Does hanging food really stop bears?

[Chris Servheen]

Your efforts to use low odor foods and package them carefully has been helpful and is good practice but this is probably not the main reason you have had little trouble with bears, Tom.  My opinion is that the main reason for few problems is that most bears are wild and do stay away from us and you have been lucky enough to not encounter a bear that has been food conditioned by someone else.  You are meticulous about your food storage and management of bear attractants and this has produced excellent results for you and the bears in the areas you have been.  Keep up the good work. Everyone should be like you. We all need to make our best effort to keep bears wild and you are an very good example of that.

[Chris Servheen]

Concerning the ability for bears to detect smells, there is nothing we can do to make foods undetectable to bears.  Bears have a sense of smell equal to or better than that of dogs.  Trained dogs are used to detect drowned humans at the bottom of lakes by putting the dog in a boat and driving around the lake.  The dog alerts when it detects a few molecules (!) from a dead body coming up through the water from the bottom of the lake.  With that kind of olfactory acuity, there is little we can do to make human food smells unavailable to bears. What we can do is minimize these smells and make these foods unavailable to bears using good food preparation and food hanging practice and keeping a clean camp.  A bear in the vicinity will know we are there and that we have foods, but the overriding driver of a wild bear’s behavior is its interest in staying away from humans and from our camps and our foods.  This desire to avoid humans will override a wild bear’s interest in human foods.

[Tom K]

“Your efforts to use low odor foods and package them carefully has been helpful and is good practice but this is probably not the main reason you have had little trouble with bears, Tom.”

I would agree with that statement wholeheartedly.  It has bothered me that James in particular seems to think I attribute my results solely with the use of OP bags.  It is but one part of a more extensive system based on the principle of evasion, as I have tried to emphasize in my posts.  I don’t think anybody in their right mind would place their food in OP sacks and let it go at that.   Proper food selection, no cook, careful campsite selection, and hiking in areas with few, if any, habituated bears are more important, as is hanging food in areas where decent limbs can be found.  In areas where canisters are required, I use a canister, just like everybody else.  Habituated bears are an entirely different story, as I learned from the two previously described encounters I had with them early on.  That was the beginning of my conversion to a strategy of evasion;  rather than hike in popular areas where poor food management inevitably leads to habituated bears, I have chosen more remote areas where the few bears I have encountered have either beaten a hasty retreat(4) or ignored me and continued on their way(1).  That, to me, is probably the most important part of my strategy.

On an academic note, not to be argumentative, but because I am curious:  Have there ever been any tests of multiple layer OP bagging under conditions approximating those encountered in the field?  I am aware of the tests conducted in highly structured environments where the bagged food is always placed in close proximity to an animal, typically a dog, but I have not heard of test(s) where the bagged food is placed at a distance, varying from, say, 100-400 meters, allowing ample room for dispersion of the relatively few ‘biomolecules” (love the precision of that term-thank you, James), that escape multiple layers of odor reducing material.  The reason I ask is that, barring such tests, I’m not sure we know with any certainty exactly how effective odor proof bags, Nylofume in particular, are at reducing the escape of odor producing biomolecules to a level where they are not practically detectable by a dog or bear.  An interesting, at least to me, follow on test would be to cover the bagged food with a layer of unwashed and, therefore, impregnated with human odors, hikers clothing.  The idea here being to see if the smell of a human would offset, by aversion as well as masking, the odors emanating from the bag.  Hypothetical, and perhaps not practical to set up, but still an interesting proposition, at least for me.

In any case, thank you for responding to what has been a very interesting, if controversial, thread.

 

[James Marco]

I would echo the praise you have received, Tom. You are doing an excellent job keeping camp and the surrounds clean and with your food. You put a LOT more effort into than I do. Thank you!

[James Marco]

No, I have not done specific tests like you describe. But from inference, I can guess OP sacks are exponentially or gaussian decreasing in effectiveness. Never reaching 0 in other words.

[Tom K]

“I would echo the praise you have received, Tom. You are doing an excellent job keeping camp and the surrounds clean and with your food. You put a LOT more effort into than I do. Thank you!”

Many thanks, James.  Coming from an experienced backpacker, that is high praise.  The effort really goes back to my last encounter with a habituated bear, which scared the dickens out of me.  Everything I have done since then has been designed to ensure it doesn’t happen again.  Secondarily, my operating principle in backpacking has long been to leave no tracks.  That is aspirational, of course, but whatever tracks I do leave, I hope a habituated bear for others to deal with is not among them.

“No, I have not done specific tests like you describe. But from inference, I can guess OP sacks are exponentially or gaussian decreasing in effectiveness. Never reaching 0 in other words.”

To one degree or another, you are likely correct, IMO.  The question for me for some time has been, beginning with the highly structured dog experiment conducted by Ike Jutkowitz some years back, just how that plays out in the field over varying distances where other masking/aversive odors come into play, for unhabituated bears.  We’ll probably never know with any certainty, which mandates very conservative general rules for food handling to ensure we do not end up creating more habituated bears.  And I will be the first to admit that what I do way the hell and gone back along The Great Western Divide and similar areas, where I do the vast majority of my backpacking, is not what I would do along the JMT or similar areas, where canisters, followed by a well executed hang are by far the more prudent way to go.

[Greg Mihalik]

I didn’t read all three pages of posts, so apologize if this is in there somewhere. I realize this thread is about hanging. But generalizations can be made.

https://andrewskurka.com/2018/bear-canister-failures/

The take away –

1. Don’t be an idiot.
2. Don’t camp where idiots have fed bears in the past.

 

[Five Star]

“First, I’m not sure what predatory instincts have to do with hanging food. Both blackies and grizz are omnivores, and our food bags need to be protected from both. That said, grizzlies’ longer claws make them poor climbers, so it’s probably more important to do a good hang around black bears than grizz.”

David T and some of you others may have read the book “Alaska Bear Tales” (survivor accounts of bear maulings).  One of the stories was a guy who got charged by a grizzly.  He scampered up a small nearby spruce maybe 20 ft., and once up there had the thought that he was safe, grizzlies can’t climb.  That was when the bear just bulldozed the tree over and then mauled him.

I suspect a grizz could do that with a lot of hangs unless they’re in BIG trees.

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