others, and every person is different. I don’t believe it should keep a woman out of the woods or that it makes her more vulnerable than a man, we were just talking about female-specific functions that in this case men don’t have to deal with. Being careful and aware is just good common sense for everyone. You’re more aware of odors and sensual things like sound yourself when you’re away from the hubbub of modern life in the woods, I find. That said, I’m more of a day-hiker and don’t go camping out in the backcountry.

    For me, it’s just a matter of convenience and I’m more comfortable to not go at that time.

  10. Mike Avatar

    By the way, this menstruation issue never scared any women I ever knew out of the woods.

    The thing that makes them veer out of the woods is guys with a beer in their hand at noon, and a gun on their hip. And trust me, they’re not the least bit impressed by that. And they will often mumble something along the lines of, “bet he has a little dick”.


Dr. Ralph Maughan is professor emeritus of political science at Idaho State University. He was a Western Watersheds Project Board Member off and on for many years, and was also its President for several years. For a long time he produced Ralph Maughan’s Wolf Report. He was a founder of the Greater Yellowstone Coalition. He and Jackie Johnson Maughan wrote three editions of “Hiking Idaho.” He also wrote “Beyond the Tetons” and “Backpacking Wyoming’s Teton and Washakie Wilderness.” He created and is the administrator of The Wildlife News.

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