Excerpt

There are three key behaviors you need to be aware of:
1. The bear that approaches is usually in command of the situation.
2. The subordinate bear does not end an engagement with a dominant bear; the dominant bear is the first to leave.
3. Merely standing still has signal value; standing still will often alter the ongoing behavior of an approaching bear.

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The magic circle around every bear is different and constantly changes in size and shape. As an example, the magic circle of a female grizzly with spring cubs will probably be larger than the magic circle of the same bear when she doesn't have cubs. ... Don't forget that you have a magic circle, too. A seasoned black bear biologist might be comfortable with a bear that's only 10 yards away, but you or I might be nervous about a black bear that's 40 yards away.

Years of experience in Denali and other national parks have proven that properly secured bear resistant food containers work.

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For some reason, bears are interested in petroleum products. When they come across a spot of oil or gas on the ground, they sometimes roll in it like a dog rolls on a carcass. After the Exxon Valdez oil spill, some bears looked like they'd been using Brylcream. My friend Hod Coburn, a bush pilot who's flown all over Alaska, told me that a black bear once got into a case of oil he stashed at a remote runway in the western part of the state. It didn't bite one can and assume there was more of the same in the others - it bit into every can.

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What about tree-climbing? You startle a bear that's 100 feet away and decide to run and climb a tree that's only 10 feet away. The bear will arrive in about 3 seconds. You wouldn't have time to climb a stepladder, let alone a tree. Even full-grown black bears can scoot up any tree with astonishing speed. An adult grizzly can "ladder" its way up a tree if the limbs are right, with a known record of 33 feet high.

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Bears key on movement and quickly notice a silhouette on a ridgeline. Steve French, an M.D. and bear researcher who's co-director of the Yellowstone Grizzly Foundation, has an excellent rule of thumb regarding the vision of bears; If you can see a bear, you should assume it can see you.

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Black bears are creatures of the forest, so in response to a threat they've always had the option of slipping into the underbrush and hiding or climbing a tree. When threatened, black bears flee. Even when black bear biologists hold squalling cubs while mama bear is just yards away, the females almost always retreat. They may make a blowing sound and clack teeth and make a rush or two toward the biologists, but ultimately, they retreat.

Not so with grizzlies. Grizzlies evolved in more open terrain. At times, there wasn't enough cover for a female and her cubs to hide from other bears or mammals. There were no trees to climb. When threatened, a female had to defend her cubs.