Met a young couple on Mt. Whitney once. They were talking about backpacking in Yosemite, and their use of ropes and a bear bag suspended from a rope thrown over a rope tied between trees.

They suspended everything, then went to sleep inside the tent. Around 3:00 AM they heard a commotion, a loud "thump", rustling, tearing and snorting. They were afraid to leave their sleeping bags, lay awake until dawn and then cautiously looked out.

Their food bag was on the ground, their food torn up and eaten. They reported the incident to the Rangers.

One of the Rangers said that they had moved that bear once already. He'd learned to climb the tree, jump out and grab the bag and hold on until it broke, sending both him and the food to the ground.

The Rangers had named that bear "Kamikaze". I thought that was funny.

Bears have learned to either chew through the rope suspending the food or the rope tied between trees. The most they've learned to do, so far, with that particular canister is to play football with it. Some folks advise putting reflective tape on it so as to be able to locate it in the dark.

The "catch" to it is a little thing much like found on some child-proof pill bottles. To turn the lid one must release that small little thing, and it's tough to do even with a thumb. Otherwise the canisters are very strong, Lexan I believe. I can imagine that one could pick it up and smash it against a sharp rock a number of times and break it. And maybe not.

They are heavy, though. Add 4 pounds when one included one for dog food.

And, thru-hikers are not required to carry them. The only exception to the rules of which I'm aware. Most do, having an interest in keeping bears away and food with them, some don't. Knew a lady once who chased a bear to get her pack back, was so mad she hit it a few times and took it away. And talked with another guy who said a bear came up behind him, grabbed his pack and dragged it off 30 feet and sat and tore it apart and ate his food while the guy watched.

I have to admit my sympathies are both with the bears and with the hikers. Let the best creature win, I guess.

Arf