I agree with most of what has been said here. However, there is one thing that has not been brought up. Bears, and most preditors I would bet, can smell fear.
I had a toe to toe encounter with a 6 foot black bear in Alaska. One of our guys was skining a bear when another bear came after him. Two of us, armed with .44s (rifles were all leaned against a tree 15 feet away) jumped in front of the bear, between it and our guy lying on the ground.
The bear stood up, just two or three feet from us, and looked at us. We weren't afraid. We had enough fire power to kill that bear.
Then the bear looked at the guy on the ground, who was turning blue from holding his breath. The bear licked his chops, and then looked back at us. We showed no fear. He was nervous about us, and he could smell the fear from the guy on the ground. He wanted to get to the guy on the ground, but he couldn't get around us.
I kept talking to the bear. I know he didn't understand what I said, but he did understand that I was clearly a threat. After a few minutes the bear turned to his left, got down on all fours, and walked away.
The guy on the ground, who had been razzing us all week for carrying sidearms, said he was going to buy a .44 tomorrow.
Now, before some of you experts start telling me how stupid that was, and how badly we could have been hurt, I know. I heard all that from the guy on the ground. He was our Guide. After the lecture he thanked us for saving his life.
BTW, the bear on the left in the picture was the one the guide was skinning.