Long ago, in my more foolish days, I was riding a bike alone in Yellowstone National Park. Like any 18 year old, I pretty much thought I was immortal. And since I could pretty much wander as I pleased in my 'home territory' of the Sierras without any fear, I somehow figured it would be okay in Yellowstone too. The sun was low in the sky, it was warm, and I wanted to visit some natural arch landmark before the sun set. So I was riding my bike up some abandoned road, about 2 miles from the campground.
Just at the farthest apex of the road, when I was about to turn around, my instincts cut in, hard. Somehow I knew that it wasn't entirely safe where I was. I slowed down my bike, wondering what was going on, and suddenly, 5 feet away, I heard crashing in the bushes. Next thing I knew, there was an enormous black bear, about 20 feet away, staring at me.
Obviously at this point, the bear was as scared of me as I was of him. This sounds silly, but in an area where many people are armed, it was a wise response by the bear. The second of eye contact I had with that bear was amazing. It was like I could read its mind. The fear flashed almost instantly to a kind of embarassment, then an understanding of sorts. We were to continue on with the afternoons activities, and pretend it never happened. The bear began foraging for food, but all the while moving slowly away from me. With every log it rooted under or tree it sniffed, it was further away. Eventually, it wandered over a hill and was gone. At that point I finally felt it appropriate to utilize the massive amounts of adrenaline I'd built up in my system and get the hell out of there.
Bears are a lot like people. They are much smarter than we think, and like people, they seem to show a wide range of emotions. But unlike people, they don't lie. If you're paying attention, you can tell what the bear wants, and in doing so, avoid problems. Black bears are generally not hunters, and I've never even heard of a case of a black bear eating a human. (Although I'm sure a bear coming upon a quite dead human might react differently). The bear I encountered didn't want any trouble, and it made that evident. Although that bear scared the crap out of me, I owe it a lot for what it taught me in those few seconds. I hope it is still doing well.
In ending, a few things should be noted. Yet one more way that bears are similar to humans is that a few out of the group will make their living by stealing from others. Bears like this are often found near areas with high human populations, like popular campgrounds. These bears, although uninterested in humans, are very interested in their food. Never leave food in bear-accessable areas (including cars) when you are in bear country. And most importantly, never try to take food from a bear. If you see a bear acting suspiciously, like wandering through a campground in broad daylight, you might want to talk to rangers or other authorities. And of course, never feed a bear. Bears that become accustomed to humans often become belligerant and must be killed, or are killed by cars or other human-related activities.
Also, if you are in an area where grizzlies are found, be cautious. Grizzlies, which have huge humps on their necks and are larger than black bears, don't follow the same rules. They are aggressive and fearless, and any attempt to act 'dominant' to a grizzly, including yelling, throwing rocks, or direct eye contact, is a very bad idea. | 
