You might have heard on the news, a while back, about a study showing Bear spray pretty darn effective at stopping bears of all species. The paper's by Smith et. al 2008. Bear spray is a souped up version of pepper spray, intended for use by hikers, hunters, and pretty much anyone having to live or work in bear country. The idea is that these Capsaicinoid sprays induce the same host of responses that occur when humans are sprayed - coughing, blindness, discomfort, etc (Miller 2001). Based on results with captive bears, a gentleman named David Miller (whom I can no longer locate, but was last seen at Colorado State University) recommended these high intensity sprays be considered as bear deterrent (Miller 1980).
I'll go out on a limb and lay out my biases: I'm for bear spray. I don't carry it myself, but I think makes a fine alternative to carrying a lethal weapon. With bear spray, both the bear and the user gets to go home at the end of the day, and the bear is unlikely to try to start things again, and I like that. That said, Smith et. al need to revisit their methodology.
My problems with their study, in a nutshell:
A) Dead men tell no tales. That's right, they couldn't interview anyone who used bear spray unsuccessfully and died. How frequent is this? I don't know! I don't think the dead people are going to be talking much about it. We do know, however, that bear fatalities occur. And we know it's slippery to try and figure out how many fatalities occur, because of the beyond-the-grave reporting issues.
Absently, I wonder what Timothy Treadwell's listed cause of attack is. I'm banking on `provoked.`
B) Bear spray is effective... compared to what? I don't see any good descriptive statistics here. Are they better or worse than doing nothing? This might sound crazy, but a number of the bear-human incidents in the study looked like they might have resolved themselves without the bear spray just as well as with! How does Bear Spray compare to fire arms? Better or worse? If we're going to make public safety recommendations based off of this study, we need to know how these categories stack against each-other. You can't analyse bear spray's effectiveness without groups of comparison.
Now. I still think bear spray is effective and worthwhile. This publication was just highly ineffective in demonstrating it.
While we're on the subject - there's a vicious rumour that polar bears are the most deadly of the bears. I hear people talk about how Polar Bears actively hunt humans, are drawn to humans in a hostile way, etc. USGS's own data, over 100 years worth, contradicts this view. In Alaska, Brown Bears make up 23% of the population, they write, but but make 86.4% of the conflicts. USGS reports this is 375% the expected if conflicts were randomly distributed across bear species. Polar Bears, to contrast, are only 30% of expected if conflicts were random, and represented only 1.5% of the conflicts in the state.
Miller, D.S. (2001). Review of oleoresin capsicum (pepper) sprays for self-defense against captive wildlife. Zoo Biology, v.20, pp. 389-398.
Miller G. D. (1980). Behavioral and physiological characteristics of grizzly and polar bears, and their relation to bear repellents. Thesis, University of Montana. Missoula, USA.
Smith, T.S., Herrero, S., Debruyn, T.D., and Wilder, J.M. (2008). Efficacy of Bear Deterrent Spray in Alaska. Journal of Wildlife Mannagement, v.72, pp.640-645.
Edit to add I've been told that the two Millers are not the same people. D.S. Miller didn't pioneer use of bear spray. Scientists can be tricky to track with just their initials.