I have first hand knowledge of a predatory black bear attack that occurred in the Cherokee National Forest on Chilhowee Mountain. You guys probably read about the little girl that was killed there a few years ago.
A vacationing mother and her two children were hiking on the Benton Mckay trail to see the scenic Benton Falls. A 300 lb male black bear flanked the family for a while, then it made its move. It went after the little girl, and the mother beat it, kicked it, and fought with everything she had to drive it away. The little boy ran, and was also attacked. Both the mother and the little boy were hospitalized, and the little girl was carried away, killed, and partially eaten. A search party of local officers and park personnel were dispatched, but her body was not found until the next day - with the the bear still guarding the body. The bear was shot at with a .380 auto, and ran away. It was later trapped, killed, and the intestinal contents proved by crime lab DNA testing that it was in fact the killer.
I don't know about the rest of you, but I think any reasonable pistol or revolver could have prevented the death of this little girl. I never hike without my Glock 10mm G20 or S&W .44 629 Mountain Gun. What biological "facts" or "knowledge" would have helped this situation? I live in that area, and absolutely KNOW (don't ask me how) that my G20 will make a predatory black bear so tame that he can't even chase away the vultures.